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Nanomaterials
Volume 6
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Nanomaterials, Volume 6, Issue 7 (July 2016) – 17 articles

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2778 KiB  
Article
Antimicrobial Properties of Biofunctionalized Silver Nanoparticles on Clinical Isolates of Streptococcus mutans and Its Serotypes
by Ángel Manuel Martínez-Robles, Juan Pablo Loyola-Rodríguez, Norma Verónica Zavala-Alonso, Rita Elizabeth Martinez-Martinez, Facundo Ruiz, René Homero Lara-Castro, Alejandro Donohué-Cornejo, Simón Yobanny Reyes-López and León Francisco Espinosa-Cristóbal
Nanomaterials 2016, 6(7), 136; https://doi.org/10.3390/nano6070136 - 22 Jul 2016
Cited by 24 | Viewed by 6156
Abstract
(1) Background: Streptococcus mutans (S. mutans) is the principal pathogen involved in the formation of dental caries. Other systemic diseases have also been associated with specific S. mutans serotypes (c, e, f, and k). Silver nanoparticles [...] Read more.
(1) Background: Streptococcus mutans (S. mutans) is the principal pathogen involved in the formation of dental caries. Other systemic diseases have also been associated with specific S. mutans serotypes (c, e, f, and k). Silver nanoparticles (SNP) have been demonstrated to have good antibacterial effects against S. mutans; therefore, limited studies have evaluated the antimicrobial activity of biofunctionalized SNP on S. mutans serotypes. The purpose of this work was to prepare and characterize coated SNP using two different organic components and to evaluate the antimicrobial activity of SNP in clinical isolates of S. mutans strains and serotypes; (2) Methods: SNP with bovine serum albumin (BSA) or chitosan (CS) coatings were prepared and the physical, chemical and microbiological properties of SNP were evaluated; (3) Results: Both types of coated SNP showed antimicrobial activity against S. mutans bacteria and serotypes. Better inhibition was associated with smaller particles and BSA coatings; however, no significant differences were found between the different serotypes, indicating a similar sensitivity to the coated SNP; (4) Conclusion: This study concludes that BSA and CS coated SNP had good antimicrobial activity against S. mutans strains and the four serotypes, and this study suggest the widespread use of SNP as an antimicrobial agent for the inhibition of S. mutans bacteria. Full article
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<p>Transmission elctron microscopy (TEM) and disperion light scattering (DLS) analysis. (<b>a</b>) BSA 16.5 nm; (<b>b</b>) BSA 23.3 nm; (<b>c</b>) BSA 115.2 nm; (<b>d</b>) CS 22.5 nm; (<b>e</b>) CS 44.1 nm; and (<b>f</b>) CS 133.7 nm.</p> Full article ">Figure 2
<p>DSC-TGA analysis. (<b>a</b>) BSA 23.3 nm and; (<b>b</b>) CS 44.1 nm. Green, brown and blue lines represent TGA, DSC, and DTG values, respectively.</p> Full article ">Figure 3
<p>The antimicrobial activity of coated SNP against <span class="html-italic">S. mutans</span> in micrograms per milliliter (µg/mL). (<b>a</b>) SNP size; (<b>b</b>) coating type; (<b>c</b>) <span class="html-italic">S. mutans</span> serotypes; and (<b>d</b>) microdilution plaque (purple coloration shows stained bacteria). Values shown are the mean ± standard deviation. Clinical strains, 34 in number, (<span class="html-italic">c</span> = 20; <span class="html-italic">e</span> = 6; <span class="html-italic">f</span> = 1 and <span class="html-italic">k</span> = 7) were assayed. Asterisks indicate significant differences (<span class="html-italic">p</span> &lt; 0.05).</p> Full article ">Figure 4
<p>The antimicrobial activity of coated SNP agasint <span class="html-italic">S. mutans</span> serotypes in microgams per milliliter (µg/mL) according to serotypes and particle size. Values shown are the mean ± standard deviation. Clinical strains, 34 in number, (<span class="html-italic">c</span> = 20; <span class="html-italic">e</span> = 6; <span class="html-italic">f</span> = 1 and <span class="html-italic">k</span> = 7) were assayed. Asteriks indicate significant differences (<span class="html-italic">p</span> &lt; 0.05).</p> Full article ">Figure 5
<p>The antimicrobial activity of different sizes of SNP with either no coating, a BSA coating or a CS coating in micrograms per milliliter (µg/mL). Values shown are the mean ± standard deviation. Clinical strains, 34 in number, (<span class="html-italic">c</span> = 20; <span class="html-italic">e</span> = 6; <span class="html-italic">f</span> = 1, and <span class="html-italic">k</span> = 7) were assayed. Asterisks indicate significant difference (<span class="html-italic">p</span> &lt; 0.05).</p> Full article ">Figure 6
<p>SEM micrographs of <span class="html-italic">S. mutans</span> (serotype <span class="html-italic">c</span>) with coated SNP. (<b>a</b>) 10.7 nm; (<b>b</b>) BSA 22.9 nm; (<b>c</b>) CS 29.7 nm; and (<b>d</b>) control (without SNP).</p> Full article ">
5171 KiB  
Article
Enhanced Deposition Uniformity via an Auxiliary Electrode in Massive Electrospinning
by Dezhi Wu, Zhiming Xiao, Lei Deng, Yu Sun, Qiulin Tan, Linxi Dong, Shaohua Huang, Rui Zhu, Yifang Liu, Wanxi Zheng, Yang Zhao, Lingyun Wang and Daoheng Sun
Nanomaterials 2016, 6(7), 135; https://doi.org/10.3390/nano6070135 - 22 Jul 2016
Cited by 8 | Viewed by 5266
Abstract
Uniform deposition of nanofibers in the massive electrospinning process is critical in the industrial applications of nanofibers. Tip-Induced Electrospinning (TIE) is a cost-effective large-scale nanofiber-manufacturing method, but it has poor deposition uniformity. An auxiliary conductive electrode connected to the emitting electrode was introduced [...] Read more.
