Development towards a novel screening method for nipecotic acid bioisosteres using molecular imprinted polymers (MIPs) as alternative to in vitro cellular uptake assays

Impaired expression of GABA transporters (GATs) is closely related to the pathogenesis of among others Parkinson's disease and epilepsy. As such, lipophilic nipecotic acid analogs have been extensively studied as GAT1-addressing drugs and radioligands but suffer from limited brain uptake due to the zwitterionic properties of the nipecotic acid moiety. Bioisosteric replacement of the carboxylic acid group is a promising strategy to improve the brain uptake, though it requires knowledge on the binding of these isosteres to GAT1. To screen nipecotic acid isosteres for their affinity to GAT1 in a time- and cost-effective manner, this research aims to develop a molecular imprinted polymer (MIP) that mimics the natural binding site of GAT1 and can act as an alternative screening tool to the current radiometric and mass spectrometry cellular-based assays. To this end, a nipecotic acid MIP was created using the electropolymerization of ortho-phenylenediamine (oPD) by cyclic voltammetry (CV). The optimization of the generated receptor layer was achieved by varying the scan rate (50-250 mV/s) and number of CV cycles (5-12), yielding an optimized MIP with an average imprinting factor of 2.6, a linear range of 1-1000 nm, and a theoretical LOD of 0.05 nm, as analyzed by electrical impedance spectroscopy (EIS). Selectivity studies facilitated the investigation of major binding interactions between the MIP and the substrate, building an experimental model that compares characteristics of various analogs. Results from this model indicate that the substrate carboxylic acid group plays a more important role in binding than an amine group, after comparing the binding of cyclohexanecarboxylic acid (average IF of 1.7) and piperidine (average IF of 0.46). The research culminates in a discussion regarding the feasibility of the in vitro model, comparing the synthetic system against the biological performance of GAT1. Thus, evaluating if it is possible to generate a synthetic GAT1 mimic, and if so, provide directions for follow-up research.

A biobased magnetic dual-dummy-template molecularly imprinted polymer using a deep eutectic solvent as a coporogen for highly selective enrichment of organophosphates

An eco-friendly magnetic dual-dummy-template molecularly imprinted polymer (MDDMIP) was prepared by a "one-pot" green synthesis using mixed-valence iron hydroxide as the magnetic material, a deep eutectic solvent as the coporogen, and caffeic acid and glutamic acid as binary monomers. The adsorption properties toward organophosphorus pesticides (OPPs) were investigated. High adsorption capacities (269.65-304.93 mg g^-1), quick adsorption times (20 s), and high imprinting factors (2.28-3.83) were obtained. The proposed MDDMIP was utilized for magnetic solid phase extraction (MSPE) of OPPs prior to quantification by high performance liquid chromatography (HPLC). The developed method exhibited outstanding linearity (0.05-500 μg L^-1), low detection limits (0.003-0.015 μg L^-1), and excellent enrichment factors (940-1310 folds). The MSPE-HPLC method was successfully applied for the detection of OPPs in vegetable, fruit, and grain samples with acceptable recoveries (80-119%). This method is a good potential method for the analysis of pesticide residues in complex matrices.

Invited review: integration of technologies and systems for precision animal agriculture-a case study on precision dairy farming

Precision livestock farming (PLF) offers a strategic solution to enhance the management capacity of large animal groups, while simultaneously improving profitability, efficiency, and minimizing environmental impacts associated with livestock production systems. Additionally, PLF contributes to optimizing the ability to manage and monitor animal welfare while providing solutions to global grand challenges posed by the growing demand for animal products and ensuring global food security. By enabling a return to the "per animal" approach by harnessing technological advancements, PLF enables cost-effective, individualized care for animals through enhanced monitoring and control capabilities within complex farming systems. Meeting the nutritional requirements of a global population exponentially approaching ten billion people will likely require the density of animal proteins for decades to come. The development and application of digital technologies are critical to facilitate the responsible and sustainable intensification of livestock production over the next several decades to maximize the potential benefits of PLF. Real-time continuous monitoring of each animal is expected to enable more precise and accurate tracking and management of health and well-being. Importantly, the digitalization of agriculture is expected to provide collateral benefits of ensuring auditability in value chains while assuaging concerns associated with labor shortages. Despite notable advances in PLF technology adoption, a number of critical concerns currently limit the viability of these state-of-the-art technologies. The potential benefits of PLF for livestock management systems which are enabled by autonomous continuous monitoring and environmental control can be rapidly enhanced through an Internet of Things approach to monitoring and (where appropriate) closed-loop management. In this paper, we analyze the multilayered network of sensors, actuators, communication, networking, and analytics currently used in PLF, focusing on dairy farming as an illustrative example. We explore the current state-of-the-art, identify key shortcomings, and propose potential solutions to bridge the gap between technology and animal agriculture. Additionally, we examine the potential implications of advancements in communication, robotics, and artificial intelligence on the health, security, and welfare of animals.

