Label-free enrichment of human adipose-derived stem cells using a continuous microfluidic sorting cascade.

Human adipose tissue is a rich source of mesenchymal stem cells (MSCs). Human adipose-derived stem cells (ADSCs) are first prepared by tissue digestion of lipoaspirate. The remaining constituent contains a mixture of ADSCs, other cell types and lysed fragments. We have developed a scalable microfluidic sorter cascade which enabled high-throughput and label-free enrichment of ADSCs prepared from tissue-digested human adipose samples to improve the quality of purified stem cell product. The continuous microfluidic sorter cascade was composed of spiral-shaped inertial and deterministic lateral displacement (DLD) sorters which separated cells based on size difference. The cell count characterization results showed >90% separation efficiency. We also demonstrated that the enriched ADSC sub-population by the microfluidic sorter cascade yielded 6× enhancement of expansion capacity in tissue culture. The incorporation of this microfluidic sorter cascade into ADSC preparation workflow facilitates the generation of transplantation-scale stem cell product. We anticipate our stem cell microfluidic sorter cascade will find a variety of research and clinical applications in tissue engineering and regeneration medicine.