Biosynthesis of precious metal nanoparticles using green algae extracts for cancer therapy.

Conventional chemical and physical methods for nanoparticle synthesis often involve toxic reagents, high energy demands, and limited biocompatibility. As a result, the biosynthesis of precious metal nanoparticles (PMNPs) using green algal extracts has gained attention as an eco-friendly, low-cost alternative, particularly for biomedical applications. This review explores the synthesis of PMNPs, i.e., silver, gold, platinum, palladium, rhodium, iridium, osmium, and ruthenium, via green algae, emphasizing the role of algal metabolites and phytochemicals in nanoparticle reduction and stabilization. Biosynthesized PMNPs consistently exhibit strong anticancer properties, including dose-dependent cytotoxicity, reactive oxygen species generation, apoptosis induction, and selective activity against cancer cells, especially in breast, cervical, liver, and colorectal cancer models. However, challenges such as limited mechanistic understanding, variability in synthesis outcomes, and scalability constraints remain. This review highlights the cancer therapeutic promise of green algae-mediated PMNPs while outlining critical directions for future research in anticancer nanomedicine.