A collaborative effect of imprinted polymers and Au nanoparticles on bioanalogous detection of organic vapors

Abstract

The development of synthetic materials for bioanalogous detection of different analytes is made simple by molecular imprinting. However, improving the ultimate performance of imprinted sensing devices for real-world applications is yet desirable. In this work, biomimetic coatings are designed for quartz crystal microbalance (QCM) based mass-sensitive devices to detect trace amounts of organic vapors. Gold (Au) nanoparticles and two types of molecularly imprinted polymers (MIPs) are synthesized separately for this purpose, and fabricated on QCM transducers as MIP/Au/MIP sandwich structures using a layer-by-layer (LbL) assembly approach. The devices are exposed to different organic vapors, including acetone, acetaldehyde, formaldehyde, ethyl acetate, methyl acetate, methanol, and water (humidity) to study sensor characteristics. The LbL-assembled biomimetic coatings exhibit highly selective sensor signal toward target analytes with many-folds enhanced sensitivity as compared to other sensitive materials. Control experiments also suggest the existence of a collaborative effect between MIPs and Au nanoparticles that offers substantially improved sensor performance. The LbL-assembled sensor coatings are easy to fabricate and highly rugged, thus delivering reproducible sensor signals at low concentrations of gaseous analytes and complementing the benefits such as selective recognition through imprinting phenomenon and improved sensitivity through higher surface availability of embedded Au nanoparticles.