Yet another study, this one published in 2006 by the International Agency for Research on Cancer said there was insufficient evidence to conclude that titanium dioxide causes cancer. However, the study also categorized the ingredient as a potential human carcinogen.
In a study published in the journal Environmental Toxicology and Pharmacology in 2020, researchers examined the effects of food additives titanium dioxide and silica on the intestinal tract by grouping and feeding mice three different food-grade particles — micro-TiO2, nano-TiO2, and nano-SiO2. With all three groups, researchers observed changes in the gut microbiota, particularly mucus-associated bacteria. Furthermore, all three groups experienced inflammatory damage to the intestine, but the nano-TiO2 displayed the most pronounced changes. The researchers wrote: “Our results suggest that the toxic effects on the intestine were due to reduced intestinal mucus barrier function and an increase in metabolite lipopolysaccharides which activated the expression of inflammatory factors downstream. In mice exposed to nano-TiO2, the intestinal PKC/TLR4/NF-κB signaling pathway was activated. These findings will raise awareness of toxicities associated with the use of food-grade TiO2 and SiO2.”
Due to its light-scattering properties, small amounts of titanium dioxide are added to certain foods to enhance their white color or opacity (1Trusted Source, 3Trusted Source).


The first study addressing the experimental convergence between in vitro spiking neurons and spiking memristors was attempted in 2013 (Gater et al., 2013). A few years later, Gupta et al. (2016) used TiO2 memristors to compress information on biological neural spikes recorded in real time. In these in vitro studies electrical communication with biological cells, as well as their incubation, was investigated using multielectrode arrays (MEAs). Alternatively, TiO2 thin films may serve as an interface material in various biohybrid devices. The bio- and neurocompatibility of a TiO2 film has been demonstrated in terms of its excellent adsorption of polylysine and primary neuronal cultures, high vitality, and electrophysiological activity (Roncador et al., 2017). Thus, TiO2 can be implemented as a nanobiointerface coating and integrated with memristive electronics either as a planar configuration of memristors and electrodes (Illarionov et al., 2019) or as a functionalization of MEAs to provide good cell adhesion and signal transmission. The known examples are electrolyte/TiO2/Si(p-type) capacitors (Schoen and Fromherz, 2008) or capacitive TiO2/Al electrodes (Serb et al., 2020). As a demonstration of the state of the art, an attempt at memristive interlinking between the brain and brain-inspired devices has been recently reported (Serb et al., 2020). The long-term potentiation and depression of TiO2-based memristive synapses have been demonstrated in relation to the neuronal firing rates of biologically active cells. Further advancement in this area is expected to result in scalable on-node processors for brain–chip interfaces (Gupta et al., 2016). As of 2017, the state of the art of, and perspectives on, coupling between the resistive switching devices and biological neurons have been reviewed (Chiolerio et al., 2017).
2. Particle Size The application often dictates the required particle size. Suppliers typically offer various grades of barium sulphate, categorized by their particle size distribution. For example, finer particle sizes are often favored in cosmetic applications, while coarser grades may be used in construction materials.