Molecular Imprinting Techniques Used for the Preparation of Biosensors

Advancements and prospects of molecularly imprinted polymers as chemical sensors: A comprehensive review

The scientific literature on molecularly imprinted polymers (MIPs) has grown significantly in the past decades, reflecting an increasing interest in their potential applications. MIPs are valued for their ability to selectively detect a broad range of analytes and mimic biological recognition in different environmental conditions. This review utilises data (Scopus data from 2010 to 2024) from a bibliometric visualisation with VOSviewer (version 1.6.2) to identify trends and research hotspots in developing MIP-based sensors. The findings from this review indicated notable advancements in molecular imprinting technology (MIT) and the challenges MIP technology faces. It also discusses how various optimisation preparation techniques can be used to overcome the inherent limitations of MIP synthesis. The review also presents a case investigation and suggests classifying MIPs as chemosensors (chemical sensors) rather than biosensors to resolve the confusion and classification difficulties encountered in the existing literature on MIP sensors. It also addresses critical issues regarding the paradoxical lack of MIP-based sensors in the commercial market despite a marked increase in scientific output. The review outlines future research directions to enhance MIP sensor technology further. It emphasises the need for more collaboration between academia and industry to bridge existing gaps and accelerate commercialisation.

Study on a TCM evaluation method based on an MIP-modified MOF sensor with highly selective electrocatalytic activity-an Artemisia annua L. perspective

Quantitative analysis of artemisinin (ART) in Artemisia annua decoction samples is crucial for the quality assessment of Artemisia annua samples; however, no comprehensive solution currently exists for its rapid and sensitive quantification. This gap necessitates a novel method that accommodates the complex composition of traditional Chinese medicine samples. In this study, we developed an electrochemical sensor suitable for determining the ART content level in Artemisia annua. By introducing MIP-MOF composites, the sensor was endowed with selectivity based on spatial and electronic structures specific to particular molecules. This sensor, which mimics the in vivo pharmacological activation process of ART, could swiftly and selectively measure ART concentrations, thereby providing a reflection of the efficacy of the samples. The sensors' limit of detection and limit of quantification were determined to be 1.738 × 10-13 M and 4.764 × 10-9 M, respectively. Methodology validation confirmed the great selectivity and accuracy of the sensor. Tests conducted across various Artemisia annua decoction samples, including those from online and offline sources, as well as deteriorated samples, yielded results consistent with the expected ART content levels, demonstrating the sensor's potential for application in Artemisia annua sample quality assessment.

Molecular Imprinted Polymer Decorated Electrochemical Sensors for Diabetes Biomarkers: A Critical Review

Diabetes is a chronic illness marked by high blood sugar or hyperglycemia, which can be caused by deficiencies in the action or secretion of insulin, or both. A prolonged period of elevated blood glucose levels can cause several tissues to malfunction. To avoid or postpone the onset of problems associated with diabetes, early diagnosis, and effective care are essential. Biomarkers and biosensors have become potential tools for monitoring and managing diabetes. Glucose, glycated hemoglobin, and other relevant biomarkers of diabetes can be detected using various biosensors, including enzymatic, electrochemical, and optical types. The molecular imprinting technique is an emerging electroanalytical method, that creates cavities in the polymer matrix with an affinity for a selected template molecule, known as molecularly imprinted polymer (MIP). Typically, the procedure involves the polymerization of monomers in the presence of a template molecule, which is then removed to leave behind imprinting sites. These polymers have been employed in molecular sensors, chemical separations, and catalysis due to their affinity for the original molecule. With special attention to their mechanisms of action, clinical applications, limitations, and the potential of emerging technologies, such as wearables and nano-biosensors, these can be used for continuous and real-time diabetes monitoring. This critical review focuses on the role of nanomaterials and conducting polymer-decorated molecularly imprinted sensors for tracking diabetes biomarkers. Additionally, this paper discusses the difficulties in developing and implementing biosensors, including selectivity, sensitivity, and real-time monitoring of glucose levels.

Recent Updates on Blood Purification: Use of Smart Polymer Materials

Blood purification is indispensable in addressing various conditions such as liver dysfunction, autoimmune diseases, and renal failure whereby toxins have to be cleared from the bloodstream effectively. Conventional methods that involve hemoperfusion, hemodialysis, and hemofiltration possess several weaknesses, including loss of plasma components and inefficient clearance of high molecular weight solutes. This review explores current developments in blood purification techniques particularly stimuli-responsive polymers for use in extracorporeal therapy among other applications. Many aspects of engineering stimuli-responsive polymers are described in terms of their role in the removal of small soluble molecules and toxins in blood purification techniques. The development of stimuli-responsive systems has introduced a new paradigm in blood purification by enabling selective, on-demand control of polymer parameters in response to external stimuli such as temperature, pH, electrolytes, and light. Such advanced materials have been demonstrated potential for toxin clearance, minimizing thrombosis, and improving blood compatibility and antifouling, which are far much better than traditional approaches. Furthermore, the review presents a perspective on stimuli-responsive polymers that could be used in developing novel extracorporeal systems for future medical purposes.

Molecularly Imprinted Polymers Coupled with Cellulosic Paper-Based Analytical Devices for Biosensing Applications

Molecularly imprinted polymers (MIPs) function as versatile and highly selective elements in biosensing, mimicking biomolecular receptors and effectively interacting with target analytes within complex matrices. Integrating MIPs with paper-based analytical devices (PADs) allows for rapid, convenient, and cost-effective deployment of molecular imprinting technologies. This review provides an overview of the advances in the fabrication process of MIP-PADs and explores their diverse applications, highlighting their utility in on-site detection using various detection mechanisms such as colorimetric, fluorometric, chemiluminescent electrochemical, photoelectrochemical, and surface enhanced Raman spectroscopy. The fabrication process involves synthesizing MIPs tailored for specific target analytes and incorporating them into cellulosic paper-based analytical devices, resulting in MIP-PADs that offer advantages such as affordability, portability, and disposability. Applications of MIP-PADs extend across environmental monitoring, food safety, and biomedical analysis, demonstrating exceptional selectivity and sensitivity toward diverse biomolecules, pathogens, and small molecules. Their affordability and user-friendly design make them particularly suitable for resource-limited settings. Lastly, the challenges and future prospects of MIP-PAD technologies are presented in the context of real-world applications.

