Conductive Composite Microneedle Sensors Based on Cellulose Acetate Phthalate: Investigating Performance and Biodegradability

Conductive microneedle patches based on carbon nanoparticle composites in which cellulose acetate phthalate (CAP) or polystyrene (PS) acted as a binder were investigated. The electrochemical properties of the composite system were assessed using ferrocyanide as a redox probe and compared with screen printed carbon electrodes. Preliminary investigations of biodegradability were conducted with the influence of soil interment assessed by electron microscopy. While the PS microneedles exhibited no breakdown, the CAP systems were found to be substantially degraded after one week with complete removal of the needle tips and, hence, piercing capability.