Metallic and metal oxide nanoparticles (NPs), including titanium dioxide NPs, among polymeric NPs, liposomes, micelles, quantum dots, dendrimers, or fullerenes, are becoming more and more important due to their potential use in novel medical therapies. Titanium dioxide (titanium(IV) oxide, titania, TiO₂) is an inorganic compound that owes its recent rise in scientific interest to photoactivity. After the illumination in aqueous media with UV light, TiO₂ produces an array of reactive oxygen species (ROS). The capability to produce ROS and thus induce cell death has found application in the photodynamic therapy (PDT) for the treatment of a wide range of maladies, from psoriasis to cancer. Titanium dioxide NPs were studied as photosensitizing agents in the treatment of malignant tumors as well as in photodynamic inactivation of antibiotic-resistant bacteria. Both TiO₂ NPs themselves, as well as their composites and combinations with other molecules or biomolecules, can be successfully used as photosensitizers in PDT. Moreover, various organic compounds can be grafted on TiO₂ nanoparticles, leading to hybrid materials. These nanostructures can reveal increased light absorption, allowing their further use in targeted therapy in medicine. In order to improve efficient anticancer and antimicrobial therapies, many approaches utilizing titanium dioxide were tested. Results of selected studies presenting the scope of potential uses are discussed in this review.

Metallic nanoparticles (NPs), among polymeric NPs, liposomes, micelles, quantum dots, dendrimers, or fullerenes, are becoming more and more important due to their potential use in the novel medical therapies. Titanium dioxide (titanium(IV) oxide, titania, TiO2) is an inorganic compound that owes its recent rise in scientific interest to photoactivity. After the illumination in aqueous media with UV light, TiO2 produces an array of reactive oxygen species (ROS). The capability to produce ROS and thus induce cell death has found application in the photodynamic therapy (PDT) for the treatment of a wide range of maladies, from psoriasis to cancer. Titanium dioxide NPs were studied as photosensitizing agents in the treatment of malignant tumors as well as in photodynamic inactivation of antibiotic-resistant bacteria. Both TiO2 NPs themselves, as well as their composites with other molecules, can be successfully used as photosensitizers in PDT. Moreover, various organic compounds can be grafted on TiO2 NPs, leading to hybrid materials. These nanostructures can reveal increased light absorption allowing their further use in targeted therapy in medicine. In order to improve efficient anticancer therapy, many approaches utilizing titanium dioxide were tested. The most significant studies are discussed in this review.

In the XXI century, application of nanostructures in oral medicine has become common. In oral medicine, using nanostructures for the treatment of dental caries constitutes a great challenge. There are extensive studies on the implementation of nanomaterials to dental composites in order to improve their properties, e.g., their adhesive strength. Moreover, nanostructures are helpful in dental implant applications as well as in maxillofacial surgery for accelerated healing, promoting osseointegration, and others. Dental personal care products are an important part of oral medicine where nanomaterials are increasingly used, e.g., toothpaste for hypersensitivity. Nowadays, nanoparticles such as macrocycles are used in different formulations for early cancer diagnosis in the oral area. Cancer of the oral cavity—human squamous carcinoma—is the sixth leading cause of death. Detection in the early stage offers the best chance at total cure. Along with diagnosis, macrocycles are used for photodynamic mechanism-based treatments, which possess many advantages, such as protecting healthy tissues and producing good cosmetic results. Application of nanostructures in medicine carries potential risks, like long-term influence of toxicity on body, which need to be studied further. The introduction and development of nanotechnologies and nanomaterials are no longer part of a hypothetical future, but an increasingly important element of today’s medicine.

Nanotechnology is an emerging field that involves the development of nanoscale particles, their fabrication methods, and potential applications. From nanosized inorganic particles to biopolymers, the variety of nanoparticles is unstoppably growing, offering huge opportunities for drug delivery. Various nanoformulations, such as nanoparticles, nanocomposites, and nanoemulsions, have been developed to enhance drug stability, solubility, and tissue penetration. Moreover, nanocarriers can be specifically engineered to target diseased cells or release the drug in a controllable manner, minimizing damage to surrounding healthy tissues and reducing side effects. This review focuses on the combinations between porphyrin derivatives and nanocarriers applied in photodynamic therapy (PDT). PDT has emerged as a significant advance in medicine, offering a low-invasive method for managing infections, the treatment of tumors, and various dermatoses. The therapy relies on the activation of a photosensitizer by light, which results in the generation of reactive oxygen species. Despite their favorable properties, porphyrins reveal non-specific distribution within the body. Nanotechnology has the capability to enhance the PS delivery and its activation. This review explores the potential improvements that are provided by the use of nanotechnology in the PDT field.

Photodynamic inactivation potential against bacteria of four chlorin derivatives with phenyl or fluorophenyl substituents was evaluated. The quantum yield values of singlet oxygen formation were in the range of 0.16–0.86. Compounds were characterized by high quantum yields of fluorescence (0.15–0.44) and moderate photostability in DMF solutions. Irradiation of chlorins in DMSO resulted in their phototransformation and then photodecomposition. Photodynamic inactivation of bacteria was performed after the compounds had been loaded into lipid vesicles. The following log reductions of growth values were obtained: Enterococcus faecalis >5.44; Staphylococcus aureus 2.74–5.34; Escherichia coli 0.01–2.14. No activity of meso-substituted chlorins was noticed against Pseudomonas aeruginosa and fungi Candida albicans and Trichophyton mentagrophytes.