Among the more than 120 different types of human papillomavirus (HPV), types 16 and 18 have been known to be high risk agents that cause cervical cancer. We examined, in an immuno-chromatographic analysis, the potential of using the early gene product, E7 protein, as a diagnostic marker of cervical cancer caused by HPV. We developed monoclonal antibodies specific to HPV-16 and 18 E7 proteins that were produced from bacterial cells using gene recombinant technology. For each E7 protein, the optimal antibody pair was selected using the immuno-chromatographic sandwichtype binding system based on the lateral flow through membrane pores. Under these conditions, this rapid testing assay had a detection capability as low as 2 ng/mL of E7 protein. Furthermore, since viral analysis required the host cell to be lysed using chemicals such as detergents, it was possible that the E7 protein was structurally damaged during this process, which would result in a decrease in detection sensitivity. Therefore, we examined the detrimental effects caused by different detergents on the E7 protein using HeLa cells as the host. In these experiments, we found that the damage caused by the detergent, nonylphenylpolyethylene glycol (NP-40), was minimal relative to Triton X-100 commonly used for the cell lysis. Temperature also affected the stability of the E7 protein, and we found that the E7 protein was stabilized at 4 o C for about 2 h, which was 4 times longer than at room temperature. Finally, a HPV-infected cervical cancer cell line, which was used as a real sample model, was treated using the optimized conditions and the presence of E7 proteins were analyzed by immuno-chromatography. The results of this experiment demonstrated that this rapid test could specifically detect HPV-infected samples.

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Rotavirus is a leading cause of death in young children worldwide. Although vaccines are currently available and reduce the disease burden, most low-income countries rely on diagnosis by point-of-care testing owing to its rapidity, simplicity, and affordability; however, its sensitivity remains a problem. Magnetically assisted antigen enrichment improves the sensitivity with increased fluorescence intensity. However, magnetic nanoparticles (NPs) strongly absorb ultraviolet light, limiting the combination of magnetic NPs and quantum dots (QDs). Therefore, this study aimed to establish a magnetic-fluorescent nanocluster composed of magnetite (Fe 3 O 4 ) NPs and CdSe−CdS core−shell QDs for a high-sensitivity lateral flow assay (LFA). Inducing a solvophobic interaction mediated by solvent polarity increased the interparticle distance. Consequently, the self-assembled nanoclusters exhibited a QD-embedded structure with Fe 3 O 4 NPs on the outer layer. The magnetic enrichment enhanced the detection limit of the rotavirus antigen up to 1.0 × 10 1 TCID 50 /mL, where TCID 50 represents the median tissue culture infectious dose. The clinical trial results showed that the established LFA platform outperformed commercial test kits. Thus, this study provides a nanotechnologybased LFA platform with increased sensitivity for inhibiting the propagation of viruses.

No abstract

The modification of a gas diffusion layer (GDL), a vital component in polymer electrolyte fuel cells, is described here for use in the electrochemical detection of antibody-antigen biosensors. Compared to other substrates (gold foil and graphite), mouse anti-rHBsAg monoclonal antibody immobilized on gold-coated GDL (G-GDL) detected analytes of goat anti-mouse IgG antibody-ALP using a relatively low potential (−0.0021 V vs. Ag/AgCl 3 M NaCl), indicating that undesired by-reactions during electrochemical sensing should be avoided with G-GDL. The dependency of the signal against the concentration of analytes was observed, demonstrating the possibility of quantitative electrochemical biosensors based on G-GDL substrates. When a sandwich method was employed, target antigens of rHBsAg with a concentration as low as 500 ng/mL were clearly measured. The detection limit of rHBsAg was significantly improved to 10 ng/mL when higher concentrations of the 4-aminophenylphosphate monosodium salt (APP) acting on substrates were used for generating a redox-active product. Additionally, it was shown that a BSA blocking layer was essential in improving the detection limit in the G-GDL biosensor.