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12 pages, 3508 KiB

Open AccessArticle

Identification of Microorganisms Using an EWOD System

by Jung-Cheng Su, Yi-Ju Liu and Da-Jeng Yao

Micromachines 2022, 13(2), 189; https://doi.org/10.3390/mi13020189 - 26 Jan 2022

Cited by 2 | Viewed by 2830

Abstract

Among the advantages of an electrowetting-on-dielectric (EWOD) chip are its uncomplicated fabrication and low cost; one of its greatest strengths that might be applied in the field of biomedical technology is that it can accurately control volume and reduces the amount of samples [...] Read more.

Among the advantages of an electrowetting-on-dielectric (EWOD) chip are its uncomplicated fabrication and low cost; one of its greatest strengths that might be applied in the field of biomedical technology is that it can accurately control volume and reduces the amount of samples and reagents. We present an EWOD for the biochemical identification of microorganisms, which is required to confirm the source of microbial contamination or quality inspection of product-added bacteria, etc. The traditional kit we used existed in the market; the detection results are judged by the pattern of color change after incubation. After a preliminary study, we confirmed that an image-processing tool (ImageJ) provides a suitable method of analysis, and that, when the concentration of the sugar reagent is 38 µg/µL, the best operating parameters for the EWOD chip in silicone oil are 40 V and 1.5 kHz. Additionally, we completed the biochemical identification of five bacterial species on the EWOD chip at the required concentration of the kit. Next, we found a decreased duration of reaction and that the least number of bacteria that were identifiable on the chip lies between 100 and 1000 CFU per droplet. Because the number of bacteria required on the chip is much smaller than for the kit, we tested whether a single colony can be used for identification, which provided a positive result. Finally, we designed an experimental flow to simulate an actual sample in an unclean environment, in which we divided the various processed samples into four groups to conduct experiments on the chip. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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18 pages, 5502 KiB

Open AccessArticle

In Situ Agarose Microfabrication Technology Using Joule Heating of Micro Ionic Current for On-Chip Cell Network Analysis

by Kenji Shimoda, Haruki Watanabe, Yoshitsune Hondo, Mitsuru Sentoku, Kazufumi Sakamoto and Kenji Yasuda

Micromachines 2022, 13(2), 174; https://doi.org/10.3390/mi13020174 - 25 Jan 2022

Cited by 1 | Viewed by 2537

Abstract

Agarose microfabrication technology is one of the micropatterning techniques of cells having advantages of simple and flexible real-time fabrication of three-dimensional confinement microstructures even during cell cultivation. However, the conventional photothermal etching procedure of focused infrared laser on thin agarose layer has several [...] Read more.

Agarose microfabrication technology is one of the micropatterning techniques of cells having advantages of simple and flexible real-time fabrication of three-dimensional confinement microstructures even during cell cultivation. However, the conventional photothermal etching procedure of focused infrared laser on thin agarose layer has several limitations, such as the undesired sudden change of etched width caused by the local change of absorbance of the bottom surface of cultivation plate, especially on the indium-tin-oxide (ITO) wiring on the multi-electrode array (MEA) cultivation chip. To overcome these limitations, we have developed a new agarose etching method exploiting the Joule heating of focused micro ionic current at the tip of the micrometer-sized capillary tube. When 75 V, 1 kHz AC voltage was applied to the tapered microcapillary tube, in which 1 M sodium ion buffer was filled, the formed micro ionic current at the open end of the microcapillary tube melted the thin agarose layer and formed stable 5 μm width microstructures regardless the ITO wiring, and the width was controlled by the change of applied voltage squared. We also found the importance of the higher frequency of applied AC voltage to form the stable microstructures and also minimize the fluctuation of melted width. The results indicate that the focused micro ionic current can create stable local spot heating in the medium buffer as the Joule heating of local ionic current and can perform the same quality of microfabrication as the focused infrared laser absorption procedure with a simple set-up of the system and several advantages. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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13 pages, 2155 KiB

Open AccessArticle

New Insights on Plasmin Long Term Stability and the Mechanism of Its Activity Inhibition Analyzed by Quartz Crystal Microbalance

by Marek Tatarko, Ilia N. Ivanov and Tibor Hianik

Micromachines 2022, 13(1), 55; https://doi.org/10.3390/mi13010055 - 29 Dec 2021

Cited by 2 | Viewed by 1768

Abstract

We used the research quartz crystal microbalance (RQCM) to monitor regulatory effects of plasmin and trypsin in the presence of their inhibitor α₂-antiplasmin. The gold surface of quartz crystals was modified with a β-casein layer that served as a substrate for [...] Read more.

