An electrochemical immunosensor based on hybrid self-assembled monolayers for rapid detection of Bombyx mori nucleopolyhedrovirus.

Bombyx mori nucleopolyhedrovirus (BmNPV) is highly contagious and poses a serious threat to sericulture production. Because there are currently no effective treatments for BmNPV, a rapid and simple detection method is urgently needed. This paper describes an electrochemical immunosensor for the detection of BmNPV. The immunosensor was fabricated by covalently immobilizing anti-BmNPV, a biorecognition element, onto the surface of the working gold electrode via 11-mercaptoundecanoic acid (MUA)/ß-mercaptoethanol (ME) hybrid self-assembled monolayers. Electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) were used to characterize the electrochemical performance and morphology of the immunosensor, respectively. Under optimum conditions, the developed immunosensor exhibited a linear response to BmNPV polyhedrin in the range of 1 × 102-1 × 108 fg/mL, with a low detection limit of 14.54 fg/mL. The immunosensor also exhibited remarkable repeatability, reproducibility, specificity, accuracy, and regeneration. Normal silkworm blood was mixed with BmNPV polyhedrin and analyzed quantitatively using this sensor, and the recovery was 92.31 %-100.61 %. Additionally, the sensor was used to analyze silkworm blood samples at different time points after BmNPV infection, and an obvious antigen signal was detected at 12 h post infection. Although this result agreed with that provided by the conventional polymerase chain reaction (PCR) method, the electroanalysis method established in this study was simpler, shorter in detection period, and lower in material cost. Furthermore, this innovative electrochemical immunosensor, developed for the ultra-sensitive and rapid detection of BmNPV, can be used for the early detection of virus-infected silkworms.

Rapid Detection of the Bursaphelenchus Xylophilus by Denaturation Bubble-mediated Strand Exchange Amplification.

Bursaphelenchus xylophilus (B. xylophilus) is one of the most important causal agents of infectious diseases in forest pathology. Obviously, the rapid detection of B. xylophilus is an urgent need for its prevention and cure. We have developed a detection method of B. xylophilus by strand exchange amplification (SEA). This method could detect 105 copies of genomic DNA of B. xylophilus, and it was sufficiently sensitive to detect a single nematode as short as 40 min. Moreover, because the amplification result could be visualized by the naked eyes, the only equipment required throughout the process was a simple isothermal block. Therefore, our method would be a potential for developing on-site detection of B. xylophilus to prevent and control its spread.