Fabrication of Microbicidal Silver Nanoparticles: Green Synthesis and Implications in the Containment of Bacterial Biofilm on Orthodontal Appliances

Abstract

Among various metal-based nanoparticles, silver nanoparticles (AgNPs) manifest superior inhibitory effects against several microorganisms. In fact, the AgNP-based treatment has been reported to inhibit both sensitive and resistant isolates of bacteria and other disease-causing microbes with equal propensity. Keeping this fact into consideration, we executed bio-mediated synthesis of AgNPs employing extract of flower and various other parts (such as bud and leaf) of the Hibiscus rosa-sinensis plant. The physicochemical characterization of as-synthesized AgNPs was executed employing transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, Fourier transform infrared (FTIR) spectroscopy, and UV-Vis spectroscopy, etc. The as-synthesized AgNPs demonstrated strong antimicrobial activity against both Gram-positive and Gram-negative bacteria with equal propensity. The as-synthesized AgNPs successfully inhibited Streptococcus mutans (S. mutans), one of the main causative bacteria responsible for dental caries. Considering the fact that orthodontic appliances facilitate infliction of the oral cavity with a range of microbes including S. mutans, we determined the growth inhibitory and anti-adherence activities of AgNPs on orthodontic appliances. We performed microbiological assays employing AgNPs adsorbed onto the surface of nickel–titanium (Ni-Ti) orthodontic wires. A topographic analysis of the decontaminated Ni-Ti orthodontic wires was performed by scanning electron microscopy. In addition to antimicrobial and anti-biofilm activities against oral S. mutans, the as-fabricated AgNPs demonstrated significant inhibitory and anti-biofilm properties against other biofilm-forming bacteria such as Escherichia coli and Listeria monocytogenes.

Green Synthesis of Hexagonal Silver Nanoparticles Using a Novel Microalgae Coelastrella aeroterrestrica Strain BA_Chlo4 and Resulting Anticancer, Antibacterial, and Antioxidant Activities

“…The negativity of C@Ag-NP surfaces could be attributed to the adsorption of biomolecules present in C. aeroterrestrica extracts onto NP surfaces, which may then play essential roles in the physical, chemical, and biological activities of C@Ag-NPs [ 68 , 69 ]. Farheen et al fabricated Ag-NPs from their precursor (AgNO 3 ) using aqueous extract of the Hibiscus rosa-sinensis plant (HRSF) and found that the HD of Ag-NPs was between 30 and 80 nm and their potential charge was equal to −25 mV, suggesting they were stabilized by HRSF biomolecules [ 70 ].…”

Use of Antimicrobial Silver Coatings on Fixed Orthodontic Appliances, Including Archwires, Brackets, and Microimplants: A Systematic Review

“…Regarding the bacteria tested, different studies assessed the antimicrobial efficacy of silver-coated orthodontic materials against various strains ( Table 1 ). For instance, S. mutans , a common bacterium associated with dental caries, was a recurrent choice for evaluating bacterial adhesion and biofilm formation [ 10 , 18 – 20 , 23 , 22 , 25 , 27 , 28 ]. Other bacteria tested included S. aureus , E. coli , L. monocytogenes , and Lactobacillus , representing a spectrum of Gram-positive and Gram-negative bacteria with different pathogenic characteristics [ 9 , 13 , 20 , 27 , 28 ].…”

“…Lee et al used layer-by-layer deposition for SS samples, demonstrating antimicrobial efficacy against S. mutans and E. coli , with surface characterization through SEM and XPS [ 28 ]. Furthermore, Farheen et al focused on NiTi orthodontic wires, utilizing CFU and biofilm formation assays against S. mutans , E. coli , and L. monocytogenes [ 27 ]. In a subsequent study, similar antimicrobial effectiveness against S. sanguinis and L. salivarius was observed [ 21 ].…”

“…These implications are particularly relevant in the context of infection prevention in orthodontic practice, where the risk of bacterial complications is inherent due to the use of orthodontic appliances. S. mutans , a well-known caries-causing organism, was frequently analyzed in the included studies [ 10 , 18 – 20 , 23 , 22 , 25 , 27 , 28 ].…”