We used the research quartz crystal microbalance (RQCM) to monitor regulatory effects of plasmin and trypsin in the presence of their inhibitor α₂-antiplasmin. The gold surface of quartz crystals was modified with a β-casein layer that served as a substrate for protease digestion. The addition of plasmin or trypsin as well as their mixtures with α₂-antiplasmin resulted in an increase of resonant frequency, f, and in a decrease of motional resistance, R_m, depending on the molar ratio of protease: antiplasmin. At equimolar concentrations of protease and α₂-antiplasmin (5 nM:5 nM) full inhibition of protease activity took place. Monitoring of plasmin activity on an hourly and daily basis revealed a prominent effect of autolysis and decrease of plasmin activity in freshly activated samples. The degree of inhibition as well as plasmin half-life (t_1/2 = 2.48 ± 0.28 days) connected with its degradation was determined. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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15 pages, 4701 KiB

Open AccessArticle

Rapid, Simple and Inexpensive Fabrication of Paper-Based Analytical Devices by Parafilm^® Hot Pressing

by Surasak Kasetsirikul, Kimberley Clack, Muhammad J. A. Shiddiky and Nam-Trung Nguyen

Micromachines 2022, 13(1), 48; https://doi.org/10.3390/mi13010048 - 29 Dec 2021

Cited by 12 | Viewed by 3354

Abstract

Paper-based analytical devices have been substantially developed in recent decades. Many fabrication techniques for paper-based analytical devices have been demonstrated and reported. Herein, we report a relatively rapid, simple, and inexpensive method for fabricating paper-based analytical devices using parafilm hot pressing. We studied [...] Read more.

Paper-based analytical devices have been substantially developed in recent decades. Many fabrication techniques for paper-based analytical devices have been demonstrated and reported. Herein, we report a relatively rapid, simple, and inexpensive method for fabricating paper-based analytical devices using parafilm hot pressing. We studied and optimized the effect of the key fabrication parameters, namely pressure, temperature, and pressing time. We discerned the optimal conditions, including a pressure of 3.8 MPa, temperature of 80 °C, and 3 min of pressing time, with the smallest hydrophobic barrier size (821 µm) being governed by laminate mask and parafilm dispersal from pressure and heat. Physical and biochemical properties were evaluated to substantiate the paper functionality for analytical devices. The wicking speed in the fabricated paper strips was slightly lower than that of non-processed paper, resulting from a reduced paper pore size after hot pressing. A colorimetric immunological assay was performed to demonstrate the protein binding capacity of the paper-based device after exposure to pressure and heat from the fabrication. Moreover, mixing in a two-dimensional paper-based device and flowing in a three-dimensional counterpart were thoroughly investigated, demonstrating that the paper devices from this fabrication process are potentially applicable as analytical devices for biomolecule detection. Fast, easy, and inexpensive parafilm hot press fabrication presents an opportunity for researchers to develop paper-based analytical devices in resource-limited environments. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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15 pages, 6863 KiB

Open AccessArticle

Efficient Decellularization by Application of Moderate High Hydrostatic Pressure with Supercooling Pretreatment

by Daiki Zemmyo, Masashi Yamamoto and Shogo Miyata

Micromachines 2021, 12(12), 1486; https://doi.org/10.3390/mi12121486 - 30 Nov 2021

Cited by 9 | Viewed by 2492

Abstract

Decellularized tissues are considered superior scaffolds for cell cultures, preserving the microstructure of native tissues and delivering many kinds of cytokines. High hydrostatic pressure (HHP) treatment could remove cells physically from biological tissues rather than chemical methods. However, there are some risks of [...] Read more.

Decellularized tissues are considered superior scaffolds for cell cultures, preserving the microstructure of native tissues and delivering many kinds of cytokines. High hydrostatic pressure (HHP) treatment could remove cells physically from biological tissues rather than chemical methods. However, there are some risks of inducing destruction or denaturation of extracellular matrices (ECMs) at an ultrahigh level of HHP. Therefore, efficient decellularization using moderate HHP is required to remove almost all cells simultaneously to suppress tissue damage. In this study, we proposed a novel decellularization method using a moderate HHP with supercooling pretreatment. To validate the decellularization method, a supercooling device was developed to incubate human dermal fibroblasts or collagen gels in a supercooled state. The cell suspension and collagen gels were subjected to 100, 150, and 200 MPa of HHP after supercooling pretreatment, respectively. After applying HHP, the viability and morphology of the cells and the collagen network structure of the gels were evaluated. The viability of cells decreased dramatically after HHP application with supercooling pretreatment, whereas the microstructures of collagen gels were preserved and cell adhesivity was retained after HHP application. In conclusion, it was revealed that supercooling pretreatment promoted the denaturation of the cell membrane to improve the efficacy of decellularization using static application of moderate HHP. Furthermore, it was demonstrated that the HHP with supercooling pretreatment did not degenerate and damage the microstructure in collagen gels. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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10 pages, 1499 KiB

