Crown ether-induced TiO₂ nanocrystals: an innovative strategy for advanced biomaterials and drug therapy

Abstract

Titanium dioxide (TiO₂) is a key material in biomedical applications, but its conventional synthesis by sol–gel method requires thermal treatments to induce crystallization, which can affect the stability of sensitive encapsulated bioactive compounds. In this work, the incorporation of crown ethers 12C4, 15C5, and 18C6 was explored as a strategy to promote TiO₂ crystallization at room temperature without the need for calcination. An amorphous TiO₂ matrix was synthesized by sol–gel, and the crown ether-induced crystallization was analyzed by HRTEM, IR, and UV–Vis spectroscopy. The results demonstrated the formation of anatase and rutile nanocrystals in all samples with crown ethers, with sizes ranging from 2 to 4.5 nm, confirming the ability of these ligands to modify TiO₂ nucleation. In particular, the TiO₂/15C5 complex showed a higher degree of crystallization, suggesting that the flexible geometry of this crown ether influences its interaction with the titanium matrix. These materials have potential applications in energy, catalysis, and drug storage. Furthermore, antimicrobial activity of TiO₂ makes it ideal for using in medical implants, antibacterial coatings, and wound healing. Its photocatalytic capacity could also be applied in photodynamic therapy against tumor cells, providing an innovative alternative in oncology. Finally, its biocompatibility and functionalization open new possibilities in tissue engineering and the development of biosensors for disease diagnosis.