Future Perspectives on the Automation and Biocompatibility of Molecularly Imprinted Polymers for Healthcare Applications

Molecular recognition is of crucial importance in several healthcare applications, such as sensing, drug delivery, and therapeutics. Molecularly imprinted polymers (MIPs) present an interesting alternative to biological receptors (e.g., antibodies, enzymes) for this purpose since synthetic receptors overcome the limited robustness, flexibility, high-cost, and potential for inhibition that comes with natural recognition elements. However, off the shelf MIP products remain limited, which is likely due to the lack of a scalable production approach that can manufacture these materials in high yields and narrow and defined size distributions to have full control over their properties. In this Perspective, we will confer how breakthroughs in the automation of MIP design, manufacturing, and evaluation of performance will accelerate the (commercial) implementation of MIPs in healthcare technology. In addition, we will discuss how prediction of the in vivo behavior of MIPs with animal-free technologies (e.g., 3D tissue models) will be critical to assess their clinical potential.

A review on molecularly imprinted magnetic solid phase extraction emphasizing the analysis of antibiotics in complex matrices:Design, preparation, and application

Magnetic solid phase extraction (MSPE) has been widely employed in the isolation and enrichment of antibiotics in complex matrices because it presents various unique advantages over traditional SPE including simple operation, fast extraction procedure, low cost and eco-friendliness. In recently years, magnetic molecularly imprinted nanoparticles (MMINs) containing highly specific recognition performance have been widely used to specific extraction of antibiotics under the format of MSPE. In this connection, recent advances of MMINs in the analysis of antibiotic residues are reviewed. Firstly, the common structure of MMINs including core-shell, core-satellite, cavity structure and nanotube/nanosheet-supported structurewere introduced. After that, a main section covers the synthesis strategies of MMINs including one-step preparation and multi-steps preparation (precipitation polymerization, emulsion polymerization, suspension polymerization and surface imprinting technique) were illustrated. Furthermore, the applications of MMINs in the selective extraction of various antibiotic residues (sulfonamides, quinolones, tetracyclines, β-lactams, aminoglycosides and so on) in environmental and food samples were summarized. Finally, the existing problems and future prospects of MMINs were outlined in the final section of the review.

Theoretical screening and electrochemical sensor for determination of norepinephrine using a molecularly imprinted poly (3-amiophenylboronic acid)

Norepinephrine (NE) is the primary catecholamine (CA) of interest in the medical field, as it plays a key role in regulating the hormonal and neurological systems. Some NE concentration dysfunction can lead to a number of serious physical conditions. As a result, quick and sensitive NE detection is most critical in medical technology. Thus, in this research, a molecularly imprinted polymer (MIP) was used to create an electrochemical sensor for the selective detection of NE. Prior to this, functional monomers were chosen through molecular modeling utilizing molecular mechanics and quantum mechanics computations. According to these studies, the 3-aminophenylboronic acid (3-APBA) functional monomer produces the most stable complex with NE in molecular modeling calculations. Based on this, by electropolymerizing 3-APBA in the presence of the template molecule NE, an imprinting polymer film is formed on the screen-printed carbon electrode (SPCE) surface. Stepwise fabrication of imprinted polymer films was examined through differential pulse voltammetry (DPV), cyclic voltammetry (CV), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The performance of the electrochemical NE sensor removal and rebinding levels of the template was studied and optimized. The selectivity for NE was confirmed by using interference studies of small molecules like dopamine, tyrosine, and serotonin. Under optimum levels, the fabricated MIP sensor had a broad linear range over NE concentrations of 0.1 pM-5 pM; sensitivity: 0.004 mA pM-1; limit of detection: 0.03 pM. It is noteworthy that the newly created MIP sensor was effectively validated for NE detection in plasma samples.

A new di-recognition and di-functional nanosurface aptamer molecularly imprinted polymer probe for trace glyphosate with SERS/RRS/Abs trimode technique

A new di-recognition nitrogen-doped carbon dot nanosurface aptamer molecularly imprinted polymer (CDNAg@MIPApt) nanocatalytic di-functional probe was prepared by microwave irradiation. The probe was utilized nitrogen-doped silver carbon dots (CDNAg) as the matrix, glyphosate (Gly) as the template molecule, α-methyl acrylate as the monomer, ethylene glycol dimethacrylate as the cross-linker, and aptamer as the biorecognition element. It could not only recognize Gly but also exhibits catalytic amplification function. It was found that CDNAg@MIPApt catalyzed the redox reaction of polyethylene glycol 400 (PEG400)-AgNO3 to generate silver nanoparticles (AgNPs). The AgNPs indicator component exhibit the effects of surface-enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs). In the presence of Gly, it binds to the surface imprinted site of CDNAg@MIPApt, to reduce AgNPs generation due to the catalytic activity of CDNAg@MIPApt decreasing. Thus, the SERS/RRS/Abs signal values decreased linearly. The linear ranges of SERS/RRS/Abs assay were 0.1-2.5 nM, 0.25-2.75 nM and 0.5-5 nM respectively. The detection limits were 0.034 nM, 0.071 nM and 0.18 nM Gly.

Preparation of pyridoxine-based polyurethane modified sensors and their use in simultaneous determination of Cu(II) - Co(II) ions

In this study, pyridoxine-based polyurethane-modified electrodes were prepared to simultaneously and sensitively measure copper (Cu(II)) and cobalt (Co(II)) ions in complex matrix samples. For the production of the electrodes, firstly, the synthesis of pyridoxine-based polyurethane structures was carried out. In these syntheses, the polymer structure was diversified by using different isocyanates. Polyethyleneglycol-200 (PEG), pyridoxine (B6), and β-cyclodextrin (β-CD) groups were used as the source of polyol. The synthesized polyurethane structures were characterized by different instrumental techniques and used in gold electrode surface modification. Modified sensor surfaces were examined by scanning electron microscopy and atomic force microscopy techniques. The prepared modified sensors were used for the simultaneous detection of Cu(II) and Co(II) ions using the differential pulse voltammetry technique. The limit of detection (LOD), limit of quantitation (LOQ), and R2 values for Cu(II) ions were calculated as 8.81 μM, 29.4 μM, and 0.993, respectively. LOD, LOQ, and R2 values for Co(II) ions were calculated as 9.84 μM, 32.8 μM, and 0.9935, respectively. For repeatability, the relative standard deviation (RSD %) of the prepared simultaneous sensors was determined as 1.54 and 1.71 for Cu(II) and Co(II), respectively. As a result, Cu(II) and Co(II) ions were measured independently and simultaneously with high sensitivity. According to these results, it is predicted that pyridoxine-based polyurethane-modified sensors may be suitable for the simultaneous detection of Cu(II) and Co(II) in medical, food, and agricultural samples.

