Biomimetic synthesis of chitosan-stabilized palladium nanoparticles for biomedical and catalytic applications

We report the biomimetic synthesis of chitosan-stabilized palladium nanoparticles (PdNPs@CS) using Bos taurus indicus (BTI) urine as a benign bioreductant and chitosan as a stability scaffold. Powder X-ray diffraction with Rietveld refinement confirmed the presence of crystalline fcc-Pd, while TEM revealed the presence of quasi-spherical PdNPs uniformly distributed on the chitosan matrix, even after catalysis. Under aqueous and dark conditions, PdNPs@CS catalyzes NaBH₄-driven hydride transfer from nitroarenes to aminoarenes via the Langmuir-Hinshelwood pathway. The reaction followed pseudo-first-order kinetics in excess NaBH₄ with representative apparent rate constants of 0.0067 s^-1 (4-NP) and 0.0087/0.0182/0.0154 s^-1 (2-/3-/4-NA). The catalyst showed robust recyclability, offering high conversions till the fifth cycle, with post-reaction XRD/TEM verifying the phase and morphological integrity. Biological assessments demonstrated favorable hemocompatibility, significant antioxidant activity, pro-angiogenic effects, and selective antiproliferative efficacy at appropriate concentrations, indicating a biocompatible interface suitable for biomedical applications. PdNPs@CS integrated the advantages of eco-friendly synthesis, efficient aqueous hydride-transfer catalysis, operational reusability, and promising biological applications, positioning this material as a multifunctional platform for water remediation and allied biomedical applications and aligning with contemporary biopolymer-engineered materials for sustainable pollutant mitigation and cycling stability.