Uniform deposition of nanofibers in the massive electrospinning process is critical in the industrial applications of nanofibers. Tip-Induced Electrospinning (TIE) is a cost-effective large-scale nanofiber-manufacturing method, but it has poor deposition uniformity. An auxiliary conductive electrode connected to the emitting electrode was introduced to improve the deposition uniformity of the nanofibers. The effects of the auxiliary electrode shape, the tilted angles and the position of the boat-like electrode on the electric field distribution, the diameter of the nanofibers, the jet control and the deposition uniformity were explored by using finite element analysis of the electric field and experiments. Experiments showed that the boat-like electrode at 20 mm above the reservoir bottom with a 5° tilted angle helped to decrease the relative deposition error of nanofibers in the greatest extent to about 5.66%, indicating such an auxiliary electrode is a good candidate method to greatly improve the deposition uniformity of nanofibers in massive electrospinning. Full article
(This article belongs to the Special Issue Electrospinning of Nanofibres for Energy Applications)
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Figure 1
<p>Schematic diagram of traditional Tip-Induced Electrospinning (TIE) setup.</p> Full article ">Figure 2
<p>Different shaped diagrams of the conductive auxiliary electrodes around the solution reservoir: (<b>a</b>) plain; (<b>b</b>) rectangular circle; and (<b>c</b>) boat-like; the tilted angle is denoted by <math display="inline"> <semantics> <mrow> <mi mathvariant="sans-serif">α</mi> </mrow> </semantics> </math>.</p> Full article ">Figure 3
<p>Electric field distribution without auxiliary electrode in (<b>a</b>) and (<b>b</b>) and with a boat-like electrode in (<b>c</b>) and (<b>d</b>); (b) and (d) show the <span class="html-italic">x</span> component electric field strength (absolute value) along the width of the reservoir with different heights above the solution surface.</p> Full article ">Figure 4
<p>(<b>a</b>) <span class="html-italic">x</span> and (<b>b</b>) <span class="html-italic">y</span> component of electric field strength distribution at 10 mm above the solution surface with and without different shapes of auxiliary electrodes.</p> Full article ">Figure 5
<p>The electric field distribution for different tilted angles and different positions of the boat-like auxiliary electrode. The schematic diagram of the auxiliary electrode at the bottom of solution reservoir (<b>a</b>) and at the height 20 mm above the bottom (<b>b</b>); <span class="html-italic">E<sub>x</sub></span> and <span class="html-italic">E<sub>y</sub></span> distributions when the boat-like auxiliary electrode was (<b>c</b>) at the bottom and (<b>d</b>) at 20 mm above the reservoir bottom.</p> Full article ">Figure 6
<p>An optical photograph of TIE setup.</p> Full article ">Figure 7
<p>(<b>a</b>) Schematic diagram of six equally distributed samples on the collector. The collector is 60 cm in width. The arrow represents the moving direction of the collection cloth. (<b>b</b>) A photograph of the arrangement of the collector belt.</p> Full article ">Figure 8
<p>Scanning electron microscope (SEM) images and diameter distributions of poly (ethylene oxide) (PEO) fibers fabricated by TIE with different structures of the additional metal electrode: (<b>a</b>,<b>b</b>) none, (<b>c</b>,<b>d</b>) plain, (<b>e</b>,<b>f</b>) rectangular circle, (<b>g</b>,<b>h</b>) boat-like.</p> Full article ">Figure 9
<p>(<b>a</b>) The optical photograph of a typical deflection angle; (<b>b</b>) the deflection angle with respect to different shapes and positions of auxiliary metal electrodes.</p> Full article ">Figure 10
<p>(<b>a</b>) The photograph of fibers on the continuous collector from TIE with no auxiliary electrode; (<b>b</b>) with a boat-like electrode with a 15° tilted angle electrode at the bottom. The length of the collector is 60 cm; (<b>c</b>) deposition efficiency distribution along <span class="html-italic">x</span>-axis for different shapes of auxiliary electrodes; (<b>d</b>) the average deposition efficiency and relative deposition deviation with different tilted angles and positions for boat-like electrodes.</p> Full article ">
2334 KiB  
Review
Nanomaterials for Tissue Engineering In Dentistry
by Manila Chieruzzi, Stefano Pagano, Silvia Moretti, Roberto Pinna, Egle Milia, Luigi Torre and Stefano Eramo
Nanomaterials 2016, 6(7), 134; https://doi.org/10.3390/nano6070134 - 21 Jul 2016
Cited by 75 | Viewed by 11166
Abstract
The tissue engineering (TE) of dental oral tissue is facing significant changes in clinical treatments in dentistry. TE is based on a stem cell, signaling molecule, and scaffold triad that must be known and calibrated with attention to specific sectors in dentistry. This [...] Read more.
The tissue engineering (TE) of dental oral tissue is facing significant changes in clinical treatments in dentistry. TE is based on a stem cell, signaling molecule, and scaffold triad that must be known and calibrated with attention to specific sectors in dentistry. This review article shows a summary of micro- and nanomorphological characteristics of dental tissues, of stem cells available in the oral region, of signaling molecules usable in TE, and of scaffolds available to guide partial or total reconstruction of hard, soft, periodontal, and bone tissues. Some scaffoldless techniques used in TE are also presented. Then actual and future roles of nanotechnologies about TE in dentistry are presented. Full article
(This article belongs to the Special Issue Nanomaterials for Tissue Engineering)
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Graphical abstract
Full article ">Figure 1
<p>Schematic section of a tooth and surrounding tissues.</p> Full article ">Figure 2
<p>Prisms of the enamel observed on the surface and in cross-section.</p> Full article ">Figure 3
<p>Dentin morphology with collagen fibers and inorganic components.</p> Full article ">Figure 4
<p>Dentinal tubules observed on the surface and in cross section.</p> Full article ">Figure 5
<p>The structure of the dental pulp.</p> Full article ">
5806 KiB  
Review
Nanomaterials for Cardiac Myocyte Tissue Engineering
by Rodolfo Amezcua, Ajay Shirolkar, Carolyn Fraze and David A. Stout
Nanomaterials 2016, 6(7), 133; https://doi.org/10.3390/nano6070133 - 19 Jul 2016
Cited by 51 | Viewed by 9146
Abstract
Since their synthesizing introduction to the research community, nanomaterials have infiltrated almost every corner of science and engineering. Over the last decade, one such field has begun to look at using nanomaterials for beneficial applications in tissue engineering, specifically, cardiac tissue engineering. During [...] Read more.
Since their synthesizing introduction to the research community, nanomaterials have infiltrated almost every corner of science and engineering. Over the last decade, one such field has begun to look at using nanomaterials for beneficial applications in tissue engineering, specifically, cardiac tissue engineering. During a myocardial infarction, part of the cardiac muscle, or myocardium, is deprived of blood. Therefore, the lack of oxygen destroys cardiomyocytes, leaving dead tissue and possibly resulting in the development of arrhythmia, ventricular remodeling, and eventual heart failure. Scarred cardiac muscle results in heart failure for millions of heart attack survivors worldwide. Modern cardiac tissue engineering research has developed nanomaterial applications to combat heart failure, preserve normal heart tissue, and grow healthy myocardium around the infarcted area. This review will discuss the recent progress of nanomaterials for cardiovascular tissue engineering applications through three main nanomaterial approaches: scaffold designs, patches, and injectable materials. Full article
(This article belongs to the Special Issue Nanomaterials for Tissue Engineering)
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Full article ">Figure 1
<p>During a myocardial infarction, blood flow is deprived to the myocardium, which, in turn, injures the tissues downstream of the obstruction. As a result, cardiomyocytes are deprived of oxygen and eventually perish. Next, myofibroblasts migrate towards this infarct area and ultimately create scar tissue that reduces the heart’s contractile ability and weakens it. The weakened area is unable to withstand the pressure and volume load on the heart, thereby causing left ventricular dilation. Over time, this scar tissue causes ongoing remodeling, and the heart becomes more spherical, thus impairing systolic and diastolic function. To combat the progress of cardiovascular disease (CVD) and ventricular remodeling, modern research has deployed the use of nanomaterials through the use of scaffolds, patches, and injectable materials for regenerating the heart tissue.</p> Full article ">Figure 2
<p>Researchers have exploited nanomaterial characteristics for biomaterial applications by increasing its surface-area ratio. This augmentation in surface-area ratio can enhance protein absorption, thus increasing the possibility of cell recruitment and attachment.</p> Full article ">Figure 3
<p>Two novel studies in cardiac tissue engineering: (<b>a</b>) electrospun polycaprolactone (PCL) nanofibrous mesh stretched across a wire ring used to create a passive load exerted by the wire allowing for cultured cardiomyocytes (CMs) to reach appropriate maturity prior to implantation [<a href="#B52-nanomaterials-06-00133" class="html-bibr">52</a>]; (<b>b</b>) nanoelectronic scaffold (blue) constructed from silicon nanowire field effect transistors capable of real-time monitoring of local electrical activity within the extracellular matrix (ECM) (green) [<a href="#B55-nanomaterials-06-00133" class="html-bibr">55</a>].</p> Full article ">Figure 4
<p>Cardiovascular patches embedded with nanomaterials play a key role in promoting stem cell growth around an infarct area of the myocardium: (<b>a</b>) the use of poly(lactic-co-glycolic) acid (PLGA) embedded with carbon nanofibers (CNFs) to generate a carbon nanofiber reinforced patch; (<b>b</b>) scanning electron micrograph of carbon nanofiber reinforced patch showing CNFs embedded in PLGA (at 10 K magnification); (<b>c</b>) atomic force micrograph of a carbon nanofiber reinforced patch depicting the topography of the patch; (<b>d</b>) using the data from atomic force micrographs to calculate the increase in surface area as one increases CNF concentration vs. protein adsorption, one can see that using CNFs can increase protein adsorption of a carbon nanofiber reinforced patch, thus increasing the possibility of cell recruitment and growth.</p> Full article ">Figure 5
<p>Following cardiac ischemic injury, lack of blood supply results in cardiomyocyte apoptosis (brown). After an inflammatory response, myofibroblasts and macrophages (green) migrate towards the injured area leading to fibrosis thus creating scar tissue (white). When scaffolds are applied to the injured area (in this case by injection via syringe (clear)), exploiting the superior material properties of nanomaterials such as gold nanoparticles (yellow) have demonstrated reduced scarring and often slowed left ventricular remodeling. The (pink) cardiomyocytes in this figure are shown to regenerate along the site of scaffold injection.</p> Full article ">
2975 KiB  
Article
A Label-Free Microelectrode Array Based on One-Step Synthesis of Chitosan–Multi-Walled Carbon Nanotube–Thionine for Ultrasensitive Detection of Carcinoembryonic Antigen
by Huiren Xu, Yang Wang, Li Wang, Yilin Song, Jinping Luo and Xinxia Cai
Nanomaterials 2016, 6(7), 132; https://doi.org/10.3390/nano6070132 - 11 Jul 2016
Cited by 18 | Viewed by 6136
Abstract
Carcinoembryonic antigen (CEA) has been an extensively used tumor marker responsible for clinical early diagnosis of cervical carcinomas, and pancreatic, colorectal, gastric and lung cancer. Combined with micro-electro mechanical system (MEMS) technology, it is important to develop a novel immune microelectrode array (MEA) [...] Read more.
