Gingerol and Chitosan-Based Coating of Thermoformed Orthodontic Aligners: Characterization, Assessment of Anti-Microbial Activity, and Scratch Resistance: An In Vitro Study.

Aim To prepare and characterize a 6-gingerol-incorporated chitosan biopolymer for coating on thermoformed aligners and evaluate its scratch resistance and antimicrobial activity. Material and methods In this in vitro study, 6-gingerol extract was prepared, incorporated with chitosan biopolymer into a coating solution and characterized using nuclear magnetic resonance imaging spectroscopy (NMR). Twenty thermoformed aligner samples were exposed to UV radiation for surface activation, then coated with a crosslinking agent. These were divided into four groups of five. The control group consisted of samples dip-coated in a chitosan solution for 15 minutes. The three test groups consisted of samples dip coated in a gingerol-chitosan coating solution, with each group representing the following time periods of dip coating: five, 10, and 15 minutes. The crosslinking of the coating with the aligner material was confirmed by a Fourier transform infrared spectroscopy (FTIR) test. A scratch test was carried out to evaluate the wear resistance of the coating, and the antibacterial properties of the coating were tested using a Disc Diffusion test. Results The NMR analysis confirmed the presence of 6-gingerol in the extract. The coating of 6-Gingerol on aligners was confirmed by FTIR spectroscopy. The wear resistance of aligners coated for 5 minutes, 10 minutes, and 15 minutes was 1.8 ± 0.09 N, 2.3 ± 0.021 N, and 3.06 ± 0.17 N, respectively, and the difference was statistically significant (p<0.05). The aligner coated for 15 minutes exhibited the widest zone of inhibition of up to 2.38 ± 0.44 mm against Streptococcus mutans, and the difference was statistically significant (p<0.05).​​​​​​ No antibacterial effect was found against E. Coli. Conclusion A novel coating material with 6-gingerol extract incorporated in chitosan biopolymer was prepared and characterized, followed by coating on thermoformed aligners. The coating showed antibacterial activity against Streptococcus mutans, and both the antimicrobial activity and wear resistance increased with coating duration.

Hydrothermal synthesis of spindle structure copper ferrite-graphene oxide nanocomposites for enhanced photocatalytic dye degradation and in-vitro antibacterial activity.

In this study, a one-step hydrothermal approach was used to make pure magnetic copper ferrite (CuFe2O4) and copper ferrite-graphene oxide (CuFe2O4-rGO) nanocomposites (NCs) and spinel structure CuFe2O4 with a single phase of tetragonal CuFe2O4-rGO-NCs was confirmed by the XRD. Then, characterization of CuFe2O4-rGO-NCs was done using ng Raman spectroscopy, FT-IR, TGA-DTA, EDS, SEM, and TEM. The synthesized NCs was exposed to UV light to evaluate its photocatalytic activity for the degradation of methylene blue (MB) and rhodamine B (RhB) with CuFe2O4 and CuFe2O4-rGO-NCs, respectively. The catalyst CuFe2O4-rGO-NCs provided higher degradation of MB (94%) than for RhB (86%) under UV light irradiation compared to CuFe2O4. Further, the antibacterial activities of CuFe2O4-NPs and CuFe2O4-rGO-NCs were tested against Gram-negative and -positive bacterial pathogens such as Vibrio cholera (V. cholera); Escherichia coli (E. coli); Pseudomonas aeruginosa (P. aeruginosa); Bacillus subtilis (B. subtilis); Staphylococcus aureus (S. aureus); and Staphylococcus epidermidis (S. epidermidis) by well diffusion method. At 100 µg/mL concentrations of CuFe2O4-rGO-NCs, maximal growth inhibition was shown against E. coli (18 mm) and minimum growth inhibition against S. epidermidis (12 mm). This study suggests that CuFe2O4-rGO-NCs as a high-efficacy antibacterial material and plays an important role in exhibiting higher sensitivity depending on concentrations. The results encourage that the synthesized CuFe2O4-rGO-NCs can be used as a promising material for the antibacterial activity and also for dye degradation in the water/wastewater treatment plants.

Synthesis of Bimetallic BiPO4/ZnO Nanocomposite: Enhanced Photocatalytic Dye Degradation and Antibacterial Applications.

Multidrug-resistant strains (MDRs) are becoming a major concern in a variety of settings, including water treatment and the medical industry. Well-dispersed catalysts such as BiPO4, ZnO nanoparticles (NPs), and different ratios of BiPO4/ZnO nanocomposites (NCs) were synthesized through hydrothermal treatments. The morphological behavior of the prepared catalysts was characterized using XRD, Raman spectra, PL, UV-Vis diffuse reflectance spectroscopy (UV-DRS), SEM, EDX, and Fe-SEM. MDRs were isolated and identified by the 16s rDNA technique as belonging to B. flexus, B. filamentosus, P. stutzeri, and A. baumannii. The antibacterial activity against MDRs and the photocatalytic methylene blue (MB) dye degradation activity of the synthesized NPs and NCs were studied. The results demonstrate that the prepared BiPO4/ZnO-NCs (B1Z4-75:300; NCs-4) caused a maximum growth inhibition of 20 mm against A. baumannii and a minimum growth inhibition of 12 mm against B. filamentosus at 80 µg mL-1 concentrations of the NPs and NCs. Thus, NCs-4 might be a suitable alternative to further explore and develop as an antibacterial agent. The obtained results statistically justified the data (p ≤ 0.05) via one-way analysis of variance (ANOVA). According to the results of the antibacterial and photocatalytic study, we selected the best bimetallic NCs-4 for the photoexcited antibacterial effect of MDRs, including Gram ve+ and Gram ve- strains, via UV light irradiation. The flower-like NCs-4 composites showed more effectiveness than those of BiPO4, ZnO, and other ratios of NCs. The results encourage the development of flower-like NCs-4 to enhance the photocatalytic antibacterial technique for water purification.