Highly efficient exosome purification from human plasma by tangential flow filtration based microfluidic chip

Abstract

Abstract Exosomes play an important role in microenvironmental regulation, cellular communication, tumor progression/metastasis and prognosis. A key challenge in the study of exosomes is the isolation and purification of exosomes from contaminants. In this study, we develop a size-dependent microfluidic chip to isolate and purify exosomes from human blood by tangential flow filtration. The microfluidic chip combines symmetrically two polymethyl methacrylate (PMMA) layers with serpentine channels and a nanoporous polycarbonate track etched (PCTE) membrane in between. Due to the uniform pore size (∼100 nm in diameter) of the nanoporous PCTE membrane, protein contaminants can be cleaned with high efficiency (> 97 %), and exosomes trapped in the microfluidic chip can be collected by reverse elution with high recovery (> 80 %). The collected exosomes are subjected to matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) analysis. Based on the fingerprint peaks of exosomes, it is demonstrated that plasma proteins are largely cleaned and only exosome proteins dominate the mass spectra. Compared to ultracentrifugation (UC) that is considered as the “gold standard” for exosome isolation and purification, the size-dependent microfluidic chip-based protocol shows higher protein cleaning efficiency and exosome recovery rate. The whole process takes