Stimuli-responsive protein-based micro/nano-waveguides

In this letter, customized protein-based micro/nano-wires with diameters of >= 150 nm have been facilely fabricated from bovine serum albumin (BSA) aqueous ink by maskless and noncontact femtosecond laser direct writing (FsLDW) technology. With the reproducible optimized morphology, the protein-based micro/nanowires here can be applied as optical micro/nano-waveguides with transmission loss of similar to 0.059 dB mm mu m(-1) for 633 nm light. Based on the nature of as-formed protein micro/nano-hydrogels (stimuli-responsive shrinking or swelling), their "smart" environmental stimuli (e.g., pH) responsive features are proved experimentally (similar to 50% output light decrease corresponding to pH value tunning range of similar to 0.4).