Sorption-induced static mode nanomechanical sensing with viscoelastic receptor layers for multistep injection-purge cycles

Nanomechanical sensors and their arrays have been attracting significant attention for detecting, distinguishing, and identifying target analytes. In the static mode operation, sensing signals are obtained by a concentration-dependent sorption-induced mechanical strain/stress. The analytical models for the static mode nanomechanical sensing with viscoelastic receptor layers have been proposed, while they are not formulated for practical conditions, such as multistep injection–purge cycles. Here, we derive an analytical model of viscoelastic material-based nanomechanical sensing by extending the theoretical model via solving differential equations with recurrence relations. The presented model is capable of reproducing the transient behaviors observed in the experimental signal responses with multistep injection- purge cycles, including drifts and/or changes in the baseline. Moreover, this model can be utilized for extracting viscoelastic properties of the receptor material/analyte pairs as well as the concentrations of analytes accurately by fitting a couple of injection–purge curves obtained from the experimental data. The parameters of the model that best fit the data can be used for predicting the entire signal response.