Tekscan pressure sensor output changes in the presence of liquid exposure.

Journal of biomechanics

PubMedID: 23122222

Jansson KS, Michalski MP, Smith SD, LaPrade RF, Wijdicks CA. Tekscan pressure sensor output changes in the presence of liquid exposure. J Biomech. 2013;46(3):612-4.
The purpose of the study was to evaluate the load output of a pressure sensor in the presence of liquid saturation in a controlled environment. We hypothesized that a calibrated pressure sensor would provide diminishing load outputs over time in controlled environments of both humidified air and while submerged in saline and the sensors would reach a steady state output once saturated. A consistent compressive load was repeatedly applied to pressure sensors over time (Model 4000, Tekscan, Inc., South Boston, MA) with a tensile testing machine (Instron ElectroPuls E10000, Norwood, MA). All sensors were initially calibrated in a dry environment and were tested in three groups: humid air, submerged in 0.9% saline solution, and dry. Linear regression of load output over time for the pressure sensors exposed to humidity and submerged showed a 4.6% and 4.7% decline in load output each hour for the initial 6h, respectively (ß=-0.046, 95% CI: [-0.053 to -0.039]; p<0.001) (ß=-0.047, 95% CI: [-0.053 to -0.042; p<0.001). Tests after 72 h of exposure had linear regression decline in load output over time of 0.40% and 0.47% per hour for humidified and submerged sensors, respectively (ß=-0.004, 95% CI: [-0.006 to -0.003]; p<0.001) (ß=-0.047, 95% CI: [-0.053 to -0.042]; p<0.001). Because outcomes in biomedical research can affect clinical practices and treatments, the diminishing load output of the sensor in the presence of liquids should be accounted for. We recommend soaking sensors for more than 48 h prior to testing in a moist environment.