Open AccessArticle

A Cylindrical Molding Method for the Biofabrication of Plane-Shaped Skeletal Muscle Tissue

by Minghao Nie, Ai Shima, Kenta Fukushima, Yuya Morimoto and Shoji Takeuchi

Micromachines 2021, 12(11), 1411; https://doi.org/10.3390/mi12111411 - 17 Nov 2021

Cited by 6 | Viewed by 3351

Abstract

Muscle tissues can be fabricated in vitro by culturing myoblast-populated hydrogels. To counter the shrinkage of the myoblast-populated hydrogels during culture, a pair of anchors are generally utilized to fix the two ends of the hydrogel. Here, we propose an alternative method to [...] Read more.

Muscle tissues can be fabricated in vitro by culturing myoblast-populated hydrogels. To counter the shrinkage of the myoblast-populated hydrogels during culture, a pair of anchors are generally utilized to fix the two ends of the hydrogel. Here, we propose an alternative method to counter the shrinkage of the hydrogel and fabricate plane-shaped skeletal muscle tissues. The method forms myoblast-populated hydrogel in a cylindrical cavity with a central pillar, which can prevent tissue shrinkage along the circumferential direction. By eliminating the usages of the anchor pairs, our proposed method can produce plane-shaped skeletal muscle tissues with uniform width and thickness. In experiments, we demonstrate the fabrication of plane-shaped (length: ca. 10 mm, width: 5~15 mm) skeletal muscle tissue with submillimeter thickness. The tissues have uniform shapes and are populated with differentiated muscle cells stained positive for myogenic differentiation markers (i.e., myosin heavy chains). In addition, we show the assembly of subcentimeter-order tissue blocks by stacking the plane-shaped skeletal muscle tissues. The proposed method can be further optimized and scaled up to produce cultured animal products such as cultured meat. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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10 pages, 3000 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Fabrication of 3D Micro-Blades for the Cutting of Biological Structures in a Microfluidic Guillotine

by Saisneha Koppaka, Kevin S. Zhang, Myra Kurosu Jalil, Lucas R. Blauch and Sindy K. Y. Tang

Micromachines 2021, 12(9), 1005; https://doi.org/10.3390/mi12091005 - 24 Aug 2021

Cited by 7 | Viewed by 4363

Abstract

Micro-blade design is an important factor in the cutting of single cells and other biological structures. This paper describes the fabrication process of three-dimensional (3D) micro-blades for the cutting of single cells in a microfluidic “guillotine” intended for fundamental wound repair and regeneration [...] Read more.

Micro-blade design is an important factor in the cutting of single cells and other biological structures. This paper describes the fabrication process of three-dimensional (3D) micro-blades for the cutting of single cells in a microfluidic “guillotine” intended for fundamental wound repair and regeneration studies. Our microfluidic guillotine consists of a fixed 3D micro-blade centered in a microchannel to bisect cells flowing through. We show that the Nanoscribe two-photon polymerization direct laser writing system is capable of fabricating complex 3D micro-blade geometries. However, structures made of the Nanoscribe IP-S resin have low adhesion to silicon, and they tend to peel off from the substrate after at most two times of replica molding in poly(dimethylsiloxane) (PDMS). Our work demonstrates that the use of a secondary mold replicates Nanoscribe-printed features faithfully for at least 10 iterations. Finally, we show that complex micro-blade features can generate different degrees of cell wounding and cell survival rates compared with simple blades possessing a vertical cutting edge fabricated with conventional 2.5D photolithography. Our work lays the foundation for future applications in single cell analyses, wound repair and regeneration studies, as well as investigations of the physics of cutting and the interaction between the micro-blade and biological structures. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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11 pages, 2168 KiB

Open AccessArticle

Loop-Mediated Isothermal Amplification in a Core-Shell Bead Assay for the Detection of Tyrosine Kinase AXL Overexpression

by Kamalalayam Rajan Sreejith, Muhammad Umer, Pradip Singha, Nhat-Khuong Nguyen, Surasak Kasetsirikul, Chin Hong Ooi, Muhammad J. A. Shiddiky and Nam-Trung Nguyen

Micromachines 2021, 12(8), 905; https://doi.org/10.3390/mi12080905 - 30 Jul 2021

Cited by 5 | Viewed by 3007

Abstract

The upregulated expression of tyrosine kinase AXL has been reported in several hematologic and solid human tumors, including gastric, breast, colorectal, prostate and ovarian cancers. Thus, AXL can potentially serve as a diagnostic and prognostic biomarker for various cancers. This paper reports the [...] Read more.

