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Biosensors
Volume 10
Issue 7
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Biosensors, Volume 10, Issue 7 (July 2020) – 7 articles

Cover Story (view full-size image): Plasmonic fiber-optic biosensors combine the flexibility and compactness of optical fibers and high sensitivity of plasmonic nanomaterials to their surrounding medium, to detect biological species such as cells, proteins, and DNA. By tracking the variations in light absorption or energy loss maxima, one can detect an unknown analyte molecule bound to the surface of plasmonic nanoparticles or detect an unknown liquid analyte that is in direct contact with a plasmonic nanofilm. Due to their small size, accuracy, low-cost, and possibility of remote sensing, plasmonic fiber-optic biosensors are promising alternatives to traditional methods for biomolecule detection and can result in significant advances in clinical diagnostics, drug discovery, food process control, disease, and environmental monitoring. View this paper.
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28 pages, 3201 KiB  
Review
Skin-Integrated Wearable Systems and Implantable Biosensors: A Comprehensive Review
by Daniela Rodrigues, Ana I. Barbosa, Rita Rebelo, Il Keun Kwon, Rui L. Reis and Vitor M. Correlo
Biosensors 2020, 10(7), 79; https://doi.org/10.3390/bios10070079 - 21 Jul 2020
Cited by 102 | Viewed by 15290
Abstract
Biosensors devices have attracted the attention of many researchers across the world. They have the capability to solve a large number of analytical problems and challenges. They are future ubiquitous devices for disease diagnosis, monitoring, treatment and health management. This review presents an [...] Read more.
Biosensors devices have attracted the attention of many researchers across the world. They have the capability to solve a large number of analytical problems and challenges. They are future ubiquitous devices for disease diagnosis, monitoring, treatment and health management. This review presents an overview of the biosensors field, highlighting the current research and development of bio-integrated and implanted biosensors. These devices are micro- and nano-fabricated, according to numerous techniques that are adapted in order to offer a suitable mechanical match of the biosensor to the surrounding tissue, and therefore decrease the body’s biological response. For this, most of the skin-integrated and implanted biosensors use a polymer layer as a versatile and flexible structural support, combined with a functional/active material, to generate, transmit and process the obtained signal. A few challenging issues of implantable biosensor devices, as well as strategies to overcome them, are also discussed in this review, including biological response, power supply, and data communication. Full article
(This article belongs to the Section Nano- and Micro-Technologies in Biosensors)
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<p>Biosensor classifications system.</p> Full article ">Figure 2
<p>Skin-integrated biosensor technologies. (<b>a</b>) Carbon nanotube-based pressure sensor for flexible electronics. (i) Photograph of vertically aligned carbon nanotubes (VACNTs) on a Si substrate; (ii) SEM images of VACNTs. The inset shows a high-magnification image highlighting the CNT alignment. (iii) Electrical resistance versus pressure for a VACNT block [<a href="#B37-biosensors-10-00079" class="html-bibr">37</a>]. (<b>b</b>) A soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat. (i) Optical image of a fabricated device mounted on the forearm. (ii) FEA results of stress distribution associated with devices on phantom skin (PDMS) and respective optical images under various mechanical distortions: stretching at 30% strain, bending with 5 cm radius, and twisting [<a href="#B40-biosensors-10-00079" class="html-bibr">40</a>]. (<b>c</b>) Electrochemical Tattoo for Real-Time Lactate Monitoring in Human Perspiration: monitoring of sweat lactate during 33 min of cycling exercise while changing the work intensity. (i) Exercise resistance profile on a stationary cycle. Subjects were asked to maintain a constant cycling rate, while the resistance was increased every 3 min for a total evaluation of 30 min. A 3-min cool down period followed the exercise. (ii) An “NE” lactate biosensor applied to a male volunteer’s deltoid; (iii and iv) Response of the LOx- (<b>a</b>) and enzyme-free (<b>b</b>) tattoo biosensors during the exercise regimen (shown in part i) using two representative subjects. Constant potential, +0.05 V (vs. Ag/AgCl); measurement intervals, 1 s [<a href="#B52-biosensors-10-00079" class="html-bibr">52</a>]. (<b>d</b>) Tattoo-based potentiometric ion-selective sensors for epidermal pH monitoring. (<b>e</b>) Influence of repeated mechanical strain (stretching) upon the response of the tattoo ISE: (i) pH-responsive behavior of the ISE tattoo sensor prior to stretching (black) and following the 40th (red) stretch on GORE-TEX; one-unit pH decrement per addition. (ii) Images of the tattoo applied to the forearm at normal, during stretching, and after the 10th stretch [<a href="#B54-biosensors-10-00079" class="html-bibr">54</a>]. (<b>f</b>). Raman spectroscopy system, actual probe setup with a subject, and glucose profile during experiment. (i) Schematic diagram of Raman spectroscopy system for in vivo animal (swine) skin measurement. (ii) Photograph of Raman probe setup. (iii) Glucose profile during the glucose clamping experiment [<a href="#B44-biosensors-10-00079" class="html-bibr">44</a>].</p> Full article ">Figure 3
