Combined Layer/Particle Approaches in Surface Molecular Imprinting of Proteins: Signal Enhancement and Competition

Abstract

Herein we report novel approaches to the molecular imprinting of proteins utilizing templates sizing around 10 nm and some 100 nm. The first step comprised synthesizing nanoparticles of molecularly imprinted polymers (MIP) towards bovine serum albumin (BSA) and characterizing them according to size and binding capacity. In a second step, they were utilized as templates. Quartz crystal microbalances (QCM) coated with MIP thin films based on BSA MIP nanoparticles lead to a two-fold increase in sensor responses, compared with the case of directly using the protein as the template. This also established that individual BSA molecules exhibit different “epitopes” for molecular imprinting on their outer surfaces. In light of this knowledge, a possible MIP-based biomimetic assay format was tested by exposing QCM coated with BSA MIP thin films to mixtures of BSA and imprinted and non-imprinted polymer (NIP) nanoparticles. At high protein concentrations (1000 ppm) measurements revealed aggregation behavior, i.e., BSA binding MIP NP onto the MIP surface. This increased sensor responses by more than 30% during proof of concept measurements. At lower a BSA concentration (500 ppm), thin films and particles revealed competitive behavior.

Molecularly Imprinted Nanogels Capable of Porcine Serum Albumin Detection in Raw Meat Extract for Halal Food Control

“…The QCM sensor is the simplest type of piezoelectric sensing device offering label-free detection based on the change in mass. − The immobilization of obtained NGs onto the QCM sensor chips was performed using self-assembled monolayers (SAM) of MUA followed by an amine coupling reaction with NHS and EDC. After the coupling reaction, obtained NGs were immobilized on the QCM sensor chip via the covalent bond between secondary amine groups on the NGs and the carboxylic group on the SAM.…”

Imprinted Polymers as Synthetic Receptors in Sensors for Food Safety

“…The versatility of Ips enables detection of small molecules (Molecularly Imprinted Polymers, MIPs) [ 17 , 18 , 19 ] and whole cells (Surface Imprinted Polymers, SIPs) [ 20 , 21 , 22 ]. Furthermore, they can be coupled to different transducing elements such as microgravimetric [ 23 , 24 , 25 ], optical [ 26 , 27 ], thermal [ 28 , 29 , 30 ] and electrochemical [ 31 , 32 , 33 , 34 ] read-out platforms, among others.…”

Sensing the classical swine fever virus with molecularly imprinted polymer on quartz crystal microbalance

“…Especially surface imprinting is of interest, because it creates binding cavities of the target directly on the surface of a cross-linked polymer layer, which makes it comparably easy to remove the template (Eersels et al, 2016). There is a variety of literature on MIP-based QCM sensors for biospecies demonstrating their feasibility in principle: Recent examples include sensors towards bovine serum albumin (Phan et al, 2018), a sensor based on the dopaminergic receptor (Naklua et al, 2016), toward Escherichia coli (Poller et al, 2017), influenza A virus (Wangchareansak et al, 2013), and Dengue virus (Lieberzeit et al, 2016). In the light of previous work, we herein report on designing MIP-QCM sensors to detect CSFV (see Figure 1).…”