Synthesis of Photodynamic Biointerfaces

A variety of pathological processes require culturing of biological cells in vitro. However, contacts between different cell types often influence cellular behavior; in some cases, cells do not function in the absence of a second cell type. Mimicking in vivo cellular responses in vitro thus requires construction of an organized co-culture of multiple cell types. Past approaches relied upon covalent surface modification, limiting throughput and wider adoption. We created an alternative method that employs printing a polymer followed by global illumination. Past results demonstrated controlled assembly of a single cell type with micrometer resolution by microcontact printing a cell-resistant amphiphilic polymer. Insertion of a photocleavable group between the hydrophilic and hydrophobic blocks affords a polymer that becomes cell adhesive after exposure to light. Microcontact printing this photosensitive ink rapidly creates co-cultures of two cell types on a variety of surfaces by printing, seeding the first cell type, converting the printed area by flood illumination and seeding the second cell type. The first cell type occupies the unprinted area, and the second cell type preferentially attaches to the now cell-adhesive printed area. The initial relief pattern of the stamp alone governs the geometry of the resulting cellular array.