Carcinoembryonic antigen (CEA) has been an extensively used tumor marker responsible for clinical early diagnosis of cervical carcinomas, and pancreatic, colorectal, gastric and lung cancer. Combined with micro-electro mechanical system (MEMS) technology, it is important to develop a novel immune microelectrode array (MEA) not only for rapid analysis of serum samples, but also for cell detection in vitro and in vivo. In this work, we depict a simple approach to modify chitosan–multi-walled carbon nanotubes–thionine (CS–MWCNTs–THI) hybrid film through one-step electrochemical deposition and the CS-MWCNTs-THI hybrid films are successfully employed to immobilize anti-CEA for fabricating simple, label-free, and highly sensitive electro-chemical immune MEAs. The detection principle of immune MEA was based on the fact that the increasing formation of the antigen-antibody immunocomplex resulted in the decreased response currents and the relationship between the current reductions with the corresponding CEA concentrations was directly proportional. Experimental results indicated that the label-free MEA had good selectivity and the limit of detection for CEA is 0.5 pg/mL signal to noise ratio (SNR) = 3. A linear calibration plot for the detection of CEA was obtained in a wide concentration range from 1 pg/mL to 100 ng/mL (r = 0.996). This novel MEA has potential applications for detecting CEA for the research on cancer cells and cancer tissue slices as well as for effective early diagnosis. Full article
(This article belongs to the Special Issue Polysaccharide-Based Nanosorbent Materials: Fundamental Science and Beyond)
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Figure 1
<p>Characteristics of chitosan-multi-walled carbon nanotubes-thionine (CS-MWCNTs-THI) hybrid film. (<b>A</b>) Scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) image of bare Au microelectrode; (<b>B</b>) SEM-EDS image of CS-MWCNTs-THI hybrid film; (<b>C</b>) SEM image of the CS-MWCNTs-THI hybrid film.</p> Full article ">Figure 2
<p>Cyclic voltammograms (CV) of microelectrode modified with CS-MWCNTs-THI/Au (<b>a</b>); anti-CEA/CS-MWCNTs-THI/Au (<b>b</b>); BSA/CS-MWCNTs-THI/Au (<b>c</b>); BSA/anti-CEA/CS-MWCNTs-THI/Au (<b>d</b>). Scan rate: 100 mV/s, solution: pH 7.4 phosphate buffer. BSA: bovine serum albumin; CEA: carcinoembryonic antigen.</p> Full article ">Figure 3
<p>(<b>A</b>) Differential pulse voltammetry (DPV) responses of the proposed immune microelectrode arrays (MEAs) after incubation with various concentrations of carcinoembryonic antigen (CEA); (<b>B</b>) Calibration curves of the immune MEAs with regard to CEA. Solution: pH 7.4 phosphate buffer.</p> Full article ">Figure 4
<p>Amperometric response of the immune MEA to 1 ng/mL CEA, 1 ng/mL CEA + 1 ng/mL IgG, 1 ng/mL CEA + 1 ng/mL BSA, 1 ng/mL CEA + 1 ng/mL glucose, 1 ng/mL CEA + 1 ng/mL AA, 1 ng/mL CEA +1 ng/mL DA, 1 ng/mL CEA + 1 ng/mL UA. DA: dopamine; UA: uric acid; AA: ascorbic acid.</p> Full article ">Figure 5
<p>Amperometric responses of five immune microelectrodes on the MEA to 1 ng/mL CEA.</p> Full article ">Figure 6
<p>The CEA concentrations of five serum samples detected by enzyme-linked immune sorbent assay (ELISA) and immune MEA.</p> Full article ">Scheme 1
<p>The fabrication procedure of the immune microelectrode array.</p> Full article ">Scheme 2
<p>Microelectrode array fabrication process schematic. (<b>a</b>) The first photolithography; (<b>b</b>) the development of the photoresist; (<b>c</b>) magnetron sputtering; (<b>d</b>) lift-off process; (<b>e</b>) chemical vapor deposition; (<b>f</b>) the second photolithography; (<b>g</b>) SF<sub>6</sub> deep reactive ion etcher; (<b>h</b>) display the microelectrode sites and pads; (<b>i</b>) cleaning step.</p> Full article ">
714 KiB  
Review
Lipid Nanovectors to Deliver RNA Oligonucleotides in Cancer
by Virginia Campani, Giuseppina Salzano, Sara Lusa and Giuseppe De Rosa
Nanomaterials 2016, 6(7), 131; https://doi.org/10.3390/nano6070131 - 9 Jul 2016
Cited by 32 | Viewed by 7202
Abstract
The growing knowledge on the mechanisms of gene silencing and gene regulation by non-coding RNAs (ncRNA), mainly small interfering RNA (siRNA) and microRNA (miRNA), is providing a significant boost to the development of new therapeutic strategies for the treatment of cancer. However, the [...] Read more.
The growing knowledge on the mechanisms of gene silencing and gene regulation by non-coding RNAs (ncRNA), mainly small interfering RNA (siRNA) and microRNA (miRNA), is providing a significant boost to the development of new therapeutic strategies for the treatment of cancer. However, the design of RNA-based therapeutics is hampered by biopharmaceutical issues, thus requiring the use of suitable delivery strategies. In this regards, lipid nanovectors have been successfully investigated to deliver RNA in different forms of cancer. Compared to other biomaterials, lipids offer advantages such as biocompatibility, biodegradability, easy production, low cost, limited toxicity and immunogenicity. The possibility to formulate these materials in the form of nanovectors allows overcoming biopharmaceutical issues associated to the therapeutic use of RNA, with the possibility to target tumors. This review takes stock of the main lipid nanovectors proposed to deliver ncRNA. For each considered delivery strategy, the rational design and the most meaningful in vitro and in vivo results are reported and discussed. Full article
(This article belongs to the Special Issue Nanomaterials for Cancer Therapies)
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<p>Chemical structure of some lipids commonly used to prepare lipid nanovectors used to deliver ncRNA.</p> Full article ">
4319 KiB  
Article
Nanostructures Derived from Starch and Chitosan for Fluorescence Bio-Imaging
by Yinxue Zu, Jingran Bi, Huiping Yan, Haitao Wang, Yukun Song, Bei-Wei Zhu and Mingqian Tan
Nanomaterials 2016, 6(7), 130; https://doi.org/10.3390/nano6070130 - 5 Jul 2016
Cited by 19 | Viewed by 7585
Abstract
Fluorescent nanostructures (NSs) derived from polysaccharides have drawn great attention as novel fluorescent probes for potential bio-imaging applications. Herein, we reported a facile alkali-assisted hydrothermal method to fabricate polysaccharide NSs using starch and chitosan as raw materials. Transmission electron microscopy (TEM) demonstrated that [...] Read more.
