Au-Polydopamine integrated polycaprolactone-based 2D plasmonic nanofibrous bimodal platform for synergistically enhanced peripheral neuropathy and superior cancer theranostics

Herein, we report bifunctional 2D aligned PCL@Au-PDA nanofibrous hybrid scaffolds composed of core-shell Au-PDA and PCL were prepared using a facile one-step electrospinning method. 36 nm sized AuNPs were surface functionalized with a 15 nm shell of PDA and resulted in Au-PDA with two concentrations of 1.5 mg and 3.0 mg uniformly dispersed in PCL that provided unique topological, biological properties and potential synergistic outcomes. Besides, PCL@Au-PDA provides exceptional extracellular matrix (ECM) for cell adhesion, nerve growth, proliferation, and differentiation of PC-12 and high affinity to S-42 cells. The gene expression analysis (qRT-PCR) showed a significantly increased expression level of the Actin beta, TREK-1, and MAP2 which further implied enhanced cell migration, proliferation, maturation, and differentiation. There was more than a 2.2-fold increase in the neurite length with PCL@Au-PDA as compared to pure PCL. Also, PCL@Au-PDA showed excellent photothermal efficiency and was found to ablate 95.23 % MCF-7 cells in 5.0 min at 0.5 W/cm² of NIR laser power. The 15 nm PDA surface coating on AuNPs amplifies the photothermal effect of PCL@Au-PDA and accelerates the conversion of light energy to heat energy which stimulates the destruction of human breast cancer cells. FACS analysis showed the apoptotic percentages for MCF-7 cells at 69.67 % with PCL@Au-PDA whereas for pure PCL only 7.93 % were recorded which suggested that the superior plasmonic photothermal efficacy of PCL@Au-PDA even at low power density. PCL@Au-PDA nanofibers could be a highly promising bioactive material for breast cancer phototherapy and a possible bioimplant for sensation restoration after breast regeneration.