Abstract
Up to now, there has been no report on target molecules detection by a piezoresistive microcantilever aptasensor. In order to evaluate the test performance and investigate the response dynamic characteristics of a piezoresistive microcantilever aptasensor, a novel method for ricin detection and kinetic analysis based on a piezoresistive microcantilever aptasensor was proposed, where ricin aptamer was immobilised on the microcantilever surface by biotin-avidin binding system. Results showed that the detection limit of ricin was 0.04μg L−1 (S/N ≥ 3). A linear relationship between the response voltage and the concentration of ricin in the range of 0.2μg L−1-40μg L−1 was obtained, with the linear regression equation of ΔUe = 0.904C + 5.852 (n = 5, R = 0.991, p < 0.001). The sensor showed no response for abrin, BSA, and could overcome the influence of complex environmental disruptors, indicating high specificity and good selectivity. Recovery and reproducibility in the result of simulated samples (simulated water, soil, and flour sample) determination met the analysis requirements, which was 90.5∼95.5% and 7.85%∼9.39%, respectively. On this basis, a reaction kinetic model based on ligand-receptor binding and the relationship with response voltage was established. The model could well reflect the dynamic response of the sensor. The correlation coefficient (R) was greater than or equal to 0.9456 (p < 0.001). Response voltage (ΔUe) and response time (t0) obtained from the fitting equation on different concentrations of ricin fitted well with the measured values.
Highlights
Sensors based on microelectromechanical systems (MEMS) have been increasingly used as mechanical transducers due to their small size, low power consumption, high sensitivity, and robustness in harsh environments.[1,2,3,4,5,6] A piezoresistive microcantilever is a new kind of electrical cantilever, with characteristics of simple read-out way, easy integration, low cost, and small volume
In order to evaluate the test performance and investigate the response dynamic characteristics of a piezoresistive microcantilever aptasensor, a novel method for ricin detection and kinetic analysis based on a piezoresistive microcantilever aptasensor was proposed, where ricin aptamer was immobilised on the microcantilever surface by biotin-avidin binding system
The sensor showed no response for abrin, bovine serum albumin (BSA), and could overcome the influence of complex environmental disruptors, indicating high specificity and good selectivity
Summary
Sensors based on microelectromechanical systems (MEMS) have been increasingly used as mechanical transducers due to their small size, low power consumption, high sensitivity, and robustness in harsh environments.[1,2,3,4,5,6] A piezoresistive microcantilever is a new kind of electrical cantilever, with characteristics of simple read-out way, easy integration, low cost, and small volume. Compared with an optical readout and dynamic-mode cantilever, it is more promising in field detection.[7,8,9,10] Molecular recognition elements of conventional biosensors generally consist of biomolecules that are poorly stable, making the sensors unable to be used out of a laboratory. Aptamers possess characteristics of high affinity, high specificity, good thermal stability, easy preparation, and simple modification for further immobilisation procedures, making them quite suitable for applications as molecular recognition elements of biosensors. Owing to the combination of these two advantages, piezoresistive microcantilever aptasensors show great application prospects in field detection, which is expected to be an ideal biosensor for target molecules detection in the future. There has been no report on target molecules detection by this kind of sensor
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