<p>Strategies for reducing foreign body response (FBR) in implantable biosensors. (<b>a</b>) Dexamethasone-releasing polyurethane coatings for glucose sensors. Micro-CT images of porous coatings created via the salt-leaching/gas-foaming technique with decreasing porogen fraction. The images show coatings of different morphologies created by varying the ammonium bicarbonate porogen concentration. (i) (ii) 90%, (iii) 60% and (iv) 30% [<a href="#B79-biosensors-10-00079" class="html-bibr">79</a>]. (<b>b</b>) In vitro release profiles of poly(lactic-co-glycolic) acid (PLGA) microspheres and PLGA microsphere/PVA hydrogel composite coatings (<span class="html-italic">n</span> = 3 ± SD) at 37 °C, phosphate buffer solution in Polymeric “smart” coating for glucose sensors [<a href="#B82-biosensors-10-00079" class="html-bibr">82</a>].</p> Full article ">Figure 4
<p>In vivo continuous glucose monitoring in mice using the implanted fibers. (<b>a</b>) Schematic illustration of the fluorescent hydrogel fiber designed for long-term in vivo glucose monitoring. (<b>b</b>) The fluorescent polyacrylamide (PAM) hydrogel fibers with and without polyethylene glycol (PEG) were implanted in mouse ears and remained in the mouse ears for one month. The fluorescence intensity of the fiber with PEG was observable through the ear skin for the entire month, whereas the fluorescence intensity of the fiber without PEG was barely detectable after one month. (<b>c</b>) Continuous glucose monitoring using implanted fibers and fluorescence intensity after implantation and after 140 days [<a href="#B86-biosensors-10-00079" class="html-bibr">86</a>].</p> Full article ">Figure 5
<p>In vivo investigation of the developed non-enzymatic continuous glucose monitoring system. (<b>a</b>) Photograph of the developed non-enzymatic continuous glucose monitoring (CGM) and MiniMed CGM as a reference, which were implanted on a rabbit. (<b>b</b>) ISF glucose values measured using the MiniMed CGM (black line with square) and the developed non-enzymatic CGM (red line with circle) in animal experiment [<a href="#B87-biosensors-10-00079" class="html-bibr">87</a>].</p> Full article ">Figure 6
<p>Power supply strategies for implantable biosensors. (<b>a</b>) Sensor implantation: (i) cuff electrodes wrapped around the tibial and peroneal nerves and (ii) implantable device inserted under the back skin of a rabbit [<a href="#B107-biosensors-10-00079" class="html-bibr">107</a>]; (<b>b</b>) Deep brain stimulation (DBS) applications using the flexible indium modified crystalline Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIMNT) energy harvester and characteristics of the flexible PIMNT film (i) a schematic illustration of DBS applications using the flexible PIMNT thin film energy harvester and (ii) a photograph of the final flexible PIMNT harvesting device completely bent by human fingers [<a href="#B109-biosensors-10-00079" class="html-bibr">109</a>].</p> Full article ">Figure 7
<p>Data transmission strategies for implantable biosensors. (<b>a</b>) The implantable sensor small size is achieved by the use of wireless power transfer provided by an external coil and the flexible substrate. The device transmits data via a low energy Bluetooth link to a receiving device; (<b>b</b>) Photos of the implantable neural interface: (i) the neural interface being flexed by a hand, (ii) the top side of the neural interface, (iii) the bottom side of the neural interface [<a href="#B131-biosensors-10-00079" class="html-bibr">131</a>] and (<b>c</b>) illustration of the heart valve monitoring system, which communicates the data by wireless [<a href="#B132-biosensors-10-00079" class="html-bibr">132</a>].</p> Full article ">Figure 8
<p>Fabrication techniques of implantable biosensors. (<b>a</b>) Structure of the polyamide foil with Cu tracks, mounted sensor and encapsulation in Implantable accelerometer system for the determination of blood pressure [<a href="#B135-biosensors-10-00079" class="html-bibr">135</a>]. (<b>b</b>) Schematic illustrations and images of steps for fabricating active, conformal electronics for cardiac electrophysiology. (i) Schematic illustration (left) and optical micrograph (right) of a collection of doped silicon nanomembranes in a unit cell. (ii) Configuration after fabrication of the source, drain, and gate contacts, with suitable interconnects and row electrodes for multiplexed addressing. (iii) Configuration after fabrication of the second metal layer, including the column output electrodes. (iv) Final layout after deposition of encapsulation layers and fabrication of the tissue-contacting electrode [<a href="#B136-biosensors-10-00079" class="html-bibr">136</a>].</p> Full article ">
9 pages, 2100 KiB  
Article
Electrochemical DNA Sensor for Sensitive BRCA1 Detection Based on DNA Tetrahedral-Structured Probe and Poly-Adenine Mediated Gold Nanoparticles
by Dezhi Feng, Jing Su, Guifang He, Yi Xu, Chenguang Wang, Mengmeng Zheng, Qiuling Qian and Xianqiang Mi
Biosensors 2020, 10(7), 78; https://doi.org/10.3390/bios10070078 - 20 Jul 2020
Cited by 23 | Viewed by 5007
Abstract
BRCA1 is the biomarker for the early diagnosis of breast cancer. Detection of BRCA1 has great significance for the genetic analysis, early diagnosis and clinical treatment of breast cancer. In this work, we developed a simple electrochemical DNA sensor based on a DNA [...] Read more.