Fluorescent nanostructures (NSs) derived from polysaccharides have drawn great attention as novel fluorescent probes for potential bio-imaging applications. Herein, we reported a facile alkali-assisted hydrothermal method to fabricate polysaccharide NSs using starch and chitosan as raw materials. Transmission electron microscopy (TEM) demonstrated that the average particle sizes are 14 nm and 75 nm for starch and chitosan NSs, respectively. Fourier transform infrared (FT-IR) spectroscopy analysis showed that there are a large number of hydroxyl or amino groups on the surface of these polysaccharide-based NSs. Strong fluorescence with an excitation-dependent emission behaviour was observed under ultraviolet excitation. Interestingly, the photostability of the NSs was found to be superior to fluorescein and rhodamine B. The quantum yield of starch NSs could reach 11.12% under the excitation of 360 nm. The oxidative metal ions including Cu(II), Hg(II)and Fe(III) exhibited a quench effect on the fluorescence intensity of the prepared NSs. Both of the two kinds of the multicoloured NSs showed a maximum fluorescence intensity at pH 7, while the fluorescence intensity decreased dramatically when they were put in an either acidic or basic environment (at pH 3 or 11). The cytotoxicity study of starch NSs showed that low cell cytotoxicity and 80% viability was found after 24 h incubation, when their concentration was less than 10 mg/mL. The study also showed the possibility of using the multicoloured starch NSs for mouse melanoma cells and guppy fish imaging. Full article
(This article belongs to the Special Issue Polysaccharide-Based Nanosorbent Materials: Fundamental Science and Beyond)
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Full article ">Figure 1
<p>Transmission electron microscopy (TEM) images of polysaccharide-based NSs prepared from starch (<b>A</b>) and chitosan (<b>B</b>). Insets show the fluorescence photographs for the polysaccharide-based NSs in aqueous solution. Excitation wavelength for each sample in the inset pictures is 312 nm.</p> Full article ">Figure 2
<p>Fourier transform infrared (FT-IR) spectra of polysaccharide-based NSs prepared from (<b>A</b>) starch, starch NSs at 1, 2, 4 h, and (<b>B</b>) chitosan, chitosan NSs at 1, 2, 4 h.</p> Full article ">Figure 3
<p>Ultra-violet visible absorption (Abs) and fluorescence (FL) emission spectra of polysaccharide-based NSs derived from starch (<b>A</b>) and chitosan (<b>B</b>). Excitation wavelengths were changed from 300 nm to 460 nm in 20 nm increments. Insets show the normalised emission spectra red-shifting with the excitation at longer wavelengths.</p> Full article ">Figure 4
<p>Photostability of the polysaccharide-based NSs prepared from starch (<b>A</b>) and chitosan (<b>B</b>), as compared with rhodamine B (<b>C</b>) and fluorescein (<b>D</b>).</p> Full article ">Figure 5
<p>Effect of metal ions on the fluorescence (FL) intensity of the polysaccharide-based NSs prepared from starch (<b>A</b>) and chitosan (<b>B</b>).</p> Full article ">Figure 6
<p>Effects of pH on the fluorescence (FL) intensity of the polysaccharide-based NSs derived from starch (<b>A</b>) and chitosan (<b>B</b>).</p> Full article ">Figure 7
<p>Cytotoxicity experiment of starch NSs. The values are the average of triplicate measurements.</p> Full article ">Figure 8
<p>Laser scanning confocal microscopy images of mouse melanoma cells under bright-field, with excitation at 405 and 488 nm. The cells without polysaccharide-based NSs used as a control. Scale bar = 170 µm. (<b>a</b>) Bright-field image, fluorescence image by excitation at (<b>b</b>) 405 and (<b>c</b>) 488 nm, as well as (<b>d</b>) overlay of images of (<b>a</b>) and (<b>c</b>) for mouse melanoma cells without polysaccharide-based NSs. (<b>e</b>) Bright-field image, fluorescence image by excitation at (<b>f</b>) 405 and (<b>g</b>) 488 nm, as well as (<b>h</b>) overlay of images of (<b>e</b>) and (<b>g</b>) for mouse melanoma cells incubated with polysaccharide-based NSs.</p> Full article ">Figure 9
<p>Ex vivo guppy fish imaging. Photograph of the starch NSs labelled guppy fish under (<b>a</b>) bright-field, (<b>b</b>) with excitation at 455 nm, and (<b>c</b>) overlay of (<b>a</b>) and (<b>b</b>) measured with CRi Meastro imaging system. Exposure time was 1500 ms. Small guppy fish in the bottom right corner was used as a control without being treated with the starch NSs.</p> Full article ">Scheme 1
<p>Synthesis fluorescent nanostructures (NSs) derived from starch and chitosan for bio-imaging.</p> Full article ">
4549 KiB  
Review
Electrospinning of Nanofibers for Energy Applications
by Guiru Sun, Liqun Sun, Haiming Xie and Jia Liu
Nanomaterials 2016, 6(7), 129; https://doi.org/10.3390/nano6070129 - 2 Jul 2016
Cited by 112 | Viewed by 11737
Abstract
With global concerns about the shortage of fossil fuels and environmental issues, the development of efficient and clean energy storage devices has been drastically accelerated. Nanofibers are used widely for energy storage devices due to their high surface areas and porosities. Electrospinning is [...] Read more.
With global concerns about the shortage of fossil fuels and environmental issues, the development of efficient and clean energy storage devices has been drastically accelerated. Nanofibers are used widely for energy storage devices due to their high surface areas and porosities. Electrospinning is a versatile and efficient fabrication method for nanofibers. In this review, we mainly focus on the application of electrospun nanofibers on energy storage, such as lithium batteries, fuel cells, dye-sensitized solar cells and supercapacitors. The structure and properties of nanofibers are also summarized systematically. The special morphology of nanofibers prepared by electrospinning is significant to the functional materials for energy storage. Full article
(This article belongs to the Special Issue Electrospinning of Nanofibres for Energy Applications)
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<p>Schematic diagram of an electrospinning set-up.</p> Full article ">Figure 2
<p>Schematics of: (<b>a</b>) Li-ion batteries; (<b>b</b>) lithium-sulfur batteries; (<b>c</b>) lithium-oxygen batteries.</p> Full article ">Figure 3
<p>Model image of the triaxial nanowire with a vapor-grown carbon fiber (VGCF) core column and the two layer shells: an outer shell of amorphous carbon and an inner composite shell of LiFePO<sub>4</sub> and amorphous carbon. Reproduced with permission from [<a href="#B53-nanomaterials-06-00129" class="html-bibr">53</a>]. Copyright American Physical Society, 2010.</p> Full article ">Figure 4
<p>Schematics of the structural design of the core-shell silicon/carbon fiber (Si/po-C@C) composite fiber: (<b>a</b>) structural formation and change of Si/po-C@C during heat treatment and cycling process, respectively; (<b>b</b>) three-dimensional (3D) sketch of the overall structure. (SEI: solid-electrolyte interphase). Reproduced with permission from [<a href="#B82-nanomaterials-06-00129" class="html-bibr">82</a>]. Copyright Royal Society of Chemistry, 2015.</p> Full article ">Figure 5
<p>Photographs of the electrospun/sprayed flexible paper electrode (<b>a</b>) before and (<b>b</b>) after carbonization with 72 wt % Si; SEM images of the 3D Si/C fiber paper electrode: (<b>c</b>–<b>e</b>) top view and (<b>f</b>) cross-section. Reproduced with permission from [<a href="#B83-nanomaterials-06-00129" class="html-bibr">83</a>]. Copyright Wiley, 2014.</p> Full article ">Figure 6
<p>(<b>a</b>) TEM micrographs of microtomed sections of 5 at. % Nb-SnO<sub>2</sub> loose tubes obtained using 8.5 <span class="html-italic">w</span>/<span class="html-italic">v</span> % SnCl<sub>2</sub>. Inset: close-up of the cross-section of a loose-tube fiber. (<b>b</b>) Loose tubes of niobium-doped SnO<sub>2</sub> (8.5 <span class="html-italic">w</span>/<span class="html-italic">v</span> % SnCl<sub>2</sub> and 5 at. % Nb) prepared using heating rates of 1, 5 and 10 °C/min during calcination. Reproduced with permission from [<a href="#B165-nanomaterials-06-00129" class="html-bibr">165</a>]. Copyright American Chemical Society, 2013.</p> Full article ">Figure 7
<p>Schematic diagram of the fabrication procedure and SEM images of the bilayer TiO<sub>2</sub> nanofiber photoanode (BNF: bigger-diameter nanofiber; SNF: smaller-diameter nanofiber). Reproduced with permission from [<a href="#B187-nanomaterials-06-00129" class="html-bibr">187</a>]. Copyright Wiley, 2011.</p> Full article ">Figure 8
<p>Photocurrent density-voltage (J-V) curves for the DSSC containing (<b>a</b>) 0.5 M 1-butyl-3-methylimidazolium iodide (BMImI)-LE and (<b>b</b>) 0.5 M BMImI-esPME. Reproduced with permission from [<a href="#B209-nanomaterials-06-00129" class="html-bibr">209</a>]. Copyright Wiley, 2015.</p> Full article ">Scheme 1
<p>Preparation of Sn@carbon nanoparticles encapsulated in hollow carbon nanofibers. Reproduced with permission from [<a href="#B88-nanomaterials-06-00129" class="html-bibr">88</a>]. Copyright Wiley, 2009.</p> Full article ">Scheme 2
<p>Formation mechanism of the TiO<sub>2</sub> nanofiber with a fiber-in-tube nanostructure from the tributyltin (TBT)-poly(vinylpyrrolidone) (PVP) composite nanofiber. Reproduced with permission from [<a href="#B92-nanomaterials-06-00129" class="html-bibr">92</a>]. Copyright Wiley, 2015.</p> Full article ">Scheme 3
<p>Schematic illustration of the typical preparation procedure for the Co<sub>3</sub>O<sub>4</sub>-based binder-free (CCTN) electrode. Reproduced with permission from [<a href="#B138-nanomaterials-06-00129" class="html-bibr">138</a>]. Copyright Royal Society of Chemistry, 2015.</p> Full article ">
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Article
Characteristic Evaluation of Graphene Oxide for Bisphenol A Adsorption in Aqueous Solution
by Thatchaphong Phatthanakittiphong and Gyu Tae Seo
Nanomaterials 2016, 6(7), 128; https://doi.org/10.3390/nano6070128 - 2 Jul 2016
Cited by 66 | Viewed by 7842
Abstract
This paper investigates the characteristics of graphene oxide (GO) for Bisphenol A (BPA) adsorption in water. Batch experiments on the influence of significant parameters were performed. While an improvement of the adsorption capacity of BPA was obtained by the increment of contact time [...] Read more.