Surface-Initiated Reversible Addition-Fragmentation Chain Transfer Polymerization (SI-RAFT) to Produce Molecularly Imprinted Polymers on Graphene Oxide for Electrochemical Sensing of Methylparathion

A nonenzymatic redox-responsive sensor was put forward for the detection of methylparathion (MP) by designing globular nanostructures of molecularly imprinted polymers on graphene oxide (GO@MIPs) via surface-initiated reversible addition-fragmentation chain transfer polymerization (SI-RAFT). Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and small-angle X-ray scattering (SAXS) studies have confirmed the successful formation of receptor layers of MIPs on RAFT agent-functionalized GO sheets. The electrochemical signal with an amplified current response was attained because of the enhanced diffusion rate of ions at the interface provided by widening the pore size of the MIP film. The analytical response of GO@MIPs, validated by recording square-wave anodic stripping voltammetry (SWASV) at varying MP concentrations, followed the linear response between 0.2 and 200 ng/mL. Under optimized conditions, the sensor exhibited a limit of detection of 4.25 ng/mL with high selectivity over other interfering ions or molecules. The anti-interfering ability and good recovery (%) in food samples directed the use of the proposed sensor toward real-time monitoring and also toward future mimicking of surfaces.

Tailoring molecularly imprinted polymer on titanium-multiwalled carbon nanotube functionalized gold electrode for enhanced chlorophyll determination in microalgae health assessment

A unique method for determining chlorophyll content in microalgae is devised employing a gold interdigitated electrode (G-IDE) with a 10-µm gap, augmented by a nano-molecularly imprinted polymer (nano-MIP) and a titanium dioxide/multiwalled carbon nanotube (TiO2/MWCNT) nanocomposite. The nano-MIP, produced using chlorophyll template voids, successfully trapped chlorophyll, while the TiO2/MWCNT nanocomposite, synthesized by the sol-gel technique, exhibited a consistent distribution and anatase crystalline structure. The rebinding of procured chlorophyll powder, which was used as a template for nano-MIP synthesis, was identified with a high determination coefficient (R2 = 0.9857). By combining the TiO2/MWCNT nanocomposite with nano-MIP, the G-IDE sensing method achieved a slightly better R2 value of 0.9892 for detecting chlorophyll in microalgae. The presented G-IDE sensor showed a significant threefold enhancement in chlorophyll detection compared with commercially available chlorophyll powder. It had a detection limit of 0.917 mL (v/v) and a linear range that spanned from 10-6 to 1 mL. The effectiveness of the sensor in detecting chlorophyll in microalgae was confirmed through validation of its repeatability and reusability.

Molecular Imprinting Technology for Advanced Delivery of Essential Oils

Essential oils (EOs) hold therapeutic potential, but their conventional delivery systems have some limitations. This review focuses on the critical review and discussion of research related to EO delivery systems. The review also explores how molecular imprinting technologies (MIT) can advance EO delivery. MIT offer several techniques, namely covalent, non-covalent, and semi-covalent imprinting, creating targeted cavities that selectively bind and release EOs. These approaches promise significant advantages including increased selectivity, controlled release, and protection from environmental degradation. However, some challenges related to the stability and biocompatibility of MIPs remain unsolved. Integrating nanotechnology through methods like nanoparticle imprinting and some lithographic techniques seems promising to overcome these limitations. Some recently established models and systems used for EO-related research are paving the way for a more efficient and targeted EO delivery approach to harnessing the therapeutic power of EOs. Therefore, some recent and future research seems promising, and eventually it will increase the effectiveness of MIP-based EO delivery systems.

Molecularly Imprinted Microspheres in Active Compound Separation from Natural Product

Molecularly Imprinted Microspheres (MIMs) or Microsphere Molecularly Imprinted Polymers represent an innovative design for the selective extraction of active compounds from natural products, showcasing effectiveness and cost-efficiency. MIMs, crosslinked polymers with specific binding sites for template molecules, overcome irregularities observed in traditional Molecularly Imprinted Polymers (MIPs). Their adaptability to the shape and size of target molecules allows for the capture of compounds from complex mixtures. This review article delves into exploring the potential practical applications of MIMs, particularly in the extraction of active compounds from natural products. Additionally, it provides insights into the broader development of MIM technology for the purification of active compounds. The synthesis of MIMs encompasses various methods, including precipitation polymerization, suspension polymerization, Pickering emulsion polymerization, and Controlled/Living Radical Precipitation Polymerization. These methods enable the formation of MIPs with controlled particle sizes suitable for diverse analytical applications. Control over the template-to-monomer ratio, solvent type, reaction temperature, and polymerization time is crucial to ensure the successful synthesis of MIPs effective in isolating active compounds from natural products. MIMs have been utilized to isolate various active compounds from natural products, such as aristolochic acids from Aristolochia manshuriensis and flavonoids from Rhododendron species, among others. Based on the review, suspension polymerization deposition, which is one of the techniques used in creating MIPs, can be classified under the MIM method. This is due to its ability to produce polymers that are more homogeneous and exhibit better selectivity compared to traditional MIP techniques. Additionally, this method can achieve recovery rates ranging from 94.91% to 113.53% and purities between 86.3% and 122%. The suspension polymerization process is relatively straightforward, allowing for the effective control of viscosity and temperature. Moreover, it is cost-effective as it utilizes water as the solvent.

An ionic liquid-modified PEDOT/Ti3C2TX based molecularly imprinted electrochemical sensor for pico-molar sensitive detection of L-Tryptophan in milk

L-Tryptophan (L-Trp) is essential for the human body and can only be obtained externally. It is important to develop a method to efficiently detect L-Trp in food. In this work, ionic liquid (IL) modified poly(3,4-ethylendioxythiophene)/ Titanium carbide (PEDOT/Ti3C2TX) was used as a substrate material to improve detection sensitivity. Molecular imprinted polymers (MIP) film for specific recognition of L-Trp was fabricated on the surface of modified electrodes using electrochemical polymerization. The monitoring results showed that the molecularly imprinted electrochemical sensors (MIECS) exhibited good linearity ranges (10-6 - 0.1 μM and 0.1-100 μM) with a low detection limit (LOD) of 2.09 × 10-7 μM. In addition, the MIECS exhibited remarkable stability, reproducibility, and immunity to interference. A good recovery (93.54-99.59%) was demonstrated in the detection of milk. The sensor was expected to be developed as a highly selective and sensitive portable assay, and applied to the detection of L-Trp in food.