BRCA1 is the biomarker for the early diagnosis of breast cancer. Detection of BRCA1 has great significance for the genetic analysis, early diagnosis and clinical treatment of breast cancer. In this work, we developed a simple electrochemical DNA sensor based on a DNA tetrahedral-structured probe (TSP) and poly-adenine (polyA) mediated gold nanoparticles (AuNPs) for the sensitive detection of BRCA1. A thiol-modified TSP was used as the scaffold on the surface of the screen-printed AuNPs electrode. The capture DNA (TSP) and reporter DNA were hybridized to the target DNA (BRCA1), respectively, to form the typical sandwich system. The nanocomposites of reporter DNA (polyA at the 5′ end) combined with AuNPs were employed for signal amplification which can capture multiple enzymes by the specificity between biotin and streptavidin. Measurements were completed in the electrochemical workstation by cyclic voltammetry and amperometry and we obtained the low limit of detection of 0.1 fM with the linear range from 1 fM to 1 nM. High sensitivity and good specificity of the proposed electrochemical DNA sensor showed potential applications in clinical early diagnosis for breast cancer. Full article
(This article belongs to the Special Issue Electrochemical Biosensors)
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<p>The principle of the development of electrochemical DNA sensor. Cyclic voltammetry (CV curve) and amperometry (IT curve) were applied to investigate the electrochemical behavior of the proposed electrochemical DNA sensor.</p> Full article ">Figure 2
<p>(<b>A</b>) Gel electrophoresis image of marker (lane M), tetrahedral-structured probes (TSPs, lane a), ABC (lane b), BCD (lane c), AB (lane d), A (lane e), and B (lane f). (<b>B</b>) Atomic force microscopy (AFM) image of TSPs. Scanning electron microscopy (SEM) results of (<b>C</b>) bare carbon electrode and (<b>D</b>) gold nanoparticles (AuNPs) electrode. The scale value was 2 μm.</p> Full article ">Figure 3
<p>Transmission electron microscope (TEM) images of (<b>A</b>) AuNPs and (<b>B</b>) AuNPs-DNA-r. The scale value was 50 nm. (<b>C</b>) The ultraviolet-visible (UV-vis) absorption spectra of the AuNPs and the AuNPs-DNA-r. Black curve indicates the AuNPs and red curve indicates the AuNPs-DNA-r.</p> Full article ">Figure 4
<p>The optimization of the concentration of (<b>A</b>) TSPs, (<b>B</b>) AuNPs-DNA-r, (<b>C</b>) streptavidin (SA-HRP). Error bars show the standard deviations (<span class="html-italic">n</span> = 4).</p> Full article ">Figure 5
<p>(<b>A</b>) The plots of currents versus the target DNA (BRCA1) concentrations: 0, 1 aM, 10 aM, 100 aM, 1 fM, 100 fM, 1 pM, 100 pM, 500 pM, 1 nM, 10 nM, 100 nM. (<b>B</b>) The linear calibration curve for BRCA1 detection with the concentrations of 1 fM, 100 fM, 1 pM, 100 pM, 500 pM and 1 nM. Inset: Histogram showing the limit of detection of BRCA1 detection by the electrochemical DNA sensor, and the dashed lines stand for the threshold (blank + 3SD). (<b>C</b>) Specificity of the proposed electrochemical DNA sensor. The concentrations of DNA-miRNA21 and DNA-miRNA155 are 1 μM while the BRCA1 is 1 nM. Error bars show the standard deviations (<span class="html-italic">n</span> = 4).</p> Full article ">
22 pages, 5591 KiB  
Review
Overview of Recent Advances in the Design of Plasmonic Fiber-Optic Biosensors
by Yashar Esfahani Monfared
Biosensors 2020, 10(7), 77; https://doi.org/10.3390/bios10070077 - 9 Jul 2020
Cited by 95 | Viewed by 8204
Abstract
Plasmonic fiber-optic biosensors combine the flexibility and compactness of optical fibers and high sensitivity of nanomaterials to their surrounding medium, to detect biological species such as cells, proteins, and DNA. Due to their small size, accuracy, low cost, and possibility of remote and [...] Read more.
Plasmonic fiber-optic biosensors combine the flexibility and compactness of optical fibers and high sensitivity of nanomaterials to their surrounding medium, to detect biological species such as cells, proteins, and DNA. Due to their small size, accuracy, low cost, and possibility of remote and distributed sensing, plasmonic fiber-optic biosensors are promising alternatives to traditional methods for biomolecule detection, and can result in significant advances in clinical diagnostics, drug discovery, food process control, disease, and environmental monitoring. In this review article, we overview the key plasmonic fiber-optic biosensing design concepts, including geometries based on conventional optical fibers like unclad, side-polished, tapered, and U-shaped fiber designs, and geometries based on specialty optical fibers, such as photonic crystal fibers and tilted fiber Bragg gratings. The review will be of benefit to both engineers in the field of optical fiber technology and scientists in the fields of biosensing. Full article
(This article belongs to the Special Issue Last Advances in Optical Biosensors)
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<p>(<b>a</b>) Diagram of a conventional optical fiber with a total internal reflection light guiding mechanism. (<b>b</b>) Plasmonic fiber-optic biosensor can be obtained by removing a part of the optical fiber cladding and the deposition of plasmonic nanoparticles/nanofilms that are in direct contact with thr biological sample (analyte). (<b>c</b>) Variations in absorption spectra (transmission spectra) of light depending on the analyte chemical/physical characteristics. The location of absorption maxima (transmission dips) can be used to detect unknown analytes or monitor the variations in analyte physical/chemical properties.</p> Full article ">Figure 2
<p>The schematic of a potential plasmonic biosensing setup based on unclad (exposed core) optical fibers.</p> Full article ">Figure 3
