We demonstrate that a novel functionalized interface, where molecularly imprinted polymer nanoparticles (nanoMIPs) are attached to screen-printed graphite electrodes (SPEs), can be utilized for the thermal detection of the cardiac biomarker troponin I (cTnI). The ultrasensitive detection of the unique protein cTnI can be utilized for the early diagnosis of myocardial infraction (i.e., heart attacks), resulting in considerably lower patient mortality and morbidity. Our developed platform presents an innovative route to develop accurate, low-cost, and disposable sensors for the diagnosis of cardiovascular diseases, specifically myocardial infraction. A reproducible and advantageous solid-phase approach was utilized to synthesize high-affinity nanoMIPs (average size = 71 nm) for cTnI, which served as synthetic receptors in a thermal sensing platform. To assess the performance and commercial potential of the sensor platform, various approaches were used to immobilize nanoMIPs onto thermocouples or SPEs: dip coating, drop casting, and a covalent approach relying on electrografting with an organic coupling reaction. Characterization of the nanoMIP-functionalized surfaces was performed with electrochemical impedance spectroscopy, atomic force microscopy, and scanning electron microscopy. Measurements from an in-house designed thermal setup revealed that covalent functionalization of nanoMIPs onto SPEs led to the most reproducible sensing capabilities. The proof of application was provided by measuring buffered solutions spiked with cTnI, which demonstrated that through monitoring changes in heat transfer at the solid–liquid interface, we can measure concentrations as low as 10 pg L–1, resulting in the most sensitive test of this type. Furthermore, preliminary data are presented for a prototype platform, which can detect cTnI with shorter measurement times and smaller sample volumes. The excellent sensor performance, versatility of the nanoMIPs, and reproducible and low-cost nature of the SPEs demonstrate that this sensor platform technology has a clear commercial route with high potential to contribute to sustainable healthcare.

In the present work, silver colloid was produced by chemical reduction of silver salt (silver nitrate) using citrates in aqueous solution. UV‐Vis spectrophotometry indicated the formation of nanoparticles. The surface plasmon resonance peak in absorption spectra of the silver colloidal solution showed an absorption maximum at 435 nm. The dynamic light scattering and zeta potential measurements showed that the size and the zeta potential of the synthesized nanoparticles were about 98 nm and −50 mV respectively. The nanoparticles have been used to modify the gold electrode for use as a potential electrochemical sensor for the analysis of arsenic in aqueous solution. The cyclic voltammogram recorded using gold electrode modified with AgNPs depicted a well‐defined reduction peak of arsenic compared to bare gold electrode. The enhancement of the signal is essentially due to the large surface area attributed to silver nanoparticles. Linear sweep voltammetry has been used to optimize the analytical conditions of arsenic in aqueous solution: it came out that the detection of arsenic in 0.1 M HNO3 was optimal while the electrode was conditioned at −0.6 v during 300 s. Under these optimum conditions, a calibration curve was plotted in the concentration range of 0.05 μM to 0.2 μM and the detection limit was estimated at 1.38×10−8 M, calculated from a ratio signal/noise 3.

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Molecular recognition has been described as the “ultimate” form of sensing and plays a fundamental role in biological processes. There is a move towards biomimetic recognition elements to overcome inherent problems of natural receptors such as limited stability, high-cost, and variation in response. In recent years, several alternatives have emerged which have found their first commercial applications. In this review, we focus on molecularly imprinted polymers (MIPs) since they present an attractive alternative due to recent breakthroughs in polymer science and nanotechnology. For example, innovative solid-phase synthesis methods can produce MIPs with sometimes greater affinities than natural receptors. Although industry and environmental agencies require sensors for continuous monitoring, the regulatory barrier for employing MIP-based sensors is still low for environmental applications. Despite this, there are currently no sensors in this area, which is likely due to low profitability and the need for new legislation to promote the development of MIP-based sensors for pollutant and heavy metal monitoring. The increased demand for point-of-use devices and home testing kits is driving an exponential growth in biosensor production, leading to an expected market value of over GPB 25 billion by 2023. A key requirement of point-of-use devices is portability, since the test must be conducted at “the time and place” to pinpoint sources of contamination in food and/or water samples. Therefore, this review will focus on MIP-based sensors for monitoring pollutants and heavy metals by critically evaluating relevant literature sources from 1993 to 2022.