Micromachined dissolved oxygen sensor based on solid polymer electrolyte

A silicon microprobe to measure dissolved oxygen levels is described. The sensors are prepared by overlaying platinum thin film electrodes with a solid state proton conductive matrix (PCM) coating. The platinum thin film electrodes are fabricated on silicon substrates by standard photolithographic techniques while the PCM coating is achieved by drop-casting methods. The size and materials of the device make it potentially suitable for medical implantation. The devices are tested in deionized water (DI water), phosphate buffered saline (PBS), and bovine blood serum (BBS). Through linear sweep voltammetry (LSV), single devices are shown to have decent performances in terms of long term stability, reliability, hysteresis, linearity, and sensitivity. Variations among different devices are characterized and correlated. The simplicity and cost effectiveness of the fabrication and packaging procedures and the decent in vitro performances of these devices make them good candidates as miniaturized, disposable, and implantable dissolved oxygen sensors for biological and biomedical use.