Improved QCM-D signal-to-noise ratio using mesoporous silica and titania

In many biological and environmental applications it is crucial to detect low concentrations of low molecular weight analytes. To accomplish this a variety of surface sensing techniques, such as quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR), have been developed. These techniques provide good sensitivity and selectivity, however, there is a need to improve these even further by enhancing the signal-to-noise ratio. One suggestion to improve the QCM-D signal is to use mesoporous coated QCM-D sensor crystals as sensing substrate. Mesoporous materials are promising to use, since they possess a high specific surface area and that their properties, such as pore size, pore geometry and surface chemistry, can be controlled. Here we demonstrate a method to increase the signal-to-noise ratio of the QCM-D signal illustrated by adsorbing dendrimers on mesoporous silica and titania coated QCM-D crystals. The experiments were performed on cubic mesoporous silica having varying pore sizes and hexagonal and cubic mesoporous titania having similar pore size. The results showed that the QCM-D signal-to-noise was improved when mesoporous material was used and that the pore size and pore geometry determined the selectivity of the adsorbing analyte. These findings are important in the detection of analytes at low concentrations using QCM-D.