Electrosprayed genipin cross-linked alginate–chitosan microcarriers for ex vivo expansion of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are potential therapeutic candidates, owing to their ability to differentiate into several cell types. However, the gap between availability and demand of MSCs requires alternative expansion methods from 2D culture flasks. Microcarriers are a promising approach for MSC expansion due to their high surface area-to-volume ratio. However, current commercial microcarriers do not provide the highest cell yield due to low cell attachment efficiencies and difficulty in cell detachment. This study developed a hydrogel-based microcarrier from genipin cross-linked alginate–chitosan beads. Alginate beads were produced by electrospraying before being coated with chitosan and cross-linked in genipin. The degree of cross-linking was determined through fluorescence reading of the genipin-chitosan conjugates. MSCs cultured on these microcarriers had a 26% higher cell attachment and twice the proliferation rate compared to the commercial microcarrier Cytodex 1. Cells easily detached from the hydrogel beads and did not require extended incubation periods or intense agitation during cell harvest. There was no significant difference in gene expression between the two microcarriers for the positive MSC surface markers CD-90, CD-105, and CD-73 as well as showing either low or no signal for negative MSC surface markers CD-45 and CD-34.