The effects of the aspect ratio and the addition of multiwall carbon nanotubes (MWCNTs) on the mo... more The effects of the aspect ratio and the addition of multiwall carbon nanotubes (MWCNTs) on the morphological, electrical, mechanical and thermal properties of high-density polyethylene (HDPE)-based nanocomposites are investigated. The HDPE nanocomposites with various amounts up to 18.74 wt.% of MWCNTs that have two different aspect ratios (AR), (200–400(M58) and 500–3000(M12)) were prepared by a melt mixing method, followed by compression molding. The results demonstrate that the addition of MWCNTs enhances the electrical, mechanical and thermal properties of the HDPE/MWCNTs nanocomposites. The HDPE nanocomposites with higher aspect ratio MWCNTs demonstrated a slightly better enhancement in the morphological and electrical properties than the other ones with lower aspect ratio MWCNTs. Additionally, Young's modulus and the thermal stability increased with increasing aspect ratio of MWCNTs.
Springer Series on Polymer and Composite Materials, 2015
The commonly used food packaging polymers are polyolefins, such as low-density polyethylene (LDPE... more The commonly used food packaging polymers are polyolefins, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), isotactic polypropylene (PP), and some polyethylene-based copolymers.
The molecular dynamics of a triblock copolymer and of expanded graphite nanoplatelets were invest... more The molecular dynamics of a triblock copolymer and of expanded graphite nanoplatelets were investigated. Composites were prepared using the solution technique. The effects of filler addition and of filler-matrix interactions were investigated using dielectric relaxation spectroscopy (DRS) and dynamic mechanical analysis (DMA). Only one relaxation was observed by DRS, which was associated with the relaxation of the main polymer chain. Both DRS and DMA demonstrated that the addition of the filler does not cause a significant change in either the temperature of the relaxation or its activation energy, which suggests the presence of weak interactions between the filler and matrix. The storage modulus of the composites increased with increasing filler content. The composite containing 8% filler exhibited a storage modulus increase of approximately 394% in the rubber area. Using the DC electrical conductivity measurements, the electrical percolation threshold was determined to be approxim...
ABSTRACT Low-temperature plasma was used to improve the surface and adhesive properties of wood. ... more ABSTRACT Low-temperature plasma was used to improve the surface and adhesive properties of wood. The pretreatment of wood surfaces using radio-frequency (RF) discharge plasma is attractive for various wood applications, mainly because of the high efficiency and low production cost of the process. In addition, a significant increase in the polar component of the wood surface energy, which is associated with the presence of acidebase interactions (electron donoreacceptor bonds), after modification by RF discharge plasma was identified. The treatment of wood by RF plasma exhibited an aging effect, with the modified surface never recovering its initial hydrophobic state. Indeed, the enhancement of the wettability of wood is necessary for promoting better adhesion with water-based adhesives and coatings, which is currently the subject of ongoing study.
Carbon nanotube thin sheets – buckypapers – were prepared from multi-walled carbon nanotubes oxid... more Carbon nanotube thin sheets – buckypapers – were prepared from multi-walled carbon nanotubes oxidised with different oxidation agents. Prepared buckypapers were characterized by mechanical testing, surface conductivity and mercury porosimetry. It was found that their mechanical properties were increased by increasing the power of oxidation agents. Nitric acid-treated buckypapers showed the highest structural integrity and surface conductivity.
... Bratislava, Slovak Republic Title: Electrochemical Oxidation of Multi-Wall Carbon Nanotubes A... more ... Bratislava, Slovak Republic Title: Electrochemical Oxidation of Multi-Wall Carbon Nanotubes Authors: Giorgos Moraitis 1 , Zdeno pitalsk 2,+ , Fotini Ravani 2 ... [6] have successfully purified single wall CNT from amorphous carbon or catalysts (Fe, Ni, etc) in a 6M KOH solution and ...
