Abstract 292: Magnetic-based Multi-layer Microparticles for Stem Cell Isolation, Enrichment, and Detachment
Due to the extensive therapeutic potential of endothelial progenitor cells (EPCs) in regenerative medicine, various techniques have been developed to isolate and expand them ex vivo. Yet these methods are limited by the use of harmful chemicals and difficulty in ex vivo stem cell expansion. The aim of this research was to develop multi-layer microparticles (MLMPs) that can magnetically isolate EPCs without using Ficoll and harsh shear forces, provide sequential proliferating and differentiating growth factor release for stem cell enrichment, and detach cells in response to temperature changes without the use of chemicals such as Trypsin. MLMPs consisted of a poly(lactic-co-glycolic acid) (PLGA) core embedded with magnetic nanoparticles and the temperature-sensitive polymer (poly(N-isopropyl acrylamide-allylamine): PNIPAAm-AH) shell. MLMPs were formulated and characterized for their physicochemical properties. Studies to investigate growth factor release, optimization concentrations of MLMPs and antibodies as well as the time required for maximal cell isolation were also carried out. Finally, effects of MLMPs on the growth of isolated cells were studied. MLMPs had core-shell structure with spherical morphology of 50-75 μm, and their growth factors were released in a sequential manner required for cell proliferation and differentiation. EPCs successfully attached to the polymer surface, while maintaining their morphology as verified from staining and SEM. Moreover, 64% EPCs were isolated over a period of 2 hours with 1 mg/ml MLMPs conjugated with 3 μg/ml CD34 antibodies. Cells were successfully detached from the particle surface by lowering the surrounding temperature to room temperature for a short time. MLMPs loaded with growth factors show an enhanced cell growth compared to those of commercial beads. These results indicate that MLMPs might have a significant impact on cell isolation and expansion technologies.
- © 2013 by American Heart Association, Inc.