Electrospun protein nanofibers with nanoscale morphological control for dopamine biosensing.

Electrospun protein-based nanofibers offer a renewable and biocompatible alternative to fully synthetic materials, benefiting from the use of naturally derived components and reduced reliance on petrochemical polymers. Despite their promise, the relationship between processing conditions and fiber morphology remains poorly understood. Here, we present a systematic study of bovine serum albumin:polyethylene oxide (BSA : PEO) nanofibers, focusing on controlling morphology and functionalization for biosensing applications. Electrospinning parameters, solution composition, and pretreatment procedures were optimized to improve process stability and reproducibility of protein-based fibers with specific morphologies. To gain insight into the chemical composition of the fibers, we used advanced characterization techniques such as scattering-type scanning near-field optical microscopy (s-SNOM) with nano-FTIR spectroscopy. This, combined with two-photon-excited green autofluorescence exhibited by the proteins in electrospun fibers, allowed us to examine the internal architecture and provide evidence of molecular-scale structural repeatability. The optimized BSA : PEO fibers served as a biocatalytic layer in model electrochemical biosensors for dopamine detection, showing high sensitivity and reproducibility. These findings highlight protein-polymer composites as strong candidates for potential medical diagnostics, due to their renewable origin and functional versatility. The ability to tune morphology and investigate molecular structure opens new avenues for eco-friendly materials in healthcare and analytical science.