Quercetin-Derived Platinum Nanomaterials Influence Particle Stability, Catalytic, and Antimicrobial Performance.

Area of Science:

• Materials Science
• Nanotechnology
• Biochemistry

Background:

• Quercetin has beneficial biological properties but suffers from poor solubility and bioavailability.
• Structural modification of quercetin is necessary to improve its applications.
• Platinum nanoparticles (PtNPs) are of interest for their catalytic and antimicrobial potential.

Purpose of the Study:

• To synthesize shape-dependent platinum nanoparticles (PtNPs) using modified quercetin (4'-QP).
• To investigate the antimicrobial activity of cuboidal (C-PtNPs) and peanut-shaped (P-PtNPs) PtNPs against Citrobacter freundii.
• To evaluate the catalytic efficiency of shape-dependent PtNPs in the reduction of 4-nitrophenol.

Main Methods:

• Aqueous synthesis of PtNPs using 4'-QP as a reducing and stabilizing agent.
• Transmission Electron Microscopy (TEM) for characterization of PtNP size and shape.
• Agar well-diffusion assay and minimum inhibitory concentration (MIC) determination for antimicrobial activity.
• Scanning Electron Microscopy (SEM) to analyze bacterial cell damage.
• Catalytic reduction of 4-nitrophenol using PtNPs and sodium borohydride.

Main Results:

• Monodispersed C-PtNPs (39.1 ± 0.20 nm) and P-PtNPs (45.1 ± 0.24 nm) were successfully synthesized.
• C-PtNPs demonstrated significantly higher antimicrobial activity against C. freundii (16.28 ± 0.10 mm zone of inhibition, 25 μg/mL MIC) compared to P-PtNPs (4.50 ± 0.15 mm zone of inhibition, 45 μg/mL MIC).
• SEM analysis revealed membrane damage and suggested a contact-killing mechanism for C-PtNPs.
• C-PtNPs exhibited superior catalytic activity (k = 0.0108 s⁻¹) for 4-nitrophenol reduction compared to P-PtNPs (k = 0.00607 s⁻¹).

Conclusions:

• Shape-dependent PtNPs synthesized using modified quercetin show promising antimicrobial and catalytic properties.
• Cuboidal PtNPs exhibit enhanced antibacterial efficacy against C. freundii, likely through membrane disruption.
• The catalytic efficiency of PtNPs in degrading pollutants is shape-dependent, with nanocubes being more effective.