<p>(top panel) The schematic of the process of lipase enzyme immobilization to create the biorecognition surface on the plasmonic fiber-optic sensor. (bottom panel) Peak absorbance wavelength shift as a function of triacylglycerides concentration in pH 7.4 solution at 37 °C standard deviation with APTES and enzyme, with APTS only and with enzyme only. Figures reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B26-biosensors-10-00077" class="html-bibr">26</a>], Copyright 2017.</p> Full article ">Figure 4
<p>Plasmonic fiber optic sensing system in [<a href="#B28-biosensors-10-00077" class="html-bibr">28</a>], (<b>a</b>) schematic of the experimental setup including light source, transmission fibers, plasmonic fiber-optic sensor, and spectrometer and (<b>b</b>) the actual photograph of the fabricated plasmonic fiber optic sensor. Figures reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B28-biosensors-10-00077" class="html-bibr">28</a>], Copyright 2017.</p> Full article ">Figure 5
<p>(<b>a</b>) Reflection spectra (normalized) of NaCl solutions with different refractive indices (RIs). (<b>b</b>) Experimental relationship between resonance wavelength location and RI of the solution. Figures reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B28-biosensors-10-00077" class="html-bibr">28</a>], Copyright 2017.</p> Full article ">Figure 6
<p>Cross section of a side-polished (D-shaped) plasmonic fiber-optic biosensor for liquid analyte detection.</p> Full article ">Figure 7
<p>(<b>a</b>) Schematic demonstration of fabrication process of side-polished optical fiber and (<b>b</b>) experimental setup of the D-shaped plasmonic fiber-optic sensor including broadband light source and spectrometer. Figures reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B31-biosensors-10-00077" class="html-bibr">31</a>], Copyright 2019.</p> Full article ">Figure 8
<p>The schematic of a potential plasmonic biosensing setup based on tapered optical fibers.</p> Full article ">Figure 9
<p>The schematic of a potential biosensing setup based on U-shaped plasmonic optical fibers.</p> Full article ">Figure 10
<p>The working principle of gold-coated U-shaped plasmonic plastics-based optical fiber (POF) biosensor for detection of Escherichia coli (<span class="html-italic">E. coli</span>) bacteria. Figure reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B35-biosensors-10-00077" class="html-bibr">35</a>], Copyright 2018.</p> Full article ">Figure 11
<p>The schematic overview of experimental setup of U-shaped plasmonic fiber-optic biosensor with a white light source (left panel) and the actual setup with light source on the left and spectrometer on the right side of the fiber probe (right panel). Figure reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B35-biosensors-10-00077" class="html-bibr">35</a>], Copyright 2018.</p> Full article ">Figure 12
<p>Cross section of a photonic crystal fibers (PCF) with a (<b>a</b>) solid core and (<b>b</b>) hollow-core. Note that PCF has several design parameters that can be adjusted to obtain the desired optical properties. The design parameters include core size, air-holes dimension, background material, center-to-center distance between air holes, and number of air holes.</p> Full article ">Figure 13
<p>Cross section of D-shaped PCF-surface plasmon resonance (SPR) biosensor that can be used to detect analytes with low or high refractive indices, depending on the design parameters.</p> Full article ">Figure 14
<p>Cross section of the D-shaped PCF-based plasmonic biosensor in [<a href="#B37-biosensors-10-00077" class="html-bibr">37</a>] with air holes diameter <span class="html-italic">d</span>, analyte-core diameter <span class="html-italic">d<sub>c</sub></span>, holes pitch <span class="html-italic">Ʌ</span>, and gold layer thickness <span class="html-italic">t</span>. Reproduced with permission from Reference [<a href="#B37-biosensors-10-00077" class="html-bibr">37</a>], Copyright 2019, IEEE.</p> Full article ">Figure 15
<p>Loss peak wavelength or resonance wavelength as a function of analyte RI for a D-shaped PCF-based plasmonic biosensor. Reproduced with permission from Reference [<a href="#B37-biosensors-10-00077" class="html-bibr">37</a>], Copyright 2019, IEEE.</p> Full article ">Figure 16
<p>Real and imaginary parts of effective index of fiber mode and plasmonic mode in a D-shaped plasmonic fiber-optic biosensor as a function of wavelength in (<b>a</b>) with a core size of <span class="html-italic">d<sub>c</sub>/</span><span class="html-italic">Ʌ</span> = 0.46 and (<b>b</b>) with a core size of <span class="html-italic">d<sub>c</sub>/</span><span class="html-italic">Ʌ</span> = 0.7. The other design parameters are n<sub>analyte</sub> = 1.5, <span class="html-italic">d/</span><span class="html-italic">Ʌ</span> = 0.23, <span class="html-italic">Ʌ</span> = 6 μm and <span class="html-italic">t</span> = 50 nm. Insets show field distribution at different points in spectra for fiber, plasmonic, and the coupled core-plasmonic modes. Reproduced with permission from Reference [<a href="#B37-biosensors-10-00077" class="html-bibr">37</a>], Copyright 2019, IEEE.</p> Full article ">Figure 17
<p>Cross section of PCF-based plasmonic biosensors based on a (<b>a</b>) trapezoidal-channel, (<b>b</b>) semi-circular channels, (<b>c</b>) H-shaped geometry with air holes, and (<b>d</b>) H-shaped microstructured geometry.</p> Full article ">Figure 18
<p>(<b>a</b>) Three-dimensional schematic view of the proposed H-shaped photonic crystal fiber-based surface plasmon resonance (PCF-SPR) sensor; (<b>b</b>) cross-section of the SPR sensor; (<b>c</b>) possible experimental setup of the SPR sensor for analyte RI detection. Figure reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B44-biosensors-10-00077" class="html-bibr">44</a>], Copyright 2020.</p> Full article ">Figure 19
