Fast parallel detection of feline panleukopenia virus DNA by multi-channel microchip electrophoresis with programmed step electric field strength

Recent advances in microchip electrophoresis for analysis of pathogenic bacteria and viruses

Life-threatening diseases, such as hepatitis B, pneumonia, tuberculosis, and COVID-19, are widespread due to pathogenic bacteria and viruses. Therefore, the development of highly sensitive, rapid, portable, cost-effective, and selective methods for the analysis of such microorganisms is a great challenge. Microchip electrophoresis (ME) has been widely used in recent years for the analysis of bacterial and viral pathogens in biological and environmental samples owing to its portability, simplicity, cost-effectiveness, and rapid analysis. However, microbial enrichment and purification are critical steps for accurate and sensitive analysis of pathogenic bacteria and viruses in complex matrices. Therefore, we first discussed the advances in the sample preparation technologies associated with the accurate analysis of such microorganisms, especially the on-chip microfluidic-based sample preparations such as dielectrophoresis and microfluidic membrane filtration. Thereafter, we focused on the recent advances in the lab-on-a-chip electrophoretic analysis of pathogenic bacteria and viruses in different complex matrices. As the microbial analysis is mainly based on the analysis of nucleic acid of the microorganism, the integration of nucleic acid-based amplification techniques such as polymerase chain reaction (PCR), quantitative PCR, and multiplex PCR with ME will result in an accurate and sensitive analysis of microbial pathogens. Such analyses are very important for the point-of-care diagnosis of various infectious diseases.

Development of a recombinase polymerase amplification assay with lateral flow dipstick for rapid detection of feline parvovirus

Feline panleukopenia caused by feline parvovirus (FPV), a single-stranded DNA virus, is typically highly contagious and often presents with lethal syndrome. The broad spectrum of possible hosts suggests its potential for transmission from animal to person through close contact with pets. FPV thus serves as an example of the importance of new rapid point-of-care field diagnostic tools for the control and prevention of transmission, especially among rare wild animals and pet cats. Recombinase polymerase amplification (RPA), as a real-time and isothermal method, could be a more affordable alternative to PCR when combined with a lateral flow dipstick (LFD) indicator. In this study, we report a novel FPV lateral flow dipstick RPA (LFD-RPA) instant detection method capable of detecting a range of different FPV strains. The LFD-RPA assay consists of specific primers, probe, and nucleic acid strip. It is capable of detecting 10² copies of target nucleic acid per reaction, which is one order of magnitude higher than the sensitivity of traditional PCR. The most suitable reaction conditions for this assay are at 38 ℃ for 15 min. This paper develops an efficient visual detection system that can eliminate the need for professional staff and expensive and sophisticated equipment for field detection.

Fast high-throughput screening of angiotensin-converting enzyme insertion/deletion polymorphism by variable programmed electric field strength-based microchip electrophoresis

An insertion (I)/deletion (D) polymorphism in angiotensin-converting enzyme (ACE) has been associated with susceptibility to various diseases in numerous studies. Traditionally, slab gel electrophoresis (SGE) after polymerase chain reaction (PCR) has been used to genotype this ACE I/D polymorphism. In this study, single- and multi-channel microchip electrophoresis (ME) methods based on variable programmed electric field strength (PEFS) (i.e., low constant, high constant, (+)/(-) staircase, and random electric field strengths) were developed for fast high-throughput screening of this specific polymorphism. The optimum PEFS conditions were set as 470V/cm for 0-9s, 129V/cm for 9-13s, 470V/cm for 13-13.9s, 294V/cm for 13.9-16s, and 470V/cm for 16-20s for single-channel ME, and 615V/cm for 0-22.5s, 231V/cm for 22.5-28.5s, and 615V/cm for 28.5-40s for multi-channel ME, respectively. In the multi-channel PEFS-ME, target ACE I/D polymorphism DNA fragments (D=190bp and I=490bp) were identified within 25s without loss of resolving power, which was ∼300 times faster than conventional SGE. In addition, PCR products of the ACE gene from human blood samples were detected after only 10 cycles by multi-channel PEFS-ME, but not by SGE. This parallel detection multichannel-based PEFS-ME method offers a powerful tool for fast high-throughput ACE I/D polymorphism screening with high sensitivity.