Evaluation of 2-hydroxyethyl methacrylate as comonomer in the preparation of water-compatible molecularly imprinted polymers for triazinic herbicides

In this work, the preparation and evaluation of water-compatible molecularly imprinted polymers for triazines using 2-hydroxyethyl methacrylate and methacrylic acid as comonomers is described. Four sets of molecularly imprinted and non-imprinted polymers for propazine were prepared at varying monomer molar ratios (from 4:0 to 1:3), and evaluated for the recognition of several triazines directly in aqueous media. The evaluation was performed by loading 1 mL of an aqueous solution containing 500 ng of each selected triazine, washing with 500 μL of acetonitrile, and eluting with 500 μL of methanol followed by 2 × 500 μL of a solution of methanol containing 10% of acetic acid. Final determinations were performed by high-performance liquid chromatography-ultraviolet detection. Improvement in molecular recognition of triazines in water was obtained on those molecularly imprinted polymers incorporating 2-hydroxyethyl methacrylate in 3:1 or 2:2 molar ratios, being the former selected as optimum providing recoveries for propazine up to 80%. A molecularly imprinted solid-phase extraction protocol was developed to ensure that triazines-selective recognition takes place inside selective binding sites in pure water media. Finally, the developed method was successfully applied to the determination of the selected triazines in environmental waters providing limits of detection from 0.16 and the 0.5 μg/L concentration range.

Molecularly imprinted polymers as a selective sorbent for forensic applications in biological samples-a review

Molecularly imprinted polymers (MIP) consist of a molecular recognition technology with applicability in different areas, including forensic chemistry. Among the forensic applications, the use of MIP in biological fluid analysis has gained prominence. Biological fluids are complex samples that generally require a pre-treatment to eliminate interfering agents to improve the results of the analyses. In this review, we address the development of this molecular imprinting technology over the years, highlighting the forensic applications of molecularly imprinted polymers in biological sample preparation for analysis of stimulant drugs such as cocaine, amphetamines, and nicotine.

Molecularly Imprinted Polymers for the Removal of Antidepressants from Contaminated Wastewater

Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressants regularly detected in the environment. This indicates that the existing wastewater treatment techniques are not successfully removing them beforehand. This study investigated the potential of molecularly imprinted polymers (MIPs) to serve as sorbents for removal of SSRIs in water treatment. Sertraline was chosen as the template for imprinting. We optimized the composition of MIPs in order to obtain materials with highest capacity, affinity, and selectivity for sertraline. We report the maximum capacity of MIP for sertraline in water at 72.6 mg g⁻¹, and the maximum imprinting factor at 3.7. The MIPs were cross-reactive towards other SSRIs and the metabolite norsertraline. They showed a stable performance in wastewater-relevant pH range between 6 and 8, and were reusable after a short washing cycle. Despite having a smaller surface area between 27.4 and 193.8 m²·g⁻¹, as compared to that of the activated carbon at 1400 m²·g⁻¹, their sorption capabilities in wastewaters were generally superior. The MIPs with higher surface area and pore volume that formed more non-specific interactions with the targets considerably contributed to the overall removal efficiency, which made them better suited for use in wastewater treatment.

