A new versatile photo-iniferter polymerization approach to obtain molecularly imprinted polymers (MIPs) on nanostructured porous silica (PSiO2) interferometers

In recent years, PSiO2-based transducers have gained attention for sensing due to their large surface area, sensitivity, cost-effectiveness, and structural strength. While efforts to immobilize natural recognition systems on porous silicon for selectivity face cost and stability issues, molecularly imprinted polymers (MIPs) offer a solution. MIPs are highly selective, stable, and cost-effective artificial receptors made by a polymerization process around a target analyte. Focusing on propranolol, we successfully develop thin MIP layers (approx. 3 nm thick) on PSiO2-based interferometers through innovative controlled radical photo-iniferter polymerization. Functionalization verification is done via UV-Vis and X-ray photoelectron spectroscopy. The resulting sensor displays excellent linearity (5-100 µM) and low detection limit (1.2 µM), effective even in tap water. Moreover, our method demonstrates versatility by imprinting atenolol, yielding MIPs with high specificity, selectivity, and stability for at least 60 days A NEW VERSATILE PHOTO-INIFERTER POLYMERIZATION APPROACH TO OBTAIN MOLECULARLY IMPRINTED POLYMERS (MIPs) ON NANOSTRUCTURED POROUS SILICA (PSiO2) INTERFEROMETERS T. DI GIULIO1, M.I. ASIF1, C. MALITESTA1, M. CORSI2, C. GONZATO3, K. HAUPT3, G. BARILLARO2, E. MAZZOTTA1* 1: Laboratorio di Chimica Analitica, Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, Università del Salento, Lecce, Italy. 2: Dipartimento di Ingegneria dell’Informazione, Università di Pisa, via G. Caruso 16, 56126 Pisa – Italy 3: UMR 7025 CNRS Enzyme and Cell Engineering Laboratory, Université de Technologie de Compiègne, Compiègne, France Abstract Methods Results Conclusions Here, we present an innovative and versatile method for molecularly imprinted polymers (MIPs) synthesis utilizing a photo-triggered polymerization approach on nanostructured materials (PSiO2 scaffolds). The MIP-based sensor was challenged toward propranolol detection and the results indicated a linear dynamic range from 5 to 100 µM with a LOD of 1.2 µM. Propranolol detection in real matrix and selectivity tests with atenolol, metoprolol and timolol demonstrate the potential of the sensor to be used in real-world applications. Acknowledgment: this work was partially funded by the European Union Horizon Europe programme under grant agreement No 101046946 (RESORB). www.resorb-project.eu presenting author: *[email protected] corresponding author: elisabetta.ma[email protected] After all the functionalization steps an increase in the EOT signal is recorded, as indirect demonstration of the successful funzionalization. XPS characterization proved the successful deposition of the polymer onto the porous layer (C 1s signal changes). Different polymerization times were tested and an increase in the EOT signal with time was observed, probably related to a higher mass of polymer deposited within the nanopores. An increase in sensor response with time was observed, reaching a maximum at 30 min (chosen as incubation time for further experiments The sensor is able to detect propranolol up to 1 mM, but a linear response was observed from 0.005 to 0.1 mM (100 µM) 5-hs MIPs showed better performance in propranolol detection The sensor proved to be highly selective against competitive molecules. Moreover, it was tested in different matrices, including tape water and good binding efficiency was observed. PSiO2scaffolds were prepared by anodic etching of p-type silicon wafer samples using an already known procedure1. Later, PSiO2 scaffolds were functionalized with MIP thin layers by a light-triggered photo-iniferter polymerization approach. Functionalization steps: •silanization of PSiO2layer with APTES (used as linker for the photo-inifierter); •anchoring of the iniferter by a coupling reaction; •photo-triggered polymerization (sample irradiated by low-intensity visible light) using a solution containing monomer, crosslinker and target (propranolol). To obtain the imprinted cavities, the target is removed from the polymer matrix by a washing procedure. References 1. Mazzotta E, Di Giulio T, Mariani S, Corsi M, Malitesta C, Barillaro G. Vapor‐Phase Synthesis of Molecularly Imprinted Polymers on Nanostructured Materials at Room‐Temperature. Small. 2023 May 24:2302274. https://www.resorb-project.eu/ target rebinding target removal A) B) MIP synthesis by photo-iniferter polymerization UV-VIS spectroscopy X-ray photo-electron spectroscopy (XPS) analysis MIP optimization MIP-based sensor performance iniferter grafting iniferter grafting iniferter grafting iniferter grafting APTES silanization photo-polymerization Universitè de technologie de Compiègne **EOT (effective optical thickness) = 2nL, where “n” is the refractive index and “L” is the thickness of the porous layer).