A core-shell structured collagen hydrogel microsphere with removable superparamagnetic alginate coating for cell coculture and rapid separation

Abstract

Coculture models have long been used in cell and tissue engineering studies. The direct contact model normally offers excellent cell-cell interactions, but difficult to separate the two cell types after coculture. The non-contact model offers a good cell separation, but the long cell-cell distance limited the cell interactions. This study proposed a conceptual 3D coculture model based on collagen hydrogel microspheres (CHMs) with removable superparamagnetic alginate coating (Alg-Mag-CHMs) to offer a minimal distance and easy separation. The Alg-Mag-CHMs fabrication was achieved using layer-by-layer encapsulation. The thickness could be tailored by applying different numbers of coating layers. Alg-Mag-CHMs had a denser alginate hydrogel shell, which prevented the risk of cell leakage. After mixture, Alg-Mag-CHMs could be rapidly separated in magnet field and the coating could be easily washed off. This study presented proof of concept data of a non-contact 3D coculture model that offered many useful features.