Developing a novel sensor based on ionic liquid molecularly imprinted polymer/gold nanoparticles/graphene oxide for the selective determination of an anti-cancer drug imiquimod

Exploring the potential of molecularly imprinted polymers and metal/metal oxide nanoparticles in sensors: recent advancements and prospects

Metal/metal oxide nanoparticles have gained increasing attention in recent years due to their outstanding features, including optical and catalytic properties, as well as their excellent conductivity. The implementation of metal/metal oxide nanoparticles, combined with molecularly imprinted polymers (MIPs) has paved the way for a new generation of building blocks to engineer and enhance the fascinating features of advanced sensors. This review critically evaluates the impact of combining metal/metal oxide nanoparticles with MIPs in sensors. It covers synthesis strategies, advantages of coupling these materials with MIPs, and addresses questions about the selectivity of these hybrid materials. In the end, the current challenges and future perspectives of this field are discussed, with a particular focus on the potential applications of these hybrid composites in the sensor field. This review highlights the exciting opportunities of using metal/metal oxide nanoparticles along with MIPs for the development of next-generation sensors.

Carbon-based biosensors from graphene family to carbon dots: A viewpoint in cancer detection

According to the latest report by International Agency for Research on Cancer, 19.3 million new cancer cases and 10 million cancer deaths were globally reported in 2020. Early diagnosis can reduce these numbers significantly, and biosensors have appeared to be a solution to this problem as, unlike the traditional methods, they have low cost, rapid process, and do not need experts present on site for use. These devices have been incorporated to detect many cancer biomarkers and measure cancer drug delivery. To design these biosensors, a researcher must know about their different types, properties of nanomaterials, and cancer biomarkers. Among all types of biosensors, electrochemical and optical biosensors are the most sensitive and promising sensors for detecting complicated diseases like cancer. The carbon-based nanomaterial family has attracted lots of attention due to their low cost, easy preparation, biocompatibility, and significant electrochemical and optical properties. In this review, we have discussed the application of graphene and its derivatives, carbon nanotubes (CNTs), carbon dots (CDs), and fullerene (C60), for designing different electrochemical and optical cancer-detecting biosensors. Furthermore, the application of these carbon-based biosensors for detecting seven widely studied cancer biomarkers (HER2, CEA, CA125, VEGF, PSA, Alpha-fetoprotein, and miRNA21) is reviewed. Finally, various fabricated carbon-based biosensors for detecting cancer biomarkers and anticancer drugs are comprehensively summarized as well.

Green Chemistry and Molecularly Imprinted Membranes

Technological progress has made chemistry assume a role of primary importance in our daily life. However, the worsening of the level of environmental pollution is increasingly leading to the realization of more eco-friendly chemical processes due to the advent of green chemistry. The challenge of green chemistry is to produce more and better while consuming and rejecting less. It represents a profitable approach to address environmental problems and the new demands of industrial competitiveness. The concept of green chemistry finds application in several material syntheses such as organic, inorganic, and coordination materials and nanomaterials. One of the different goals pursued in the field of materials science is the application of GC for producing sustainable green polymers and membranes. In this context, extremely relevant is the application of green chemistry in the production of imprinted materials by means of its combination with molecular imprinting technology. Referring to this issue, in the present review, the application of the concept of green chemistry in the production of polymeric materials is discussed. In addition, the principles of green molecular imprinting as well as their application in developing greenificated, imprinted polymers and membranes are presented. In particular, green actions (e.g., the use of harmless chemicals, natural polymers, ultrasound-assisted synthesis and extraction, supercritical CO2, etc.) characterizing the imprinting and the post-imprinting process for producing green molecularly imprinted membranes are highlighted.

Determination of dopamine based on a temperature-sensitive PMEO2MA and Au@rGO-MWCNT nanocomposite-modified electrode

