Statistical optimization of Chlorella vulgaris polysaccharides-mediated synthesis of platinum nanoparticles with dual functions: anticancer and anticoagulant activities

The biomedical application of platinum nanoparticles (PtNPs) has gained increasing attention in recent years; however, conventional chemical synthesis often depends on harsh conditions and toxic reagents, which restrict their medical use due to concerns of cytotoxicity and environmental hazards. As a result, the development of eco-friendly and biocompatible methods has become a major focus in nanobiotechnology. This study introduces a green method using intracellular polysaccharides from Chlorella vulgaris strain ESA251 as reducing and stabilizing agents to create biocompatible CV-PtNPs, evaluating their dual anticancer and anticoagulant activities. Polysaccharides were extracted from Chlorella vulgaris strain ESA251 and characterized by GC-MS, revealing a heteropolysaccharide composition rich in glucose, mannose/galactose, rhamnose, and uronic acid. Platinum nanoparticles were synthesized under optimized conditions (20 mL polysaccharide extract, 40 mL 0.5 mM Hexachloroplatinic acid hexahydrate (H2PtCl6.6H2O), 97 °C, pH 12, 1 h, identified by plackett-Burman design (PBD). UV-Vis, Fourier Transform Infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) confirmed the formation of quasi-spherical, well-dispersed nanoparticles predominantly within the nanoscale range (~ 5–20 nm) stabilized by hydroxyl, carbonyl, and ether groups. In vitro assays showed dose-dependent cytotoxicity against Human Breast Adenocarcinoma (MCF-7) and Human Hepatocellular Carcinoma (HepG-2) cancer cells, with IC50 values of 20.9 µg/mL and 74.1 µg/mL, respectively. These values suggest promising anticancer activity compared with previously reported chemically synthesized PtNPs. Anticoagulant studies demonstrated inhibition of visible clot formation under the tested in vitro conditions, highlighting them as potential anticoagulant candidates requiring further validation. This dual functionality may provide a basis for future exploration of combined anticancer and anticoagulant strategies, potentially relevant to limiting circulating tumor cell survival. These findings demonstrate that Chlorella vulgaris functions as an efficient microbial platform for the statistically optimized and sustainable biosynthesis of biologically active platinum nanoparticles, supporting their further evaluation in anticancer and anticoagulant research.