Rapidly dissolving nanofiber filters for efficient sampling and on-site detection of airborne bacteria

Exposure to airborne bacteria poses significant risks to human health, highlighting the need for on-site sampling and detection to facilitate control and early warning. Commercial dissolvable gelatin filters are efficient samplers but can only dissolve in warm water. This study developed nanofiber gelatin filters that can rapidly dissolve in room-temperature water, facilitating on-site sampling and detecting of airborne bacteria when combined with adenosine triphosphate (ATP) analysis. To enhance the dissolvability of gelatin filters, the electrospinning technique was employed to fabricate the nanofiber filters with a high surface area but low mass. The physical and biological sampling efficiencies of the developed filters were then measured using NaCl particles and airborne bacteria, respectively. The feasibility of on-site detection of airborne bacteria was demonstrated through laboratory and field tests. The results indicate that the developed filters dissolved rapidly in room-temperature water within 2 s. The physical sampling efficiency was 98.96 %, and the biological sampling efficiency was 90 % higher than that of the standard Andersen impactor. Both laboratory and field experiments demonstrated that the proposed method could achieve on-site detection of airborne bacteria within 12 min. This study simplifies the steps and reduces the time needed for on-site sampling and detection of airborne bacteria.