Directed Molecular Assembly and Crosslinking for Conformal Coating of Mesenchymal Stem Cells Using a Bispecific DNA-Enzyme Conjugate

Abstract

Current cell encapsulation methods face problems with large encapsulation volumes. In this study, we present a modular cell-surface conformal coating strategy using a bispecific DNA-enzyme conjugate to direct molecular assembly and crosslinking. The bispecific conjugate exhibited sustained retention on the cell membrane with a half-life on the order of hours. The conjugate catalyzed the formation of a 10 to 20 μm thick fibrin layer upon addition of fibrinogen, allowing the adsorption and deposition of alginate and poly-L-lysine crosslink the coating. The platform was compatible with spheroids spanning ∼200 μm to 1 mm in diameter while maintaining uniform surface coverage. The coating efficiency was 100%, with no empty capsules observed. Encapsulation improved structural stability of spheroids in extracellular matrix culture, preventing spheroid spreading and immune attack while preserving morphology over extended incubation. Encapsulated spheroids maintained high viability and secreted a range of angiogenic factors. These factors enhanced endothelial cell viability, promoted tube formation, and increased cell migration. Therefore, this study successfully demonstrates a strategy for conformal cell coating by displaying a bispecific DNA-enzyme conjugate on the cell surface.