Photo-iniferter polymerization: a convenient approach for integrating Molecularly Imprinted Polymers with nanostructured sensors

TIZIANO DI GIULIO1, COSIMINO MALITESTA1, CARLO GONZATO2, KARSTEN HAUPT2, MARTINA CORSI3, GIUSEPPE BARILLARO3, ELISABETTA MAZZOTTA3. 1Dipartimento di Scienze e Tecnologie Biologiche e Ambientali (Di.S.Te.B.A.), Università del Salento, Lecce, Italy 2CNRS Enzyme and Cell Engineering Laboratory, Université de Technologie de Compiègne, Sorbonne Universités, Compiègne, France 3Dipartimento di Ingegneria dell’Informazione, Università di Pisa, Pisa, Italy 19 June 2024 Photo-iniferter polymerization: a convenient approach for integrating Molecularly Imprinted Polymers with nanostructured sensors OBJECT OF THE RESEARCH Novel, effective route enabling the preparation of artificial receptors on nanostructured materials, here used as optical transducer, and demonstrate its versatility MIPs Imprinted poly(MAAco-EGDMA) Nanostructured material Nanoporous silica Target molecules Propranolol Atenolol 1 NANOPOROUS SILICA (nPSiO2) as optical transducer Nanostructured material Nanoporous silica Reflectance (%) Wavelenght (nm) Nanoporous silicon oxide (nPSiO2) scaffolds with high aspect ratio >100 different optical structures (i.e., interferometers, resonant cavities, waveguides) Scale bar 100 nm Scale bar 1 m 2 NANOPOROUS SILICA (nPSiO2) as optical transducer (interferometer) Nanostructured material Nanoporous silica Thickness: 4m Porous diameter: 50 nm Porosity: 75% reflecte d light FFT Signal modification is produced by: A) insertion/grafting; B) removal or C) adsorption of compounds on porous silica layer A B C A B C m=2nd/λm EOT (effective optical thickness): 2nL light n: refractive index L: thickness 3 MIPs Integration of MIPs on the transducer surface is a key issue for sensing applications, being still challenging on nanostructured materials When using nanostructured materials as transducers, two aspects must be considered: 1.The transducer properties must be maintained after coupling with receptors. 2.Only homogeneous functionalization of the transducer can prevent issues with sensor reproducibility and repeatability Imprinted poly(MAA)- co-EGDMA 4 PHOTO-INIFERTER POLYMERIZATION The term "iniferter" is derived from the combination of "initiator," "transfer agent," and "terminator." The iniferter serves multiple roles: it initiates the polymerization, transfers the growing chain, and terminates the chain growth, thereby providing control over the polymerization process. INIFERTER Photo-iniferter monomer light polymer dithiocarbamates trithiocarbamates dithiocarbazate dithiobenzoates i) On/off process; ii) reversible deactivation process → better control over the molecular weight (and then the thickness) 5 PHOTO-INIFERTER POLYMERIZATION ON PSIO2 What’s new in the proposed approach? PHOTO-INIFERTER anchored onto the inner surface of the nanostructured PSiO2 surface-initiated photo-iniferter polymerization to obtain molecularly imprinted polymers ADVANTAGES: i)after photo-iniferter exposure to the light, the radicals are confined to the surface and initiate polymerization of monomers near the surface; ii) polymer chains grow directly anchored to the surface; iii) the growth of free oligo/polymer in the polymerization solution is avoided, thus preventing the possible blocking of nanopores. paper in preparation 6 PSiO2FUNCTIONALIZATION AND IMPRINTING PROCEDURE target polymer Target removal Target rebinding iniferter anchoring photo-iniferter polymerization I N I F E R T E R PSiO2 M I P P o l y m e r visible light paper in preparation bare PSiO2photo-iniferter on PSiO2scaffolds polymer deposition on PSiO2 polymerization solution containing MAA/EGDMA and target molecules (propranolol) 7 (washing with MetOH/HAc) X-ray photo-electron spectroscopy (XPS) and Scanning Electron Microscopy (SEM) characterization PSiO2scaffold MIP 10 20 30 40 50 60 0 2 4 6 8 10 12 14 16 18 Relative frequency (%) Equivalent diameter (nm) 10 20 30 40 50 60 0 2 4 6 8 10 12 14 16 Relative frequency (%) Equivalent diameter (nm) Thickness estimation: by measuring variations in the intensity of photoelectron signals before and after deposition. ൗ𝐼𝑆𝑖 𝑝𝑜𝑙𝑦𝑚𝑒𝑟 𝐼𝑆𝑖 𝑃𝑆𝑖𝑂2 = 𝑒𝑥𝑝 −Τ 𝑡 𝜆𝑆𝑖 𝑝𝑜𝑙𝑦𝑚𝑒𝑟 where 𝐼𝑆𝑖 𝑃𝑆𝑖𝑂2 and 𝐼𝑆𝑖 𝑝𝑜𝑙𝑦𝑚𝑒𝑟 is the Si 2p intensity recorded before and after polymer deposition t is the film thickness (unknown parameter), and 𝜆𝑆𝑖 𝑝𝑜𝑙𝑦𝑚𝑒𝑟 is the attenuation length. thickness (d)= 3.7 nm 8 THANKS FOR YOUR KIND ATTENTION! European Union Horizon Europe programme under grant agreement No 101046946 (RESORB)