Internet-of-things-integrated molecularly imprinted polymer-based electrochemical nano-sensors for pesticide detection in the environment and food products

To ensure environmental and health safety, relevant pollutants such as pesticides must be screened thoroughly to set their permissible limit. Various approaches have been used to identify pesticides such as capillary electrophoresis, gas and liquid-liquid chromatography, high-performance liquid chromatography, and enzyme-linked immune-absorbent tests. However, these techniques have some drawbacks, including time-consuming difficult steps, expensive bulky equipment, expert personnel, and a lack of selectivity. Recent advances in the field of biosensing have introduced biosensors for the onsite detection of pesticides which offer several advantages including rapid, simple, selective, sensitive, low-cost operation, and on-site detection. With the advent of molecularly imprinted polymer which substituted the traditional biorecognition elements (BREs) such as enzymes and antibodies, biosensors' sensitivity, selectivity, and reproducibility enhanced many folds. Molecularly imprinted polymers (MIP) are artificial polymer molecules that resemble natural BREs. They are synthesized when functional monomers are polymerized in the presence of a target analyte. Owing to the advantages of MIP, in this paper, the development of MIP-based electrochemical biosensors for pesticide detection is reviewed critically. A brief introduction to pesticides and the use of MIPs-based electrochemical sensors for pesticide detection is presented along with pros and cons. Further, Internet of Things (IoT) integrated MIP-based nanosensors for pesticide detection and information distribution have been discussed. In the end, future perspectives and challenges while implementing MIP-based nanosensors for onsite pesticide recognition have eventually been highlighted.

Electrochemical detection of glutamate and histamine using redox-labeled stimuli-responsive polymer as a synthetic target receptor

Glutamate (Glu) and histamine (His) are two major neurotransmitters that play many critical roles in brain physiological functions and neurological disorders. Therefore, specific and sensitive monitoring of Glu and His is essential in the diagnosis and treatment of various mental health and neurodegenerative disorders. Both being non-electroactive species, direct electrochemical detection of Glu and His has been challenging. Herein, we report a stimuli-responsive polymer-based biosensor for the electrochemical detection of Glu and His. The polymer-based target receptors consist of a linear chain stimuli-responsive templated polymer hybrid that is labeled with an osmium-based redox-active reporter molecules to elicit conformation-dependent electrochemical responses. The polymers are then attached to a gold electrode to implement an electrochemical sensor. The cyclic voltammetry (CV) and square-wave voltammetry (SWV) results confirmed the polymers' conformational changes due to the specific target (i.e., Glu and His) recognition and the corresponding electrochemical detection capabilities. The voltammetry results indicate that this biosensor can be used as a 'signal-on' and 'signal-off' sensors for the detection of Glu and His concentrations, respectively. The developed biosensor also showed excellent regeneration capability by fully recovering the initial current signal after rinsing with deionized water. To further validate the polymer's utility as a target bioreceptor, the surface plasmon resonance (SPR) technique was used to characterize the binding affinity between the designed polymers and the target chemical. The SPR results exhibited the equilibrium dissociation constants (KD) of 2.40 μM and 1.54 μM for the polymer-Glu and polymer-His interactions, respectively. The results obtained this work strongly suggest that the proposed sensing technology could potentially be used as a platform for monitoring non-electroactive neurochemicals from animal models.

Strategy, Design, and Fabrication of Electrochemical Biosensors: A Tutorial

Advanced healthcare requires novel technologies capable of real-time sensing to monitor acute and long-term health. The challenge relies on converting a real-time quantitative biological and chemical signal into a desired measurable output. Given the success in detecting glucose and the commercialization of glucometers, electrochemical biosensors continue to be a mainstay of academic and industrial research activities. Despite the wealth of literature on electrochemical biosensors, reports are often specific to a particular application (e.g., pathogens, cancer markers, glucose, etc.), and most fail to convey the underlying strategy and design, and if it is transferable to detection of a different analyte. Here we present a tutorial review for those entering this research area that summarizes the basic electrochemical techniques utilized as well as discusses the designs and optimization strategies employed to improve sensitivity and maximize signal output.

The sensor applications for prostate and lung cancer biomarkers in terms of electrochemical analysis

Prostate and lung cancers are the most common types of cancer and affect a large part of the population around the world, causing deaths. Therefore, the rapid identification of cancer can profoundly impact reducing cancer-related death rates and protecting human lives. Significant resources have been dedicated to investigating new methods for early disease detection. Cancer biomarkers encompass various biochemical entities, including nucleic acids, proteins, sugars, small metabolites, cytogenetic and cytokinetic parameters, and whole tumor cells in bodily fluids. These tools can be utilized for various purposes, such as risk assessment, diagnosis, prognosis, treatment efficacy, toxicity evaluation, and predicting a return. Due to these versatile and critical purposes, there are widespread studies on the development of new, sensitive, and selective approaches for the determination of cancer biomarkers. This review illustrates the significant lung and prostate cancer biomarkers and their determination utilizing electrochemical sensors, which have the advantage of improved sensitivity, low cost, and simple analysis. Additionally, approaches such as improving sensitivity with nanomaterials and ensuring selectivity with MIPs are used to increase the performance of the sensor. This review aims to overview the most recent electrochemical biosensor applications for determining vital biomarkers of prostate and lung cancers in terms of nanobiosensors and molecularly imprinted polymer (MIP)-based biosensors.

