Nanocomposite of bimetallic nanodendrite and reduced graphene oxide as a novel platform for molecular imprinting technology

Molecularly Imprinted Polymers Using Yeast as a Supporting Substrate

Molecularly imprinted polymers (MIPs) have gained significant attention as artificial receptors due to their low cost, mild operating conditions, and excellent selectivity. To optimize the synthesis process and enhance the recognition performance, various support materials for molecular imprinting have been explored as a crucial research direction. Yeast, a biological material, offers advantages such as being green and environmentally friendly, low cost, and easy availability, making it a promising supporting substrate in the molecular imprinting process. We focus on the preparation of different types of MIPs involving yeast and elaborate on the specific roles it plays in each case. Additionally, we discuss the advantages and limitations of yeast in the preparation of MIPs and conclude with the challenges and future development trends of yeast in molecular imprinting research.

Green Aspects in Molecularly Imprinted Polymers by Biomass Waste Utilization

Molecular Imprinting Polymer (MIP) technology is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. In the last decades, MIP technology has gained much attention from the scientific world as summarized in several reviews with this topic. Furthermore, green synthesis in chemistry is nowadays one of the essential aspects to be taken into consideration in the development of novel products. In accordance with this feature, the MIP community more recently devoted considerable research and development efforts on eco-friendly processes. Among other materials, biomass waste, which is a big environmental problem because most of it is discarded, can represent a potential sustainable alternative source in green synthesis, which can be addressed to the production of high-value carbon-based materials with different applications. This review aims to focus and explore in detail the recent progress in the use of biomass waste for imprinted polymers preparation. Specifically, different types of biomass waste in MIP preparation will be exploited: chitosan, cellulose, activated carbon, carbon dots, cyclodextrins, and waste extracts, describing the approaches used in the synthesis of MIPs combined with biomass waste derivatives.

A novel highly sensitive soy aptasensor for antigen β-conglycinin determination

β-Conglycinin, composed of three subunits (α', α and β), is the main allergen of soy protein which can cause severe allergic reactions, such as diarrhea, decreased growth performance and even death. Among them, the β subunit is more stable and difficult to remove, being one of the main nutritional inhibitors, which can be used to evaluate the concentration of β-conglycinin. However, there is no effective, accurate method for its β subunit rapid detection. Herein, we have successfully selected a high affinity β subunit aptamer (Kd = 6.9 nM) and developed a highly sensitive aptasensor. The aptasensor displayed high specificity and the β subunit at a concentration of 70-350 nM could be detected with a detection limit of 4.48 nM (3S/N). In addition, the recoveries of β subunit were more than 90%, demonstrating its practical properties for complicated conditions such as food quality control and disease diagnosis, without requiring expensive and sophisticated equipment.

Application of magnetic nanomaterials in electroanalytical methods: A review

Magnetic nanomaterials (MNMs) have gained high attention in different fields of studies due to their ferromagnetic/superparamagnetic properties and their low toxicity and high biocompatibility. MNMs contain magnetic elements such as iron and nickel in metallic, bimetallic, metal oxide, and mixed metal oxide. In electroanalytical methods, MNMs have been applied as sorbents for sample preparation before the electrochemical detection (sorbent role), as the electrode modifier (catalytic role), and the integration of the above two roles (as both sorbent and catalytic agent). In this paper, the application of MNMs in electroanalytical methods have been classified based on the main role of the nanomaterial and discussed separately. Furthermore, catalytic activities of MNMs in electroanalytical methods such as redox electrocatalytic, nanozymes catalytic (peroxidase, catalase activity, oxidase activity, superoxide dismutase activity), catalyst gate, and nanocontainer have been discussed.

Preparation of hemoglobin (Hb)-imprinted poly(ionic liquid)s via Hb-catalyzed eATRP on gold nanodendrites

Hemoglobin (Hb)-imprinted poly(ionic liquid)s (HIPILs) were prepared on the surface of Au electrode modified with gold nanodendrites (Au/ND/HIPILs). HIPILs were synthesized with 1-vinyl-3-propyl imidazole sulfonate ionic liquids as functional monomers via electrochemically mediated atom transfer radical polymerization (eATRP) catalyzed by Hb. The Au/ND/HIPILs electrode was examined by cyclic voltammetry (CV), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The Au/ND/HIPILs electrode was also used as an electrochemical sensor to determine Hb by differential pulse voltammetry (DPV). Under the optimal conditions, the detection range of Hb was from 1.0 × 10^-14 to 1.0 × 10^-4 mg/mL with a limit of detection of 5.22 × 10^-15 mg/mL (S/N = 3). Compared with other methods, the sensor based on poly(ionic liquid)s had the broader linear range and lower detection limit. Graphical Abstract.

