E1 20:20 substrate depending on the applied power ([Figure 1](#sensors-20-00579-f001){ref-type="fig"}d) is similar to that of micro-hotplate manufactured by SAMLAB.

Recently, cellulose-based structures have attracted a remarkable interest in the field of functional materials and devices due to their intrinsic properties and environmentally friendly character \[[@B24-sensors-20-00579],[@B25-sensors-20-00579],[@B26-sensors-20-00579],[@B27-sensors-20-00579]\]. Cellulose is the most abundant polymer in nature. It is formed by monomers of glucose bounded by β→1,4 links and may be produced by plants, tunicates, fungi, and bacteria. Bacterial, or microbial, cellulose has different properties from plant-cellulose. It is produced by acetic acid bacteria from the Acetobacteraceae family. These aerobic gram-negative bacteria actively ferment at temperatures between 25 and 30 °C and pH from 3 to 7 using saccharides as carbon sources. In particular, the bacterial cellulose (BC) is composed of three-dimensional hierarchical structures presenting a very high degree of polymerization and crystallinity. This can be attributed to the clenched organization of parallel fiber molecules which width is within 5--50 nm \[[@B24-sensors-20-00579],[@B25-sensors-20-00579]\]. The first level of fiber connection is due to the H-bond interaction, which is quite important since it directly affects the physical and mechanical properties of the final BC layer ([Figure 1](#sensors-20-00579-f001){ref-type="fig"}a). To have specific properties the resulting microbial cellulose can be tailored by controlling synthesis methods (bacterial physiology and the growth condition). In water containing nutrition, the bacteria will create tiny fibers that will be extruded parallel to the long axis of the cell and vowel together to a gelatinous mat at the air/water interface. These films can be used as substrates for multiple applications \[[@B26-sensors-20-00579],[@B27-sensors-20-00579],[@B28-sensors-20-00579]\]. BC was used for the fabrication of UV ligh