Preparation of cell-culturing glass surfaces that release branched polyethyleneimine triggered by thiol–disulfide exchange

To develop a chemical stimulus-responsive substrate for culturing cells, polyethyleneimine (PEI) having a pyridyl disulfide moiety was attached via disulfide linkages to a glass coverslip modified with a silane coupling agent having a thiol group. The surface modification was confirmed by X-ray photoelectron spectroscopy and zeta potential analysis. The obtained surface exhibited sufficiently high cell adhesiveness. Zeta potential measurements revealed that the PEI derivatives were released from the surface through thiol–disulfide exchange when the modified glass coverslip was immersed in a neutral pH buffer containing cysteine. The cell viability assay demonstrated that this chemical stimulus was substantially nontoxic to 293T cells. Because PEI is a widely used transfection reagent, this functional glass coverslip would be potentially useful as an experimental platform for reverse transfection.