Performance assessment of interdigital sensor for varied coating thicknesses to detect CTX-I

Two most important features of a sensor are selectivity and sensitivity. In this paper, the role of the coating thickness on the sensitivity of the planar interdigital sensors has been investigated. The sensor had been coated with two different types of materials: acrylic lacquer as a protective layer and Molecular Imprinted Polymer (MIP) as a selective layer. The performance of the coated-sensor was studied by estimating the sensitivity of the sensor with various coating thicknesses. C-terminal telopeptide of type-I collagen (CTX-I) sample was used for this study. It was concluded that the MIP-coated sensor exhibited more sensitivity compared to the acrylic-coated one for CTX-I measurement. The Dip-coating method was employed to coat the sensor. The effect of the two important parameters, withdrawal speed and immersion time, on the thickness of the coating layer was studied. This investigation concluded that the faster the withdrawal speed, the thicker the coating layer. Moreover, the thickness of the coating layer was increased by increasing the dipping time. However, the results show that increasing the thickness enhances the saturated level. Depending on the application you need to have a trade off between the saturation level and the sensitivity obtained by varying the coating thickness.