This paper investigates the characteristics of graphene oxide (GO) for Bisphenol A (BPA) adsorption in water. Batch experiments on the influence of significant parameters were performed. While an improvement of the adsorption capacity of BPA was obtained by the increment of contact time and the initial BPA concentration, the increment of pH above 8, GO dosage, and temperature showed the reverse results. The thermodynamic study suggested that BPA adsorption on GO was an exothermic and spontaneous process. The kinetics was explained by the pseudo-second-order model which covers all steps of adsorption. The fit of the results with the Langmuir isotherm indicated the monolayer adsorption. At 298 K, the adsorption reached equilibrium within 30 min with the maximum adsorption capacity of 49.26 mg/g. The low BPA adsorption capacity of GO can be interpreted by the occurrence of oxygen-containing functional groups (OCFGs) that are able to form hydrogen bonds with the surrounding OCFGs and water molecules. This effect inhibited the role of π–π interactions that are mainly responsible for the adsorption of BPA. Full article
(This article belongs to the Special Issue 2D Nanomaterials: Graphene and Beyond Graphene)
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<p>The powder X-ray diffraction (XRD) patterns of graphite and GO.</p> Full article ">Figure 2
<p>Effect of contact time and initial concentration on the adsorption of bisphenol A (BPA) by GO. Error bars represent the standard deviations of three replicates. q<sub>t</sub>: The amounts of BPA adsorbed on GO at time interval t (mg/g).</p> Full article ">Figure 3
<p>Effect of the GO dosage on the adsorption of BPA. q<sub>e</sub>: the amounts of BPA adsorbed on GO at equilibrium (mg/g).</p> Full article ">Figure 4
<p>Effect of pH on the adsorption capacity of BPA.</p> Full article ">Figure 5
<p>Effect of temperature on the adsorption of BPA by GO.</p> Full article ">Figure 6
<p>Adsorption kinetics of BPA on GO at the initial BPA concentration of 60 mg/L.</p> Full article ">Figure 7
<p>Adsorption isotherms of BPA on GO at a temperature of 298 K. C<sub>e</sub>: the concentration of BPA at equilibrium (mg/L).</p> Full article ">Figure 8
<p>SEM images of (<b>A</b>) GO surface and (<b>B</b>) cross-section.</p> Full article ">Figure 9
<p>The oxygen-containing functional groups (OCFGs) on the GO surface analyzed by Fourier transform infrared spectroscopy (FTIR).</p> Full article ">Figure 10
<p>Schematic representation of π–π interactions and hydrogen bonding between BPA and GO.</p> Full article ">Figure 11
<p>Hydrogen bonding: (<b>A</b>) OCFGs–H<sub>2</sub>O; and (<b>B</b>) OCFGs–OCFGs.</p> Full article ">
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Article
A Gallium Oxide-Graphene Oxide Hybrid Composite for Enhanced Photocatalytic Reaction
by Seungdu Kim, Kook In Han, In Gyu Lee, Won Kyu Park, Yeojoon Yoon, Chan Sei Yoo, Woo Seok Yang and Wan Sik Hwang
Nanomaterials 2016, 6(7), 127; https://doi.org/10.3390/nano6070127 - 1 Jul 2016
Cited by 10 | Viewed by 6121
Abstract
Hybrid composites (HCs) made up of gallium oxide (GaO) and graphene oxide (GO) were investigated with the intent of enhancing a photocatalytic reaction under ultraviolet (UV) radiation. The material properties of both GaO and GO were preserved, even after the formation of the [...] Read more.
Hybrid composites (HCs) made up of gallium oxide (GaO) and graphene oxide (GO) were investigated with the intent of enhancing a photocatalytic reaction under ultraviolet (UV) radiation. The material properties of both GaO and GO were preserved, even after the formation of the HCs. The incorporation of the GO into the GaO significantly enhanced the photocatalytic reaction, as indicated by the amount of methylene blue (MB) degradation. The improvements in the reaction were discussed in terms of increased surface area and the retarded recombination of generated charged carriers. Full article
(This article belongs to the Special Issue Nanomaterials for Flexible and Stretchable Devices: Synthesis, Processes, and Applications)
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<p>Schematic illustrations of hybrid composite (HC) growth depending on (<b>a</b>) a 4% graphene oxide (GO) solution and (<b>b</b>) a 10% GO solution. The scale bar in the scanning electron microscopy (SEM) is 1 μm.</p> Full article ">Figure 2
<p>(<b>a</b>) X-Ray Diffraction (XRD) spectra of different HCs made up of gallium oxide (GaO) and with/without GO; (<b>b</b>) Full-width at half maximum (FWHM) variation for XRD peaks from (<b>a</b>) and grain size of the HCs as a function of GO concentration in the solution; (<b>c</b>) Raman of different HCs using the same proportions as in (<b>a</b>).</p> Full article ">Figure 3
<p>The absorbance spectra of the methylene blue (MB) solution where (<b>a</b>) GaO; (<b>b</b>) an HC of GaO and 4% GO; and (<b>c</b>) an HC of GaO and 10% GO were added to the MB. Each sample was exposed to 254 nm of radiation at different times.</p> Full article ">Figure 4
<p>Schematic illustrations of charged carrier generation and transfer, as well as the water splitting mechanism of (<b>a</b>) the Ga oxide and (<b>b</b>) the HC of Ga oxide and GO. hν is ultraviolet light energy, where h is Planck’s constant and ν is frequency.</p> Full article ">
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Article
Quaternized Chitosan-Capped Mesoporous Silica Nanoparticles as Nanocarriers for Controlled Pesticide Release
by Lidong Cao, Huirong Zhang, Chong Cao, Jiakun Zhang, Fengmin Li and Qiliang Huang
Nanomaterials 2016, 6(7), 126; https://doi.org/10.3390/nano6070126 - 28 Jun 2016
Cited by 126 | Viewed by 13401
Abstract
Nanotechnology-based pesticide formulations would ensure effective utilization of agricultural inputs. In the present work, mesoporous silica nanoparticles (MSNs) with particle diameters of ~110 nm and pore sizes of ~3.7 nm were synthesized via a liquid crystal templating mechanism. A water-soluble chitosan (CS) derivative [...] Read more.