Nano/Micro-Structural Supramolecular Biopolymers: Innovative Networks with the Boundless Potential in Sustainable Agriculture

Sustainable agriculture plays a crucial role in meeting the growing global demand for food while minimizing adverse environmental impacts from the overuse of synthetic pesticides and conventional fertilizers. In this context, renewable biopolymers being more sustainable offer a viable solution to improve agricultural sustainability and production. Nano/micro-structural supramolecular biopolymers are among these innovative biopolymers that are much sought after for their unique features. These biomaterials have complex hierarchical structures, great stability, adjustable mechanical strength, stimuli-responsiveness, and self-healing attributes. Functional molecules may be added to their flexible structure, for enabling novel agricultural uses. This overview scrutinizes how nano/micro-structural supramolecular biopolymers may radically alter farming practices and solve lingering problems in agricultural sector namely improve agricultural production, soil health, and resource efficiency. Controlled bioactive ingredient released from biopolymers allows the tailored administration of agrochemicals, bioactive agents, and biostimulators as they enhance nutrient absorption, moisture retention, and root growth. Nano/micro-structural supramolecular biopolymers may protect crops by appending antimicrobials and biosensing entities while their eco-friendliness supports sustainable agriculture. Despite their potential, further studies are warranted to understand and optimize their usage in agricultural domain. This effort seeks to bridge the knowledge gap by investigating their applications, challenges, and future prospects in the agricultural sector. Through experimental investigations and theoretical modeling, this overview aims to provide valuable insights into the practical implementation and optimization of supramolecular biopolymers in sustainable agriculture, ultimately contributing to the development of innovative and eco-friendly solutions to enhance agricultural productivity while minimizing environmental impact.

A dual action electrochemical molecularly imprinted aptasensor for ultra-trace detection of carbendazim

Carbendazim is often used in agriculture to prevent crop diseases, even though it has been associated with health concerns. To ensure the safety of food products and comply with environmental regulations, an ultrasensitive method for carbendazim determination must be developed. In this study, a new electrochemical molecularly imprinted polymer-aptasensor based on hemin-Al-metal organic framework@gold nanoparticles (H-Al-MOF@AuNPs) was developed for sensitive and selective carbendazim detection. Hemin linked to the surface of the Al-metal organic framework also possesses outstanding peroxidase-like qualities that can electrocatalyse the reduction of H2O2. Thus, H-Al-MOF functions as an in-situ probe. Additionally, AuNPs offer many binding sites to load carbendazim aptamers and create an imprinted polymer-aptasensing interface. Dopamine is the chemical functional monomer in the electropolymerised film, while carbendazim is the template molecule. Thus, compared to the molecularly imprinted polymer or aptasensor alone, the molecularly imprinted polymer-aptasensor showed greater selectivity due to the synergistic action of the polymer and carbendazim aptamer towards carbendazim. A decrease in peak current was observed by differential pulse voltammetry (DPV) and chronoamperometry (CA) as the concentration of carbendazim increased. This possibly resulted from carbendazim connecting to the carbendazim aptamer and simultaneously blocking the imprinted polymer cavities on the surface of the modified electrode, which reduced the transfer of electrons. Signals were observed for hemin DPV and H2O2 catalytic reduction CA. DPV and CA showed that the linear ranges for carbendazim were 0.3 fmol L-1-10 pmol L-1 and 0.7 fmol L-1-10 pmol L-1, respectively, with limits of detection of 80 and 300 amol L-1. Satisfactory recoveries were obtained with tap water, apple juice, and tomato juice samples, demonstrating that the proposed sensor has potential for food and environmental analysis.

Molecularly imprinted polymer hydrogel sheets with metalloporphyrin-incorporated molecular recognition sites for protein capture

Metalloporphyrins are often found in nature as coordination recognition sites within biological process, and synthetically offer the potential for use in therapeutic, catalytic and diagnostic applications. While porphyrin containing biological recognition elements have stability limitations, molecularly imprinted polymers bearing these structures offer an alternative with excellent robustness and the ability to work in extreme conditions. In this work, we synthesised a polymerizable porphyrin and metalloporphyrin and have incorporated these as co-monomers within a hydrogel thin-sheet MIP for the specific recognition of bovine haemoglobin (BHb). The hydrogels were evaluated using Scatchard analysis, with Kd values of 10.13 × 10-7, 5.30 × 10-7, and 3.40 × 10-7 M, for the control MIP, porphyrin incorporated MIP and the iron-porphyrin incorporated MIP, respectively. The MIPs also observed good selectivity towards the target protein with 73.8%, 77.4%, and 81.2% rebinding of the BHb target for the control MIP, porphyrin incorporated MIP and the iron-porphyrin incorporated MIP, respectively, compared with the non-imprinted (NIP) counterparts. Specificity was determined against a non-target protein, Bovine Serum Albumin (BSA). The results indicate that the introduction of the metalloporphyrin as a functional co-monomer is significantly beneficial to the recognition of a MIP, further enhancing MIP capabilities at targeting proteins.

Mobile Point-of-Care Device Using Molecularly Imprinted Polymer-Based Chemosensors Targeting Interleukin-1β Biomarker

Molecularly imprinted polymers (MIPs) have garnered significant attention as a promising material for engineering specific biological receptors with superior chemical complementarity to target molecules. In this study, we present an electrochemical biosensing platform incorporating MIP films for the selective detection of the interleukin-1β (IL-1β) biomarker, particularly suitable for mobile point-of-care testing (POCT) applications. The IL-1β-imprinted biosensors were composed of poly(eriochrome black T (EBT)), including an interlayer of poly(3,4-ethylene dioxythiophene) and a 4-aminothiophenol monolayer, which were electrochemically polymerized simultaneously with template proteins (i.e., IL-1β) on custom flexible screen-printed carbon electrodes (SPCEs). The architecture of the MIP films was designed to enhance the sensor sensitivity and signal stability. This approach involved a straightforward sequential-electropolymerization process and extraction for leaving behind cavities (i.e., rebinding sites), resulting in the efficient production of MIP-based biosensors capable of molecular recognition for selective IL-1β detection. The electrochemical behaviors were comprehensively investigated using cyclic voltammograms and electrochemical impedance spectroscopy responses to assess the imprinting effect on the MIP films formed on the SPCEs. In line with the current trend in in vitro diagnostic medical devices, our simple and effective MIP-based analytical system integrated with mobile POCT devices offers a promising route to the rapid detection of biomarkers, with particular potential for periodontitis screening.

