ABSTRACT
ZnO nanoparticles (NPS) with different morphologies were synthesized, and the antibacterial and anticancer activity was studied, herein. The physicochemical characterization was carried out by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR) and UV-visible. To study the antibacterial and anticancer capability of ZnO NPS, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria and HeLa cancer cells were exposed at different doses of ZnO NPS (7-250 µg/mL). TEM analysis confirmed the obtention of spherical, hexagonal and rod ZnO NPS with an average diameter of 20 ± 4 nm, 1.17 ± 0.3 µm and 1.11 ± 1.2 µm, respectively. XRD diffractograms showed the characteristic pattern of crystalline ZnO in wurtzite phase. FTIR and UV-vis spectra showed slight differences of the main absorption peaks, revealing that different ZnO NPS morphologies may cause shifts in spectra. Biological essays showed that the number of E. coli and S. aureus bacteria as well as HeLa cells decreases linearly by increasing the nanoparticle concentration. However, the best anticancer and antibacterial activity was shown by spherical ZnO NPS at 100 µg/mL. The better capability of spherical ZnO NPS than hexagonal and rod ZnO NPS is related with its small particle size. The present results suggest that the spherical ZnO NPS has a great potential as an antibacterial and anticancer agent.
ABSTRACT
It has been shown that the cellular responses such as adhesion, proliferation and differentiation are influenced by the surface properties, such as the topography or the surface energy. However, less is known about the effect of the chemical composition and type of material on the differentiation potential. The objective of the present paper is to compare the differentiation potential of periodontal ligament cells (HPLC) into adipocytes, osteoblasts, chondroblasts and cementoblasts of three type of materials (metals, ceramics and polymers) without using any biological induction media, but keeping the average roughness values within a limited range of 2.0-3.0µm. The samples were produced as discs of 14×2mm; (n=30 for each type of material). Two samples of each type were chosen; stainless-steel 316L and commercially pure titanium for the metallic samples. The polymers were polymethyl methacrylate and high-density polyethylene, and finally for the ceramics; zirconia and dental porcelain were used. The surfaces properties of the samples (wettability, chemical composition and point of zero charge, PZC) were measured in order to correlate them with the biological response. To evaluate the potential of differentiation, human periodontal ligament cells obtained from extracted teeth were used since they are a promising source for periodontal tissue regeneration. Cell proliferation was initially tested to assure non-toxic effects using a viability colorimetric assay. Finally, the differentiation pattern was evaluated using real time reverse transcription quantitative polymerase chain reaction for 5, 10 and 15days without adding any induction medium. The results indicated that the relative expression of genes related to a particular phenotype were different for each surface. However, not clear correlation between the type of material or their surface properties (morphology, chemical composition, wettability or point of zero charge) and the expression pattern could be identified. For example, bone markers were mainly expressed on cpTi and PMMA; one metallic hydrophobic and one polymeric hydrophilic sample which have similar Ra values but presented different topographical features, although both samples have in common a PZC below 7.
