We demonstrate a chemical route to attain simple, clean,
scalable,
photopatternable, chemically adjustable, and versatile systems to
fabricate reactive organic thin films. Their surfaces exhibit effective
biocompatibility, controlled reactivity, and processability on various
surface types, i.e., photo-crosslinkable polymeric thin films with
various functionalities, further applicable for the definition of
surface activity for interfacing biological objects. The copolymers
were synthesized with three monomers: a poly(ethylene glycol)-containing
monomer, a monomer releasing a primary amine upon exposure to UV light,
and a monomer bearing cyclic dithiocarbonate or glycidyl groups that
are highly reactive with the amine. The resulting copolymers were
processed with polar solvents such as water or alcohol for coating
and were readily crosslinked under UV light illumination to form a
highly stable molecular network, beneficial for defining selective
reactive surfaces in a desired region on a variety of organic and
inorganic substrates. The designed system was chemically versatile
in immobilizing biologically relevant molecules on the surfaces by
(i) post-crosslinking modification through the reaction of bovine
serum albumin on the remaining surface reactive group with a primary
amine in the protein and (ii) pre-crosslinking formulation with reactive
gelatin that has the functionality to crosslink in the composite thin
film. We further showed that the resulting coating on a glass or polystyrene
substrate provided excellent biocompatibility and growth of C2C12
murine myocytes.