Molecularly imprinted self-buffering double network hydrogel containing bi-amidoxime functional groups for the rapid hydrolysis of organophosphates

Cellulose-based molecularly imprinted core-shell microspheres with dual environment responsiveness for specific recognition and enrichment of paclitaxel

Paclitaxel (PTX), a natural diterpene alkaloid with potent anticancer activity, has been a focus of global research due to its complex structure, significant biological effects, unique mechanism of action, and limited natural availability. In this study, cellulose was used as the raw material to synthesize functionalized pH-responsive modified cellulose porous hydrogel microspheres (MCC/SA/MA-POSS-PTX) via inverse suspension polymerization, using sodium alginate (SA) as the pH-responsive material. Based on this using PTX as the template molecule, 4-VP as the functional monomer, N-isopropylacrylamide (NIPAM) as the thermosensitive monomer, cellulose-based PTX molecularly imprinted hydrogel microspheres (CDLMIHM-PTX) with dual pH and temperature responsiveness were prepared. The adsorption mechanism of the novel material was elucidated through a series of characterization and adsorption experiments. The CDLMIHM-PTX exhibited exceptional adsorption capacity (35.12 mg·g-1) and selectivity, as well as good reusability (6 of cycles). Specific enrichment of PTX from the crude extract of Taxus × media branches was achieved, increasing its content from 7.59 % to 55.98 %. This highlights the capability of CDLMIHM-PTX for targeted enrichment and separation of PTX from complex plant matrices, suggesting promising industrial applications. This work explores the construction of pH/temperature dual responsive cellulose-based molecularly imprinted hydrogel microspheres for the selective capture of target compounds, with potential for practical applications.

Hydrogel-based fluorescence assay kit for simultaneous determination of ceftazidime and avibactam

Monitoring the concentration of antibiotics rapidly and cost-effectively is crucial for accurate clinical medication and timely identification of drug-induced illnesses. Here, we constructed a novel fluorescent assay kit to monitor Zavicefta, an effective antibiotic composed of avibactam (AVI) and ceftazidime (CFZ) to treat carbapenem-resistant gram-negative bacteria infections. AVI can emit fluorescence, but CFZ cannot. To enable simultaneous measurement of both in one kit, we designed molecularly imprinted polymer (MIP) modified quantum dots (QDs) for CFZ determination. MIPs have received significant attention as an artificial antibody due to their exceptional specificity for various targets, particularly drugs with small molecular weight. Under the excitation wavelength of 350 nm, the detection process involves a decrease in QDs' fluorescence signal at 600 nm owing to the "gate effect" between MIP and CFZ and the internal filtration effect between CFZ and QDs. Simultaneously, a fluorescence emission characteristic peak at 420 nm for AVI emerges. In addition, to simplify the operation procedure and improve determination throughput, the detection agents were incorporated into a hydrogel and placed in a 96-well plate, enabling concurrent quantification of AVI and CFZ within the respective range of 80-1000 μM and 1-1000 μM. The developed assay kit successfully determined AVI and CFZ in human serums and therapeutic drug monitoring in a live rabbit model. Recoveries of AVI and CFZ were 92.7-114%, with relative standard deviations below 6.0%. Moreover, a smartphone was employed to read the fluorescence signals, which was beneficial for cost reduction and out-of-lab analysis. This study will deliver a pragmatic resolution to developing high-throughput assay kits for drug determination.

Hazardous Materials from Threats to Safety: Molecularly Imprinted Polymers as Versatile Safeguarding Platforms

Hazards associated with highly dangerous pollutants/contaminants in water, air, and land resources, as well as food, are serious threats to public health and the environment. Thus, it is imperative to detect or decontaminate, as risk-control strategies, the possible harmful substances sensitively and efficiently. In this context, due to their capacity to be specifically designed for various types of hazardous compounds, the synthesis and use of molecularly imprinted polymers (MIPs) have become widespread. By molecular imprinting, affinity sites with complementary shape, size, and functionality can be created for any template molecule. MIPs' unique functions in response to external factors have attracted researchers to develop a broad range of MIP-based sensors with increased sensitivity, specificity, and selectivity of the recognition element toward target hazardous compounds. Therefore, this paper comprehensively reviews the very recent progress of MIPs and smart polymer applications for sensing or decontamination of hazardous compounds (e.g., drugs, explosives, and biological or chemical agents) in various fields from 2020 to 2024, providing researchers with a rapid tool for investigating the latest research status.

