Immobilization of Molecularly Imprinted Polymer Nanoparticles onto Surfaces Using Different Strategies: Evaluating the Influence of the Functionalized Interface on the Performance of a Thermal Assay for the Detection of the Cardiac Biomarker Troponin I

Abstract

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.

Molecularly Imprinted Polymer Nanoparticles Enable Rapid, Reliable, and Robust Point-of-Care Thermal Detection of SARS-CoV-2

“… 57 The experimental protocol for the electrografting procedure ( Figure 1 d) is comprehensively outlined in our previous work. 34 SARS-CoV-2 antibody-functionalized SPEs and NIP-functionalized SPEs were prepared according to the same electrografting protocol.…”

“…This was followed by curing at 60 °C for 30 min with a dielectric material (Gwent Electronic Materials Ltd.), which was used to define the rectangular shape of the SPE for easy handling . The experimental protocol for the electrografting procedure (Figure d) is comprehensively outlined in our previous work . SARS-CoV-2 antibody-functionalized SPEs and NIP-functionalized SPEs were prepared according to the same electrografting protocol.…”

“…Previously, we have incorporated nanoMIPs into a sensor platform, which utilizes the heat transfer method (HTM) for the detection of various targets such as protein biomarkers and antibiotics. − The sensor platform measures the thermal resistance at the solid–liquid interface and possesses key advantages over many traditional diagnostic methods such as low-cost components, rapid and accurate detection, and simple quantitative analysis. , Thermal detection technology can be implemented into portable devices to facilitate point-of-care testing. However, these point-of-care devices are yet to reach the mass market .…”

Electrochemical Improvements Can Be Realized via Shortening the Length of Screen-Printed Electrochemical Platforms

“…In the former case, a range of geometries have been realized such as microbands, − dual-microbands, microband electrode arrays, microdisc arrays, microelectrodes and microelectrode arrays, and back-to-back configurations, highlighting the versatility of the SPE production methodology. SPEs are used extensively in the production of sensing platforms, with examples ranging from ions − and small molecules ,, to larger biological analytes such as proteins. − They have even been utilized outside of electrochemical sensing platforms due to their large surface area, ease of modification, disposability, and low cost. − As such, it is critical that SPEs can be reliably compared between different reported works.…”

Preparation of Rosin-Based Composite Membranes and Study of Their Dencichine Adsorption Properties

“…The commonly used adsorbents are activated carbon, iron oxide, silica gel, starch, adsorption resin, clay minerals and composite membranes. They use the porous matrices [ 19 , 20 , 21 ] as an adsorption platform and have good application prospects in the mass transfer and adsorption process. Among them, the composite membranes [ 22 , 23 , 24 , 25 ] have excellent thermal stability, high adsorption capacities and stable three-dimensional structure.…”