. . . "Although the sensor devices of the subject invention may be disposable, for reusable embodiments, it is preferable that the material of the micro-needles and/or micro-needle arrays is able to withstand sterilization cycles. [0033] The micro-needles and/or the array of micro-needles may be formed of or coated with an insulating material, such as a ceramic, glass, silica, polymer, plastics." .