Film-rupture actuated pump-free capillary enrichment for near-source airborne sampling

Area of Science:

• Biomimetic engineering
• Microfluidics
• Environmental science

Background:

• Billions lack access to timely diagnostics for airborne diseases and pollutants, especially in low-resource areas.
• Conventional pump-suction samplers are costly, power-dependent, and prone to analyte loss.

Purpose of the Study:

• To develop a pump-free airborne sampler that unifies collection, recovery, and readout.
• To address limitations of existing sampling technologies for improved accessibility and efficiency.

Main Methods:

• Developed a film-rupture actuated capillary enrichment (FACE) sampler inspired by butterfly proboscis.
• Utilized a biomimetic ring-and-capillary design with a suspending liquid film for collection and film-rupture for autonomous recovery.
• Employed a film-rupture augmented Washburn model and an "empty-effect" design criterion for optimization.

Main Results:

• The FACE sampler achieves submillisecond triggering (<0.5 ms) and high-velocity enrichment (>50 mm s^-1) with near-zero residue.
• Demonstrated superior sampling efficiency and reduced dilution compared to pump-suction devices, enabling lower detection levels.
• Fabricated from low-cost polymers (~$0.12), the sampler is portable, pump-free, and adaptable to various targets and detection methods.

Conclusions:

• The FACE sampler offers a sustainable, scalable, and cost-effective solution for airborne diagnostics.
• Enables high-performance point-of-care technologies for environmental monitoring, agricultural safety, and public healthcare.
• Facilitates equitable access to essential diagnostic services globally.