The upregulated expression of tyrosine kinase AXL has been reported in several hematologic and solid human tumors, including gastric, breast, colorectal, prostate and ovarian cancers. Thus, AXL can potentially serve as a diagnostic and prognostic biomarker for various cancers. This paper reports the first ever loop-mediated isothermal amplification (LAMP) in a core-shell bead assay for the detection of AXL gene overexpression. We demonstrated simple instrumentation toward a point-of-care device to perform LAMP. This paper also reports the first ever use of core-shell beads as a microreactor to perform LAMP as an attempt to promote environmentally-friendly laboratory practices. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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12 pages, 2596 KiB

Open AccessArticle

Doxorubicin Anticancer Drug Monitoring by ds-DNA-Based Electrochemical Biosensor in Clinical Samples

by Firouzeh Hassani Moghadam, Mohammad A. Taher and Hassan Karimi-Maleh

Micromachines 2021, 12(7), 808; https://doi.org/10.3390/mi12070808 - 9 Jul 2021

Cited by 31 | Viewed by 3890

Abstract

In this research, glassy carbon electrode (GCE) amplified with single-wall carbon nanotubes (SWCNTs) and ds-DNA was fabricated and utilized for voltammetric sensing of doxorubicin with a low detection limit. In this technique, the reduction in guanine signal of ds-DNA in the presence of [...] Read more.

In this research, glassy carbon electrode (GCE) amplified with single-wall carbon nanotubes (SWCNTs) and ds-DNA was fabricated and utilized for voltammetric sensing of doxorubicin with a low detection limit. In this technique, the reduction in guanine signal of ds-DNA in the presence of doxorubicin (DOX) was chosen as an analytical factor. The molecular docking study revealed that the doxorubicin drug interacted with DNA through intercalation mode, which was in agreement with obtained experimental results. The DOX detection performance of ds-DNA/SWCNTs/GCE was assessed at a concentration range of 1.0 nM–20.0 µM. The detection limit was found to be 0.6 nM that was comparable and even better (in many cases) than that of previous electrochemical reported sensors. In the final step, the ds-DNA/SWCNTs/GCE showed powerful ability for determination of the DOX in injection samples with acceptable recovery data. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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12 pages, 3941 KiB

Open AccessArticle

Rapid Fabrication of Superhydrophobic Virtual Walls for Microfluidic Gas Extraction and Sensing

by Wojciech Raj, Daisy Yang and Craig Priest

Micromachines 2021, 12(5), 514; https://doi.org/10.3390/mi12050514 - 2 May 2021

Cited by 5 | Viewed by 2505

Abstract

Based on the virtual walls concept, where fluids are guided by wettability, we demonstrate the application of a gas phase extraction microfluidic chip. Unlike in previous work, the chip is prepared using a simple, rapid, and low-cost fabrication method. Channels were cut into [...] Read more.

Based on the virtual walls concept, where fluids are guided by wettability, we demonstrate the application of a gas phase extraction microfluidic chip. Unlike in previous work, the chip is prepared using a simple, rapid, and low-cost fabrication method. Channels were cut into double-sided adhesive tape (280 µm thick) and bonded to hydrophilic glass slides. The tape was selectively made superhydrophobic by ‘dusting’ with hydrophobic silica gel to enhance the wettability contrast at the virtual walls. Finally, the two glass slides were bonded using tape, which acts as a spacer for gas transport from/to the guided liquids. In our example, the virtual walls create a stable liquid–vapor–liquid flow configuration for the extraction of a volatile analyte (ammonia), from one liquid stream to the other through the intermediate vapor phase. The collector stream contained a pH indicator to visualize the mass transport. Quantitative analysis of ammonium hydroxide in the sample stream (<1 mM) was possible using a characteristic onset time, where the first pH change in the collector stream was detected. The effect of gap length, flow rates, and pH of the collector stream on the onset time is demonstrated. Finally, we demonstrate the analysis of ammonium hydroxide in artificial human saliva to show that the virtual walls chip is suitable for extracting volatile analytes from biofluids. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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11 pages, 2417 KiB