<p>(<b>a</b>) Real part of the y-polarized core mode (black solid curve) and y-polarized surface plasmon polariton (SPP) mode at analyte RI of 1.43, 1.45, and 1.47 (red solid, red dashed, red dotted curves); (<b>b</b>) Imaginary part or loss spectra of the y-polarized core mode at analyte RI of 1.43, 1.45, and 1.47; (<b>c</b>) y-polarized electric field distributions of core mode and SPP mode at different wavelengths (A for core mode at 800 nm, B for SPP mode at 992 nm, C for core mode at 1006 nm with <span class="html-italic">n</span><sub>a</sub> = 1.43, D for core mode at 1367 nm, and E for core mode at 1791 nm with <span class="html-italic">n</span><sub>a</sub> = 1.47). Figure reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B44-biosensors-10-00077" class="html-bibr">44</a>], Copyright 2020.</p> Full article ">Figure 20
<p>The schematic of a potential plasmonic biosensing setup based on tilted fiber Bragg gratings.</p> Full article ">Figure 21
<p>(<b>a</b>) Schematic demonstration of tilted fiber Bragg grating plasmonic biosensor in [<a href="#B50-biosensors-10-00077" class="html-bibr">50</a>]. (<b>b</b>) Transmission spectra of the Bragg grating under P and S polarization, and (<b>c</b>) experimental setup for detection of bio-species using tilted fiber Bragg grating plasmonic biosensor. Figure reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B50-biosensors-10-00077" class="html-bibr">50</a>], Copyright 2017.</p> Full article ">Figure 22
<p>The process of protein identification and immobilization on the plasmonic sensing region of the biosensor for glycoprotein detection. The sensor was first dipped in boronic acid derivative for 24 h, and then block the unreacted carboxyl by dipping the sensor to the BSA, and different concentrations of glycoprotein. Figure reproduced under the terms of the CC-BY Creative Commons attribution 4.0 from Reference [<a href="#B50-biosensors-10-00077" class="html-bibr">50</a>], Copyright 2017.</p> Full article ">
29 pages, 6745 KiB  
Review
Screen-Printed Electrodes: Promising Paper and Wearable Transducers for (Bio)Sensing
by Paloma Yáñez-Sedeño, Susana Campuzano and José Manuel Pingarrón
Biosensors 2020, 10(7), 76; https://doi.org/10.3390/bios10070076 - 9 Jul 2020
Cited by 72 | Viewed by 10726
Abstract
Screen-printing technology has revolutionized many fields, including that of electrochemical biosensing. Due to their current relevance, this review, unlike other papers, discusses the relevant aspects of electrochemical biosensors manufactured using this technology in connection to both paper substrates and wearable formats. The main [...] Read more.
Screen-printing technology has revolutionized many fields, including that of electrochemical biosensing. Due to their current relevance, this review, unlike other papers, discusses the relevant aspects of electrochemical biosensors manufactured using this technology in connection to both paper substrates and wearable formats. The main trends, advances, and opportunities provided by these types of devices, with particular attention to the environmental and biomedical fields, are addressed along with illustrative fundamentals and applications of selected representative approaches from the recent literature. The main challenges and future directions to tackle in this research area are also pointed out. Full article
(This article belongs to the Special Issue Dedication to Professor Agustín Costa-García: Screen-Printed Electrodes-Based (Bio)sensors: Development and New Challenges of the 21st Century)
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<p>Fabrication process of conductive paper containing sensor patterns for dimethyl methylphosphonate (DMMP) based on poly(aniline) (PANI)/graphene composite. Reproduced and adapted with permission of American Chemical Society [<a href="#B15-biosensors-10-00076" class="html-bibr">15</a>].</p> Full article ">Figure 2
<p>(<b>A</b>) Schematics of fabrication steps and (<b>B</b>) computer-aided design (CAD) drawing of the disposable cellulose paper-based electrochemical sensor for on-site testing of H<sub>2</sub>O<sub>2</sub> in exhaled breath with poly-methylmethacrylate (PMMA) carrier. (<b>C</b>) Model of a filter extension for respiratory mask. (<b>D</b>) Image of respiratory mask with the commercial filter extension with customized sidewalls, containing the sensor chip. Reproduced and adapted with permission of American Chemical Society [<a href="#B29-biosensors-10-00076" class="html-bibr">29</a>].</p> Full article ">Figure 3
<p>(<b>A</b>) Synthesis of Fe<sub>3</sub>O<sub>4</sub>@Au@SiO<sub>2</sub>-MIP, (<b>B</b>) preparation of the sensor for serotonin, and (<b>C</b>) electrochemical detection using the 3D-ePAD. Reproduced and adapted with permission of Elsevier [<a href="#B30-biosensors-10-00076" class="html-bibr">30</a>].</p> Full article ">Figure 4
<p>(<b>A</b>) Preparation of thiol-terminated poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC-SH)-AuNPs/SPCE. (<b>B</b>–<b>F</b>) Steps for preparation of the PMPC-SH-AuNPs/SPCE/PAD sensor for the differential pulse voltammetry (DPV) determination of C-reactive protein (CRP). Reproduced and adapted with permission of Springer [<a href="#B31-biosensors-10-00076" class="html-bibr">31</a>].</p> Full article ">Figure 5
<p>Schematic displays of the modification and assay procedure for the implementation of an immunosensor for the determination of alpha-fetoprotein (AFP) using paper-based microfluidic channels to integrate sampling, detection and adsorption zones, and a reduced graphene oxide (rGO)-tetraethylene pentamine (TEPA)/AuNPs nanocomposite for immobilization of specific AFP antibodies. Reproduced with permission of Elsevier [<a href="#B35-biosensors-10-00076" class="html-bibr">35</a>].</p> Full article ">Figure 6