Nanotechnology-based pesticide formulations would ensure effective utilization of agricultural inputs. In the present work, mesoporous silica nanoparticles (MSNs) with particle diameters of ~110 nm and pore sizes of ~3.7 nm were synthesized via a liquid crystal templating mechanism. A water-soluble chitosan (CS) derivative (N-(2-hydroxyl)propyl-3-trimethyl ammonium CS chloride, HTCC) was successfully capped on the surface of pyraclostrobin-loaded MSNs. The physicochemical and structural analyses showed that the electrostatic interactions and hydrogen bonding were the major forces responsible for the formation of HTCC-capped MSNs. HTCC coating greatly improved the loading efficiency (LC) (to 40.3%) compared to using bare MSNs as a single encapsulant (26.7%). The microstructure of the nanoparticles was revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The pyraclostrobin-loaded nanoparticles showed an initial burst and subsequent sustained release behavior. HTCC-capped MSNs released faster than bare MSNs in the initial stage. Pyraclostrobin-loaded HTCC-capped MSNs with half doses of pyraclostrobin technical demonstrated almost the same fungicidal activity against Phomopsis asparagi (Sacc.), which obviously reduced the applied pesticide and enhanced the utilization efficiency. Therefore, HTCC-decorated MSNs demonstrated great potential as nanocarriers in agrochemical applications. Full article
(This article belongs to the Special Issue Polysaccharide-Based Nanosorbent Materials: Fundamental Science and Beyond)
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<p>Molecular structures of <span class="html-italic">N</span>-2-hydroxypropyl trimethyl ammonium chloride chitosan (HTCC) (<b>a</b>) and pyraclostrobin (<b>b</b>).</p> Full article ">Figure 2
<p>Schematic illustration of the pyraclostrobin-loaded HTCC-capped mesoporous silica nanoparticles (MSNs) (Py@MSNs-HTCC) formation process.</p> Full article ">Figure 3
<p>Scanning electron microscopy (SEM) images of MSNs (<b>a</b>) and pyraclostrobin-loaded HTCC-capped MSNs (<b>b</b>); Transmission electron microscopy (TEM) images of MSNs (<b>c</b>) and pyraclostrobin-loaded HTCC-capped MSNs (<b>d</b>).</p> Full article ">Figure 4
<p>Fourier transform infrared (FTIR) spectra of pyraclostrobin (Py), MSNs, HTCC and Py@MSNs-HTCC.</p> Full article ">Figure 5
<p>Thermogravimetric analysis (TGA) of pyraclostrobin, MSNs, HTCC and Py@MSNs-HTCC.</p> Full article ">Figure 6
<p>Nitrogen adsorption-desorption isotherms of MSNs, Py@MSNs and Py@MSNs-HTCC.</p> Full article ">Figure 7
<p>Barrett–Joyner–Halenda (BJH) pore-size-distribution curves of MSNs and Py@MSNs.</p> Full article ">Figure 8
<p>Release profiles of pyraclostrobin (Py) from pyraclostrobin technical, Py@MSNs and Py@MSNs-HTCC at room temperature. Each data point represents the mean ± standard deviation of three determinations.</p> Full article ">Figure 9
<p>The images of the fungicidal activity of pyraclostrobin technical (PT), pyraclostrobin-loaded HTCC-capped MSNs (NP) and blank carrier MSNs-HTCC (BC) against <span class="html-italic">P</span>. <span class="html-italic">asparagi</span> on the 1st, 3rd and 6th days. The numbers after the abbreviations are the corresponding concentrations (mg/L).</p> Full article ">
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Review
Soft Interaction in Liposome Nanocarriers for Therapeutic Drug Delivery
by Domenico Lombardo, Pietro Calandra, Davide Barreca, Salvatore Magazù and Mikhail A. Kiselev
Nanomaterials 2016, 6(7), 125; https://doi.org/10.3390/nano6070125 - 25 Jun 2016
Cited by 144 | Viewed by 14440
Abstract
The development of smart nanocarriers for the delivery of therapeutic drugs has experienced considerable expansion in recent decades, with the development of new medicines devoted to cancer treatment. In this respect a wide range of strategies can be developed by employing liposome nanocarriers [...] Read more.
The development of smart nanocarriers for the delivery of therapeutic drugs has experienced considerable expansion in recent decades, with the development of new medicines devoted to cancer treatment. In this respect a wide range of strategies can be developed by employing liposome nanocarriers with desired physico-chemical properties that, by exploiting a combination of a number of suitable soft interactions, can facilitate the transit through the biological barriers from the point of administration up to the site of drug action. As a result, the materials engineer has generated through the bottom up approach a variety of supramolecular nanocarriers for the encapsulation and controlled delivery of therapeutics which have revealed beneficial developments for stabilizing drug compounds, overcoming impediments to cellular and tissue uptake, and improving biodistribution of therapeutic compounds to target sites. Herein we present recent advances in liposome drug delivery by analyzing the main structural features of liposome nanocarriers which strongly influence their interaction in solution. More specifically, we will focus on the analysis of the relevant soft interactions involved in drug delivery processes which are responsible of main behaviour of soft nanocarriers in complex physiological fluids. Investigation of the interaction between liposomes at the molecular level can be considered an important platform for the modeling of the molecular recognition processes occurring between cells. Some relevant strategies to overcome the biological barriers during the drug delivery of the nanocarriers are presented which outline the main structure-properties relationships as well as their advantages (and drawbacks) in therapeutic and biomedical applications. Full article
(This article belongs to the Special Issue Nanomaterials for Cancer Therapies)
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<p>Relevant shape factor influencing nanocarrier morphology. Aggregate structures of amphilphilic molecules can be predicted from the critical packing parameter <span class="html-italic">Cpp</span>.</p> Full article ">Figure 2
<p>Schematic representation of the charge distribution around the charged surface of a liposome. The electrical double layer (EDL) is composed of a layer of ions strongly bound to the charged surface (Stern layer) and an adjacent region of loosely associated mobile ions (diffuse layer).</p> Full article ">Figure 3
<p>Models for the heterotopic aggregates formed by the self-assembly of anionic porphyrins (HTTPS) entangled in cationic amphiphilic modified cyclodextrins (SC6CDNH2) (<b>A</b>), at a different porphyrins/cyclodextrins (TPPS/SC6CDNH2) ratio. Reduction of the relative amount of modified cyclodextrin causes an increase in aggregate dimension as evidenced at the different ratio [TPPS/SC6CDNH2] = 1:50 (<b>B</b>), 1:2 (<b>C</b>), and 1:1 (<b>D</b>) [<a href="#B58-nanomaterials-06-00125" class="html-bibr">58</a>].</p> Full article ">Figure 4
<p>Schematic representation of the PEGylated phospholipid (DSPE-PEG2000) 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] ammonium salt (<b>A</b>). View of sterically stabilised lipid bilayers (<b>B</b>). PEG, polyethylene glycol.</p> Full article ">Figure 5
<p>Sketch of the Derjaguin–Landau–Verwey–Overbeek (DLVO)-type interaction energy as a function of particle separation. The net energy is given by the sum of the double layer repulsion <span class="html-italic">V<sub>R</sub></span> represented by a Yukawa type potential (electrostatic repulsion screened by ionic species in solution) and the Van der Waals attractive forces potential <span class="html-italic">V<sub>A</sub></span>.</p> Full article ">Figure 6
<p>Hydrogen bond mechanism (solvation-desolvation) involved before (<b>A</b>) and after (<b>B</b>) the formation and structural organization of a ligand-protein complex.</p> Full article ">Figure 7
<p>Schematic representation of the interaction of biotin with the tetrameric protein streptavidin.</p> Full article ">Figure 8
<p>Representation of the aggregation of biotinylated liposomes induced by the tetrameric streptavidin protein.</p> Full article ">Figure 9
<p>Schematic representation of the deoxyribonucleic acids (DNA)-induced vesicle fusion process [<a href="#B90-nanomaterials-06-00125" class="html-bibr">90</a>].</p> Full article ">Figure 10
<p>Chemical structures of drug molecules employed in liposomal formulations for clinical trials in the treatment of different typology of cancer.</p> Full article ">Figure 11
<p>Schematic representation of the different types of liposomal drug delivery systems: Charge and polymer stabilized (<b>A</b>), targeted (<b>B</b>), and theranostic (<b>C</b>) liposomes.</p> Full article ">
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Article
Nanostructured TiO2 Surfaces Promote Human Bone Marrow Mesenchymal Stem Cells Differentiation to Osteoblasts
by Marco Vercellino, Gabriele Ceccarelli, Francesco Cristofaro, Martina Balli, Federico Bertoglio, Gianna Bruni, Laura Benedetti, Maria Antonietta Avanzini, Marcello Imbriani and Livia Visai
Nanomaterials 2016, 6(7), 124; https://doi.org/10.3390/nano6070124 - 24 Jun 2016
Cited by 27 | Viewed by 6350
Abstract
Micro- and nano-patterning/modification are emerging strategies to improve surfaces properties that may influence critically cells adherence and differentiation. Aim of this work was to study the in vitro biological reactivity of human bone marrow mesenchymal stem cells (hBMSCs) to a nanostructured titanium dioxide [...] Read more.
