Sun Protective Means: The Characteristics and Action Efficiency

Modern sun protective means (SPM) represent complex compositions of substances which provide effective protection of a person’s skin against sunlight. Organic and inorganic sun protective filters (sunscreens) or combinations of them are used as the active components of SPM. Organic sunscreens absorb ultraviolet radiation due to the presence of chromophores in their structure; while action of inorganic sunscreens is based on physical mechanism of protection, such as dispersion, absorption and reflection of ultraviolet (UV) radiation by inorganic particles. Silicon nanocrystals have attracted increasing attention as a new promising sun protective agent. They possess extremely high extinction coefficient in UV region of the spectrum and at the same time are transparent for visible light. The combination of physical properties related to the quantum size effect of silicon nanoparticles and their biological compatibility allows the development of highly effective sun protective skincare compositions. Efficiency and quality of SPM depend on many factors. The variety of known sunscreens allows finding optimum structures for creation of the most effective sun protective means. The review of the literature presented is devoted to consideration of existing SPM, their characteristics and effective properties. Then a comparative analysis of a totally new sun protective material based on silicon nanocrystals with known, widely used UV protectors is performed.