Hydrogel Patches on Live Cells through Surface-Mediated Polymerization

Many naturally occurring cells possess an intrinsic ability to cross biological barriers that block conventional drug delivery, and these cells offer a possible mode of active transport across the blood-brain barrier or into the core of tumor masses. While many technologies for the formation of complete, nanoparticle-loaded coatings on cells exist, a complete coating on the cell surface would disrupt the interaction of cells with their environments. To address this issue, cell surface patches that partially cover cell surfaces might provide a superior approach for cell-mediated therapeutic delivery. The goal of this study is to establish a simplified approach to producing polymeric patches of arbitrary shapes on a live cell via surface-mediated photopolymerization. Cell surfaces were nonspecifically labeled with eosin, and polyethylene (glycol) diacrylate (PEGDA) coatings were directed to specific sites using 530 nm irradiation through a chrome-coated photomask. These coatings may entrap drug-loaded or imaging particles. The extent of nonspecific formation of PEGDA hydrogel coatings increased with irradiation time, light intensity, and initiating species; 40 mW/cm² irradiation for 5 min delivered high-resolution patterns on the surface of A549 cells, and these cells remained viable for 48 h postpatterning with fluorescent nanoparticle-loaded coatings. This work first demonstrated the feasibility of photopatterning polymer patches directly on the surface of cells.