Surface modification of nucleopolyhedrovirus with polydopamine to improve its properties.

Background: Baculoviruses have been developed as promising biopesticides to control pests due to their high host specificity and virulence, and nontoxicity to humans and nontarget animals. However, their sensitivity to ultraviolet (UV) radiation and instability in the natural environment are major constraints to its large-scale application. In this study, polydopamine-nucleopolyhedrovirus microcapsules were established to improve the instability of baculoviruses in sunlight.

Results: The optimal conditions for the preparation of polydopamine-nucleopolyhedrovirus microcapsules were as follows:  Spodoptera exigua nucleopolyhedrovirus (SeMNPV)concentration of 2 × 10  polyhedral inclusion body（PIB） mL , reaction time of 6 h, and pH of 9.0. The particle size of the obtained microcapsules was about 1 μm. The microencapsulated baculovirus improved its thermal stability and wettability, and enhanced its insecticidal activity against Spodoptera exigua. Moreover, under the same UV treatment, the insecticidal effect against S. exigua larvae of microencapsulated baculovirus was only reduced by 8.89%, whereas that of the nonmicroencapsulated baculovirus was reduced by 27.27%.

Conclusion: Polydopamine-nucleopolyhedrovirus microcapsules provided better UV resistance and preparation stability compared with unmodified SeMNPV, and demonstrate an idea for the development of a baculovirus-based stabilized product. © 2021 Society of Chemical Industry.