Micropatterned conductive polymer biosensors on flexible PDMS films

Flexible devices are particularly important for applications in the bioelectronics arena as materials interface with soft and mechanically compliant surfaces. Polydimethylsiloxane (PDMS) is an elastomer that can form a versatile, inexpensive substrate for electronic components while conferring flexibility, oxygen permeability, and biocompatibility. However, the ability to form microcircuits while maintaining integration of these components to the surfaces without delamination continues to be challenging. Here, we present the development of a benchtop, scalable photolithographic technique that can pattern the conducting polymer PEDOT:PSS on thin photocurable PDMS membranes via a conducting composite ink composed of the polymer and a biofriendly silk protein carrier. The fully aqueous process can result in high resolution microelectrodes that can function as biosensors utilizing both non-specific and specific sensing modalities via entrapped biorecognition molecules. The biosensors display excellent direct detection of dopamine and ascorbic acid with high sensitivity. Also, enzyme loaded sensors can detect glucose in a highly sensitive manner over physiologically relevant glucose concentration range. Owing to the covalent linkage between the ink and the photo-PDMS, the electrodes do no delaminate or lose function under mechanical flexure. The work demonstrates the potential for realization of flexible devices using photoreactive PDMS such as biosensors or electronic skin.