Physicochemical characterization, preliminary biological activity, and exploratory computational analysis of Au-Pt-Ag nanofluids

The increasing prevalence of drug-resistant Mycobacterium tuberculosis and inflammation-associated disorders motivates the investigation of multimetallic nanomaterials with well-characterized physicochemical and biological properties. Au-Pt-Ag nanofluids were characterized using complementary optical, structural, surface-chemical, morphological, and elemental methods. The analyses support the presence of Au, Pt, and Ag and their co-distribution at the spatial resolution of elemental mapping, but do not establish an atomically homogeneous ternary alloy. The nanofluid showed inhibition of BSA denaturation (IC₅₀ = 12.78 ± 0.56 μg/mL) and a fitted antimycobacterial IC₅₀ of 0.46 ± 0.04 μg/mL against Mycobacterium tuberculosis H37Rv. In Vero-cell MTT testing, viability remained 74.6 ± 2.9% at 100 μg/mL; a four-parameter logistic model gave an extrapolated CC₅₀ estimate of 184.52 ± 6.41 μg/mL (R² = 0.9924), corresponding to a nominal selectivity index of 401.13 based on fitted point estimates. Docking, 50 ns molecular dynamics, DCCM, DFT, and ADMET analyses are retained as exploratory computational studies using a simplified cluster representation. Their outputs generate hypotheses about possible nano-bio interactions but do not establish binding affinity, protein inhibition, alloy-specific mechanisms, pharmacokinetics, or safety.