Durable and biofunctional polydimethylsiloxane surfaces engineered with photocrosslinkable terpolymers for aligned...

Polydimethylsiloxane (PDMS) is widely used in biomicrodevices owing to its excellent processability, flexibility, and optical properties. However, the poor cell adhesiveness of PDMS limits its application as a stable substrate for long-term cell cultures. To address these challenges, we synthesized a photocrosslinkable terpolymer composed of N-(2-hydroxypropyl)acrylamide, N-benzophenone acrylamide, and N-succinimidyl acrylate (NSA), and covalently grafted it onto PDMS surfaces using UV irradiation. The ternary polymer coatings exhibited long-term stability in aqueous media and suppressed thenonspecific adsorption of proteins and cell adhesion. Furthermore, the immobilization of collagen on the side groups of NSA provides selective cell-adhesive functionality. In particular, PDMS surfaces modified with a ternary polymer containing 10 mol% NSA supported the robust and sustained adhesion of C2C12 myoblasts. When combined with stripe-patterned microstructures, these surfaces promoted unidirectional alignment, efficient myotube formation, and strong expression of dystrophin, with the 25 μm-pitch pattern demonstrating the most pronounced effects. Notably, spontaneous contraction of the formed myotubes confirmed advanced functional differentiation. These results demonstrate that the proposed facile and durable surface modification strategy for PDMS imparts both anti-biofouling properties and selective biofunctionality. The PDMS modification strategy provides a versatile platform for engineering functional muscle fibers and expanding the potential of PDMS-based bio-microdevices and tissue-engineered constructs.