Systematic review on toxicological effects of platinum nanoparticles: Towards their use as safe biomedical tools

Platinum nanoparticles (PtNP) have received considerable attention in the nanomedicine field due to their magnetic, catalytic, and optical properties. However, the potential toxicity of PtNP has not been properly evaluated yet, and current information on the possible risks related to their use is still limited. On this basis, the main objective of this systematic review was to gather available data on PtNP biological behaviour and potential harmful effects, as well as to highlight the gaps of knowledge that need to be filled in to progress in their use in clinical practice. A total of 441 studies were obtained and reviewed from the initial search; 108 fulfilled the selection criteria and were included in the revision. Mainly in vitro but also in vivo studies were reported using a variety of biological systems and animal models, with no data from human epidemiological studies published so far. All these studies were extensively evaluated to provide useful information on the PtNP biocompatibility and their potential to be employed for medical purposes. In particular, information on the physicochemical features of the PtNP influencing their biological behaviour, methods employed for toxicity evaluation, biological systems used, and outcomes addressed were analysed and discussed. In general, the results obtained showed a good biocompatibility of these NP, although some of them detected significant toxicity highly dependent of size, concentration/dose, coating, or exposed biological system. Furthermore, anticancer or protective effects were also described for PtNP in several revised studies. These findings encourage to continue exploring the benefits of PtNP for clinical practice.