Micro- and nano-patterning/modification are emerging strategies to improve surfaces properties that may influence critically cells adherence and differentiation. Aim of this work was to study the in vitro biological reactivity of human bone marrow mesenchymal stem cells (hBMSCs) to a nanostructured titanium dioxide (TiO2) surface in comparison to a coverglass (Glass) in two different culture conditions: with (osteogenic medium (OM)) and without (proliferative medium (PM)) osteogenic factors. To evaluate cell adhesion, hBMSCs phosphorylated focal adhesion kinase (pFAK) foci were analyzed by confocal laser scanning microscopy (CLSM) at 24 h: the TiO2 surface showed a higher number of pFAK foci with respect to Glass. The hBMSCs differentiation to osteoblasts was evaluated in both PM and OM culture conditions by enzyme-linked immunosorbent assay (ELISA), CLSM and real-time quantitative reverse transcription PCR (qRT-PCR) at 28 days. In comparison with Glass, TiO2 surface in combination with OM conditions increased the content of extracellular bone proteins, calcium deposition and alkaline phosphatase activity. The qRT-PCR analysis revealed, both in PM and OM, that TiO2 surface increased at seven and 28 days the expression of osteogenic genes. All together, these results demonstrate the capability of TiO2 nanostructured surface to promote hBMSCs osteoblast differentiation and its potentiality in biomedical applications. Full article
(This article belongs to the Special Issue Nanomaterials for Tissue Engineering)
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<p>Scanning electron micrographs (SEM) of the Glass surface at: 10,000× (<b>A</b>); 50,000× (<b>B</b>); and 100,000× (<b>C</b>); SEM of the nanostructured TiO<sub>2</sub> surface at: 10,000× (<b>D</b>); 50,000× (<b>E</b>); and 100,000× (<b>F</b>).</p> Full article ">Figure 2
<p>Human bone marrow mesenchymal stem cells (hBMSCs) adhesion and morphology on Glass and nanostructured TiO<sub>2</sub> surfaces at 24 h. (<b>A</b>,<b>B</b>) confocal laser scanning microscopy (CLSM) images of focal adhesion for cells seeded on Glass (<b>A</b>) and TiO<sub>2</sub> (<b>B</b>): adherent hBMSCs were fixed, permeabilized and immunostained against phosphorylated focal adhesion kinase (pFAK) as indicated in Materials and Methods section. Nuclei were counterstained with Hoechst 33342. (<b>C</b>) Graphical Estimation of relative foci per cell on Glass and TiO<sub>2</sub>. Bars represent normalized values from three or more fields at 20×. (*: <span class="html-italic">p</span> &lt; 0.05). (<b>D</b>–<b>G</b>) CLSM images of tubulin (green fluorescence) and actin (red fluorescence) staining of the hBMSCs cytoskeleton seeded on Glass (<b>D</b>,<b>E</b>) and TiO<sub>2</sub> (<b>F</b>,<b>G</b>). Magnifications: 20× (<b>D</b>,<b>F</b>) and 40× (<b>E</b>,<b>G</b>) for both surfaces, Glass and TiO<sub>2</sub>. Nuclei were counterstained with Hoechst 33342.</p> Full article ">Figure 3
<p>CLSM representative images of hBMSC cells seeded and cultured on Glass and on nanostructured TiO<sub>2</sub> at seven days: (<b>A</b>,<b>C</b>) the cytoskeleton of cells cultured in proliferative medium and (<b>B</b>,<b>D</b>) cells cultured in osteogenic medium on Glass (<b>A</b>,<b>B</b>) and TiO<sub>2</sub> (<b>C</b>,<b>D</b>). Tubulin was stained with goat anti-rabbit Alexa flour 488 antibody, whereas actin was colored in red (Phalloidin). Nuclei were counterstained with Hoechst 33342.</p> Full article ">Figure 4
<p>Gene expression of the indicated bone-specific markers as determined by real-time quantitative reverse transcription PCR (qRT-PCR). hBMSCs were seeded and cultured in proliferative medium and osteogenic medium on Glass and TiO<sub>2</sub> for seven and 28 days, respectively: (<b>A</b>,<b>B</b>) qRT-PCR were performed on cells cultivated in proliferation medium (PM) and osteogenic medium (OM) for 7 (<b>A</b>) and 28 (<b>B</b>) days. The graph shows the fold induction of gene expression expressed in arbitrary units setting the expressions of the indicated genes in cells grown in Glass as equal to 1. Statistical significance values are indicated as *: <span class="html-italic">p</span> &lt; 0.05, **: <span class="html-italic">p</span> &lt; 0.001.</p> Full article ">Figure 5
<p>Immunolocalization of Type 1 Collagen (<b>A</b>,<b>D</b>,<b>G</b>,<b>L</b>), Osteocalcin (<b>B</b>,<b>E</b>,<b>H</b>,<b>M</b>) and Osteopontin (<b>C</b>,<b>F</b>,<b>I</b>,<b>N</b>) on Glass (<b>A</b>–<b>C</b>,<b>G</b>–<b>I</b>) ) and TiO<sub>2</sub> (<b>D</b>–<b>F</b>,<b>L</b>–<b>N</b>) after 28 days in PM (<b>A</b>–<b>F</b>) and OM (<b>G</b>–<b>I</b>,<b>L</b>–<b>N</b>), respectively. Magnification: 20×; the scale bar shown represents 100 μm. Nuclei (blue) of samples were counterstained with Hoechst 33342.</p> Full article ">Figure 6
<p>Alkaline phosphatase (ALP) of hBMSC cells seeded onto Glass and TiO<sub>2</sub> and cultured in proliferative medium (<b>A</b>,<b>B</b>) or in osteogenic medium (<b>C</b>,<b>D</b>). (<b>A</b>–<b>D</b>) Immunolocalization of ALP following incubation with rabbit anti-human ALP primary antibody and detected with goat anti-rabbit secondary antibody (Alexa flour 488). Nuclei (in red) were counterstained with propidium iodide. (<b>E</b>) ALP activity determined calorimetrically, corrected for the protein content measured with the bicynchoninic acid (assay) (BCA) Protein Assay Kit and expressed as millimoles of <span class="html-italic">p</span>-nitrophenol produced per min per mg of protein. Bars express the mean values ± SEM of results from three experiments in two separated experiments (*: <span class="html-italic">p</span> &lt; 0.05; **: <span class="html-italic">p</span> &lt; 0.01).</p> Full article ">Figure 7
<p>Representative CLSM images at 20× magnification (the scale bar shown represents 100 μm) of calcium deposits from hBM-MSCs cells cultured onto Glass (<b>A</b>) or TiO<sub>2</sub> (<b>B</b>). (<b>C</b>) Mineralization of extracellular matrix produced by hBM-MSCs cells seeded onto Glass and TiO<sub>2</sub> as determined by quantification of calcium content. Results are expressed on a per-surfaces basis and are presented as an average ± standard deviation of three measurements in two separated experiments.</p> Full article ">
3980 KiB  
Article
Stress Waves and Characteristics of Zigzag and Armchair Silicene Nanoribbons
by Yu-Cheng Fan, Te-Hua Fang and Tao-Hsing Chen
Nanomaterials 2016, 6(7), 120; https://doi.org/10.3390/nano6070120 - 24 Jun 2016
Cited by 9 | Viewed by 5306
Abstract
The mechanical properties of silicene nanostructures subject to tensile loading were studied via a molecular dynamics (MD) simulation. The effects of temperature on Young’s modulus and the fracture strain of silicene with armchair and zigzag types were examined. The maximum in-plane stress and [...] Read more.