Open AccessArticle

Non-Enzymatic Glucose Detection Based on NiS Nanoclusters@NiS Nanosphere in Human Serum and Urine

by Mani Arivazhagan, Yesupatham Manova Santhosh and Govindhan Maduraiveeran

Micromachines 2021, 12(4), 403; https://doi.org/10.3390/mi12040403 - 5 Apr 2021

Cited by 16 | Viewed by 3387

Abstract

Herein, we report a non-enzymatic electrochemical glucose sensing platform based on NiS nanoclusters dispersed on NiS nanosphere (NC-NiS@NS-NiS) in human serum and urine samples. The NC-NiS@NS-NiS are directly grown on nickel foam (NF) (NC-NiS@NS-NiS|NF) substrate by a facile, and one-step electrodeposition strategy under [...] Read more.

Herein, we report a non-enzymatic electrochemical glucose sensing platform based on NiS nanoclusters dispersed on NiS nanosphere (NC-NiS@NS-NiS) in human serum and urine samples. The NC-NiS@NS-NiS are directly grown on nickel foam (NF) (NC-NiS@NS-NiS|NF) substrate by a facile, and one-step electrodeposition strategy under acidic solution. The as-developed nanostructured NC-NiS@NS-NiS|NF electrode materials successfully employ as the enzyme-mimic electrocatalysts toward the improved electrocatalytic glucose oxidation and sensitive glucose sensing. The NC-NiS@NS-NiS|NF electrode presents an outstanding electrocatalytic activity and sensing capability towards the glucose owing to the attribution of great double layer capacitance, excessive electrochemical active surface area (ECASA), and high electrochemical active sites. The present sensor delivers a limit of detection (LOD) of ~0.0083 µM with a high sensitivity of 54.6 µA mM⁻¹ cm⁻² and a wide linear concentration range (20.0 µM–5.0 mM). The NC-NiS@NS-NiS|NF-based sensor demonstrates the good selectivity against the potential interferences and shows high practicability by glucose sensing in human urine and serum samples. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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11 pages, 20131 KiB

Open AccessArticle

Magnetic Bead Chain-Based Continuous-Flow DNA Extraction for Microfluidic PCR Detection of Salmonella

by Yuhe Wang, Wuzhen Qi, Lei Wang, Jianhan Lin and Yuanjie Liu

Micromachines 2021, 12(4), 384; https://doi.org/10.3390/mi12040384 - 1 Apr 2021

Cited by 10 | Viewed by 4545

Abstract

Nucleic acid extraction is crucial for PCR detection of pathogenic bacteria to ensure food safety. In this study, a new magnetic extraction method was developed using 3D printing and magnetic silica beads (MSBs) to extract the target DNA from a large volume of [...] Read more.

Nucleic acid extraction is crucial for PCR detection of pathogenic bacteria to ensure food safety. In this study, a new magnetic extraction method was developed using 3D printing and magnetic silica beads (MSBs) to extract the target DNA from a large volume of bacterial sample and combined with microfluidic PCR to determine the bacteria. After proteinase K was added into a bacterial sample to lyse the bacteria and release the DNA, it was continuous-flow injected into the serpentine channel of the extraction chip, where magnetic silica bead chains had been formed in advance using a homogeneous magnetic field generated by two concentric semicircle magnets to capture the MSBs. Then, the flowing DNA was captured by the MSB chains, washed with alcohol, dried with gas, and eluted with deionized water to obtain the purified and concentrated DNA. Finally, the extracted DNA templates were injected into a microfluidic PCR chip with lyophilized amplification reagents and determined using a commercial qPCR device. The experimental results showed that the DNA extraction efficiency was more than 90%, and the lower detection limit of Salmonella was 10² CFU/mL. This new Salmonella detection method is promising to provide the rapid, sensitive, and simultaneous detection of multiple foodborne pathogens. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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Review

Jump to: Research

17 pages, 5008 KiB

Open AccessReview

Advances in Single-Cell Printing

by Xiaohu Zhou, Han Wu, Haotian Wen and Bo Zheng

Micromachines 2022, 13(1), 80; https://doi.org/10.3390/mi13010080 - 3 Jan 2022

Cited by 18 | Viewed by 4594

Abstract

Single-cell analysis is becoming an indispensable tool in modern biological and medical research. Single-cell isolation is the key step for single-cell analysis. Single-cell printing shows several distinct advantages among the single-cell isolation techniques, such as precise deposition, high encapsulation efficiency, and easy recovery. [...] Read more.

