Showing papers in "Mikrochimica acta in 2022"
TL;DR: Laser-induced graphene (LIG) is a class of three-dimensional (3D) porous carbon nanomaterial as discussed by the authors , which can be prepared by direct laser writing on some polymer materials in the air.
Abstract: Laser-induced graphene (LIG) is a class of three-dimensional (3D) porous carbon nanomaterial. It can be prepared by direct laser writing on some polymer materials in the air. Because of its features of simplicity, fast production, and excellent physicochemical properties, it was widely used in medical sensing devices. This minireview gives an overview of the characteristics of LIG and LIG-driven sensors. Various methods for preparing graphene were compared and discussed. The applications of the LIG in biochemical sensors for ions, small molecules, microRNA, protein, and cell detection were highlighted. LIG-based physical physiological sensors and wearable electronics for medical applications were also included. Finally, our insights into current challenges and prospects for LIG-based medical sensing devices were presented.
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TL;DR: In this article , a gold nanotriangles (AuNTs) functionalized with dithiolated oligonucleotides have been employed to develop an amplification-free electrochemical biosensor for SARS-CoV-2 in patient samples.
Abstract: Gold nanotriangles (AuNTs) functionalized with dithiolated oligonucleotides have been employed to develop an amplification-free electrochemical biosensor for SARS-CoV-2 in patient samples. Gold nanotriangles, prepared through a seed-mediated growth method and exhaustively characterized by different techniques, serve as an improved electrochemical platform and for DNA probe immobilization. Azure A is used as an electrochemical indicator of the hybridization event. The biosensor detects either single stranded DNA or RNA sequences of SARS-CoV-2 of different lengths, with a low detection limit of 22.2 fM. In addition, it allows to detect point mutations in SARS-CoV-2 genome with the aim to detect more infective SARS-CoV-2 variants such as Alpha, Beta, Gamma, Delta, and Omicron. Results obtained with the biosensor in nasopharyngeal swab samples from COVID-19 patients show the possibility to clearly discriminate between non-infected and infected patient samples as well as patient samples with different viral load. Furthermore, the results correlate well with those obtained by the gold standard technique RT-qPCR, with the advantage of avoiding the amplification process and the need of sophisticated equipment.
16 citations
TL;DR: This review summarizes the recent progress that has been made in the field of CPNs for biological and biomedical applications with special emphasis on biosensing, imaging, and theranostics and gives an outlook on the potential future trends onCPNs as advanced healthcare material.
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TL;DR: A sensitive SERS-based microfluidic immunosensor was developed to separate and detect Escherichia coli O157:H7 in romaine lettuce and provides a reliable, selective, and sensitive approach for the detection of various pathogens in complex food samples.
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TL;DR: The as-prepared biosensor was feasible for accurate and quantitative detection of miRNA-21 in normal human serum samples with RSD below 5.86%, which showed a great potential in clinical analysis and disease diagnosis.
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TL;DR: In this paper , the authors present a summary of the COVID-19 pandemic, clinical features and epidemiology and pathogenesis, focusing on the recent advances in bioanalytical diagnostic methods based on various techniques for SARS-CoV-2 sensing that have recently been published (2020-2021).
Abstract: A new epidemic of acute respiratory viral pneumonia was discovered in central China at the end of 2019. The disease was given the name coronavirus disease 2019 (COVID-19), and the virus that caused this disease was known as severe acute respiratory syndrome coronavirus (SARS-CoV-2). So far, diagnostic methods have been focused on (a) human antibody detection, (b) viral antigen detection and (c) viral gene detection, the latter using RT-PCR being the most accurate approach. In this paper, we present a summary of the COVID-19 pandemic, clinical features and epidemiology and pathogenesis. Also, we focus on the recent advances in bioanalytical diagnostic methods based on various techniques for SARS-CoV-2 sensing that have recently been published (2020-2021). Furthermore, we present the mechanisms, advantages and disadvantages of the most common biosensors for COVID-19 detection, which include optical, electrochemical and piezoelectric biosensors as well as wearable and smart nanobiosensors, immunosensors, aptasensors and genosensors.
TL;DR: This review focuses on the state of the art in multiplexed detection of biomarkers based on nanomaterial-assisted microfluidics, which have been extensively applied in various domains and show great potential in future point-of-care testing and clinical diagnostics.
TL;DR: The newest modulated CDs for targeted live-cell imaging of whole-cell, cell organelles, pH, ions, small molecules, and proteins are elaborately discussed, and their challenges in these fields are explained.
