Single Viable Bioaerosol Particle Discerning Using Naked Eye Assisted with Laser Trapping and Microwaving

XINYUE LI, Maosheng Yao, Peking University

     Abstract Number: 100
     Working Group: Bioaerosols

Abstract
Viable microbial aerosol detection remains a grant challenge. Instruments replying on laser-induced florescence often produce false positives as chemicals also emit similar florescence when irradiated. Here, we pioneered a new system that integrates laser trapping and microwave irradiation for online discerning of single viable microbial aerosol particle through naked eye. To test the system, three fungal species Aspergillus niger, Aspergillus oryzae, and Trichoderma harzianum and three non-biological particles such as MnO2, active carbon, and Fe3O4 were suspended and laser trapped in the air inside a house-made glass cube. When microwave irradiated, viable fungal spores, containing microwave energy absorbing molecules such as water, were observed to rapidly escape the trapping and even burst with abrupt morphology changes for a longer irradiation time. In contrast, those non-biological particles were observed to behave differently with little morphology change without the cell burst. For all particles tested, microwave irradiation resulted in particle movement within the trapping region, and a particle trapping was then re-established in a new location. Depending on particle type and irradiation time, light scattering properties also differ between biological and non-biological particles when irradiated. Terminating the microwave irradiation was observed to render the non-biological particles to return where they are being laser trapped. Using the developed system, we have demonstrated the viable microbial aerosol detection using naked eye by simply observing the morphology changes and cell burst upon the laser trapping and microwave irradiation. Further efforts on this development could lead to a new generation of bioaerosol detection strategy.