Exploring Matrix Effects on Binding Properties and Characterization of Cotinine Molecularly Imprinted Polymer on Paper-Based Scaffold

Commercially available sorbent materials for solid-phase extraction are widely used in analytical laboratories. However, non-selective binding is a major obstacle for sample analysis. To overcome this problem, molecularly imprinted polymers (MIPs) were used as selective adsorbent materials prior to determining target analysts. In this study, the use of non-covalent molecularly imprinted polymers (MIPs) for cotinine adsorption on a paper-based scaffold was studied. Fiberglass paper was used as a paper scaffold for cotinine-selective MIP adsorption with the use of 0.5% agarose gel. The effects of salt, pH, sample matrix, and solvent on the cotinine adsorption and extraction process were investigated. Under optimal conditions, the adsorption isotherm of synthesized MIPs increased to 125.41 µg/g, whereas the maximum adsorption isotherm of non-imprinted polymers (NIPs) was stable at 42.86 µg/g. The ability of the MIP paper scaffold to absorb cotinine in water medium was approximately 1.8–2.8-fold higher than that of the NIP scaffold. From Scatchard analysis, two dissociation constants of MIPs were calculated to be 2.56 and 27.03 µM. Nicotine, myosmine, and N-nitrosonornicotine were used for selectivity testing, and the calculated selectivity factor of cotinine to nicotine, myosmine, and N-nitrosonornicotine was 1.56, 2.69, and 2.05, respectively. Overall, the MIP paper scaffold is promising for simple onsite sampling of cotinine and can be used to assess tobacco smoke exposure.

Contractile Response of Bovine Lateral Saphenous Vein to Ergotamine Tartrate Exposed to Different Concentrations of Molecularly Imprinted Polymer

Ergot alkaloids, in their active isomeric form, affect animal health and performance, and adsorbents are used to mitigate toxicities by reducing bioavailability. Adsorbents with high specificity (molecularly imprinted polymers: MIP) adsorb ergot alkaloids in vitro, but require evaluation for biological implications. Using ex vivo myography, synthetic polymers were evaluated for effects on the bioactivity of ergotamine tartrate (ETA). Polymers were first evaluated using isotherms. Lateral saphenous veins were collected from 17 steers for four independent studies: dose response of ETA, adsorbent dose response, validation of pre-myograph incubation conditions and MIP/ non-molecularly imprinted polymer (NIP) comparison. Norepinephrine normalized percent contractile response to increasing ETA exhibited a sigmoidal dose response (max: 88.47 and log of the effective molar concentration (EC50) (-log [ETA]) of 6.66 ± 0.17 M). Although sample preparation time affected contractile response (p < 0.001), pre-myograph incubation temperature (39 vs. 21 °C, 1 h) had no effect (p > 0.05). Isothermal adsorption showed a maximum adsorption of 3.27E-008 moles·mg-1 and affinity between 0.51 and 0.57 mg (R²: 0.83-0.92) for both polymers, with no significant difference between polymers (p > 0.05). No significant differences in maximum inhibitory (p = 0.96) and IC50 responses (p = 0.163) between MIP and NIP were noticed. Normalized percent contraction could be predicted from the in vitro adsorption data (R² = 0.87, p < 0.01), for both polymers. These studies indicate that synthetic polymers are potentially effective adsorbents to mitigate ergot toxicity caused by ergot alkaloids, with little evidence of significant differences between MIP and NIP in aqueous media.

Determination of triazine herbicides from honey samples based on hydrophilic molecularly imprinted resins followed by high performance liquid chromatography-tandem mass spectrometry

A facile, novel and efficient approach to extract six triazine herbicides from honey samples based on hydrophilic molecularly imprinted resins (MIRs) was described.

