Rev. Biol. Biomed. Sci. 2019 2 (1) 1-11 DOI: 10.31178/rbbs.2019.2.1.1 Current photocatalytic applications of nano-scaled titanium dioxide in the new era of "smart" technologies Ionela Cristina Nica, Miruna Silvia Stan  , Anca Dinischiotu Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095 Bucharest, Romania  Correspondence to: Miruna Silvia Stan, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095 Bucharest, Romania E-mail: miruna.stan@bio.unibuc.ro Received: 2 March 2018 / Revised: 17 July 2018 / Accepted: 13 August 2018 / Available online: 22 August 2018 Abstract Over the past decades, nanotechnology has increasingly developed and reached to monopolize almost all of the human activity areas. Materials with nanoscaled dimensions are not only developed for technological or medical purposes, but also, they can be found in daily commercial products. So, nanoparticles' applications found a well- defined place in our modern life. Almost 70% of global pigment production is based on titanium dioxide (TiO 2 ), which represents also one of the top five nanoparticles used in consumer products. TiO 2 surrounds our lives, being always present whether we want to take care of our health, wash our teeth or protect ourselves from harmful ultraviolet (UV) radiation. Moreover, TiO 2 is commonly used as a white pigment in different inks, paints, varnishes, plastics, papers, cosmetic products, also being the most common food additive (E171). But, the main perspectives of TiO 2 nanoparticles are related to different photo-induced phenomena, leading to the complete mineralization of pathogens and toxic non-biodegradable compounds, with low costs and high efficiency. Here, the authors aimed to present a brief review mainly focused on the ability of TiO 2 to create surfaces with self-cleaning, anti-fogging and antibacterial properties, as well as on the current photocatalytic applications of TiO 2 in new medical sanitizing techniques and biomedical devices development, wastewater management and air purification, energy and hydrogen production, and for obtaining "smart" clothes. Keywords: titanium dioxide, photocatalysis, self-cleaning Introduction Manufactured nanomaterials (MNMs) are increasingly used as they have many unique and improved properties compared to conventional materials. Different products are already available on the market, ranging from nano- composites used for car and aircraft construction, cosmetics, textiles or food packaging to medical applications (imaging techniques and nano-carrier pharmacological compounds). Nanoparticles' applications are widespread in all aspects of modern life, but photocatalysis received particular attention due to its capacity to convert solar energy with low costs and high efficiency (Wang et al., 2015; Fujishima et al., 2007). Furthermore, on the surfaces coated with a thin layer of photocatalyst, inactivation of microorganisms and mineralization of organic matter was noticed following advanced oxidation processes (AOPs) (Bogdan et al., 2015). The photodegradation mechanism is a global research topic because photocatalytic mineralization is a complex process in which most of the involved chemical species are difficult to distinguish as a consequence of their very short lifetimes (Shi et al., 2013). Titanium dioxide (TiO 2 ) is one of the most studied models for the photocatalytic process because it has ideal chemical properties, also being cheaper than other photocatalysts. A major disadvantage of TiO 2 is the limited absorption of radiation, only in the UV region of the solar spectrum (<400 nm) (Tryba 2008). For this reason, many researchers have successfully doped TiO 2 nanoparticles (NPs) with other metals (Cu, Fe) or non- metals (C, N) to extend their photocatalytic activity in visible light, and thus enhancing the efficiency of contaminant agents' degradation (Nica et al., 2016). What is already known regarding MNMs toxicity is that the same properties that make them both fascinating and useful are also a cause of serious concern. The effects generated by TiO 2 NPs in mammalian systems are well correlated with their physicochemical properties, such as the size, shape and crystal phase (Wang and Fan 2014). Reviews in Biological and Biomedical Sciences