A MOFs/MIPs@GAs Ternary Composite Catalytic System with Graphene Oxide Aerogels as the Multifunctional Skeleton for High-Efficiency Detoxification of Organophosphate Nerve Agents in Pure Water

Organophosphate nerve agents (OPs) are widely used as pesticides and chemical agents and pose a threat to human health and life. At present, most personal protective equipment usually only serves as physical protection and does not have an effect of chemical detoxification. In this work, ultra lightweight graphene oxide aerogels (GAs) have been used as a multifunctional skeleton to integrate the metal-organic frameworks (MOFs) and molecularly imprinted polymers (MIPs) together for obtaining a high-performance hybrid material (MOFs/MIPs@GAs) on hydrolysis detoxification of OPs. As a porous three-dimensional material full of carboxyl groups, GAs can not only support excellent mass transfer performance but also provide a proper pH self-buffering catalytic reaction external environment for hydrolyzing OPs. The obtained MOFs/MIPs@GAs can catalyze dimethyl-4-nitrophenyl phosphate (DMNP) hydrolysis detoxification rapidly in pure water (kobs = 0.2227 min-1, t1/2 = 3.11 min). This ternary hybrid material with exceptional performance and practical applicability has vast application prospects for the development of protective equipment.

Dynamic simulation and experimental studies of molecularly imprinted label-free sensor for determination of milk quality marker

Bovine serum albumin (BSA) has emerged as a biomarker for mammary gland health and cow quality, being recognized as a significant allergenic protein. In this study, a novel flexible molecular imprinted electrochemical sensor by surface electropolymerization using pyrrole (Py) as functional monomer, which can be better applied to the detection of milk quality marker BSA. Based on computational results, with regard to all polypyrrole (PPy) conformations and amino-acid positions within the protein, the BSA molecule remained firmly embedded into PPy polymers with no biological changes. The molecular imprinted electrochemical sensor displayed a broad linear detection range from 1.0 × 10-4 to 50 ng·mL-1 (R2 = 0.995) with a low detection limit (LOD) of 4.5 × 10-2 pg·mL-1. Additionally, the sensor was highly selective, reproducible, stable and recoverable, suggesting that it might be utilized for the evaluation of milk quality.

Designed Metal-Containing Peptoid Membranes as Enzyme Mimetics for Catalytic Organophosphate Degradation

The detoxification of lethal organophosphate (OP) residues in the environment is crucial to prevent human exposure and protect modern society. Despite serving as excellent catalysts for OP degradation, natural enzymes require costly preparation and readily deactivate upon exposure to environmental conditions. Herein, we designed and prepared a series of phosphotriesterase mimics based on stable, self-assembled peptoid membranes to overcome these limitations of the enzymes and effectively catalyze the hydrolysis of dimethyl p-nitrophenyl phosphate (DMNP)─a nerve agent simulant. By covalently attaching metal-binding ligands to peptoid N-termini, we attained enzyme mimetics in the form of surface-functionalized crystalline nanomembranes. These nanomembranes display a precisely controlled arrangement of coordinated metal ions, which resemble the active sites found in phosphotriesterases to promote DMNP hydrolysis. Moreover, using these highly programmable peptoid nanomembranes allows for tuning the local chemical environment of the coordinated metal ion to achieve enhanced hydrolysis activity. Among the crystalline membranes that are active for DMNP degradation, those assembled from peptoids containing bis-quinoline ligands with an adjacent phenyl side chain showed the highest hydrolytic activity with a 219-fold rate acceleration over the background, demonstrating the important role of the hydrophobic environment in proximity to the active sites. Furthermore, these membranes exhibited remarkable stability and were able to retain their catalytic activity after heating to 60 °C and after multiple uses. This work provides insights into the principal features to construct a new class of biomimetic materials with high catalytic efficiency, cost-effectiveness, and reusability applied in nerve agent detoxification.