ABSTRACT The preparation of Phase Change Materials (PCM) with improved thermal conductivity, base... more ABSTRACT The preparation of Phase Change Materials (PCM) with improved thermal conductivity, based on linear low-density polyethylene (LLDPE), paraffin wax with a melting point of approximately 42C and expanded graphite as well as the investigation of their physical behavior is reported in this paper. The absorption of heat energy is realized by phase transitions in the wax structure, i.e., solid–solid transitions between different crystalline structures of wax and, primarily, by a solid–liquid transition. An estimate of the total heat energy that can be reversibly absorbed or released by the designed materials was determined using Differential Scanning Calorimetry (DSC). The improvement in the thermal conductivity of the polymeric materials was obtained by incorporating expanded graphite into the blends. Expanded graphite has a reinforcing effect on the PCM, resulting in an increase in the toughness (Young's modulus) Significant amounts of wax are leached from the samples, and a higher wax content also results in more wax leakage. Graphite significantly reduces the wax loss from the samples.
International Journal of Biological Macromolecules
Fused deposition modelling (FDM) is a process of additive manufacturing allowing creating of high... more Fused deposition modelling (FDM) is a process of additive manufacturing allowing creating of highly precise complex three-dimensional objects for a large range of applications. The principle of FDM is an extrusion of the molten filament and gradual deposition of layers and their solidification. Potential applications in pharmaceutical and medical fields require the development of biodegradable and biocompatible thermoplastics for the processing of filaments. In this work, the potential of production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) filaments for FDM was investigated in respect to its thermal stability. Copolymer P(3HB-co-4HB) was biosynthesised by Cupriavidus malaysiensis. Rheological and mechanical properties of the copolymer were modified by the addition of plasticizers or blending with poly(lactic acid). Thermal stability of mixtures was studied employing thermogravimetric analysis and rheological analyses by monitoring the time-dependent changes in the complex viscosity of melt samples. The plasticization of P(3HB-co-4HB) slightly hindered its thermal degradation but the best stabilization effect was found in case of the copolymer blended with poly(lactic acid). Overall, rheological, thermal and mechanical properties demonstrated that the plasticized P(3HB-co-4HB) is a potential candidate of biodegradable polymer for FDM processes.
Abstract The incorporation of carbon nanotubes (CNTs) into a polymer matrix can significantly imp... more Abstract The incorporation of carbon nanotubes (CNTs) into a polymer matrix can significantly improve its mechanical and electrical properties. In the case of the aligned CNTs in a polymer matrix, the mechanical properties along the alignment direction are significantly enhanced comparing to the perpendicular direction. Hence, the CNT alignment is a crucial step in the fabrication of a CNT-reinforced nanocomposite. The aligned growth of the CNTs or a post-incorporation CNT alignment are two options mainly used. In our work, we present a facile and scalable preparation method for the polyamide nanocomposite film containing a self-assembled layer of the aligned CNTs. The nanocomposite was prepared by spraying the polyamide solution onto a Langmuir film of the aligned CNTs. The nanocomposite films were characterized by the tensile strength measurements, Raman spectroscopy and broadband dielectric spectroscopy. The measured tensile strength along the CNT alignment was up to 12× higher than that in the perpendicular direction and the electrical conductivity increased from 10−15 S/cm to 10-7 S/cm. Our results show that even a rather simple method can provide a substantial enhancement of mechanical and electrical properties of a polymer by incorporation of CNTs.
This paper reports a simple route for the preparation of graphene/poly(styrene-b-butadiene-b-styr... more This paper reports a simple route for the preparation of graphene/poly(styrene-b-butadiene-b-styrene) (SBS) nanocomposite films employing a vacuum filtration method. Graphene is exfoliated well by an electrochemical procedure and homogeneously dispersed in the polymer matrix. The prepared nanocomposite films were characterized by XRD, Fourier transform IR (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, AFM and SEM. Morphological studies showed that graphene formed a smooth coating over the surface of SBS. The increase in graphene concentration induces the wrinkling of graphene sheets at the composite surface which causes a further increase in surface roughness. The FTIR, Raman and XPS spectra of graphene/SBS nanocomposite films indicate the strong interactions between graphene and the polymer matrix. According to the XRD patterns, introducing SBS into graphene did not modify the graphene structure additionally, i.e. the crystal lattice parameters do ...