<p>Schemes of (<b>A</b>) Ferrocene-labeled DNA (Fc-DNA) immobilization on paper and CNTs-SPEs, and (<b>B</b>) miRNA assay for the recognition of miR-21 (left), and the electrochemical response to the released DNAzymes (right). Reproduced and adapted with permission of American Chemical Society [<a href="#B38-biosensors-10-00076" class="html-bibr">38</a>].</p> Full article ">Figure 7
<p>SPEs printed on flower (<b>a</b>), skull (<b>b</b>), panda bear (<b>c</b>), and marijuana (<b>d</b>) shapes. SPEs fabricated on a temporary tattoo (<b>e</b>), bendable bandage (<b>f</b>), textile substrate (<b>g</b>), glove (<b>h</b>), water-soluble silk thin-film substrates (transferred to tooth enamel) (<b>i</b>), contact lens (<b>j</b>), or incorporated in a mouthguard (<b>k</b>), eyeglasess (<b>l</b>) or ring (<b>m</b>). Reprinted and adapted with permission of Springer [<a href="#B68-biosensors-10-00076" class="html-bibr">68</a>] (<b>e</b>,<b>j</b>,<b>k</b>) Wiley [<a href="#B81-biosensors-10-00076" class="html-bibr">81</a>] (<b>f</b>), Elsevier [<a href="#B82-biosensors-10-00076" class="html-bibr">82</a>] (<b>a</b>,<b>g</b>), Elsevier [<a href="#B82-biosensors-10-00076" class="html-bibr">82</a>](<b>b</b>), Wiley [<a href="#B83-biosensors-10-00076" class="html-bibr">83</a>] (<b>c</b>), Wiley [<a href="#B65-biosensors-10-00076" class="html-bibr">65</a>] (<b>h</b>), Nature Research [<a href="#B84-biosensors-10-00076" class="html-bibr">84</a>] (<b>i</b>), Elsevier [<a href="#B85-biosensors-10-00076" class="html-bibr">85</a>] (<b>l</b>), and Elsevier [<a href="#B86-biosensors-10-00076" class="html-bibr">86</a>] (<b>c</b>,<b>m</b>).</p> Full article ">Figure 8
<p>TYR biosensing using a bandage electrochemical sensor modified with a CAT-containing agarose gel and involving wireless chronoamperometric data transmission to a smart device (<b>a</b>). Chronoamperometric responses provided by the bandage sensors before (black line) and after (red line) 2 min interaction with skin pork samples untreated (1) and treated with 0.5 (2), and 2.5 mg mL<sup>−1</sup> TYR (3) (<b>b</b>). Reprinted and adapted with permission of Wiley [<a href="#B81-biosensors-10-00076" class="html-bibr">81</a>].</p> Full article ">Figure 9
<p>Wearable iontophoretic biosensing device developed on a printed tattoo platform for simultaneous glucose and alcohol monitoring in interstitial fluid (ISF) and sweat, respectively, and wireless real-time transmission of the recorded response (<b>a</b>). Schematic display of the iontophoretic operation to simultaneously induce generation of alcohol-containing sweat by iontophoretic delivery of pilocarpine at the anode and sampling of ISF glucose at the cathode by reverse iontophoretic (<b>b</b>); biosensing operations to detect amperometrically alcohol in the stimulated sweat and of glucose in the extracted ISF by measuring the hydrogen peroxide generated in the AOx and GOx enzymatic reactions (<b>c</b>). Reprinted and adapted with permission of Wiley [<a href="#B83-biosensors-10-00076" class="html-bibr">83</a>].</p> Full article ">Figure 10
<p>Epidermal tattoo organophosphorus hydrolase (OPH)-based biosensor for vapor-phase detection of OP through SWV measurements of the p-nitrophenol generated after interaction of the MPOx micro-droplets released from the nebulizer with the OPH layer (<b>a</b>). Pictures of the OPH based epidermal tattoo (up) and textile (down) biosensors integrated with the flexible electronic interface and SWV responses they provide upon spraying 0 (i), 5 (ii), 10 (iii), and 15 (iv) mM MPOx in the vapor phase (<b>b</b>). Reprinted and adapted with permission of Elsevier [<a href="#B82-biosensors-10-00076" class="html-bibr">82</a>].</p> Full article ">Figure 11
<p>Schematic cartoon of the fluidic device, wireless electronics integrated into the eyeglasses platform, enzymatic detections of alcohol and glucose by chronoamperometry and non-enzymatic determination of vitamins by SWV in collected tears (<b>a</b>). Ring-based sensor platform embedded with marijuana designed sensor for detecting THC and alcohol in undiluted saliva samples using SWV and chronoamperometry (<b>b</b>). Reprinted and adapted with permission of Elsevier [<a href="#B85-biosensors-10-00076" class="html-bibr">85</a>] (<b>a</b>) and [<a href="#B86-biosensors-10-00076" class="html-bibr">86</a>] (<b>b</b>).</p> Full article ">Figure 12
<p>Automated taste discrimination in food samples through chemical sensing at the robot fingertips (<b>a</b>) Prototype of the screen-printed robotic sense fingers (carbon-printed sour-finger in green, GOx PB-printed sweet-finger in blue and carbon-printed spicy-finger in red) with long connections to the electronic interface (<b>b</b>). Images and corresponding electrochemical responses (in red) of: robotic sour-finger dipped in orange juice and the square wave voltammetry (SWV) signature of ascorbic acid (i), robotic sweet-finger in cherry juice and amperometry data of glucose (ii), spicy-finger on green-pepper, and SWV feedback response to the presence of capsaicin (iii). For comparison purposes the response obtained in phosphate buffer saline (PBS) response are displayed in black dotted lines (<b>c</b>). Reprinted and adapted with permission of American Chemical Society [<a href="#B72-biosensors-10-00076" class="html-bibr">72</a>].</p> Full article ">
12 pages, 3633 KiB  
Article
A Self-Powered Biosensor for Monitoring Maximal Lactate Steady State in Sport Training
by Yupeng Mao, Wen Yue, Tianming Zhao, MaiLun Shen, Bing Liu and Song Chen
Biosensors 2020, 10(7), 75; https://doi.org/10.3390/bios10070075 - 8 Jul 2020
Cited by 38 | Viewed by 5358
Abstract
A self-powered biosensor for monitoring the maximal lactate steady state (MLSS) during exercise has been developed for intelligently assisting training system. It has been presented to create poly (vinylidene fluoride) (PVDF)/Tetrapod-shaped ZnO (T-ZnO)/enzyme-modified nanocomposite film through an efficient and cost-effective fabrication process. This [...] Read more.
