“…Among others, TiO 2 (Wang M. et al, 2019), WO 3 (Liu et al, 2015), SnO 2 (Dong and Zheng, 2014), and ZnO (Zhang et al, 2019) have attracted considerable attention due to their electrochemical sensitive properties (Enesca et al, 2012a) and energy band alignment (Enesca et al, 2012b) suitable for enzyme based biosensors. Another advantage of these materials is represented by a large number of cost effective synthesis methods such as co-precipitation (Dong and Zheng, 2014), sonochemical precipitation (Zhou et al, 2013), thermal oxidation (Li et al, 2010), chemical etching (Liu et al, 2010), polyol (Elahi et al, 2019), hydrothermal (Zhou et al, 2017), or sol-gel (Rathinamala et al, 2019) allowing the formation of various morphologies such as porous quasi-nanospheres (Liu H. et al, 2017), hollow nano-spheres (Santos et al, 2016), nanorods (Dong et al, 2017), nanosheets (Zhang et al, 2020), or flower-like particles (Feng et al, 2018). Additionally, these materials can be combined between them or with others to form tandem heterostructures (Enesca et al, 2015), hybrid structures (Mihaly et al, 2008), or composite structures (Visa et al, 2016) with advanced electrochemical properties which can be adapted to a specific biosensor application.…”