Generic sensor platform based on electro-responsive molecularly imprinted polymer nanoparticles (e-NanoMIPs)

The present research describes the design of robust electrochemical sensors based on electro-responsive molecularly imprinted polymer nanoparticles (e-MIPs). The e-MIPs, tagged with a redox probe, combine both recognition and reporting functions. This system replaces enzyme-mediator pairs used in traditional biosensors. The analyte recognition process relies on the generic actuation phenomenon when the polymer conformation of e-MIPs is changing in response to the presence of the template analyte. The analyte concentration is measured using voltammetric methods. In an exemplification of this technology, electrochemical sensors were developed for the determination of concentrations of trypsin, glucose, paracetamol, C4-homoserine lactone, and THC. The present technology allows for the possibility of producing generic, inexpensive, and robust disposable sensors for clinical, environmental, and forensic applications

Design and fabrication of a smart sensor using in silico epitope mapping and electro-responsive imprinted polymer nanoparticles for determination of insulin levels in human plasma

A robust and highly specific sensor based on electroactive molecularly imprinted polymer nanoparticles (nanoMIP) was developed. The nanoMIP tagged with a redox probe, combines both recognition and reporting capabilities. The developed nanoMIP replaces enzyme-mediator pairs used in traditional biosensors thus, offering enhanced molecular recognition for insulin, improving performance in complex biological samples, and yielding high stability. Also, most of existing sensors show poor performance after storage. To improve costs of the logistics and avoid the need of cold storage in the chain supply, we developed an alternative to biorecognition system that relies on nanoMIP. NanoMIP were computationally designed using “in-silico” insulin epitope mapping and synthesized by solid phase polymerisation. The characterisation of the polymer nanoparticles was performed by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform Infrared (FT-IR) and surface plasmon resonance (SPR). The electrochemical sensor was developed by chemical immobilisation of the nanoMIP on screen printed platinum electrodes. The insulin sensor displayed satisfactory performances and reproducible results (RSD = 4.2%; n = 30) using differential pulse voltammetry (DPV) in the clinically relevant concentration range from 50 to 2000 pM. The developed nanoMIP offers the advantage of large number of specific recognition sites with tailored geometry, as the resultant, the sensor showed high sensitivity and selectivity to insulin with a limit of detection (LOD) of 26 and 81 fM in buffer and human plasma, respectively, confirming the practical application for point of care monitoring. Moreover, the nanoMIP showed adequate storage stability of 168 days, demonstrating the robustness of sensor for several rounds of insulin analysis

Disposable paracetamol sensor based on electroactive molecularly imprinted polymer nanoparticles for plasma monitoring

A highly sensitive disposable electrochemical sensor for paracetamol was devised using electroactive molecularly imprinted polymers nanoparticles (nanoMIPs). NanoMIPs were prepared by solid-phase synthesis. Polymer composition included itaconic acid as a specific functional monomer and ferrocene as redox label, which confers electroactivity to the nanoparticles. NanoMIPs were characterised by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and scanning electron microscopy (SEM). Sensors were fabricated by covalent attachment of nanoMIPs on screen-printed carbon electrodes and then employed for electrochemical determination of paracetamol using differential pulse voltammetry (DPV). The sensor was successfully evaluated in spiked human plasma with recoveries at 94–108 % and presenting a sensitivity of 6.18 ± 0.22 μA mM−1. The limit of detection and limit of quantification for the sensor were found to be 50 μM and 167 μM, respectively, in a linear concentration range between 0.1 and 1 mM. High selectivity was demonstrated, with no interference found in the presence of caffeine, procainamide or ethyl 4-aminobenzoate. The sensors exhibited high reproducibility (RSD, 4.8 %), fast response time (∼8 s) and acceptable shelf life (90 days), confirming its suitability for point of care diagnostic applications