RESUMO
This study aimed to develop Ca2+ doped ZnO nanoparticles (NPs) and investigate their antibacterial properties against microorganisms of dental interest. Zn-Ca NPs were synthesized by the sol-gel method with different concentrations of Ca2+ (1, 3, and 5 wt. %) and subsequently characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis spectroscopy and Fourier transform infrared spectroscopy (FT-IR). The Kirby-Bauer method was used to measure antibacterial effects. NPs showed the wurzite phase of ZnO and bandgap energies (Eg) from 2.99 to 3.04 eV. SEM analysis showed an average particle size of 80 to 160 nm. The treatments that presented the best antibacterial activity were Zn-Ca 3% and Zn-Ca 5%. ZnO NPs represent an alternative to generate and improve materials with antibacterial capacity for dental applications.
Assuntos
Nanopartículas Metálicas , Nanocompostos , Óxido de Zinco , Antibacterianos/química , Antibacterianos/farmacologia , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Nanocompostos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Zinco/farmacologia , Óxido de Zinco/química , Óxido de Zinco/farmacologiaRESUMO
Mixed oxide nanoparticles (MONs, TiO2-ZnO-MgO) obtained by the sol-gel method were characterized by transmission electron microscopy, (TEM, HRTEM, and SAED) and thermogravimetric analysis (TGA/DTGA-DTA). Furthermore, the effect of MONs on microbial growth (growth profiling curve, lethal and sublethal effect) of Escherichia coli, Salmonella paratyphi, Staphylococcus aureus and Listeria monocytogenes, as well as the toxicity against Artemia salina by the lethal concentration test (LC50) were evaluated. MONs exhibited a near-spherical in shape, polycrystalline structure and mean sizes from 17 to 23 nm. The thermal analysis revealed that the anatase phase of MONs is completed around 480-500 °C. The normal growth of all bacteria tested is affected by the MONs presence compared with the control group. MONs also exhibited a reduction on the plate count from 0.58 to 2.10 log CFU/mL with a sublethal cell injury from 17 to 98%. No significant toxicity within 24 h was observed on A. salina. A bacteriostatic effect of MONs on bacteria was evidenced, which was strongly influenced by the type of bacteria, as well as no toxic effects (LC50 >1000 mg/L; TiO2-ZnO (5%)-MgO (5%)) on A. salina were detected. This study demonstrates the potential of MONs for industrial applications.
