Titanium is one of the most abundant elements in the earth’s crust and while there are many examples of its bioactive properties and use by living organisms, there are few studies that have probed its biochemical reactivity in physiological environments. In the cosmetic industry, TiO2 nanoparticles are widely used. They are often incorporated in sunscreens as inorganic physical sun blockers, taking advantage of their semiconducting property, which facilitates absorbing ultraviolet (UV) radiation. Sunscreens are formulated to protect human skin from the redox activity of the TiO2 nanoparticles (NPs) and are mass-marketed as safe for people and the environment. By closely examining the biological use of TiO2 and the influence of biomolecules on its stability and solubility, we reassess the reactivity of the material in the presence and absence of UV energy. We also consider the alarming impact that TiO2 NP seepage into bodies of water can cause to the environment and aquatic life, and the effect that it can have on human skin and health, in general, especially if it penetrates into the human body and the bloodstream.

https://www.mdpi.com/1996-1944/12/14/2317/pdf

Fueling a Hot Debate on the Application of TiO2 Nanoparticles in Sunscreen.

Exploring titanium(IV) chemical proximity to iron(III) to elucidate a function for Ti(IV) in the human body

Due to the rapid mutation of pathogenic microorganisms, drug-resistant superbugs have evolved. Antimicrobial-resistant germs may share their resistance genes with other germs, making them untreatable. The search for more combative antibiotic compounds has led researchers to explore metal-based strategies centered on perturbing the bioavailability of essential metals in microbes and examining the therapeutic potential of metal complexes. Given the limited knowledge on the application of titanium(IV), in this work, eight Ti(IV) complexes and some of their corresponding ligands were screened by the Community for Open Antimicrobial Drug Discovery for antimicrobial activity. The compounds were selected for evaluation because of their low cytotoxic/antiproliferative behavior against a human non-cancer cell line. At pH 7.4, these compounds vary in terms of their solution stability and ligand exchange lability; therefore, an assessment of their solution behavior provides some insight regarding the importance of the identity of the metal compound to the antimicrobial therapeutic potential. Only one compound, Ti(deferasirox)2, exhibited promising inhibitory activity against the Gram-positive bacteria methicillin-resistant Staphylococcus aureus and minimal toxicity against human cells. The ability of this compound to undergo transmetalation with labile Fe(III) sources and, as a consequence, inhibit Fe bioavailability and ribonucleotide reductase is evaluated as a possible mechanism for its antibiotic effect.

https://www.mdpi.com/2079-6382/11/2/158/pdf

Exploring Titanium(IV) Complexes as Potential Antimicrobial Compounds

The title compound, tetra­sodium bis­[tris­(salicylato­titanate(IV)] undeca­hydrate, Na4[Ti(C7H4O3)3]2·11H2O, crystallizes with two titanium salicylate complex ions, four sodium ions and 11 water mol­ecules in the asymmetric unit. One water O atom is disordered over two positions, having 0.74 (5) and 0.26 (5) occupancy. Both Ti atoms and three sodium ions adopt a distorted octa­hedral coordination by O atoms. The fourth sodium ion has a distorted trigonal–bipyramidal coordination by oxygen, sharing one edge with a sodium coordination octa­hedron.

Kakoli Mukharjee

Papers

A titanium salicylate, Na4[Ti(C7H4O3)3]2·11H2O