Resumen:
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The use of nanomaterials in the field of bone tissue engineering implants is continuously dealing with the development of innovative solutions to common problems, as infection by colonization with common microbial agents, antibiotic bacterial resistance, and the formation of new bone tissue. Among them, ZnO nanostructures are promising candidates thanks to their intrinsic antimicrobial activity and high biocompatibility.
In this paper we aim to analyse the behaviour of ZnO nanocrystals (ZnO NCs), prepared with a new synthetic approach and not embedded in any composite matrix, for bone implants applications in-vitro. In particular, we have developed a novel, fast and reproducible microwave-assisted synthesis, obtaining highly-crystalline, round-shaped ZnO NCs of 20 nm in diameter as an extremely-stable colloidal solution in ethanol. Part of them were also chemically functionalized by anchoring amino-propyl groups to the ZnO surface (ZnO-NH2 NCs). Thus, the role of both ZnO NCs concentration and surface chemistry are tested in terms of biocompatibility towards pre-osteoblasts cells, promotion of cell proliferation and differentiation, and also in terms of antimicrobial activity against Gram positive and negative bacteria, such as Escherichia coli and Staphylococcus aureus, respectively. The results propose the ZnO-NH2 NCs as the most promising candidate to solve infections disease in bone implants and promote bone tissue proliferation at the same time, even at high concentrations. Whereas further investigations are needed for example to clarify the mechanism inhibiting biofilm formation and to investigate their role in in-vivo assays, we demonstrated that a fine and reproducible control over the chemical and structural parameters in ZnO nanomaterials can open new horizons in the use of functionalized ZnO NCs as a highly biocompatible and osteoinductive nanoantibiotic agent for bone tissue engineering.
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