A self-powered biosensor for monitoring the maximal lactate steady state (MLSS) during exercise has been developed for intelligently assisting training system. It has been presented to create poly (vinylidene fluoride) (PVDF)/Tetrapod-shaped ZnO (T-ZnO)/enzyme-modified nanocomposite film through an efficient and cost-effective fabrication process. This sensor can be readily attached to the skin surface of the tester. Due to the piezoelectric surface coupling effect, this biosensor can monitor/sense and analyze physical information in real-time under the non-invasive condition and work independently without any battery. By actively outputting piezoelectric signals, it can quickly and sensitively detect body movements (changes of joint angle, frequency relative humidity during exercise) and physiological information (changes of lactate concentration in sweat). A practical application has been demonstrated by an excellent professional speed skater (male). The purpose of this study is to increase the efficiency of MLSS evaluation, promote the development of piezoelectric surface coupling effect and motion monitoring application, develop an intelligently assisting training system, which has opened up a new direction for human motion monitoring. Full article
(This article belongs to the Section Biosensors and Healthcare)
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Figure 1
<p>Structure of self-powered biosensor. (<b>a</b>) Optical image of the device. (<b>b</b>) Device structure. (<b>c</b>) SEM image of T-ZnO/poly (vinylidene fluoride) (PVDF)/fabric. (<b>d</b>) SEM image of organic fabric. (<b>e</b>) SEM image of one single T-ZnO. (<b>f</b>–<b>j</b>) High-power SEM images of T-ZnO/PVDF/fabric with different magnification.</p> Full article ">Figure 2
<p>A working mechanism sketch of self-powered biosensor. (<b>a</b>) Power generation mechanism of T-ZnO/PVDF/fabric. (<b>b</b>) Enzymatic reaction. (<b>c</b>) Piezoelectric surface coupling effect.</p> Full article ">Figure 3
<p>Biosensor for detecting angle and frequency in real-time. (<b>a</b>) Measurement system. The inset shows the outputting piezoelectric voltage of one cycle. (<b>b</b>) Outputting piezoelectric voltage of the sensor against different angles (1.5 Hz). (<b>c</b>) The relationship between angle and outputting piezoelectric voltage. (<b>d</b>) Outputting piezoelectric voltage of the sensor against different frequency (74°). (<b>e</b>) The relationship between the frequency and outputting piezoelectric voltage.</p> Full article ">Figure 4
<p>The biosensor performance for detecting lactate concentration (<b>a</b>) The outputting piezoelectric voltage of the biosensor (modified with lacticoxidase (LOx)) against different lactate concentration from 0 to 8 mmol/L (45°). (<b>b</b>) The outputting piezoelectric voltage of the biosensor (modified LOx) in pure water (45°). (<b>c</b>) Outputting piezoelectric voltage of the biosensor (unmodified with LOx) against different lactate concentration from 0 to 8 mmol/L. (<b>d</b>) The outputting piezoelectric voltage and response of the three devices.</p> Full article ">Figure 5
<p>(<b>a</b>) The outputting piezoelectric voltage of biosensor against different relative humidity. (<b>b</b>) The outputting piezoelectric voltage and response of the biosensor against different relative humidity. (<b>c</b>) The stability of the biosensor. (<b>d</b>) The lifetime of the biosensor.</p> Full article ">Figure 6
<p>The practical application of biosensor. (<b>a</b>) Optical image of subject power bicycle tests. (<b>b</b>) The optical image of the joint position (stretching and bending) with the biosensor. (<b>c</b>) Blood lactate concentration of tester at different time points by the commercial sensor. (<b>d</b>) The real-time outputting piezoelectric voltage of biosensor. (<b>e</b>) The real-time response of biosensor.</p> Full article ">
22 pages, 5877 KiB  
Article
Factors Influencing the Long-Term Stability of Electronic Tongue and Application of Improved Drift Correction Methods
by Zoltan Kovacs, Dániel Szöllősi, John-Lewis Zinia Zaukuu, Zsanett Bodor, Flóra Vitális, Balkis Aouadi, Viktória Zsom-Muha and Zoltan Gillay
Biosensors 2020, 10(7), 74; https://doi.org/10.3390/bios10070074 - 7 Jul 2020
Cited by 30 | Viewed by 4436
Abstract
Temperature, memory effect, and cross-contamination are suspected to contribute to drift in electronic tongue (e-tongue) sensors, therefore drift corrections are required. This paper aimed to assess the disturbing effects on the sensor signals during measurement with an Alpha Astree e-tongue and to develop [...] Read more.
