The realization of neuromorphic resistive memory in TiO₂ thin films (Strukov et al., 2008) marked an important milestone in the search for bio-inspired technologies (Chua and Kang, 1976). Many research proposals urged a focus on memristivity as the common feature of two electrical models: (i) electromigration of point defects in titanium oxide systems (Baiatu et al., 1990; Jameson et al., 2007) and (ii) voltage-gated ionic channels in the membranes of biological neurons (Hodgkin and Huxley, 1952). In this regard, memristors functionally mimic the synaptic plasticity of biological neurons, and thus can be implemented in artificial and hybrid neural networks. This includes a new paradigm of future computing systems (Zidan, 2018) and biocompatible electronics such as biointerfaces and biohybrid systems (Chiolerio et al., 2017).

Titanium dioxide is an inert earth mineral used as a thickening, opacifying, and sunscreen ingredient in cosmetics. It protects skin from UVA and UVB radiation and is considered non-risky in terms of of skin sensitivity. Because it is gentle, titanium dioxide is a great sunscreen active for sensitive, redness-prone skin. It’s great for use around the eyes, as it is highly unlikely to cause stinging.