The mechanical properties of silicene nanostructures subject to tensile loading were studied via a molecular dynamics (MD) simulation. The effects of temperature on Young’s modulus and the fracture strain of silicene with armchair and zigzag types were examined. The maximum in-plane stress and the corresponding critical strain of the armchair and the zigzag silicene sheets at 300 K were 8.85 and 10.62, and 0.187 and 0.244 N/m, respectively. The in-plane stresses of the silicene sheet in the armchair direction at the temperatures of 300, 400, 500, and 600 K were 8.85, 8.50, 8.26, and 7.79 N/m, respectively. The in-plane stresses of the silicene sheet in the zigzag direction at the temperatures of 300, 400, 500, and 600 K were 10.62, 9.92, 9.64, and 9.27 N/m, respectively. The improved mechanical properties can be calculated in a silicene sheet yielded in the zigzag direction compared with the tensile loading in the armchair direction. The wrinklons and waves were observed at the shear band across the center zone of the silicene sheet. These results provide useful information about the mechanical and fracture behaviors of silicene for engineering applications. Full article
(This article belongs to the Special Issue Nanomaterials for Flexible and Stretchable Devices: Synthesis, Processes, and Applications)
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Figure 1
<p>Deformation of an armchair silicene sheet at different tensile strains of (<b>a</b>) 0.1; (<b>b</b>) 0.156; (<b>c</b>) 0.226; and (<b>d</b>) 0.3.</p> Full article ">Figure 2
<p>A deformation snapshot of a zigzag silicene sheet at different tensile strains of (<b>a</b>) 0.1; (<b>b</b>) 0.156; (<b>c</b>) 0.226; and (<b>d</b>) 0.3.</p> Full article ">Figure 3
<p>Stress–strain plot of the silicene sheet under uniaxial in (<b>a</b>) the armchair direction and (<b>b</b>) the zigzag direction at different temperatures.</p> Full article ">Figure 4
<p>The stress–strain curves in (<b>a</b>) the armchair and (<b>b</b>) the zigzag silicene under uniaxial tensile strain. The tensile velocity is 10 m/s at 300 K.</p> Full article ">Figure 5
<p>Snapshots of (<b>a</b>–<b>d</b>) the armchair and (<b>e</b>–<b>h</b>) the zigzag silicene sheets at uniaxial peak tensile loading at a temperature of 300 K.</p> Full article ">Figure 6
<p>The hole defect diameter is 2.0 nm in the armchair silicene. The colors show the potential energy distribution. The tensile test shows at the strain of (<b>a</b>) 0.172; (<b>b</b>) 0.184; (<b>c</b>) 0.208; and (<b>d</b>) 0.216 under a tensile velocity of 10 m/s.</p> Full article ">Figure 7
<p>The defect radius is 1.0 nm in zigzag silicene. The colors show the potential energy distribution. The tensile test shows strains of (<b>a</b>) 0.224, (<b>b</b>) 0.24, (<b>c</b>) 0.244, and (<b>d</b>) 0.252 in the velocity of 10 m/s.</p> Full article ">Figure 8
<p>In-plane stiffness using a linear fit of the stress–strain data from the tensile strains of 0.04–0.08.</p> Full article ">
145 KiB  
Editorial
Nanoparticles for Catalysis
by Sergio Navalón and H. García
Nanomaterials 2016, 6(7), 123; https://doi.org/10.3390/nano6070123 - 23 Jun 2016
Cited by 61 | Viewed by 5735
Abstract
Nanoscience emerged in the last decades of the 20th century with the general aim to determine those properties that appear when small particles of nanometric dimensions are prepared and stabilized.[...] Full article
(This article belongs to the Special Issue Nanoparticles for Catalysis)
143 KiB  
Editorial
Plasma Nanoengineering and Nanofabrication
by Krasimir Vasilev and Melanie Macgregor Ramiasa
Nanomaterials 2016, 6(7), 122; https://doi.org/10.3390/nano6070122 - 23 Jun 2016
Cited by 3 | Viewed by 4902
Abstract
With the recent advances in nanotechnology, plasma nanofabrication has become an exciting new niche because plasma-based approaches can deliver unique structures at the nanoscale that cannot be achieved by other techniques and/or in a more economical and environmentally friendly manner.[...] Full article
(This article belongs to the Special Issue Plasma Nanoengineering and Nanofabrication)
2095 KiB  
Article
A Fast Response Ammonia Sensor Based on Coaxial PPy–PAN Nanofiber Yarn
by Penghong Liu, Shaohua Wu, Yue Zhang, Hongnan Zhang and Xiaohong Qin
Nanomaterials 2016, 6(7), 121; https://doi.org/10.3390/nano6070121 - 23 Jun 2016
Cited by 37 | Viewed by 6379
Abstract
Highly orientated polypyrrole (PPy)–coated polyacrylonitrile (PAN) (PPy–PAN) nanofiber yarn was prepared with an electrospinning technique and in-situ chemical polymerization. The morphology and chemical structure of PPy–PAN nanofiber yarn was characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), transmission electron [...] Read more.
Highly orientated polypyrrole (PPy)–coated polyacrylonitrile (PAN) (PPy–PAN) nanofiber yarn was prepared with an electrospinning technique and in-situ chemical polymerization. The morphology and chemical structure of PPy–PAN nanofiber yarn was characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FTIR), which indicated that the PPy as the shell layer was homogeneously and uniformly polymerized on the surface of PAN nanofiber. The effects of different concentration of doping acid on the responses of PPy–PAN nanofiber yarn sensor were investigated. The electrical responses of the gas sensor based on the PPy–PAN nanofiber yarn to ammonia were investigated at room temperature. The nanoyarn sensor composed of uniaxially aligned PPy–PAN nanofibers with a one-dimensional structure exhibited a transient response, and the response time was less than 1 s. The excellent sensing properties mentioned above give rise to good potential application prospects in the field of ammonia sensor. Full article
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Full article ">Figure 1
<p>(<b>A</b>) Scanning electron microscopy (SEM) image of coaxial polypyrrole (PPy)-coated polyacrylonitrile (PAN) nanofiber yarn; (<b>B</b>) Field emission scanning electron microscopy (FESEM) image of aligned PPy–PAN nanofibers; (<b>C</b>) Transmission electron microscopy (TEM) image of PPy–PAN nanofiber.</p> Full article ">Figure 2
<p>Fourier transform infrared spectroscopy (FTIR) spectra of PAN and PPy–PAN coaxial nanofiber yarn.</p> Full article ">Figure 3
<p>(<b>A</b>) Response of PPy–PAN nanoyarn exposed to different ammonia concentrations; (<b>B</b>) The linear relationship between the sensitivity of the PPy–PAN nanoyarn and different ammonia concentrations. (The concentration of <span class="html-italic">p</span>-toluenesulfonic acid (<span class="html-italic">p</span>-TSA) was 0.004 M).</p> Full article ">Figure 4
<p>The sensitivity of the PPy–PAN nanoyarn exposed to an ammonia concentration of 2000 ppm during cycle tests. (The concentration of <span class="html-italic">p</span>-toluenesulfonic acid (<span class="html-italic">p</span>-TSA) was 0.004 M).</p> Full article ">Figure 5
<p>Sensitivity of the PPy–PAN nanoyarn with different <span class="html-italic">p</span>-TSA concentrations exposed to an ammonia concentration of 2000 ppm.</p> Full article ">Figure 6
<p>Selectivity of PPy–PAN nanofiber yarn sensor. Concentration of the gas is 500 ppm. (The concentration of <span class="html-italic">p</span>-toluenesulfonic acid (<span class="html-italic">p</span>-TSA) was 0.004 M).</p> Full article ">
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