First, the nanocomposite Au@rGO-MWCNT was synthesized by a hydrothermal method. Next, a temperature-controlled composite sensing film was prepared by composite modification of poly(2-(2-methoxyethoxy)ethyl methacrylate) (PMEO₂MA) and Au@rGO-MWCNT on a glassy carbon electrode (GCE). This sensor was shown to exhibit good temperature sensitivity and reversibility to dopamine. When the testing temperature is lower than the lower critical solution temperature (LCST) of the polymer, the PMEO₂MA chain is in a stretched state, which increases the distance between the Au@rGO layers and leads to the inability of MWCNTs in one layer to contact another Au@rGO layer and to low conductivity. Therefore, in this state, dopamine cannot detect an electrochemical signal, and it is termed an "off" state. When the temperature is higher than the LCST of the polymer, the PMEO₂MA chain shrinks, allowing the MWCNTs to make contact with another layer of Au@rGO; the electron transfer rate of the modified film increases, and the electrochemical behavior of dopamine turns to an "on" state. Moreover, the sensor has a wide detection range (0.1 to 9.0 μM and 9.0 to 239.0 μM), and the limit of detection of dopamine is as low as 30 nM. This method has been successfully applied to the determination of dopamine in human serum samples. The on-off sensor provides a new avenue for the application of temperature-sensitive polymers.

Gold-Carbon Nanocomposites for Environmental Contaminant Sensing

The environmental crisis, due to the rapid growth of the world population and globalisation, is a serious concern of this century. Nanoscience and nanotechnology play an important role in addressing a wide range of environmental issues with innovative and successful solutions. Identification and control of emerging chemical contaminants have received substantial interest in recent years. As a result, there is a need for reliable and rapid analytical tools capable of performing sample analysis with high sensitivity, broad selectivity, desired stability, and minimal sample handling for the detection, degradation, and removal of hazardous contaminants. In this review, various gold–carbon nanocomposites-based sensors/biosensors that have been developed thus far are explored. The electrochemical platforms, synthesis, diverse applications, and effective monitoring of environmental pollutants are investigated comparatively.

Eco-friendly ionic liquid imprinted polymer based on a green synthesis strategy for highly selective adsorption tylosin in animal muscle samples

A novel eco-friendly molecularly imprinted polymer (MIP) was proposed as solid-phase extraction (SPE) adsorbent to selective adsorption tylosin (TYL) in animal muscle samples. The MIP was synthesized in aqueous by using 1,4-butanediyl-3,3-bis-1-vinyl imidazolium chloride and 2-acrylamide-2-methylpropanesulfonic acid as bifunctional monomer. The obtained MIP had excellent selectivity towards TYL in water, and the maximum binding capacity can reach 123.45 mg g^-1. Combined with high-performance liquid chromatography, the presented MIP can be used as SPE sorbent to recognize and detect TYL in the range of 0.008 to 0.6 mg L^-1 (R² = 0.9995). The limit of detection and limit of quantification were 0.003 mg L^-1 and 0.008 mg L^-1, and the intraday and interday precision were 1.05% and 3.36%, respectively. Under the optimal condition, the established MIP-SPE-HPLC method was successfully applied to separate and determine trace TYL in chicken, pork, and beef samples with satisfactory recoveries ranged from 94.0 to 106.3%, and the MIP-SPE cartridge can be cycled at least 20 times. This study implies a promising green MIP-SPE-HPLC method for highly selective adsorption and analysis trace TYL in complex matrices.

Innovative Hyperbranched Polybenzoxazine-Based Graphene Oxide-Poly(amidoamines) Nanomaterials

The covalent functionalization of graphene oxide (GO) surface with hyperbranched benzoxazine (BZ) structures has been achieved using poly(amidoamine) dendrimers (PAMAM) of different generations. By increasing the PAMAM generation, multiple benzoxazine rings were synthesized decorating the GO layers. The polymerization process and the exfoliation behavior were investigated. The novel BZ-functionalized GO hybrid materials were characterized by a combination of techniques such as FT-IR, XPS, and 1H-NMR for the confirmation of benzoxazine formation onto the GO layer surfaces. Raman and XRD investigation showed that the GO stacking layers are highly disintegrated upon functionalization with hyperbranched benzoxazine monomers, the exfoliation being more probably to occur when lower PAMAM generation (G) is involved for the synthesis of hybrid GO-BZ nanocomposites. The polymerization of BZ rings may occur either between the BZ units from the same dendrimer molecule or between BZ units from different dendrimer molecules, thus influencing the intercalation/exfoliation of GO. DSC data showed that the polymerization temperature strongly depends on the PAMAM generation and a significant decrease of this value occurred for PAMAM of higher generation, the polymerization temperature being reduced with ~10 °C in case of GO-PAMAM(G2)-BZ. Moreover, the nanoindentation measurements showed significant mechanical properties improvement in case of GO-PAMAM(G2)-BZ comparing to GO-PAMAM(G0)-BZ in terms of Young modulus (from 0.536 GPa to 1.418 GPa) and stiffness (from 3617 N/m to 9621 N/m).