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Updated: Aug 5, 2026
Evaluation of Antimicrobial Activities of Nanoparticles and Nanostructured Surfaces In Vitro
Published on: April 21, 2023
Comparative evaluation of clindamycin-loaded silver or gold-based nanoparticle coatings with and without polyethylene
Mamta Verma1, Ashish Agrawal1, Bratindranath Mukherjee2
1Unit of Orthodontics and Dentofacial Orthopedics, Faculty of Dental Science, IMS Banaras Hindu University, 221005 Varanasi Uttar Pradesh, India.
Objective:
To compare the surface morphology and time-dependent antimicrobial effectiveness of antibiotic-loaded silver and gold nanoparticle coatings, with or without polyethylene glycol, applied to anodized titanium orthodontic mini-implants.
Methods:
Twenty-eight Ti-6Al-4V mini-implants (ARROW) were divided into four groups: Ti-AgNP-PEG-CM (Group A), Ti-AgNP-CM (Group B), Ti-AuNP-PEG-CM (Group C), and Ti-AuNP-CM (Group D). After anodization and SILAR nanoparticle deposition, the surface morphology was examined by HR-SEM and atomic force microscopy (AFM), the chemical composition was analysed by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), and crystallographic phase characterisation was performed by X-ray diffraction (XRD). Antibacterial activity against Staphylococcus aureus and Enterococcus faecalis was quantitatively evaluated at 6, 24, 48, and 72hours using a standard colony-forming unit (CFU/mL) assay. A two-way repeated-measures ANOVA with Bonferroni correction was used for statistical analysis.
Results:
PEG-containing groups demonstrated lower surface roughness on AFM and more homogeneous surface morphology on SEM. XRD suggest crystalline fcc nanoparticle deposition in respective groups. ATR-FTIR spectra showed characteristic bands attributable to PEG (1070-1110cm-1) and clindamycin-related functional groups (600-3400cm-1) across the coated groups. Group C achieved the lowest average colony counts for both S. aureus. Coating over time showed a significant interaction (P<0.001).
Conclusions:
Ti-AuNP-PEG-CM demonstrated the most effective antibacterial performance against both test organisms throughout the 72-hour evaluation period. Although direct drug-release kinetics were not measured in this study, PEG emerged as an important formulation factor across nanoparticle types. These findings support further in vivo evaluation of PEG-based nanocomposite coatings to reduce early peri-implant bacterial colonization.