Inactivation of Bacterial and Viral Bioaerosols by Lactoferrin-Coated Filters under Various Environmental Conditions

Accumulation of viable bioaerosols on air filters poses significant occupational health risks, particularly regarding secondary aerosolization during maintenance in high-density indoor environments. To address this challenge, this study developed a bovine lactoferrin-functionalized polypropylene (LfCF) filter as an active engineering control intervention. The filtration performance was evaluated against E. coli and  phage virus under varying environmental conditions. Results demonstrated broad-spectrum inactivation efficacy, with the 2.0 mg coating achieving optimal performance in a dose-dependent manner. Crucially, the lactoferrin coating exhibited superior environmental stability; unlike traditional biopolymers (e.g., chitosan), its antimicrobial efficiency remained consistent across 30–70% relative humidity (RH), ensuring reliability in damp HVAC systems. To validate realistic use scenarios, a field test was conducted in a dental clinic waiting area, achieving an ~83% reduction in airborne bacteria. This study positions LfCFs as a robust, “Safe-by-Design” solution for mitigating bioaerosol exposure and enhancing occupational safety in healthcare and public facilities.