TL;DR: In this paper , a 3D printed batch injection analysis (BIA) cell and an electrochemical platform with eight sensing electrodes were used for biological fluid analysis, and the performance of the 3D-printed system was evaluated using adrenaline (ADR) as target analyte and its redox activities were carefully evaluated through different voltammetric techniques.
Abstract: The 3D printing is described of a complete and portable system comprising a batch injection analysis (BIA) cell and an electrochemical platform with eight sensing electrodes. Both BIA and electrochemical cells were printed within 3.4 h using a multimaterial printer equipped with insulating, flexible, and conductive filaments at cost of ca. ~ U$ 1.2 per unit, and their integration was based on a threadable assembling without commercial component requirements. Printed electrodes were exposed to electrochemical/Fenton pre-treatments to improve the sensitivity. Scanning electron microscopy and electrochemical impedance spectroscopy measurements upon printed materials revealed high-fidelity 3D features (90 to 98%) and fast heterogeneous rate constants ((1.5 ± 0.1) × 10-3 cm s-1). Operational parameters of BIA cell were optimized using a redox probe composed of [Fe(CN)6]4-/3- under stirring and the best analytical performance was achieved using a dispensing rate of 9.0 µL s-1 and an injection volume of 2.0 µL. The proof of concept of the printed device for bioanalytical applications was evaluated using adrenaline (ADR) as target analyte and its redox activities were carefully evaluated through different voltammetric techniques upon multiple 3D-printed electrodes. The coupling of BIA system with amperometric detection ensured fast responses with well-defined peak width related to the oxidation of ADR applying a potential of 0.4 V vs Ag. The fully 3D-printed system provided suitable analytical performance in terms of repeatability and reproducibility (RSD ≤ 6%), linear concentration range (5 to 40 µmol L-1; R2 = 0.99), limit of detection (0.61 µmol L-1), and high analytical frequency (494 ± 13 h-1). Lastly, artificial urine samples were spiked with ADR solutions at three different concentration levels and the obtained recovery values ranged from 87 to 118%, thus demonstrating potentiality for biological fluid analysis. Based on the analytical performance, the complete device fully printed through additive manufacturing technology emerges as powerful, inexpensive, and portable tool for electroanalytical applications involving biologically relevant compounds.
TL;DR: In this paper , a novel electrochemical sensor is reported for the detection of the antiviral drug favipiravir based on the core-shell nanocomposite of flower-like molybdenum disulfide (MoS2) nanospheres and molecularly imprinted polymers (MIPs).
Abstract: A novel electrochemical sensor is reported for the detection of the antiviral drug favipiravir based on the core-shell nanocomposite of flower-like molybdenum disulfide (MoS2) nanospheres and molecularly imprinted polymers (MIPs). The MoS2@MIP core-shell nanocomposite was prepared via the electrodeposition of a MIP layer on the MoS2 modified electrode, using o-phenylenediamine as the monomer and favipiravir as the template. The selective binding of target favipiravir at the MoS2@MIP core-shell nanocomposite produced a redox signal in a concentration dependent manner, which was used for the quantitative analysis. The preparation process of the MoS2@MIP core-shell nanocomposite was optimized. Under the optimal conditions, the sensor exhibited a wide linear response range of 0.01 ~ 100 nM (1.57*10-6 ~ 1.57*10-2 μg mL-1) and a low detection limit of 0.002 nM (3.14*10-7 μg mL-1). Application of the sensor was demonstrated by detecting favipiravir in a minimum amount of 10 μL biological samples (urine and plasma). Satisfied results in the recovery tests indicated a high potential of favipiravir monitoring in infectious COVID-19 samples.
TL;DR: In this article , a facile electrochemical method to detect COVID-19 spike protein was developed for quick point-of-care testing using screen-printed electrodes (SPEs).
Abstract: The rapid spread of the novel human coronavirus 2019 (COVID-19) and its morbidity have created an urgent need for rapid and sensitive diagnostics. The real-time polymerase chain reaction is the gold standard for detecting the coronavirus in various types of biological specimens. However, this technique is time consuming, labor intensive, and expensive. Screen-printed electrodes (SPEs) can be used as point-of-care devices because of their low cost, sensitivity, selectivity, and ability to be miniaturized. The ability to detect the spike protein of COVID-19 in serum, urine, and saliva was developed using SPE aided by magnetic beads (MBs) and a portable potentiostat. The antibody-peroxidase-loaded MBs were the captured and catalytic units for the electrochemical assays. The MBs enable simple washing and homogenous deposition on the working electrode using a magnet. The assembly of the immunological MBs and the electrochemical system increases the measuring sensitivity and speed. The physical and electrochemical properties of the layer-by-layer modified MBs were systematically characterized. The performance of these immunosensors was evaluated using spike protein in the range 3.12-200 ng mL-1. We achieved a limit of detection of 0.20, 0.31, and 0.54 ng mL-1 in human saliva, urine, and serum, respectively. A facile electrochemical method to detect COVID-19 spike protein was developed for quick point-of-care testing.
