Microplastic and Nanoplastic Particle Isolation from Liquid and Biological Samples via Mini-Extruder Filtration

Microplastic pollution poses an increasing environmental and human health risk and additional techniques are needed to facilitate nondestructive, quantitative particle recovery and analysis. Using a mini-extruder filtration (MEF) device, the efficiency of pristine particle capture from solution and digested biological tissue (blood clots) was assessed. Polystyrene particles in both the submicron (100, 300, and 500 nm) and micron range (2, 5, 7, and 10 µm) with aminated, carboxylated, or unmodified surface modifications were explored. The MEF-isolated-particle recovery was analyzed pre- and postseparation isolation and quantified via a Nanosight LM10 particle tracking system (submicron particles) or hemacytometer (micron particles). Particles’ surface chemistry and concentration did not impact recovery compared to unfiltered samples with smaller particle sizes reducing recovery efficiency. Micron particle size recovery averaged 86.8 ± 4.3% across all surface chemistries at the same concentration; however, submicron particle recoveries varied by size and charge with 500 nm exhibiting recoveries of 80.6 ± 16.6%, 300 nm 73.0 ± 10.4%, and 100 nm particles 17.0 ± 10.3%. The mini-extruder device, used as a filtration recovery system, efficiently captures 10 to 0.5 µm particles from environmental and tissue samples making it an effective and low-cost platform facilitating the nondestructive capture of diverse microplastics for subsequent analysis.