Silicon Microdevices for Novel Microbial Separations

Techniques for the size-based separation of particles have long been established, but there are fewer methods for separating microscopic objects by shape. Using silicon microfabrication, we develop filters that can isolate elongated, high-aspect-ratio particles from more spherical ones. We house the filtration chip in a microfluidic cell that incorporates forward, reverse, and crossflow circulation to aid blockage removal and increase filtration efficacy and lifetime. We used thin film deposition to control hydrophobicity and biocompatibility, and analyze particle shape and size distributions with algorithmic image processing.

At the current scale, we see applications in microbial testing, water quality analysis and microplastics research. Future goals include scaling down to filter cross-reactive antigens, minimizing false test results, and down to the nanoscale for prion–protein separation and identification of cancer biomarkers. Success at this level could advance early detection techniques for prion-based diseases and cancers. The chip also performs conventional filtration, applicable to same-shape particles with narrow tolerances such as mycoplasma. Scalable microfabrication enables cost-effective production for medical and industrial applications.