Endoluminal Procedures and Devices for Esophageal Tract Investigation: A Critical Review

Diseases of the esophageal tract represent a heterogeneous class of pathological conditions for which diagnostic paradigms continue to emerge. In the last few decades, innovative diagnostic devices have been developed, and several attempts have been made to advance and standardize diagnostic algorithms to be compliant with medical procedures. To the best of our knowledge, a comprehensive review of the procedures and available technologies to investigate the esophageal tract was missing in the literature. Therefore, the proposed review aims to provide a comprehensive analysis of available endoluminal technologies and procedures to investigate esophagus health conditions. The proposed systematic review was performed using PubMed, Scopus, and Web of Science databases. Studies have been divided into categories based on the type of evaluation and measurement that the investigated technology provides. In detail, three main categories have been identified, i.e., endoluminal technologies for the (i) morphological, (ii) bio-mechanical, and (iii) electro-chemical evaluation of the esophagus.

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.

Immunopurification Reagents and Their Application in Biologics and Biomarker Quantitation Using LC-MS/MS in Drug Discovery

The LC-MS/MS technology is one of the most utilized bio-analytical tools owing to its advantage of selectivity, sensitivity and multitasking. The advent of novel biological therapies and increasing demand for protein biomarker identification and quantitation have put the LC-MS/MS technology at the forefront. The questions which are been posed to the LC-MS/MS scientist are complex. The complexity of the question increases further with the matrices in which these questions need to be answered. To bring down the complexity of the analysis, LC-MS/MS technology is utilizing the immunopurification (IP) technique as the new sample preparation technique. The IP reagents are the most common reagents which are used to decrease the matrices' complexity and allow the LC-MS/MS system to reach greater sensitivity. The utilization of these reagents is increasing every day, but the proper utilization of these reagents is still unknown to the common analyst in drug discovery. The present review throws light on the utilization aspect of these reagents, as we have classified these reagents on basis of their utilization, which will allow the readers to gain an understanding of these reagents. This review will also talk about the merits and the demerits of each approach and the current understanding of utilizing these reagents.

Development and Characterization of a Molecularly Imprinted Polymer for the Selective Removal of Brilliant Green Textile Dye from River and Textile Industry Effluents

In this paper, we present an alternative technique for the removal of Brilliant Green dye (BG) in aqueous solutions based on the application of molecularly imprinted polymer (MIP) as a selective adsorbent for BG. The MIP was prepared by bulk radical polymerization using BG as the template; methacrylic acid (MAA) as the functional monomer, selected via computer simulations; ethylene glycol dimethacrylate (EGDMA) as cross-linker; and 2,2'-azobis(2-methylpropionitrile) (AIBN) as the radical initiator. Scanning electron microscopy (SEM) analyses of the MIP and non-molecularly imprinted polymer (NIP)-used as the control material-showed that the two polymers exhibited similar morphology in terms of shape and size; however, N2 sorption studies showed that the MIP displayed a much higher BET surface (three times bigger) compared to the NIP, which is clearly indicative of the adequate formation of porosity in the former. The data obtained from FTIR analysis indicated the successful formation of imprinted polymer based on the experimental procedure applied. Kinetic adsorption studies revealed that the data fitted quite well with a pseudo-second order kinetic model. The BG adsorption isotherm was effectively described by the Langmuir isotherm model. The proposed MIP exhibited high selectivity toward BG in the presence of other interfering dyes due to the presence of specific recognition sites (IF = 2.53) on its high specific surface area (112 m2/g). The imprinted polymer also displayed a great potential when applied for the selective removal of BG in real river water samples, with recovery ranging from 99 to 101%.

Preparation of biochar-based surface molecularly imprinted polymers and evaluation of their selective adsorption and removal of carbaryl from rice and corn

The residue of carbaryl in food is a threat to human health. In this study, activated soybean shell biochar (A-SBC) was used as a carrier, methacrylic acid (MAA) was used as a functional monomer, and carbaryl was used as a template molecule to synthesize the activated biochar surface molecularly imprinted polymer (A-SBC@MIP). The synthesized A-SBC@MIP was characterized by SEM, FT-IR, XRD and XPS techniques, and then applied as adsorbent for carbaryl removal. The adsorption capacity of A-SBC@MIP for carbaryl was 8.6 mg‧g-1 and the imprinting factor was 1.49 at the optimum ionic strength and pH. The kinetic and isothermal data indicated that it had fast mass transfer rate and high binding capacity(Qmax=47.9 mg‧g-1). A-SBC@MIP showed good regenerative properties and the adsorption of carbaryl was excellent in its structural analogues. A solid-phase extraction (SPE) column composed of A-SBC@MIP was developed for the detection of rice and corn under optimized conditions, with recoveries of 93-101% for the spiked carbaryl. The limit of detection (LOD) of the method was 3.6 μg‧kg-1 with good linearity (R2=0.994) in the range of 0.01-5.00 mg‧L-1. The results show that the developed MIPs-SPE can enrich carbaryl from food samples as a specific and cost-effective method.

Transitioning from Supramolecular Chemistry to Molecularly Imprinted Polymers in Chemical Sensing

This perspective article focuses on the overwhelming significance of molecular recognition in biological processes and its emulation in synthetic molecules and polymers for chemical sensing. The historical journey, from early investigations into enzyme catalysis and antibody-antigen interactions to Nobel Prize-winning breakthroughs in supramolecular chemistry, emphasizes the development of tailored molecular recognition materials. The discovery of supramolecular chemistry and molecular imprinting, as a versatile method for mimicking biological recognition, is discussed. The ability of supramolecular structures to develop selective host-guest interactions and the flexible design of molecularly imprinted polymers (MIPs) are highlighted, discussing their applications in chemical sensing. MIPs, mimicking the selectivity of natural receptors, offer advantages like rapid synthesis and cost-effectiveness. Finally, addressing major challenges in the field, this article summarizes the advancement of molecular recognition-based systems for chemical sensing and their transformative potential.

Molecularly Imprinted Polymers for Pharmaceutical Impurities: Design and Synthesis Methods

The safety of a medicinal product is determined by its pharmacological and toxicological profile, which depends not only on the active substance's toxicological properties, but also on the impurities it contains. Because impurities are a problem that must be considered to ensure the safety of a drug product, many studies have been conducted regarding the separation or purification of active pharmaceutical ingredients (APIs) and the determination of impurities in APIs and drug products. Several studies have applied molecularly imprinted polymers (MIPs) to separate impurities in active ingredients and as adsorbents in the sample preparation process. This review presents the design of MIPs and the methods used to synthesise MIPs to separate impurities in APIs and drug product samples, the application of MIPs to separate impurities, and a view of future studies involving MIPs to remove impurities from pharmaceutical products. Based on a comparison of the bulk and surface-imprinting polymerisation methods, the MIPs produced by the surface-imprinting polymerisation method have a higher adsorption capacity and faster adsorption kinetics than the MIPs produced by the bulk polymerisation method. However, the application of MIPs in the analysis of APIs and drug products are currently only related to organic compounds. Considering the advantages of MIPs to separate impurities, MIPs for other impurities still need to be developed, including multi-template MIPs for simultaneous separation of multiple impurities.