TL;DR: In this paper , the authors focus on critical scientific barriers that the field of point-of-care (POC) testing of SARS-CoV-2 is facing and possible solutions to overcome these barriers using functional nucleic acid (FNA)-based technology.
Abstract: This review focuses on critical scientific barriers that the field of point-of-care (POC) testing of SARS-CoV-2 is facing and possible solutions to overcome these barriers using functional nucleic acid (FNA)-based technology. Beyond the summary of recent advances in FNA-based sensors for COVID-19 diagnostics, our goal is to outline how FNA might serve to overcome the scientific barriers that currently available diagnostic approaches are suffering. The first introductory section on the operationalization of the COVID-19 pandemic in historical view and its clinical features contextualizes essential SARS-CoV-2-specific biomarkers. The second part highlights three major scientific barriers for POC COVID-19 diagnosis, that is, the lack of a general method for (1) designing receptors of SARS-CoV-2 variants; (2) improving sensitivity to overcome false negatives; and (3) signal readout in resource-limited settings. The subsequent part provides fundamental insights into FNA and technical tricks to successfully achieve effective COVID-19 diagnosis by using in vitro selection of FNA to overcome receptor design barriers, combining FNA with multiple DNA signal amplification strategies to improve sensitivity, and interfacing FNA with portable analyzers to overcome signal readout barriers. This review concludes with an overview of further opportunities and emerging applications for FNA-based sensors against COVID-19.
TL;DR: In this paper , a dual recognition biosensor was developed via introducing aptamer strings and molecular imprinting polymer (MIP) for the selective detection of intact SARS-CoV-2 virus based on screen printed carbon electrode (SPCE) modified with nickel-benzene tricarboxylic acid-metal-organic framework (Ni3(BTC)2 MOF).
Abstract: A dual recognition biosensor was developed via introducing aptamer strings and molecular imprinting polymer (MIP) for the selective detection of intact SARS-CoV-2 virus based on screen printed carbon electrode (SPCE) modified with nickel-benzene tricarboxylic acid-metal-organic framework (Ni3(BTC)2 MOF) synthesized by in situ growth method, SARS-CoV-2 S protein-specific amino-aptamer and electropolymerization of dopamine (ePDA). The proposed biosensor showed an excellent linear relationship between charge transfer resistance (Rct) and increase in virus concentration in the range 10 to 108 plaque-forming units/mL (PFU/mL) with a low detection limit of 3.3 ± 0.04 PFU/mL and response time of 20 min. Compared with single-element sensors (aptamer or MIP), it showed higher selectivity for the SARS-CoV-2 virus and facilitated detection in real samples.
TL;DR: A sensitive colorimetric platform for trypsin activity determination was constructed through measuring the absorbance of produced oxTMB at 652 nm, providing a linear detection range of 5 to 500 ng/mL and a low detection limit of 2.8 ng/ mL.
TL;DR: In this article , a homemade carbon black composite filament with polylactic acid (CB-PLA) was used for detecting catechol and hydroquinone in water samples and detecting hydrogen peroxide in milk.
Abstract: The development of a homemade carbon black composite filament with polylactic acid (CB-PLA) is reported. Optimized filaments containing 28.5% wt. of carbon black were obtained and employed in the 3D printing of improved electrochemical sensors by fused deposition modeling (FDM) technique. The fabricated filaments were used to construct a simple electrochemical system, which was explored for detecting catechol and hydroquinone in water samples and detecting hydrogen peroxide in milk. The determination of catechol and hydroquinone was successfully performed by differential pulse voltammetry, presenting LOD values of 0.02 and 0.22 µmol L-1, respectively, and recovery values ranging from 91.1 to 112% in tap water. Furthermore, the modification of CB-PLA electrodes with Prussian blue allowed the non-enzymatic amperometric detection of hydrogen peroxide at 0.0 V (vs. carbon black reference electrode) in milk samples, with a linear range between 5.0 and 350.0 mol L-1 and low limit of detection (1.03 µmol L-1). Thus, CB-PLA can be successfully applied as additively manufactured electrochemical sensors, and the easy filament manufacturing process allows for its exploration in a diversity of applications.
TL;DR: A novel “signal-off” PEC aptasensor mediated by enzymatic amplification was proposed for the sensitive and selective detection of 17β-estradiol (E2) and provided novel insight into the design of potential phoelectroactive materials and the application of signal amplification strategy in environmental analysis field.