Novel Prostate Specific Antigen plastic antibody designed with charged binding sites for an improved protein binding and its application in a biosensor of potentiometric transduction

Abstract

This work shows that the synthesis of protein plastic antibodies tailored with selected charged monomers around the binding site enhances protein binding. These charged receptor sites are placed over a neutral polymeric matrix, thus inducing a suitable orientation the protein reception to its site. This is confirmed by preparing control materials with neutral monomers and also with non-imprinted template. This concept has been applied here to Prostate Specific Antigen (PSA), the protein of choice for screening prostate cancer throughout the population, with serum levels >10 ng/mL pointing out a high probability of associated cancer. Protein Imprinted Materials with charged binding sites (C/PIM) have been produced by surface imprinting over graphene layers to which the protein was first covalently attached. Vinylben-zyl(trimethylammonium chloride) and vinyl benzoate were introduced as charged monomers labelling the binding site and were allowed to self-organize around the protein. The subsequent polymerization was made by radical polymerization of vinylbenzene. Neutral PIM (N/PIM) prepared without oriented charges and non imprinted materials (NIM) obtained without template were used as controls. These materials were used to develop simple and inexpensive potentiometric sensor for PSA. They were included as ionophores in plasticized PVC membranes, and tested over electrodes of solid or liquid conductive contacts, made of conductive carbon over a syringe or of inner reference solution over micropipette tips. The electrodes with charged monomers showed a more stable and sensitive response, with an average slope of-44.2 mV/decade and a detection limit of 5.8 × 10 −11 mol/L (2 ng/mL). The corresponding non-imprinted sensors showed lower sensitivity, with average slopes of-24.8 mV/decade. The best sensors were successfully applied to the analysis of serum, with recoveries ranging from 96.9 to 106.1% and relative errors of 6.8%.

Imprinting Technology in Electrochemical Biomimetic Sensors

“…The sensors were entrapped in PVC membranes with a solvent plasticizer and applied to conventional solid-contact carbon electrodes. The analytical performance of the sensor was evaluated by potentiometric assays by means of calibration curve, selectivity study and sample analysis [167]. …”

Bioinspired intelligent molecularly imprinted polymers for chemosensing: A mini review

“…Initially, it seemed that it was difficult to fabricate an electrochemical sensor with the acrylic based MIPs because of lack of direct path for electron conduction from the recognition sites of molecularly imprinted cavities to the electrode surface [22]. Integration of these non-conducting films with different conducting scaffolds, mostly of carbon allotropes, helped to circumvent these difficulties [23][24][25][26][27].…”

Synthesis of molecular biomimetics

“…Several carbon allotropes have been employed with success in biomimetic technologies, including graphite (Almeida et al, 2012), graphene (Rebelo et al, 2014, Truta et al, 2014, and CNTs (Moreira et al, 2011a,b;Queiros et al, 2012). Graphite is an inexpensive material with reasonable electrical features to be applied in electrical-based strategies.…”