Detection of monkeypox virus using helicase dependent amplification and recombinase polymerase amplification combined with lateral flow test.

The monkeypox virus (MPXV) is a zoonotic DNA virus that belongs to the poxvirus family. Conventional laboratory methods for detecting MPXV are complex and expensive, making them unsuitable for detecting the virus in regions with limited resources. In this study, we using the Helicase dependent amplification (HDA) method and the Recombinase polymerase amplification (RPA) technique in combination with the lateral flow test (LFT), together with a self-designed qPCR technique for the detection of the MPXV specific conserved fragment F3L, to compare the sensitivity and specificity of the three assays. By analyzing the sensitivity detection results using Probit, it can be seen that the limit of detection (LOD) of the HDA-LFT detection target is 9.86 copies/µL (95% confidence interval, CI 7.52 copies/µL lower bound), the RPA-LFT detection target is 6.97 copies/µL (95% CI 3.90 copies/µL lower bound), and the qPCR detection target is 479.24 copies/mL (95% CI 273.81 copies/mL lower bound). The specificity test results showed that the specificity of the three methods mentioned above was higher than 90% in detecting pseudoviruses of the same genus of MPXV. The simple, highly sensitive, and specific MPXV assay developed in this study is anticipated to provide a solid foundation for future applications in the early screening, diagnosis, and evaluation of the efficacy of MPXV. This is the first time the HDA-LFT assay has been utilized to detect MPXV infection.

Addition of dNTPs can improve the detection sensitivity of catalytic hairpin assembly.

Ever since the catalytic hairpin assembly (CHA) circuit has been highlighted as a powerful nucleic acid detection tool, nucleic acid detection methods based on CHA have been widely studied. However, the detection sensitivity of CHA-based methods is insufficient. The relatively high background signals resulting from the spontaneous reaction between the two hairpin probes is one of the major reasons for limiting the sensitivity of CHA. In this study, we established that the addition of deoxynucleotide triphosphates (dNTPs) to the reaction system can significantly reduce the background leakage of CHA. The dNTPs-CHA, coupled with a fluorescence lateral flow assay strip, is used for the rapid and highly sensitive detection of miRNA. It is capable of reliably detecting miRNA in serum samples down to a limit of 100 aM, which is an improvement in the lower detection limit by nearly five orders of magnitude compared to that of the pure CHA.

Isothermal nucleic acid amplification technology in HIV detection.

Nucleic acid testing for HIV plays an important role in the early diagnosis and monitoring of antiretroviral therapy outcomes in HIV patients and HIV-infected infants. Currently, the main molecular diagnostic methods employed are complex, time-consuming, and expensive to operate in resource-limited areas. Isothermal nucleic acid amplification technology overcomes some of the shortcomings of traditional assays and makes it possible to use point-of-care tests for molecular HIV detection. Here, we summarize and discuss the latest technological advances in isothermal nucleic acid amplification for HIV detection, with the intent of providing guidance for the development of subsequent HIV assays with high sensitivity and specificity.