Multiphoton Fabrication of Proteinaceous Nanocomposite Microstructures with Photothermal Activity in the Infrared

Two-photon laser writing is used here to fabricate 3D proteinaceous microstructures with photothermal functionality in the near-infrared spectral region and tunable elasticity. The photo-cross-linking is initiated in bovine serum albumin (BSA) by rose bengal or methylene blue and the photo-thermal effect arises from gold non-spherically symmetric nanoparticles dispersed in the ink. Massive energy transfer of the plasmonic resonances of the gold nanoparticles to methylene blue prevents effective photo-crosslinking of BSA. However, stable microstructures with photo-thermal functionality can be fabricated in the rose bengal proteinaceous inks. On these microstructures, with a gold atom concentration as low as 1% w/w, a highly localized temperature increase can be quickly ( approximately equal to 1 s) reached and maintained under continuous wave laser irradiation at 800 nm. The photothermal efficiency under continuous wave laser irradiation depends on the thickness of the microstructure and can reach 12.2 +/- 0.4 degrees C W-1 These proteinaceous microstructures represent therefore a promising platform for future applications in the fields like physical stimulation of cells for regenerative nanomedicine.