An alternative clean-up column for the determination of polychlorinated biphenyls in solid matrices

The need for continuous monitoring of polychlorinated biphenyls (PCBs) has necessitated the development of analytical techniques that are sensitive and selective with minimal reagent requirement. In light of this, we developed a column for clean-up of soil and sediment extracts, which is less demanding in terms of the amount of solvent and sorbent. The dual-layer column consists of acidified silica gel and molecularly imprinted polymers (MIPs). MIPs were synthesized via aqueous suspension polymerization using PCB 15 as the dummy template, 4-vinylpyridine as the functional monomer and ethylene glycol dimethacrylate as the cross-linker and the obtained particles characterized via SEM, BET, and batch rebinding assays. Pre-concentration of the spiked real-world water sample using MISPE gave recoveries between 85.2 and 104.4% (RSD < 8.69). On the other hand, the specific dual-layer column designed for clean-up of extracts from complex matrices provided recoveries of 91.6-102.5% (RSD < 4%) for spiked soil, which was comparable to clean-up using acidified silica (70.4-90.5%; RSD < 3.72%) and sulfoxide modified silica (89.7-103.0%; RSD < 13.0%). However, the polymers were reusable maintaining recoveries of 79.8-111.8% after 30 cycles of regeneration and re-use, thereby availing a cost-effective clean-up procedure for continuous monitoring of PCBs. Method detection limits were 0.01-0.08 ng g(-1) and 0.002-0.01 ng mL(-1) for solid matrices and water, respectively.

Applications of molecularly imprinted polymers to the analysis and removal of personal care products: A review

Personal-care products (PCPs) involve a variety of chemicals whose persistency along with their constant release into the environment raised concern to their potential impact on wildlife and humans health. Regarded as emergent contaminants, PCPs demonstrated estrogenic activity leading to the need of new methodologies to detect and remove those compounds from the environment. Molecular imprinting starts with a complex between a template molecule and a functional monomer, which is then polymerized in the presence of a cross-linker. After template removal, the polymer will contain specific cavities. Based on a good selectivity towards the template, molecularly imprinted polymers (MIPs) have been investigated as efficient materials for the analysis and extraction of the so called emergent pollutants contaminants. Rather than lowering the limit of detections, the key theoretical advantage of MIP over existing methodologies is the potential to target specific chemicals. This unique feature, sometime named specificity (as synonym to very high selectivity) allows to use cheap, simple and/or rapid quantitative techniques such as fast separation with ultra-violet (UV) detection, sensors or even spectrometric techniques. When a high degree of selectivity is achieved, samples extracted with MIPs can be directly analyzed without the need of a separation step. However, while some papers clearly demonstrated the specificity of their MIP toward the targeted PCP, such prove is often lacking, especially with real matrices, making it difficult to assess the success of the different approaches. This review paper focusses on the latest development of MIPs for the analysis of personal care products in the environment, with particular emphasis on design, preparation and practical applications of MIPs.

A triple-function zwitterion for preparing water compatible diclofenac imprinted polymers

A novel zwitterion acting as both a functional monomer and a crosslinker with the protein-resistant ability concomitantly was synthesized for preparing water compatible diclofenac imprinted polymers. This new imprinted polymer showed high imprinting efficiency for template and strong anti-protein adsorption in aqueous medium.

Surface plasmon resonance sensor for femtomolar detection of testosterone with water-compatible macroporous molecularly imprinted film

A novel water-compatible macroporous molecularly imprinted film (MIF) has been developed for rapid, sensitive, and label-free detection of small molecule testosterone in urine. The MIF was synthesized by photo copolymerization of monomers (methacrylic acid [MAA] and 2-hydroxyethyl methacrylate [HEMA]), cross-linker (ethylene glycol dimethacrylate, EGDMA), and polystyrene nanoparticles (PS NPs) in combination with template testosterone molecules. The PS NPs and template molecules were subsequently removed to form an MIF with macroporous structures and the specific recognition sites of testosterone. Incubation of artificial urine and human urine on the MIF and the non-imprinted film (NIF), respectively, indicated undetectable nonspecific adsorption. Accordingly, the MIF was applied on a surface plasmon resonance (SPR) sensor for the detection of testosterone in phosphate-buffered saline (PBS) and artificial urine with a limit of detection (LOD) down to 10(-15)g/ml. To the best of our knowledge, the LOD is considered as one of the lowest among the SPR sensors for the detection of small molecules. The control experiments performed with analogue molecules such as progesterone and estradiol demonstrated the good selectivity of this MIF for sensing testosterone. Furthermore, this MIF-based SPR sensor shows high stability and reproducibility over 8months of storage at room temperature, which is more robust than protein-based biosensors.