High-density polyethylene (HDPE)-based nanocomposites incorporating three different types of grap... more High-density polyethylene (HDPE)-based nanocomposites incorporating three different types of graphene nanoplatelets (GnPs) were fabricated to investigate the size effects of GnPs in terms of both lateral size and thickness on the morphological, thermal, electrical, and mechanical properties. The results show that the inclusion of GnPs enhance the thermal, electrical, and mechanical properties of HDPE-based nanocomposites regardless of GnP size. Nevertheless, the most significant enhancement of the thermal and electrical conductivities and the lowest electrical percolation threshold were achieved with GnPs of a larger lateral size. This could have been attributed to the fact that the GnPs of larger lateral size exhibited a better dispersion in HDPE and formed conductive pathways easily observable in scanning electron microscope (SEM) images. Our results show that the lateral size of GnPs was a more regulating factor for the above-mentioned nanocomposite properties compared to their t...
Abstract In this work, laboratory prepared PANI and it’s composite with carbon nanotubes (PANI/CN... more Abstract In this work, laboratory prepared PANI and it’s composite with carbon nanotubes (PANI/CNTs) were used for the fabrication of micropatterns on flexible polyethylene terephthalate (PET) substrate using the drop cast method and plasma technology. Plasma technology was employed as an adhesion promoter between the PET substrate and PANI layers, as was confirmed by the peel tests. The PANI and PANI-CNTs deposited layers on PET were thoroughly characterized in terms of the surface, as well as the structural morphology, by various microscopic and scanning probe techniques. Moreover, the electrical conductivity of the deposited layers was confirmed by broadband dielectric spectroscopy (BDS) and conductive atomic force microscopy (ORCA-AFM). The presence of CNTs in the PANI/CNTs composite was responsible for the more uniform and compact deposited layers and better electrical conductivity. The laboratory prepared PANI/CNTs samples excelled in terms of their stable conductivity in the whole frequency range.
The electrically conductive, transparent, and flexible self-standing thin nanocomposite films bas... more The electrically conductive, transparent, and flexible self-standing thin nanocomposite films based on copolyamide matrix (coPA:Vestamelt X1010) modified with 2D Ti3C2Tx (MXene) nanosheets were prepared by casting and their electrical, mechanical and optical properties and then, were investigated. The percolation threshold of the MXene filler within the coPA matrix was found to be 0.05 vol. %, and the highest determined electrical conductivity was 1.4 × 10−2 S·cm−1 for the composite filled with 5 wt. % (1.8 vol. %) of MXene. The electrical conductivity of the as-prepared MXene was 9.1 S·cm–1, and the electrical conductivity of the MAX phase (the precursor for MXene preparation) was 172 S·cm–1. The transparency of the prepared composite films exceeded 75%, even for samples containing 5 wt. % of MXene, as confirmed by UV spectroscopy. The dynamic mechanical analysis confirmed the improved mechanical properties, such as the storage modulus, which improved with the increasing MXene cont...
Inimitable properties of carbon quantum dots as well as a cheap production contribute to their po... more Inimitable properties of carbon quantum dots as well as a cheap production contribute to their possible application in biomedicine especially as antibacterial and antibiofouling coatings. Fluorescent hydrophobic carbon quantum dots are synthesized by bottom-up condensation method and used for deposition of uniform and homogeneous Langmuir–Blodgett thin films on different substrates. It is found that this kind of quantum dots generates singlet oxygen under blue light irradiation. Antibacterial and antibiofouling testing on four different bacteria strains (Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Pseudomonas aeruginosa) reveals enhanced antibacterial and antibiofouling activity of hydrophobic carbon dots thin films under blue light irradiation. Moreover, hydrophobic quantum dots show noncytotoxic effect on mouse fibroblast cell line. These properties enable potential usage of hydrophobic carbon quantum dots thin films as excellent antibacterial and antibiofouling coatings for different ...