Single-cell analysis is becoming an indispensable tool in modern biological and medical research. Single-cell isolation is the key step for single-cell analysis. Single-cell printing shows several distinct advantages among the single-cell isolation techniques, such as precise deposition, high encapsulation efficiency, and easy recovery. Therefore, recent developments in single-cell printing have attracted extensive attention. We review herein the recently developed bioprinting strategies with single-cell resolution, with a special focus on inkjet-like single-cell printing. First, we discuss the common cell printing strategies and introduce several typical and advanced printing strategies. Then, we introduce several typical applications based on single-cell printing, from single-cell array screening and mass spectrometry-based single-cell analysis to three-dimensional tissue formation. In the last part, we discuss the pros and cons of the single-cell strategies and provide a brief outlook for single-cell printing. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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33 pages, 2158 KiB

Open AccessReview

Point-of-Care Testing—The Key in the Battle against SARS-CoV-2 Pandemic

by Florina Silvia Iliescu, Ana Maria Ionescu, Larisa Gogianu, Monica Simion, Violeta Dediu, Mariana Carmen Chifiriuc, Gratiela Gradisteanu Pircalabioru and Ciprian Iliescu

Micromachines 2021, 12(12), 1464; https://doi.org/10.3390/mi12121464 - 27 Nov 2021

Cited by 19 | Viewed by 5766

Abstract

The deleterious effects of the coronavirus disease 2019 (COVID-19) pandemic urged the development of diagnostic tools to manage the spread of disease. Currently, the “gold standard” involves the use of quantitative real-time polymerase chain reaction (qRT-PCR) for SARS-CoV-2 detection. Even though it is [...] Read more.

The deleterious effects of the coronavirus disease 2019 (COVID-19) pandemic urged the development of diagnostic tools to manage the spread of disease. Currently, the “gold standard” involves the use of quantitative real-time polymerase chain reaction (qRT-PCR) for SARS-CoV-2 detection. Even though it is sensitive, specific and applicable for large batches of samples, qRT-PCR is labour-intensive, time-consuming, requires trained personnel and is not available in remote settings. This review summarizes and compares the available strategies for COVID-19: serological testing, Point-of-Care Testing, nanotechnology-based approaches and biosensors. Last but not least, we address the advantages and limitations of these methods as well as perspectives in COVID-19 diagnostics. The effort is constantly focused on understanding the quickly changing landscape of available diagnostic testing of COVID-19 at the clinical levels and introducing reliable and rapid screening point of care testing. The last approach is key to aid the clinical decision-making process for infection control, enhancing an appropriate treatment strategy and prompt isolation of asymptomatic/mild cases. As a viable alternative, Point-of-Care Testing (POCT) is typically low-cost and user-friendly, hence harbouring tremendous potential for rapid COVID-19 diagnosis. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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40 pages, 2307 KiB

Open AccessReview

E-Skin: The Dawn of a New Era of On-Body Monitoring Systems

by Alina-Cristina Bunea, Violeta Dediu, Edwin Alexandru Laszlo, Florian Pistriţu, Mihaela Carp, Florina Silvia Iliescu, Octavian Narcis Ionescu and Ciprian Iliescu

Micromachines 2021, 12(9), 1091; https://doi.org/10.3390/mi12091091 - 10 Sep 2021

Cited by 30 | Viewed by 7966

Abstract

Real-time “on-body” monitoring of human physiological signals through wearable systems developed on flexible substrates (e-skin) is the next target in human health control and prevention, while an alternative to bulky diagnostic devices routinely used in clinics. The present work summarizes the recent trends [...] Read more.

Real-time “on-body” monitoring of human physiological signals through wearable systems developed on flexible substrates (e-skin) is the next target in human health control and prevention, while an alternative to bulky diagnostic devices routinely used in clinics. The present work summarizes the recent trends in the development of e-skin systems. Firstly, we revised the material development for e-skin systems. Secondly, aspects related to fabrication techniques were presented. Next, the main applications of e-skin systems in monitoring, such as temperature, pulse, and other bio-electric signals related to health status, were analyzed. Finally, aspects regarding the power supply and signal processing were discussed. The special features of e-skin as identified contribute clearly to the developing potential as in situ diagnostic tool for further implementation in clinical practice at patient personal levels. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2021)

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