Effects of biomedical sterilization processes on performance characteristics of MEMS pressure sensors
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The effects of steam and gamma sterilization on the performance of bulk-micromachined pressure sensors were investigated using a variable pressure setup. Commercially available piezoresistive MEMS (microelectromechanical systems) pressure sensor die were characterized prior and subsequent to sterilization over a 0–500 Torr pressure range. The effects of sterilization were examined as changes in sensor output voltage (ΔV) at various applied pressures. For steam sterilization, ΔV decreased with applied pressure ranging from +0.27 mV at 100 Torr to −0.14 mV at 500 Torr. In contrast, the corresponding values for gamma-sterilized sensors were lower, decreasing from +0.01 mV 100 Torr to −0.06 mV at 500 Torr. The increased variation in ΔV for the steam-sterilized sensors was attributed to the formation of an oxide film, which was confirmed using energy dispersive X-ray (EDX) spectroscopy. Statistical analysis revealed that the effect of both sterilization procedures on sensor performance was insignificant.
KeywordsSterilization MEMS Pressure sensor Gamma irradiation Biocompatibility Disinfection Silicon
The authors would like to thank following persons for their assistance: Ilya Gordon and Aaron Rood in the Department of Biomedical Engineering and Spine Research Laboratory, respectively at The Cleveland Clinic; and Mark Freas of BIOMEC Inc. (Cleveland, OH). This project was partially supported by grants from the Glennan Microsystems Initiative and Ohio Technology Action Fund.
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