Nanostructured Molecular Imprinted Polymers for Chemosensing of Hormone Proteins

Abstract

Immunoassays and high-performance liquid chromatography combined with mass spectrometry are common methods to selectively determine protein biomarkers in biological samples. The excellent accuracy of these determinations is at the expense of a high cost, including the cost of specific antibodies supply or instrumentation and experienced operation. Several biosensors were devised and fabricated for fast and selective quantification of the protein biomarkers. The most interesting protein biomarkers belong to the glycoprotein family. Unfortunately, it seems challenging to generate antibodies for this family because of low immunogenicity. Thus, an alternative research field is developing which claims to synthesize more stable artificial antibody-like receptors for the replacement of natural antibodies.Here, a semi-covalent procedure is proposed to elaborate surface imprinted polymers for selective recognition of gonadotropin hormones.1,2 Briefly, this strategy consists of a combination of three methods, namely, (i) lithography, (ii) surface imprinting, and (iii) semi-covalent imprinting. Hard template silica beads were used as a mold to prepare a highly organized opal structure. On top of this, template proteins were immobilized. Later, the protein was derivatized with functional monomers. These functionalized template molecules were electrochemically cross-linked with an excess of cross-linking monomer. Removal of the silica mold creates a nanostructure containing molecular cavities on the surface. Such nanostructures are advantageous for non-restrictive diffusion of bulky proteins toward the respective molecular cavities.We confirmed regular and hexagonal packing of silica beads, resulting in inverse opal surface imprinted molecular films, by Scanning Electron Microscope (SEM). The recognition of proteins by the nanostructured molecular imprinted polymer films was transduced with the help of capacitive impedimetry. The suitability of the synthetic receptor was further confirmed by measuring proteins in real blood serum samples.