We investigated the therapeutic capacity of nano-sized graphene sheets, called graphene quantum d... more We investigated the therapeutic capacity of nano-sized graphene sheets, called graphene quantum dots (GQD), in experimental autoimmune encephalomyelitis (EAE), an animal model of immune-mediated central nervous system (CNS) damage. Intraperitoneally administered GQD (10 mg/kg/day) accumulated in the lymph node and CNS cells of Dark Agouti rats in which EAE was induced by immunization with spinal cord homogenate in complete Freund's adjuvant. GQD significantly reduced clinical signs of EAE when applied throughout the course of the disease (day 0-32), while the protection was less pronounced if the treatment was limited to the induction (day 0-7 post-immunization) or effector (from day 8 onwards) phase of the disease. GQD treatment diminished immune infiltration, demyelination, axonal damage, and apoptotic death in the CNS of EAE animals. GQD also reduced the numbers of interferon (IFN)-γ-expressing T helper (Th)1 cells, as well as the expression of Th1 transcription factor T-bet and proinflammatory cytokines tumor necrosis factor, interleukin-1, and granulocyte-macrophage colony-stimulating factor in the lymph nodes and CNS immune infitrates. The protective effect of GQD in EAE was associated with the activation of p38 and p42/44 mitogen-activated protein kinases (MAPK) and Akt in the lymph nodes and/or CNS. Finally, GQD protected oligodendrocytes and neurons from T cell-mediated damage in the in vitro conditions. Collectively, these data demonstrate the ability of GQD to gain access to both immune and CNS cells during neuroinflammation, and to alleviate immune-mediated CNS damage by modulating MAPK/Akt signaling and encephalitogenic Th1 immune response.
The effects of the aspect ratio and the addition of multiwall carbon nanotubes (MWCNTs) on the mo... more The effects of the aspect ratio and the addition of multiwall carbon nanotubes (MWCNTs) on the morphological, electrical, mechanical and thermal properties of high-density polyethylene (HDPE)-based nanocomposites are investigated. The HDPE nanocomposites with various amounts up to 18.74 wt.% of MWCNTs that have two different aspect ratios (AR), (200–400(M58) and 500–3000(M12)) were prepared by a melt mixing method, followed by compression molding. The results demonstrate that the addition of MWCNTs enhances the electrical, mechanical and thermal properties of the HDPE/MWCNTs nanocomposites. The HDPE nanocomposites with higher aspect ratio MWCNTs demonstrated a slightly better enhancement in the morphological and electrical properties than the other ones with lower aspect ratio MWCNTs. Additionally, Young's modulus and the thermal stability increased with increasing aspect ratio of MWCNTs.
Springer Series on Polymer and Composite Materials, 2015
The commonly used food packaging polymers are polyolefins, such as low-density polyethylene (LDPE... more The commonly used food packaging polymers are polyolefins, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), isotactic polypropylene (PP), and some polyethylene-based copolymers.
The molecular dynamics of a triblock copolymer and of expanded graphite nanoplatelets were invest... more The molecular dynamics of a triblock copolymer and of expanded graphite nanoplatelets were investigated. Composites were prepared using the solution technique. The effects of filler addition and of filler-matrix interactions were investigated using dielectric relaxation spectroscopy (DRS) and dynamic mechanical analysis (DMA). Only one relaxation was observed by DRS, which was associated with the relaxation of the main polymer chain. Both DRS and DMA demonstrated that the addition of the filler does not cause a significant change in either the temperature of the relaxation or its activation energy, which suggests the presence of weak interactions between the filler and matrix. The storage modulus of the composites increased with increasing filler content. The composite containing 8% filler exhibited a storage modulus increase of approximately 394% in the rubber area. Using the DC electrical conductivity measurements, the electrical percolation threshold was determined to be approxim...
ABSTRACT Low-temperature plasma was used to improve the surface and adhesive properties of wood. ... more ABSTRACT Low-temperature plasma was used to improve the surface and adhesive properties of wood. The pretreatment of wood surfaces using radio-frequency (RF) discharge plasma is attractive for various wood applications, mainly because of the high efficiency and low production cost of the process. In addition, a significant increase in the polar component of the wood surface energy, which is associated with the presence of acidebase interactions (electron donoreacceptor bonds), after modification by RF discharge plasma was identified. The treatment of wood by RF plasma exhibited an aging effect, with the modified surface never recovering its initial hydrophobic state. Indeed, the enhancement of the wettability of wood is necessary for promoting better adhesion with water-based adhesives and coatings, which is currently the subject of ongoing study.
