Biomedical applications of poly (acrylonitrile-co-vinyl acetate) nanofibers functionalized with rhodamine-based Schiff base and its copper (II) complex.

Multifunctional electrospun nanofibrous structures integrating bioactive Schiff base ligands and metal complexes by strategic design present a robust method for advancing next-generation therapeutic biomedical materials. The present work aims to functionalize poly(acrylonitrile-co-vinyl acetate) (PAN) nanofibers with a rhodamine-based Schiff base (FBO) and its copper(II) complex (CuFBO) by the technique of electrospinning. The resulted FBO/PAN and CuFBO/PAN nanofibers were fully characterized and assessed concerning their antioxidant, antidiabetic, antimicrobial, biofilm inhibition, DNA cleavage, and photo antimicrobial activities. DPPH assay demonstrated that PAN exhibited minimal radical-scavenging activity (<1%), whereas FBO/PAN significantly enhanced antioxidant performance, reaching 34.24% at 100 µg/mL. Incorporation of Cu2+ into FBO/PAN slightly reduced antioxidant efficiency, likely due to donor site occupation. Antidiabetic activity evaluation revealed negligible inhibition for PAN, moderate improvement for FBO/PAN (up to 54.86%), and the highest activity for CuFBO/PAN (69.07% at 100 µg/mL), indicating that Cu2+ ions coordination enhances enzyme inhibition. DNA cleavage assay confirmed that none of the composites induced strand breaks. Antimicrobial and anti-biofilm evaluations showed that FBO/PAN markedly suppressed microbial growth and biofilm formation in a concentration-dependent manner, with CuFBO/PAN exhibiting the strongest effects, achieving complete inhibition at higher concentrations. Photodynamic therapy (PDT) experiments demonstrated 100% microbial suppression for both FBO/PAN and CuFBO/PAN, whereas PAN remained inactive. Overall, these findings established that FBO-functionalized PAN nanofibers, particularly their Cu(II) complexes, are multifunctional materials with potent antioxidant, antidiabetic, antimicrobial, anti-biofilm, and photodynamic antimicrobial properties, offering promising potential for biomedical and therapeutic applications.