Wearable Insulin Biosensors for Diabetes Management: Advances and Challenges

We present a critical review of the current progress in wearable insulin biosensors. For over 40 years, glucose biosensors have been used for diabetes management. Measurement of blood glucose is an indirect method for calculating the insulin administration dosage, which is critical for insulin-dependent diabetic patients. Research and development efforts aiming towards continuous-insulin-monitoring biosensors in combination with existing glucose biosensors are expected to offer a more accurate estimation of insulin sensitivity, regulate insulin dosage and facilitate progress towards development of a reliable artificial pancreas, as an ultimate goal in diabetes management and personalised medicine. Conventional laboratory analytical techniques for insulin detection are expensive and time-consuming and lack a real-time monitoring capability. On the other hand, biosensors offer point-of-care testing, continuous monitoring, miniaturisation, high specificity and sensitivity, rapid response time, ease of use and low costs. Current research, future developments and challenges in insulin biosensor technology are reviewed and assessed. Different insulin biosensor categories such as aptamer-based, molecularly imprinted polymer (MIP)-based, label-free and other types are presented among the latest developments in the field. This multidisciplinary field requires engagement between scientists, engineers, clinicians and industry for addressing the challenges for a commercial, reliable, real-time-monitoring wearable insulin biosensor.

Recent Advances in Functional Nanomaterials for Diagnostic and Sensing Using Self-Assembled Monolayers

Functional nanomaterials have attracted attention by producing different structures in any field. These materials have several potential applications, including medicine, electronics, and energy, which provide many unique properties. These nanostructures can be synthesized using various methods, including self-assembly, which can be used for the same applications. This unique nanomaterial is increasingly being used for biological detection due to its unique optical, electrical, and mechanical properties, which provide sensitive and specific sensors for detecting biomolecules such as DNA, RNA, and proteins. This review highlights recent advances in the field and discusses the fabrication and characterization of the corresponding materials, which can be further applied in optical, magnetic, electronic, and sensor fields.

Molecularly Imprinted Polymer-Based Electrochemical Sensors for the Diagnosis of Infectious Diseases

The appearance of biological molecules, so-called biomarkers in body fluids at abnormal concentrations, is considered a good tool for detecting disease. Biomarkers are usually looked for in the most common body fluids, such as blood, nasopharyngeal fluids, urine, tears, sweat, etc. Even with significant advances in diagnostic technology, many patients with suspected infections receive empiric antimicrobial therapy rather than appropriate treatment, which is driven by rapid identification of the infectious agent, leading to increased antimicrobial resistance. To positively impact healthcare, new tests are needed that are pathogen-specific, easy to use, and produce results quickly. Molecularly imprinted polymer (MIP)-based biosensors can achieve these general goals and have enormous potential for disease detection. This article aimed to overview recent articles dedicated to electrochemical sensors modified with MIP to detect protein-based biomarkers of certain infectious diseases in human beings, particularly the biomarkers of infectious diseases, such as HIV-1, COVID-19, Dengue virus, and others. Some biomarkers, such as C-reactive protein (CRP) found in blood tests, are not specific for a particular disease but are used to identify any inflammation process in the body and are also under consideration in this review. Other biomarkers are specific to a particular disease, e.g., SARS-CoV-2-S spike glycoprotein. This article analyzes the development of electrochemical sensors using molecular imprinting technology and the used materials' influence. The research methods, the application of different electrodes, the influence of the polymers, and the established detection limits are reviewed and compared.

An ultrasensitive bacterial imprinted electrochemical sensor for the determination of Lactobacillus rhamnosus GG

An ultrasensitive label-free electrochemical sensor based on a homemade imprinted polypyrrole (PPy) polymer film was prepared to achieve quantitative determination of Lactobacillus rhamnosus GG (LGG). The LGG-imprinted polymer (LIP) film was deposited on a portable screen-printed electrode (SPE) via electropolymerization, which constituted an independent integrated system. The main preparation parameters of the LIP sensor were investigated to obtain optimal performance. Under optimized conditions, the peak current response of the LIP sensor showed a linear relationship with the logarithmic value of LGG concentration in the range from 10¹ to 10⁹ CFU mL^-1 and a detection limit of 5 CFU mL^-1. The proposed LIP sensor has achieved efficient, ultrasensitive, highly selective, and cost-effective detection of LGG and can be further developed for practical applications in the quality inspection and development of probiotic products.

Preparation and Application Progress of Imprinted Polymers

Due to the specific recognition performance, imprinted polymers have been widely investigated and applied in the field of separation and detection. Based on the introduction of the imprinting principles, the classification of imprinted polymers (bulk imprinting, surface imprinting, and epitope imprinting) are summarized according to their structure first. Secondly, the preparation methods of imprinted polymers are summarized in detail, including traditional thermal polymerization, novel radiation polymerization, and green polymerization. Then, the practical applications of imprinted polymers for the selective recognition of different substrates, such as metal ions, organic molecules, and biological macromolecules, are systematically summarized. Finally, the existing problems in its preparation and application are summarized, and its prospects have been prospected.

Molecularly imprinted polymers (MIPs): emerging biomaterials for cancer theragnostic applications

Cancer is a disease caused by abnormal cell growth that spreads through other parts of the body and threatens life by destroying healthy tissues. Therefore, numerous techniques have been employed not only to diagnose and monitor the progress of cancer in a precise manner but also to develop appropriate therapeutic agents with enhanced efficacy and safety profiles. In this regard, molecularly imprinted polymers (MIPs), synthetic receptors that recognize targeted molecules with high affinity and selectivity, have been intensively investigated as one of the most attractive biomaterials for theragnostic approaches. This review describes diverse synthesis strategies to provide the rationale behind these synthetic antibodies and provides a selective overview of the recent progress in the in vitro and in vivo targeting of cancer biomarkers for diagnosis and therapeutic applications. Taken together, the topics discussed in this review provide concise guidelines for the development of novel MIP-based systems to diagnose cancer more precisely and promote successful treatment. Molecularly imprinted polymers (MIPs), synthetic receptors that recognize targeted molecules with high affinity and selectivity, have been intensively investigated as one of the most attractive biomaterials for cancer theragnostic approaches. This review describes diverse synthesis strategies to provide the rationale behind these synthetic antibodies and provides a selective overview of the recent progress in the in vitro and in vivo targeting of cancer biomarkers for diagnosis and therapeutic applications. The topics discussed in this review aim to provide concise guidelines for the development of novel MIP-based systems to diagnose cancer more precisely and promote successful treatment.

