Visible-Light Photo-Iniferter Polymerization of Molecularly Imprinted Polymers for Direct Integration with Nanotransducers

Abstract

Molecularly Imprinted Polymers (MIPs) have gained prominence as synthetic receptors, combining simplicity of synthesis with robust molecular recognition akin to antibodies and enzymes. One of their main application areas is chemical sensing. However, direct integration of MIPs with nanostructured transducers, crucial for enhancing sensing capabilities and broadening MIPs sensing applications, remains limited. This limitation mainly arises from the need for precise control over the MIP features (such as thickness) during deposition on nanostructured transducers. This work explores the potential of depositing MIPs directly onto nanostructured transducers via controlled radical photopolymerization, focusing on nanoporous silica (PSiO₂) with pore sizes of 40 nm and aspect ratio exceeding 100 as an interferometric optical nanotransducer. Leveraging the covalent attachment of a photo-iniferter agent onto the PSiO₂ surface, we achieved effective control over the polymerization process, resulting in the deposition of thin and uniform MIP layers on PSiO₂. As a case study, we developed an MIP-based PSiO₂ optical sensor for propranolol, used as the template molecule, showcasing excellent linearity, a low detection limit, and efficacy in real matrices such as tap water. The results further demonstrate the sensor selectivity for the target molecule, along with its reusability and stability for at least 60 days.