Carbon nanotube thin sheets – buckypapers – were prepared from multi-walled carbon nanotubes oxid... more Carbon nanotube thin sheets – buckypapers – were prepared from multi-walled carbon nanotubes oxidised with different oxidation agents. Prepared buckypapers were characterized by mechanical testing, surface conductivity and mercury porosimetry. It was found that their mechanical properties were increased by increasing the power of oxidation agents. Nitric acid-treated buckypapers showed the highest structural integrity and surface conductivity.
... Bratislava, Slovak Republic Title: Electrochemical Oxidation of Multi-Wall Carbon Nanotubes A... more ... Bratislava, Slovak Republic Title: Electrochemical Oxidation of Multi-Wall Carbon Nanotubes Authors: Giorgos Moraitis 1 , Zdeno pitalsk 2,+ , Fotini Ravani 2 ... [6] have successfully purified single wall CNT from amorphous carbon or catalysts (Fe, Ni, etc) in a 6M KOH solution and ...
ABSTRACT The preparation of Phase Change Materials (PCM) with improved thermal conductivity, base... more ABSTRACT The preparation of Phase Change Materials (PCM) with improved thermal conductivity, based on linear low-density polyethylene (LLDPE), paraffin wax with a melting point of approximately 42C and expanded graphite as well as the investigation of their physical behavior is reported in this paper. The absorption of heat energy is realized by phase transitions in the wax structure, i.e., solid–solid transitions between different crystalline structures of wax and, primarily, by a solid–liquid transition. An estimate of the total heat energy that can be reversibly absorbed or released by the designed materials was determined using Differential Scanning Calorimetry (DSC). The improvement in the thermal conductivity of the polymeric materials was obtained by incorporating expanded graphite into the blends. Expanded graphite has a reinforcing effect on the PCM, resulting in an increase in the toughness (Young's modulus) Significant amounts of wax are leached from the samples, and a higher wax content also results in more wax leakage. Graphite significantly reduces the wax loss from the samples.
International Journal of Biological Macromolecules
Fused deposition modelling (FDM) is a process of additive manufacturing allowing creating of high... more Fused deposition modelling (FDM) is a process of additive manufacturing allowing creating of highly precise complex three-dimensional objects for a large range of applications. The principle of FDM is an extrusion of the molten filament and gradual deposition of layers and their solidification. Potential applications in pharmaceutical and medical fields require the development of biodegradable and biocompatible thermoplastics for the processing of filaments. In this work, the potential of production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) filaments for FDM was investigated in respect to its thermal stability. Copolymer P(3HB-co-4HB) was biosynthesised by Cupriavidus malaysiensis. Rheological and mechanical properties of the copolymer were modified by the addition of plasticizers or blending with poly(lactic acid). Thermal stability of mixtures was studied employing thermogravimetric analysis and rheological analyses by monitoring the time-dependent changes in the complex viscosity of melt samples. The plasticization of P(3HB-co-4HB) slightly hindered its thermal degradation but the best stabilization effect was found in case of the copolymer blended with poly(lactic acid). Overall, rheological, thermal and mechanical properties demonstrated that the plasticized P(3HB-co-4HB) is a potential candidate of biodegradable polymer for FDM processes.
Abstract The incorporation of carbon nanotubes (CNTs) into a polymer matrix can significantly imp... more Abstract The incorporation of carbon nanotubes (CNTs) into a polymer matrix can significantly improve its mechanical and electrical properties. In the case of the aligned CNTs in a polymer matrix, the mechanical properties along the alignment direction are significantly enhanced comparing to the perpendicular direction. Hence, the CNT alignment is a crucial step in the fabrication of a CNT-reinforced nanocomposite. The aligned growth of the CNTs or a post-incorporation CNT alignment are two options mainly used. In our work, we present a facile and scalable preparation method for the polyamide nanocomposite film containing a self-assembled layer of the aligned CNTs. The nanocomposite was prepared by spraying the polyamide solution onto a Langmuir film of the aligned CNTs. The nanocomposite films were characterized by the tensile strength measurements, Raman spectroscopy and broadband dielectric spectroscopy. The measured tensile strength along the CNT alignment was up to 12× higher than that in the perpendicular direction and the electrical conductivity increased from 10−15 S/cm to 10-7 S/cm. Our results show that even a rather simple method can provide a substantial enhancement of mechanical and electrical properties of a polymer by incorporation of CNTs.
