Molecular Imprinting on the Nanoscale – Rapid Detection of Ag Nanoparticles by QCM Sensors

Within this paper, we report first attempts of molecular imprinting with man-made nanoparticles as templates of the imprinting process. In a first step, we screened different polymers for their respective affinities towards silver nanoparticles by the respective frequency shifts observed with quartz crystal microbalance (QCM) sensors. Polyurethanes and polystyrenes show almost similar effects, where the latter reach about 80% of the effects on the former. In comparison, polyvinyl alcohol for this system yields only 5% signal compared to the polyurethane. Sedimentation surface imprinting turned out successful: NP MIP reveal cavities of the correct dimensions (20 nm in this case) on their surfaces, which cannot be seen on the respective NIP. Successful imprinting is further corroborated by first mass-sensitive measurements on QCM revealing ∼6 times higher signals on the MIP compared to the NIP and concentration-dependent, reversible sensor signals. To the best of our knowledge, this constitutes first successful MIP sensors for silver nanoparticles.