## 4 Physicochemical Properties of Titanium Dioxide and Its General Applications
Titania can be used as an antibacterial and antifungal agent. In dermatology, it was used in new methods of treating diseases such as acne and atopic dermatitis [83]. [PERSON] et al. evaluated TiO\({}_{2}\) and Ag-TiO\({}_{2}\) antibacterial properties against _E. coli_, _P. aeruginosa_, and _S. aureus_[84]. A different study reported that ROS resulting from UVA excitation of TiO\({}_{2}\) eradicated _E. coli_, methicillin-resistant _S. aureus_, and _C. albicans_ fungi. The addition of sodium bromide increased this effect by up to 3 logs reduction (which means that the number of germs was 1000 times smaller) [85]. In another study, [PERSON] et al. analyzed the antibacterial activity of Ni-doped and N-doped TiO\({}_{2}\) nanoparticles against _E. coli_ and _S. aureus_[86]. The researchers observed the inactivation of both bacteria strains by N-doped and Ni-doped TiO\({}_{2}\). N-doped material showed better antibacterial properties than Ni-doped, mainly due to better sensitization toward visible light. Figure 3: Representative charge-transfer route in the type-II heterojunction photocatalysts; CB—conduction band, VB—valence band, PC I—photocatalyst I, PC II—photocatalyst II (based on references [78; 79]). Titanium dioxide is a biocompatible material and can be used in many sciences, industries, and medicine branches including stomatology and implantation technology. Nano-TiO\({}_{2}\) is a biocompatible material used to replace body tissues, as in through bone implants. Thanks to its biocompatibility, it can be used to reconstruct facial tissues and in dental implants--it also induces faster bone growth, improves the durability of implants, accelerates healing, and has anti-infective effects [87]. In the study carried out on mouse pre-osteoblastic cells MC3T3-E1 implanted on mineral matrix, Si-TiO\({}_{2}\) prominently meliorated expression of osteogenic differentiation genes. In in vivo tests in rat femur silicon doped titanium dioxide nanotubes compared to TiO\({}_{2}\) nanotubes and titanium implants enhanced durability of implant fixation by properly 18% and 54%, respectively. Moreover, Si-TiO\({}_{2}\) stimulated osteogenic differentiation of osteoblastic cells, which led to better integration of Ti with the bone structure [88]. In addition, [PERSON] et al. studied the antibacterial action and biocompatibility of N-doped TiO\({}_{2}\) nanoparticles for use in dental resin formulation [89]. Many sensor properties of TiO\({}_{2}\) have been analyzed. Nanoparticles of TiO\({}_{2}\)@ZnO and their hybrids with graphene oxide were studied as new drug delivery carriers for curcumin where the release of the load was pH-dependent [90]. [PERSON] et al. created a photoelectrochemical sensor with nano-Au and self-doped TiO\({}_{2}\) nanotube arrays, which revealed the ability to detect kanamycin selectivity [82]. Nanocomposites of polyaniline films with TiO\({}_{2}\) and RuO\({}_{2}\) nanoparticles on multi-walled carbon nanotubes were used for the electrochemical detection of epinephrine [91]. Nanorods of TiO\({}_{2}\) functionalized with quantum dots (CdS) were used as a substrate to confine glucose dehydrogenase for visible light-driven glucose oxidation and were used as part of the bioachode in a platform based on a cell visible light-driven biofuel [92]. In a different study, sensors based on carbon paste electrodes were prepared and modified by Ru-doped TiO\({}_{2}\) nanoparticles (from the liquid impregnation process). The sensor's task was to detect clozapine in pharmaceutical formulations and human urine [93]. [PERSON] et al. presented applications of self-assembled quantum scale structured (Q-structured) TiO\({}_{\text{x}}\) in surface-enhanced Raman spectroscopy (SERS), which is a technique used in biomolecular detection of DNA, RNA, and proteins [94]. In order to overcome limitations of Raman spectroscopy and to perform the assay, a SERS template is necessary. The most commonly used materials in SERS are noble metals like Au and Ag.