This paper reports a simple route for the preparation of graphene/poly(styrene-b-butadiene-b-styr... more This paper reports a simple route for the preparation of graphene/poly(styrene-b-butadiene-b-styrene) (SBS) nanocomposite films employing a vacuum filtration method. Graphene is exfoliated well by an electrochemical procedure and homogeneously dispersed in the polymer matrix. The prepared nanocomposite films were characterized by XRD, Fourier transform IR (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, AFM and SEM. Morphological studies showed that graphene formed a smooth coating over the surface of SBS. The increase in graphene concentration induces the wrinkling of graphene sheets at the composite surface which causes a further increase in surface roughness. The FTIR, Raman and XPS spectra of graphene/SBS nanocomposite films indicate the strong interactions between graphene and the polymer matrix. According to the XRD patterns, introducing SBS into graphene did not modify the graphene structure additionally, i.e. the crystal lattice parameters do ...
High-density polyethylene (HDPE)-based nanocomposites incorporating three different types of grap... more High-density polyethylene (HDPE)-based nanocomposites incorporating three different types of graphene nanoplatelets (GnPs) were fabricated to investigate the size effects of GnPs in terms of both lateral size and thickness on the morphological, thermal, electrical, and mechanical properties. The results show that the inclusion of GnPs enhance the thermal, electrical, and mechanical properties of HDPE-based nanocomposites regardless of GnP size. Nevertheless, the most significant enhancement of the thermal and electrical conductivities and the lowest electrical percolation threshold were achieved with GnPs of a larger lateral size. This could have been attributed to the fact that the GnPs of larger lateral size exhibited a better dispersion in HDPE and formed conductive pathways easily observable in scanning electron microscope (SEM) images. Our results show that the lateral size of GnPs was a more regulating factor for the above-mentioned nanocomposite properties compared to their t...
Abstract In this work, laboratory prepared PANI and it’s composite with carbon nanotubes (PANI/CN... more Abstract In this work, laboratory prepared PANI and it’s composite with carbon nanotubes (PANI/CNTs) were used for the fabrication of micropatterns on flexible polyethylene terephthalate (PET) substrate using the drop cast method and plasma technology. Plasma technology was employed as an adhesion promoter between the PET substrate and PANI layers, as was confirmed by the peel tests. The PANI and PANI-CNTs deposited layers on PET were thoroughly characterized in terms of the surface, as well as the structural morphology, by various microscopic and scanning probe techniques. Moreover, the electrical conductivity of the deposited layers was confirmed by broadband dielectric spectroscopy (BDS) and conductive atomic force microscopy (ORCA-AFM). The presence of CNTs in the PANI/CNTs composite was responsible for the more uniform and compact deposited layers and better electrical conductivity. The laboratory prepared PANI/CNTs samples excelled in terms of their stable conductivity in the whole frequency range.
The electrically conductive, transparent, and flexible self-standing thin nanocomposite films bas... more The electrically conductive, transparent, and flexible self-standing thin nanocomposite films based on copolyamide matrix (coPA:Vestamelt X1010) modified with 2D Ti3C2Tx (MXene) nanosheets were prepared by casting and their electrical, mechanical and optical properties and then, were investigated. The percolation threshold of the MXene filler within the coPA matrix was found to be 0.05 vol. %, and the highest determined electrical conductivity was 1.4 × 10−2 S·cm−1 for the composite filled with 5 wt. % (1.8 vol. %) of MXene. The electrical conductivity of the as-prepared MXene was 9.1 S·cm–1, and the electrical conductivity of the MAX phase (the precursor for MXene preparation) was 172 S·cm–1. The transparency of the prepared composite films exceeded 75%, even for samples containing 5 wt. % of MXene, as confirmed by UV spectroscopy. The dynamic mechanical analysis confirmed the improved mechanical properties, such as the storage modulus, which improved with the increasing MXene cont...