Temperature, memory effect, and cross-contamination are suspected to contribute to drift in electronic tongue (e-tongue) sensors, therefore drift corrections are required. This paper aimed to assess the disturbing effects on the sensor signals during measurement with an Alpha Astree e-tongue and to develop drift correction techniques. Apple juice samples were measured at different temperatures. pH change of apple juice samples was measured to assess cross-contamination. Different sequential orders of model solutions and apple juice samples were applied to evaluate the memory effect. Model solutions corresponding to basic tastes and commercial apple juice samples were measured for six consecutive weeks to model drift of the sensor signals. Result showed that temperature, cross-contamination, and memory effect influenced the sensor signals. Three drift correction methods: additive drift correction based on all samples, additive drift correction based on reference samples, and multi sensor linear correction, were developed and compared to the component correction in literature through linear discriminant analysis (LDA). LDA analysis showed all the four methods were effective in reducing sensor drift in long-term measurements but the additive correction relative to the whole sample set gave the best results. The results could be explored for long-term measurements with the e-tongue. Full article
(This article belongs to the Section Intelligent Biosensors and Bio-Signal Processing)
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<p>Principal component analysis plots demonstrating component correction for citric acid week 0 (red points) and week 1 (blue points). (<b>a</b>) original data and (<b>b</b>) component correction and (<b>c</b>) modified component (correction subtracting twice the drift from week 1).</p> Full article ">Figure 2
<p>(<b>a</b>) Discriminant analysis score plot of the different concentrations of apple juice at different temperatures and (<b>b</b>) the Euclidian multidimensional distance between the groups of apple juices with different concentrations and (<b>c</b>) with different temperatures with the fitted regression models.</p> Full article ">Figure 3
<p>The increase of pH of apple juice samples versus electronic tongue measurement repeats.</p> Full article ">Figure 4
<p>Principle component analysis score plots of the electronic tongue results of apple juice and model solution samples measured in three different sample orders: (<b>a</b>) citric acid NaCl, MSG, apple juice and: (<b>b</b>) reverse sample order: citric acid, apple juice, MSG, NaCl and: (<b>c</b>) citric acid, NaCl, apple juice, MSG.</p> Full article ">Figure 5
<p>Linear discriminant analysis plots for raw data (non-drift corrected) of the e-tongue measurements of apple juice samples (red symbols) and model solutions: citric acid (green symbols), NaCl (gold symbols), and MSG (gray symbols). The solid circles indicate the measurements on week 0 which was used to build the linear discriminant analysis model, and the different symbols (diamond, triangle, plus, asterisk, and circle) stand for the different weeks 1–5, respectively.</p> Full article ">Figure 6
<p>Linear discriminant analysis plots for the drift corrected dataset using the additive correction relative to the whole dataset method of the e-tongue measurements of apple juice samples (red symbols) and model solutions: citric acid (green symbols), NaCl (gold symbols), and MSG (gray symbols). The solid circles indicate the measurements on week 0 which was used to build the linear discriminant analysis model, and the different symbols (diamond, triangle, plus, asterisk, and circle) stand for the different weeks 1–5, respectively.</p> Full article ">Figure 7
<p>Linear discriminant analysis plots for the drift corrected dataset using the additive correction relative to reference samples method of the e-tongue measurements of apple juice samples (red symbols) and model solutions: citric acid (green symbols), NaCl (gold symbols), and MSG (gray symbols). The solid circles indicate the measurements on week 0 which was used to build the linear discriminant analysis model, and the different symbols (diamond, triangle, plus, asterisk, and circle) stand for the different weeks 1–5, respectively.</p> Full article ">Figure 8
<p>Linear discriminant analysis plots for the drift corrected dataset using the multi sensor linear correction method of the e-tongue measurements of apple juice samples (red symbols) and model solutions: citric acid (green symbols), NaCl (gold symbols), and MSG (gray symbols). The solid circles indicate the measurements on week 0 which was used to build the linear discriminant analysis model, and the different symbols (diamond, triangle, plus, asterisk, and circle) stand for the different weeks 1–5, respectively.</p> Full article ">Figure 9
<p>Linear discriminant analysis plots for the drift corrected dataset using the component correction method of the e-tongue measurements of apple juice samples (red symbols) and model solutions: citric acid (green symbols), NaCl (gold symbols), and MSG (gray symbols). The correction was performed based on pairing the first and last week. The solid circles indicate the measurements on week 0 which was used to build the linear discriminant analysis model, and the different symbols (diamond, triangle, plus, asterisk, and circle) stand for the different weeks 1–5, respectively.</p> Full article ">Figure 10
<p>Linear discriminant analysis plots for the drift corrected dataset using the modified component correction method of the e-tongue measurements of apple juice samples (red symbols) and model solutions: citric acid (green symbols), NaCl (gold symbols), and MSG (gray symbols). The correction was performed based on pairing each week to week 0. The solid circles indicate the measurements on week 0 which was used to build the linear discriminant analysis model, and the different symbols (diamond, triangle, plus, asterisk, and circle) stand for the different weeks 1–5, respectively.</p> Full article ">Figure 11
<p>Comparison of the mean and standard deviation of the relative Euclidean distances of the apple juice samples from the center of week 0 calculated in the space of linear discriminant analysis models built based on the non-corrected and differently drift corrected data of e-tongue measurements. The intervals show the variation in distance for the threefold linear discriminant analysis cross-validation results.</p> Full article ">
6 pages, 181 KiB  
Editorial
Noninvasive Early Disease Diagnosis by Electronic-Nose and Related VOC-Detection Devices
by Alphus Dan Wilson
Biosensors 2020, 10(7), 73; https://doi.org/10.3390/bios10070073 - 6 Jul 2020
Cited by 40 | Viewed by 6010
Abstract
This editorial provides an overview and summary of recent research articles published in Biosensors journal, volumes 9 (2019) and 10 (2020), within the Special Issue “Noninvasive Early Disease Diagnosis”, which focused on recent sensors, biosensors, and clinical instruments developed for the [...] Read more.
This editorial provides an overview and summary of recent research articles published in Biosensors journal, volumes 9 (2019) and 10 (2020), within the Special Issue “Noninvasive Early Disease Diagnosis”, which focused on recent sensors, biosensors, and clinical instruments developed for the noninvasive early detection and diagnosis of human, animal, and plant diseases or invasive pests. The six research articles included in this Special Issue provide examples of some of the latest electronic-nose (e-nose) and related volatile organic compound (VOC)-detection technologies, which are being tested and developed to improve the effectiveness and efficiency of innovative diagnostic methodologies for the early detection of particular diseases and pest infestations in living hosts, prior to symptom development. Full article
(This article belongs to the Special Issue Noninvasive Early Disease Diagnosis)
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