We present a novel self-aligned and hybrid polymer fabrication process for an electro-enzymatic glucose sensor. The
self-aligned fabrication process is performed using polydimethylsiloxane (PDMS) as a process substrate material, SU-8
as a sensor structural material, and gold as an electrode material. PDMS has many advantages as a process substrate over
conventional substrates such as bare silicon or glass. During the fabrication process, SU-8 has good adhesion to the
PDMS. However, after completion of all fabrication steps, the SU-8 based sensors can be easily peeled-off from the
PDMS. The PDMS is prepared on a glass handle wafer, and is reusable for many process cycles. Such an SU-8 release
technique from a PDMS substrate has never been proposed before. The novel process is employed to realize a glucose
sensor with active and reference gold electrodes that are sandwiched between two SU-8 layers with contact pad openings
and the active area opening to the top SU-8 layer. The enzyme glucose oxidase is immobilized within the confined active
area opening to provide an active electrode sensing surface.
After successful fabrication using the hybrid process, the overall thickness of the sensors is measured between 166.15 μm
and 210.15 μm. The sensor area and the electrode area are 2mm x 3mm and 2mm x 2mm respectively. The resulting
glucose sensors are mechanically flexible. A linear response is observed for the glucose sensors, typically between
50mg/dl and 600mg/dl glucose concentrations.
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