The diversity of biological models for bio-inspired aerosol filters.

Abstract

Innovative filtration systems are essential to enhance air quality or improve aerosol sampling for analysis, while addressing challenges such as high energy consumption, clogging and inefficiencies in capturing a wide range of particle diameters. Bio-inspiration provides novel design strategies by translating natural particle separation mechanisms (PSMs) into more efficient, adaptive and sustainable filtration technologies. This review systematically identifies six organismic groups as biological models that use distinct particle capture mechanisms to retain airborne particles for nutrition, reproduction and protection. Filtration-based PSMs in air, such as insect spiracles, hornet silk caps and spider webs, employ dead-end filtration with varying mesh structures to either purify air or capture prey. Non-filtration PSMs, including nasal cavities and wind pollination, rely on passive aerodynamic mechanisms such as impaction, interception and settling for particle retention. Flow regime control is crucial for non-filtration PSMs, where structures like nasal turbinates and pine cone surfaces optimize local airflows. Adhesive mechanisms, found in spider webs and nasal mucus, improve particle attachment. By mapping these principles to aerosol filtration challenges-such as particle adhesion, flow optimization and efficient removal of submicrometre particles-this review identifies promising pathways for bio-inspired aerosol filters in environmental monitoring, industrial hygiene and public health.