MIPs and Aptamers for Recognition of Proteins in Biomimetic Sensing

Abstract

Biomimetic binders and catalysts have been generated in order to substitute the biological pendants in separation techniques and bioanalysis. The two major approaches use either “evolution in the test tube” of nucleotides for the preparation of aptamers or total chemical synthesis for molecularly imprinted polymers (MIPs). The reproducible production of aptamers is a clear advantage, whilst the preparation of MIPs typically leads to a population of polymers with different binding sites. The realization of binding sites in the total bulk of the MIPs results in a higher binding capacity, however, on the expense of the accessibility and exchange rate. Furthermore, the readout of the bound analyte is easier for aptamers since the integration of signal generating labels is well established. On the other hand, the overall negative charge of the nucleotides makes aptamers prone to non-specific adsorption of positively charged constituents of the sample and the “biological” degradation of non-modified aptamers and ionic strength-dependent changes of conformation may be challenging in some application.

Electrosynthesized molecularly imprinted polyscopoletin nanofilms for human serum albumin detection

“…[1] In this respect general synthetic processes with broad applicability in terms of targets to be recognized such as molecular imprinting of polymers are especially appealing. [2,3] Molecular imprinting uses the target as a template during polymerization of functional monomers.…”

“…[12][13][14] While the molecular imprinting concept is fairly universal the functional monomers to provide selective recognition are not, i.e., the library of monomers is rather limited and monomers adequate for a certain protein target may not be necessarily optimal for another. [15] While high affinity MIPs were reported for a number of targets [16,17], the selectivity of protein-MIPs is often enhanced by incorporating in the MIPs compounds known to interact with the target, e.g. substrates or inhibitors of an enzyme target [18,19], aptamers [20] and various nanomaterials [16,21].…”

“…The difficulty to achieve this goal is largely due to the lack of universally applicable monomer library, i.e., in case of electropolymerized MIPs generally only a single monomer is used for the synthesis of MIPs. [15] Given the diversity of proteins in terms of physical chemical properties it is unlikely to have the full range of interactions for high affinity binding covered by these simple MIPs. Therefore, the success rate of this probabilistic approach was increased in many cases by focusing on proteins with distinctive properties [8,23] that facilitates the likelihood of obtaining binding sites with both strong and selective interaction with the target.…”

Enzymes as Tools in MIP-Sensors

“…Chemosensors 2017, 5, 11 2 of 16 than 1200 papers on MIPs are published per year [5][6][7][8][9]. Some ten percent of MIP papers describe artificial receptors for proteins [7,[10][11][12][13], including enzymes [13][14][15][16][17][18][19][20][21].…”

“…Since then, the technique of self-polymerization has been employed in several studies for the imprinting of proteins on various platforms such as magnetic [51,52], gold [53], or silica nanoparticles [54,55], silicon nanowires [56], 4-vinylphenylboronic acid-based monolithic skeletons [57], gold electrodes [58,59], or multi-walled carbon nanotubes [60]. These studies showed that apart from the advantage of controllable thickness, MIPs comprised of polydopamine exhibit good to excellent binding properties, have high hydrophilicity, biocompatibility, as well as pH (3)(4)(5)(6)(7)(8)(9)(10)(11) and longtime stability [61].…”