Optimizing Desmostachya bipinnata-derived platinum nanoparticles for enhanced antibacterial and biofilm reduction

This study presents the green synthesis and comprehensive characterization of platinum nanoparticles (PtNPs) using Desmostachya bipinnata (Db) extract, incorporated into two innovative mouthwash formulations (MW1 and MW2). UV–Vis spectroscopy confirmed the successful synthesis of PtNPs, with distinct absorption peaks between 250 and 600 nm. Fourier-transform infrared (FTIR) spectroscopy identified hydroxyl and carbonyl functional groups, critical for the bioreduction and stabilization of PtNPs. High-resolution transmission electron microscopy (HR-TEM) revealed uniformly dispersed, spherical nanoparticles with a size range of 10–20 nm, while dynamic light scattering (DLS) confirmed a hydrodynamic diameter of 10–30 nm and a low polydispersity index (PDI) of 0.238, indicating excellent stability. Both formulations exhibited robust antimicrobial, antibiofilm, and anti-plaque properties, with MW2 showing superior efficacy, particularly against Staphylococcus aureus and Escherichia coli, as well as a notable 70 % reduction in biofilm formation and a 60 % plaque reduction within 2 h of treatment. The study underscores the potential of Desmostachya bipinnata-derived PtNPs as a promising alternative to conventional mouthwash, offering enhanced antimicrobial efficacy, biofilm disruption, and plaque prevention, alongside excellent stability and biocompatibility for oral healthcare applications. [Display omitted] •Eco-friendly synthesis of Pt NPs was achieved using Desmostachya bipinnata extract.•Pt NPs were characterized via UV–Vis, FTIR, HR-TEM, and DLS for stability.•Pt NP-based mouthwash (LM1, LM2) showed potent antibacterial effects in assays.•A 60 % reduction in plaque was observed within 2 h of Pt NP mouthwash use.•GTFB gene downregulation in S. mutans biofilms indicated reduced virulence.