“…The implementation of sensor systems within the latter gives rise to numerous concerns where issues over probe size and disposability can be problematic—especially where sample sizes may be limited (as in the case of clinic DFU sampling) or in vivo application is desired. A number of research avenues have been explored to counter these issues and both potentiometric [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] and voltammetric [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ] methodologies have been pursued. In most cases, a functional material containing pH sensitive components is applied to the surface of an appropriate sensor substrate through a variety of methods that include: Adsorption/monolayer [ 20 , 29 ], polymer films [ 17 , 34 ], screen printed inks [ 16 , 19 , 21 , 28 ], covalent attachment [ 27 , 28 ] or electrodeposition [ 13 , 14 , 18 , 23 , 24 , 25 , 33 ].…”