Inimitable properties of carbon quantum dots as well as a cheap production contribute to their po... more Inimitable properties of carbon quantum dots as well as a cheap production contribute to their possible application in biomedicine especially as antibacterial and antibiofouling coatings. Fluorescent hydrophobic carbon quantum dots are synthesized by bottom-up condensation method and used for deposition of uniform and homogeneous Langmuir–Blodgett thin films on different substrates. It is found that this kind of quantum dots generates singlet oxygen under blue light irradiation. Antibacterial and antibiofouling testing on four different bacteria strains (Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Pseudomonas aeruginosa) reveals enhanced antibacterial and antibiofouling activity of hydrophobic carbon dots thin films under blue light irradiation. Moreover, hydrophobic quantum dots show noncytotoxic effect on mouse fibroblast cell line. These properties enable potential usage of hydrophobic carbon quantum dots thin films as excellent antibacterial and antibiofouling coatings for different ...
We investigated the therapeutic capacity of nano-sized graphene sheets, called graphene quantum d... more We investigated the therapeutic capacity of nano-sized graphene sheets, called graphene quantum dots (GQD), in experimental autoimmune encephalomyelitis (EAE), an animal model of immune-mediated central nervous system (CNS) damage. Intraperitoneally administered GQD (10 mg/kg/day) accumulated in the lymph node and CNS cells of Dark Agouti rats in which EAE was induced by immunization with spinal cord homogenate in complete Freund's adjuvant. GQD significantly reduced clinical signs of EAE when applied throughout the course of the disease (day 0-32), while the protection was less pronounced if the treatment was limited to the induction (day 0-7 post-immunization) or effector (from day 8 onwards) phase of the disease. GQD treatment diminished immune infiltration, demyelination, axonal damage, and apoptotic death in the CNS of EAE animals. GQD also reduced the numbers of interferon (IFN)-γ-expressing T helper (Th)1 cells, as well as the expression of Th1 transcription factor T-bet and proinflammatory cytokines tumor necrosis factor, interleukin-1, and granulocyte-macrophage colony-stimulating factor in the lymph nodes and CNS immune infitrates. The protective effect of GQD in EAE was associated with the activation of p38 and p42/44 mitogen-activated protein kinases (MAPK) and Akt in the lymph nodes and/or CNS. Finally, GQD protected oligodendrocytes and neurons from T cell-mediated damage in the in vitro conditions. Collectively, these data demonstrate the ability of GQD to gain access to both immune and CNS cells during neuroinflammation, and to alleviate immune-mediated CNS damage by modulating MAPK/Akt signaling and encephalitogenic Th1 immune response.
The trend in food packaging technology consists from research and development of new material tha... more The trend in food packaging technology consists from research and development of new material that exhibits significantly improved barrier properties against gases and vapors. Low-permeable materials can decrease the total amount of packaging materials required, as they are made of thin or lightweight materials with high-barrier properties. A significant trend in food packaging technology today is convenience, especially with regard to manufacturing, distribution, transportation, sales, marketing, consumption, and waste disposal. Another important trend is safety as it relates to public health and security against bioterrorism. The Foodborne illnesses and the malicious alteration of foods must be eliminated from the food chain. The food safety will become a major active food packaging application. Food packaging technologies are linked also to consumer studies. Consumers tend to seek out new materials with new functions, and new food packaging systems reflect current food processing technologies, lifestyle changes, and scientific research.
