Spheroid Formation of Human Adipose-Derived Stem Cells on Environmentally Friendly BMA/SBMA/HEMA Copolymer-Coated Anti-Adhesive Surface

Surface coating with sulfobetaine methacrylate (SBMA) containing polymers is a simple method for reducing non-specific protein adsorption and cell adhesion to biomaterials. It has been shown that copolymers of zwitterionic monomers and butyl methacrylate (BMA) could be adsorbed onto hydrophobic substrates in order to provide anti-fouling properties. However, the copolymers of BMA/SBMA dissolved in organic solvents such as DMSO and THF, which is harmful to the host and environment, but not in environmentally friendly solvents, such as methanol and ethanol. Hydroxyethyl methacrylate (HEMA) was introduced in the copolymers in order to enhance the solubility of BMA/SBMA copolymers in methanol and ethanol. The solubility of the copolymers in methanol, ethanol and DMSO were examined. BMA/SBMA/HEMA copolymers in different solvents were coated on polystyrene (PS) plates, and the surface hydrophilicity and anti-fouling capacity were investigated. On the other hand, many studies have pointed out that spheroid formations of stem cells have the abilities to boost functionality and enhance their therapeutic potential. Therefore, the spheroid formation of human adipose-derived stem cells (hASCs) was studied on a plate coated with copolymers. The substrates coated with the copolymers prevented the adhesion of human adipose-derived stem cells (hASCs); moreover, hASCs formed spheroids after 24 hours of culture. In conclusion, the addition of HEMA in the BMA/SBMA copolymers made the copolymers soluble in methanol and ethanol. With the coating of copolymers, cell adhesion was inhibited and the stem cell spheroids were formed on the plate. The copolymers showed a potential for surface modification under an environmentally friendly condition for anti-fouling and stem cell spheroid application.