Advances in Molecularly Imprinting Technology for Bioanalytical Applications

In recent years, along with the rapid development of relevant biological fields, there has been a tremendous motivation to combine molecular imprinting technology (MIT) with biosensing. In this situation, bioprobes and biosensors based on molecularly imprinted polymers (MIPs) have emerged as a reliable candidate for a comprehensive range of applications, from biomolecule detection to drug tracking. Unlike their precursors such as classic immunosensors based on antibody binding and natural receptor elements, MIPs create complementary cavities with stronger binding affinity, while their intrinsic artificial polymers facilitate their use in harsh environments. The major objective of this work is to review recent MIP bioprobes and biosensors, especially those used for biomolecules and drugs. In this review, MIP bioprobes and biosensors are categorized by sensing method, including optical sensing, electrochemical sensing, gravimetric sensing and magnetic sensing, respectively. The working mechanism(s) of each sensing method are thoroughly discussed. Moreover, this work aims to present the cutting-edge structures and modifiers offering higher properties and performances, and clearly point out recent efforts dedicated to introduce multi-sensing and multi-functional MIP bioprobes and biosensors applicable to interdisciplinary fields.

A novel surface plasmon resonance sensor based on a functionalized graphene oxide/molecular-imprinted polymer composite for chiral recognition of l-tryptophan

Herein, a novel surface plasmon resonance (SPR) sensor based on a functionalized graphene oxide (GO)/molecular-imprinted polymer composite was developed for the chiral recognition of l-tryptophan (l-Trp). The composite's recognition element was prepared via a facile and green synthesis approach using polydopamine as both a reducer of GO and a functional monomer as well as a cross-linker for molecular imprinting. The composite was characterized via Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. After attaching the composite onto the gold surface of an SPR chip, the sensor was characterized using contact-angle measurements. The sensor exhibited excellent selectivity and chiral recognition for the template (i.e., l-Trp). Density functional theory computations showed that the difference in hydrogen bonding between the composite element and l-Trp and d-Trp played an important role in chiral recognition.

Electrochemical sensing using magnetic molecularly imprinted polymer particles previously captured by a magneto-sensor

The determination of 1-chloro-2,4-dinitrobenzene (CDNB) was used as a proof-of-concept to a simple analytical practical configuration applying magnetic molecularly imprinted particles (mag-MIPs). Mag-MIPs were captured from an emulsion by a home-made magneto-sensor (where a small magnet was entrapped by a graphite-epoxy composite) and then, this sensor, was transferred to the solution containing the analyte, where, after binding to the mag-MIPs, the analyte was directly analysed using differential pulse voltammetry (DPV) since the magneto-sensor acted as the working electrode. After optimization, a detection limit of 6.0 μmol L^-1 with a RSD of 2.7% was achieved along with suitable recoveries and selectivity. This methodology offers a different approach for electroanalytical methodologies using mag-MIPs.

Electrochemical sensors based on magnetic molecularly imprinted polymers: A review

Participation of magnetic component in molecularly imprinted polymers (MIPs) has facilitated enormously the incorporation of these polymeric materials on electrode surfaces allowing the design of electrochemical sensors with very attractive analytical characteristics in terms of simplicity, reproducibility, low fabrication cost, high sensitivity and selectivity and rapid assay time. The magnetically susceptible resultant MIPs (MMIPs) allowed a simple and fast elution of the template molecules from MMIPs, are easily and faster collected without filtration, centrifugation or other complex operations and are also faster assembled and removed from the electrode surface by simply using an external magnetic field. A wide range of different (nano)materials such as gold nanoparticles (AuNPs), graphene oxide, single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) as well as different electrode modifiers (ionic liquids (ILs) and surfactants/dispersants) have been incorporated into the MMIPs to improve the analytical performance of the resulting electrochemical sensors which have demonstrated great promise for determination of relevant analytes in environmental, food and clinical analyses.

A battle between spherical and cube-shaped Ag/AgCl nanoparticle modified imprinted polymer to achieve femtogram detection of alpha-feto protein

In this work, a sensitive and selective molecularly imprinted polymer modified electrochemical sensor was developed for the detection of the hepatocellular carcinoma (HCC) biomarker, alpha feto protein (AFP) on the surface of specifically designed Ag/AgCl nanoparticles. Herein, for the first time, the effect of the shape of nanoparticles on the behavior of an imprinted polymer was studied using cube- and spherical-shaped Ag/AgCl nanoparticles. It was found that cube-shaped nanoparticles have high surface to volume ratios and higher electrocatalytic activity, and are, therefore, a suitable platform for the synthesis of imprinted polymers. Herein, we have demonstrated how a change in the morphology of the nanomaterials can affect the electrochemical and adsorption properties of an imprinted polymer towards the target analyte (here, AFP). A cube-shaped nanoparticle@imprinted polymer was used for the fabrication of the electrochemical sensor, the analytical performance of which was shown, by a square wave stripping voltammetric technique, to be good for the detection of AFP. The current response of the electrochemical sensor was linear for AFP concentrations in the range from 0.10 to 700.0 pg mL-1, with an ultra trace detection limit of 24.6 fg mL-1. This sensor offers high selectivity, sensitivity, simplicity and clinical applicability for AFP determination in human blood serum, plasma, and urine, without using antibodies or any biological components, this has not been reported for previously reported systems. The proposed sensor has the potential to be used as an alternative to the commercially available, costly, sophisticated enzyme-linked immunosorbent assay kits for AFP determination.