F. Bakhtiari, Yasin Ghabool, Najmeh Amiri, Sara Movahedi Roudi, Fateme Gohari Moghaddam, Hadi Zare-Zardini, Bita Behboodian, Ali Es-haghi, Mohammad Ehsan Taghavizadeh Yazdi
The clinical application of metallic nanoparticles (NPs) in cancer therapy, particularly against hepatocellular carcinoma (HepG2), is often hindered by challenges in controlling their structural stability and biological efficacy using biocompatible materials. This study addresses this need by investigating the synthesis of Copper Nanoparticles (CuNPs) and Silver-doped Copper Nanoparticles (Ag-doped CuNPs) using two distinct, natural biopolymers: gelatin (a simple polypeptide) and egg white albumen (a complex globular protein mixture). The novelty of this work lies in the detailed, head-to-head comparison of how the structural disparity of these two biocompatible capping agents dictates the resulting physicochemical and cytotoxic properties of the bimetallic system. Comprehensive characterization was performed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), and zeta potential measurements. The results demonstrated that the gelatin-stabilized nanoparticles exhibited smaller, spherical morphologies (average size 71.25 nm) and superior colloidal stability (+17.4 mV), while albumen promoted the formation of much larger, elongated particles (average dimensions 2500 nm × 800 nm). Silver doping consistently reduced the crystallite size, notably in the gelatin-stabilized samples (20.63 nm). Furthermore, the cytotoxicity of these nanoparticles was evaluated against hepatocellular carcinoma (HepG2). Both gelatin- and albumen-capped Ag-doped CuNPs demonstrated concentration-dependent cytotoxicity, reducing cell viability to approximately 15–20% at high concentrations. Crucially, the apoptosis assay confirmed a dose-dependent mechanism, with gelatin-capped Ag-doped CuNPs inducing extensive apoptosis, reaching 85.6% cell death at high concentrations. This study highlights that gelatin is superior for producing small, stable, and highly effective NPs. The findings provide critical insights into tailoring biocompatible bimetallic nanoparticles with optimized structural and stability characteristics for enhanced therapeutic applications in cancer treatment.