Molecularly Imprinted Polymer Waveguides for Direct Optical Detection of Low‐Molecular‐Weight Analytes

Abstract

New composite layer architecture of 3D hydrogel polymer network that is loaded with molecularly imprinted polymer nanoparticles (nanoMIP) is reported for direct optical detection of low-molecular-weight compounds. This composite layer is attached to the metallic surface of a surface plasmon resonance (SPR) sensor in order to simultaneously serve as an optical waveguide and large capacity binding-matrix for imprinted target analyte. Optical waveguide spectroscopy (OWS) is used as a labelfree readout method allowing direct measurement of refractive index changes that are associated with molecular binding events inside the matrix. This approach is implemented by using a photocrosslinkable poly( N -isopropylacrylamide)-based hydrogel and poly[(ethylene glycol dimethylacrylate)-(methacrylic acid)] nanoparticles that are imprinted with L -Boc-phenylalanine-anilide ( L -BFA, molecular weight 353 g mol −1 ). Titration experiments with the specifi c target and other structurally similar reference compounds show good specifi city and limit of detection for target L -BFA as low as 2 × 10 −6 M .

Diffusion and Permeation of Labeled IgG in Grafted Hydrogels

“…Polymer networks that form hydrogels become irreplaceable building blocks in diverse fields ranging from actuators , to shape memory , and self-healing materials, − and they rapidly find applications in the biomedical domain for tissue engineering, , drug delivery, implants, and wound dressings , as well as in analytical technologies for the biomarker analysis present in complex biological samples. − In particular, the biomedical areas take advantage of hydrogel architectures with tailored interaction and transport of biomolecules through the polymer networks. For instance, responsive hydrogels can be designed to serve as inert antifouling materials , or as systems for on-demand capture or release of specific biomolecules. , In the analytical field, numerous biosensor technologies rely on hydrogel materials attached at the interface between a physicochemical transducer and the analyzed liquid sample. − Such an interfacial architecture is typically engineered to suppress fouling of the sensor surface by unspecific binding of a large number of different molecules abundantly present in the analyzed sample. Furthermore, the hydrogel layer can serve to accommodate large density of ligands that are accessible for specific capture of target analyte while allowing efficient transport of target analyte in and out of the networks.…”

Nanoporous thin films in optical waveguide spectroscopy for chemical analytics

“…As a result of the proximity of the template molecules to the outer surface, the distribution of effective binding sites on imprinted nanoparticles after template extraction is considerably improved. This new structure is called molecularly imprinted polymeric rod array (MIP-NRAs) and offers a number of advances over planar arrangements [124], but also compared to MIP nanoparticles coupled to a hydrogel waveguide [125]: (1) the inner surface area of this structure is much higher than the geometrical dimensions of the planar waveguide; (2) analyte solution can freely diffuse through the MIP nanorods; (3) the optical interrogation of the polymeric cavities, filled with the analyte molecules, occurs throughout the cross section of the waveguide (and not just on its surface).…”

Hydrogel Decorated Chips for Convenient DNA Test

“…Hydrogels represent high surface area interfaces, and therefore have great capability to advance 2D detection systems. A new approach of detecting low‐molecular weight compounds via molecularly imprinted polymer nanoparticles that are loaded onto a polymer network utilizes this advantage . In addition, other molecules that bind according to the lock and key model can be introduced as recognition units, e.g., the macromolecule deoxyribonucleic acid (DNA).…”