Tetramethacrylic benzylidene cyclopentanone dye for one- and two-photon photopolymerization

Abstract

The crystalline one-component methacrylate containing photoinitiator 4MetBAC was synthesized and characterized by 1H NMR, 13C NMR, IR-, UV–Vis spectrum, and X-Ray analysis. The one- and two-photon absorption, photoluminescence, and electrochemical properties of 4MetBAC in solution were investigated. The polymerization of PETA was induced directly by 4MetBAC (2.5–11.5 mM) under irradiation with LED@380 (1PP) or focused beam of femtosecond laser with wavelength 780 nm (2PP). The polymer nanostructures with intricate architecture («sleepers-rails»-, «cell scaffold»- and cylindrical spiral structures) were fabricated by the DLW method. The polymerization threshold of the composition based on 4Met-BAC (11.5 mM) was 0.9 mW at the recording speed of 170 μm/s. The smallest stable structures with the linear fragment sizes of 72 ± 5 nm (less than λ/10) have been obtained by nanolithography. Due to the polymerizable groups, 4Met-BAC has the ability to link into the polymer networks. Experiments with human dermal fibroblasts and cells of the HEK 293 line have been demonstrated that the final polymers prepared by both one- and two-photon photopolymerization (cell scaffold) are biosafety. Hence we believe that the PETA composition based on one-component methacrylate-containing photoinitiator 4Met-BAC opens up wide capabilities for creating three-dimensional topological structures with high submicron resolution by the DLW method for optoelectronic and biological applications.