CORE-SHELL NANOPARTICLES FOR GAS PHASE DETECTION BASED ON SILVER NANOSPHERES COATED WITH A THIN MOLECULARLY IMPRINTED POLYMER ADSORBED ON A CHEMIRESISTOR

This study¹ presents a novel gas phase detection prototype based on assembling core-shell nanospheres made of silver core and coated with a molecularly imprinted polymer (MIP) adsorbed onto an interdigitated array (IDA) electrode chemiresistor (CR). Specifically, we synthesized and very carefully analyzed core-shell nano MIPs made of a silver core and an ultrathin organic MIP shell. The core-shell nanospheres, AgNP@MIPs, were imprinted with linalool, as a model system for a volatile compound. The thickness of the MIP layer was tuned to a few nanometers to enable the facile ingress and egress of the linalool, as well as to enhance the electrical transduction through the Ag core. The latter is responsible for transducing the MIP recognition event into a measurable increase in the IDA-CR resistance. The AgNP@MIPs were spread onto the IDA-CR modified with various positively charged polymers, by drop casting and dip-coating. The AgNP@MIPs were characterized by various techniques such as extra high-resolution scanning and tunnelling electron microscopy and X-ray diffractometer. The response to linalool exposure and removal was fast and the device was fully recovered and could be reused after simple removal of the analyte. Finally, the difference in the resistance change between imprinted and non-imprinted nanospheres was substantial and clearly confirms the crucial role of molecular imprinting of the core-shell nanoparticles. We believe this study proves the great potential of the synergetic capabilities of MIPs along with IDA-CR devices and establishes good foundations for furtherexploration and development of new MIP–based IDA-CR sensors.

1. Shahar T., Feldheim G., Marx S., Mandler D., Nanoscale, submitted.