In all fields of food science, there is an increasing interest in utilizing nanostructures for im... more In all fields of food science, there is an increasing interest in utilizing nanostructures for improving the performance of food products and processes. Many structures in foods are within 100 nm size range, and because of their unique physical properties, take a significant task in the delivery of nutrients or more in general, show enhanced bioactivity. By manufacturing foods using particular processing or environmental conditions, it is possible to obtain nanostructures. The small size affects their functional properties, when compared to structures with similar composition, but larger in size. In foods, these structures are usually dispersed in solution, and they are not biologically persistent, i.e., they are digested and hydrolyzed, and they do not accumulate in organs or in the environment. Because of their physical properties and especially their enhanced surface area, these structures tend to be more efficacious in encapsulating bioactive and improving texture and structures or more in general show some improved processing and nutritional functionality. The low-temperature discharge plasma treatment of polymers is used for surface sterilization of food packaging foils. The bulk and mass transport properties of discharge plasma-treated films must be explored and quantified. These properties are important for packages, and they are suitable for both respiring and non-respiring foods and also for safety product assessment. The use of discharge plasma to aid in the deposition of biologically actives and antimicrobials can help expand the emerging field of edible films and active food packaging. Future studies should focus on study of antimicrobial efficiency after their immobilization on low-temperature plasma-grafted polyolefin surfaces. The use of natural antimicrobial agents is a very promising alternative because of their appeal as natural The food security is a big issue in the world, and antimicrobial packaging could play a role in food security assurance, comprehensively agreed with industrial sectors, farmers, producers, wholesalers, retailers, governments, and consumers. A following trend in food packaging technology consists from research and development of new material that exhibits significantly improved barrier properties against gases and vapors. Low-permeable materials can decrease the total amount of packaging materials required, as they are made of thin or lightweight materials with high-barrier properties. A significant trend in food packaging technology today is convenience, especially with regard to manufacturing, distribution, transportation, sales, marketing, consumption, and waste disposal. Another important trend is safety as it relates to public health and security against bioterrorism. The Foodborne illnesses and the malicious alteration of foods must be eliminated from the food chain. The food safety will become a major active food packaging application. Food packaging technologies are linked also to consumer studies. Consumers tend to seek out new materials with new functions, and new food packaging systems reflect current food processing technologies, lifestyle changes, and scientific research.
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sales, marketing, consumption, and waste disposal. Another important trend is safety as it relates to public health and security against bioterrorism. The Foodborne
illnesses and the malicious alteration of foods must be eliminated from the food chain. The food safety will become a major active food packaging application. Food packaging technologies are linked also to consumer studies. Consumers tend to seek out new materials with new functions, and new food packaging systems reflect current food processing technologies, lifestyle changes, and scientific research.
foods are within 100 nm size range, and because of their unique physical properties, take a significant task in the delivery of nutrients or more in general, show enhanced
bioactivity. By manufacturing foods using particular processing or environmental conditions, it is possible to obtain nanostructures. The small size affects their
functional properties, when compared to structures with similar composition, but larger in size. In foods, these structures are usually dispersed in solution, and they
are not biologically persistent, i.e., they are digested and hydrolyzed, and they do not accumulate in organs or in the environment. Because of their physical properties
and especially their enhanced surface area, these structures tend to be more efficacious in encapsulating bioactive and improving texture and structures or more in
general show some improved processing and nutritional functionality. The low-temperature discharge plasma treatment of polymers is used for surface sterilization
of food packaging foils. The bulk and mass transport properties of discharge plasma-treated films must be explored and quantified. These properties are
important for packages, and they are suitable for both respiring and non-respiring foods and also for safety product assessment. The use of discharge plasma to aid in the deposition of biologically actives and antimicrobials can help expand the emerging field of edible films and active food packaging. Future studies should focus on study of antimicrobial efficiency after their immobilization on low-temperature plasma-grafted polyolefin surfaces. The use of natural antimicrobial
agents is a very promising alternative because of their appeal as natural The food security is a big issue in the world, and antimicrobial packaging could play a role in
food security assurance, comprehensively agreed with industrial sectors, farmers, producers, wholesalers, retailers, governments, and consumers. A following trend in food packaging technology consists from research and
development of new material that exhibits significantly improved barrier properties against gases and vapors. Low-permeable materials can decrease the total amount
of packaging materials required, as they are made of thin or lightweight materials with high-barrier properties. A significant trend in food packaging technology today
is convenience, especially with regard to manufacturing, distribution, transportation, sales, marketing, consumption, and waste disposal. Another important trend is safety as it relates to public health and security against bioterrorism. The Foodborne illnesses and the malicious alteration of foods must be eliminated from the food chain. The food safety will become a major active food packaging application. Food packaging technologies are linked also to consumer studies. Consumers tend to seek out new materials with new functions, and new food packaging systems reflect
current food processing technologies, lifestyle changes, and scientific research.