Green versus chemical synthesis of platinum nanoparticles: antibacterial, antibiofilm and biocompatibility studies on clinical MDR isolates

The rise of multidrug-resistant bacteria (MDR) poses a serious threat to public health, particularly in hospital environments. Acinetobacter baumannii (A. baumannii) and Staphylococcus hominis (S.hominis) are key pathogens associated with bloodstream infections in surgical patients. This study aimed to evaluate the antibacterial and antibiofilm activities of platinum nanoparticles (PtNPs) synthesized via green (using Mangifera indica leaf extract) and chemical methods. The nanoparticles were characterized using various analytical techniques. Their antibacterial activity was tested against clinical isolates obtained from patient blood samples. The results showed that chemically synthesized PtNPs (PtNPs-Che) exhibited superior antibacterial activity compared to green-synthesized PtNPs (PtNPs-Green), as indicated by lower minimum inhibitory concentration (MIC) values and larger inhibition zones. At 100 µg/mL, inhibition zones reached 20.9 mm for A. baumannii and 25.6 mm for S. hominis, while green PtNPs showed 14.0 mm and 21.0 mm, respectively. Additionally, chemically synthesized PtNPs demonstrated stronger antibiofilm activity, whereas green PtNPs exhibited enhanced stability due to natural capping agents. Both nanoparticle types showed low hemolytic activity at tested concentrations. Molecular docking supported the experimental findings by revealing higher binding affinity of chemically synthesized PtNPs toward bacterial targets. Overall, PtNPs represent a promising strategy for combating MDR bacterial infections.