Recent Advances in Polymer-Based Biosensors for Food Safety Detection

The excessive use of pesticides and drugs, coupled with environmental pollution, has resulted in the persistence of contaminants on food. These pollutants tend to accumulate in humans through the food chain, posing a significant threat to human health. Therefore, it is crucial to develop rapid, low-cost, portable, and on-site biosensors for detecting food contaminants. Among various biosensors, polymer-based biosensors have emerged as promising probes for detection of food contaminants in recent years, due to their various functions such as target binding, enrichment, and simple signal reading. This paper aims to discuss the characteristics of five types of food pollutants-heavy metals, pesticide residues, pathogenic bacteria, allergens, and antibiotics-and their adverse effects on human health. Additionally, this paper focuses on the principle of polymer-based biosensors and their latest applications in detecting these five types of food contaminants in actual food samples. Furthermore, this review briefly examines the future prospects and challenges of biosensors for food safety detection. The insights provided in this review will facilitate the development of biosensors for food safety detection.

Rapid quantification of 2,4-dichlorophenol in river water samples using molecularly imprinted polymers coupled to ambient plasma mass spectrometry

Rapid quantification of environmental pollutants is important for water quality control and environmental monitoring. In this work, we report the development of molecularly imprinted polymers (MIPs) obtained from poly(methyl vinyl ether-alt-maleic acid) polymer. The synthesized materials were used for selective preconcentration of 2,4-dichlorophenol, a priority pollutant which creates a threat to public health. The structure of poly(methyl vinyl ether-alt-maleic acid) was functionalized with 4-aminomethylpyridine (4-AMP) to incorporate pyridine groups presumably responsible for increased affinity towards 2,4-dichlorophenol. The synthesis was performed with different degree (10%, 20% and 30%) of 4-AMP functionalization to investigate the influence of pyridine group content on the final MIPs properties. The molecular imprinting process was conducted by amidation of polymers' anhydride groups with diethylenetriamine. Moreover, the experimental data indicated that maximum adsorption capacity was observed for the highest 4-AMP functionalization degree. Similarly, MIPs with the highest 4-AMP content proved to possess the highest selectivity towards the analyte. Finally, the functionalized MIPs were used to quantify 2,4-dichlorophenol by their direct introduction into a specially designed ambient mass spectrometry setup. The detection limits were improved significantly over the ones measured for pure analyte solution. The proposed analytical technique was used to quantify 2,4-dichlorophenol in river water and wastewater samples. Good recovery results were obtained, which proves that the method can be used for analysis of complex real-life samples.

Hyperbranched polyethyleneimine-functionalised chitosan aerogel for highly efficient removal of melanoidins from wastewater

Melanoidins are hazardous dark-coloured substances contained in molasses-based distillery wastewater. Adsorption is an effective approach to eliminate melanoidins from wastewater. However, melanoidin adsorption capacities of available adsorbents are unsatisfactory, which seriously limits their practical application. A hyperbranched polyethyleneimine-functionalised chitosan aerogel (HPCA) was fabricated as an effective adsorbent for melanoidin scavenging. HPCA demonstrated superior melanoidin adsorption efficiency because of its high specific surface area, abundant amino functional groups, and high hydrophilicity. Melanoidin removal rate of HPCA was 94.95%, which remained at 91.45% after 5 cycles. Notably, using the Langmuir isothermal model, the maximum melanoidin adsorption capacity of HPCA was determined to be 868.36 mg/g, surpassing those of most of previously reported adsorbents. Toxicity experiments indicated that HPCA can be considered a safe adsorbent with excellent biocompatibility that hardly threatens aquatic organisms. The efficient melanoidin removal of HPCA was attributed to electrostatic attraction, H-bonding, and van der Waals force. However, the adsorption might be predominantly controlled by electrovalent interaction between protonated amino groups of HPCA and carboxyl/carboxylate groups of melanoidins. Two novel models, namely, external diffusion resistance-internal diffusion resistance mixed model and adsorption on active site model, were employed to describe the dynamic mass transfer characteristics of melanoidin adsorption by HPCA.