Rapid, inexpensive, and laboratory-free diagnostic of viral pathogens is highly critical in controlling viral pandemics. In recent years, nanopore-based sensors have been employed to detect, identify, and classify virus particles. By tracing ionic current containing target molecules across nano-scale pores, nanopore sensors can recognize the target molecules at the single-molecule level. In the case of viruses, they enable discrimination of individual viruses and obtaining important information on the physical and chemical properties of viral particles. Despite classical benchtop virus detection methods, such as amplification techniques (e.g., PCR) or immunological assays (e.g., ELISA), that are mainly laboratory-based, expensive and time-consuming, nanopore-based sensing methods can enable low-cost and real-time point-of-care (PoC) and point-of-need (PoN) monitoring of target viruses. This review discusses the limitations of classical virus detection methods in PoN virus monitoring and then provides a comprehensive overview of nanopore sensing technology and its emerging applications in quantifying virus particles and classifying virus sub-types. Afterward, it discusses the recent progress in the field of nanopore sensing, including integrating nanopore sensors with microfabrication technology, microfluidics and artificial intelligence, which have been demonstrated to be promising in developing the next generation of low-cost and portable biosensors for the sensitive recognition of viruses and emerging pathogens.

Purpose The purpose of the study is to explore the potential possibility of using the conductive and piezoresistive nanocomposites that consist of insulating poly(dimethylsiloxane), a very popular silicone polymer, and the amazing properties of carbon nanotubes (CNT) in sensing applications. This nanocomposite is prepared by an optimized process to achieve a high-quality nanocomposite with uniform properties. Design/methodology/approach The optimized process achieved in this study to provide PDMS/CNT nanocomposite includes the appropriate use of ultrasonic bath, magnetic stirrer, molding and curing in certain circumstances that results in obtaining high-quality nanocomposite with uniform properties. Experiments to characterize the influence of some factors such as pressure, temperature and the impact of CNT’s concentration on the electrical properties of the prepared nanocomposite have been designed and carried out. Findings The obtained preparing method of this nanocomposite is found to have better homogeneity in comparison to other methods for CNT/PDMS nanocomposite. This nanocomposite has both desirable properties of the PDMS elastomer and the additional conductive CNT, and it can be used to create all-polymer systems. Furthermore, the conductivity values of these nanocomposites can be changed by varying some factors such as temperature and pressure, so that those can be used in temperature- and pressure-sensoring applications. Originality/value In the present research, a convenient, inexpensive and reproducible method for preparing CNT/PDMS nanocomposite was investigated. These nanocomposites with the unique properties of both PDMS elastomer and CNTs and also with high electrical conductivity, piezoresistive properties and temperature dependent resistivity can be used in different sensoring applications.

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Molecularly imprinted polymers (MIPs) and cellimprinter polymers (CIPs) have emerged as synthetic recognition elements in biomimetic sensors. In this paper, we have conducted a parametric study to optimize a bulk polymerization methodology for uniform functionalization of stainless steel microwires (MWs) with CIPs comprising single to fourplex combinations of functional monomers (FMs). MWs are widely used in biosensors, and their functionalization with single-FM MIPs has been demonstrated. Complex MIPs comprising multiple FMs have shown enhanced selectivity toward microorganisms, but their coating on MWs has yet to be shown. Moreover, imprinting microorganisms into these coatings has not been reported. In our studies, solvent, FM, crosslinker-to-FM ratio, polymerization temperature, and time were found to significantly influence the thickness and uniformity of CIP coatings on MWs. Reproducible CIP coatings with a thickness of 2.2 ± 0.4 μm, imprinted with E. coli OP50 as the template, were achieved. E. coli rebinding assays demonstrated a 76 ± 10% capture efficiency in a suspension with an initial bacteria count of 10 4 CFU/mL, using a 3 cm long CIP-MW with an optimized fourplex CIP composition, while the capture efficiency obtained by using a single-monomer CIP composition was 30 ± 5%. Our results indicated a higher binding capacity of fourplex CIP-MWs to target bacteria, while nonsignificant binding was obtained using single-monomer CIP-MWs. The addition of N-vinylpyrrolidone significantly increased the binding performance due to its hydrophobic−hydrophilic functional groups interacting with counterparts on the surface of bacterial cells. The developed CIP-MWs can be integrated with microfluidic sensing systems as low-cost and stable working electrodes for future transduction of CIP-target binding events to an electrical read-out in CIP-based electrochemical biomimetic sensors.

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