Development and application of a thin-film molecularly imprinted polymer for the measurement of mycophenolic acid in human plasma

BACKGROUND

Mycophenolic acid (MPA) is used to suppress the immune response following organ transplantation; however, complex pharmacokinetic behavior and a large interpersonal variability necessitate therapeutic drug monitoring. To overcome the limitations of current sample preparation techniques, we present a novel thin-film molecularly imprinted polymer (TF-MIP) extraction device as part of a simple, sensitive, and fast method for analysis of MPA from human plasma.

METHODS

Mycophenolic acid is extracted from plasma using a tailor-made TF-MIP that is subsequently desorbed into an organic solvent system compatible with mass spectrometry. The MIP yielded higher recovery of MPA relative to a corresponding non-imprinted polymer. The method allows for the determination of MPA in 45 min including analysis time and can be scaled for high throughput to process as many as 96 samples per hour.

RESULTS

The method gave an LOD of 0.3 ng mL^-1 and was linear from 5 to 250 ng mL^-1 . Patient plasma samples (35 μL) were diluted using charcoal-stripped pooled plasma to a final extraction volume of 700 μL; when MPA in patient plasma is high, this ratio can easily be adjusted to ensure samples are within the method linear range. Intra- and inter-day variability were 13.8% and 4.3% (at 15 ng mL^-1 ) and 13.5% and 11.0% (at 85 ng mL^-1 ), respectively (n = 3); inter-device variability was 9.6% (n = 10).

CONCLUSIONS

Low inter-device variability makes these devices suitable for single use in a clinical setting, and the fast and robust method is suitable for therapeutic drug monitoring, where throughput and time-to-result are critical.

Application of Chitosan-Based Molecularly Imprinted Polymer in Development of Electrochemical Sensor for p-Aminophenol Determination

Molecularly Imprinted Polymers (MIPs) have specific recognition capabilities and have been widely used for electrochemical sensors with high selectivity. In this study, an electrochemical sensor was developed for the determination of p-aminophenol (p-AP) by modifying the screen-printed carbon electrode (SPCE) with chitosan-based MIP. The MIP was made from p-AP as a template, chitosan (CH) as a base polymer, and glutaraldehyde and sodium tripolyphosphate as the crosslinkers. MIP characterization was conducted based on membrane surface morphology, FT-IR spectrum, and electrochemical properties of the modified SPCE. The results showed that the MIP was able to selectively accumulate analytes on the electrode surface, in which MIP with glutaraldehyde as a crosslinker was able to increase the signal. Under optimum conditions, the anodic peak current from the sensor increased linearly in the range of 0.5-35 µM p-AP concentration, with sensitivity of (3.6 ± 0.1) µA/µM, detection limit (S/N = 3) of (2.1 ± 0.1) µM, and quantification limit of (7.5 ± 0.1) µM. In addition, the developed sensor exhibited high selectivity with an accuracy of (94.11 ± 0.01)%.

Terminally Phosphorylated Triblock Polyethers Acting Both as Templates and Pore-Forming Agents for Surface Molecular Imprinting of Monoliths Targeting Phosphopeptides

The novel process reported here described the manufacture of monolithic molecularly imprinted polymers (MIPs) using a terminally functionalized block copolymer as the imprinting template and pore-forming agent. The MIPs were prepared through a step-growth polymerization process using a melamine-formaldehyde precondensate in a biphasic solvent system. Despite having a relatively low imprinting factor, the use of MIP monolith in liquid chromatography demonstrated the ability to selectively target desired analytes. An MIP capillary column was able to separate monophosphorylated peptides from a tryptic digest of bovine serum albumin. Multivariate data analysis and modeling of the phosphorylated and nonphosphorylated peptide retention times revealed that the number of phosphorylations was the strongest retention contributor for peptide retention on the monolithic MIP capillary column.

Molecularly Imprinted Cryogels for the Selective Adsorption of Salicylic Acid

In this study, molecularly imprinted cryogels were fabricated for selective adsorption of salicylic acid. Cryogelation was performed at - 20 °C using a cationic monomer N,N-dimethylaminoethyl methacrylate as a functional monomer for salicylic acid. The morphology, swelling behaviors, and chemical structures of the cryogels were investigated. The general structure and porosities of cryogels were compared with the traditional hydrogels using field emission scanning electron microscopy (FE-SEM). The adsorption performance of cryogels toward salicylic acid was studied to investigate the optimal adsorption conditions. Adsorption capacity of the imprinted cryogels was 1.95 and 7.51 times higher than those of non-imprinted and bare PHEMA cryogels, respectively, due to the specific binding sites toward salicylic acid. Molecularly imprinted cryogels exhibited significant stability and reusability by keeping more than 85% of their adsorption capacity after ten regeneration cycles. Considering the fabrication process, adsorption capacity, selectivity, and reusability of the imprinted cryogels, these new materials could be utilized as a promising alternative for selective adsorption of drug molecules.

Application of Molecular Imprinting for Creation of Highly Selective Sorbents for Extraction and Separation of Rare-Earth Elements

The aim of the work is to study the effectiveness of a molecular imprinting technique application for the creation of highly selective macromolecular sorbents for selective sorption of light and heavy rare-earth metals (for example, samarium and gadolinium, respectively) with subsequent separation from each other. These sorbents seem to be promising due to the fact that only the target rare-earth metal will be sorbed owing to the fact that complementary cavities are formed during the synthesis of molecularly imprinted polymers. In other words, the advantage of the proposed macromolecules is the absence of accompanying sorption of metals with close chemical properties. Two types of molecularly imprinted polymers (MIP) were synthetized based on methacrylic acid (MAA) and 4-vinylpyridine (4VP) functional monomers. The sorption properties (extraction degree, exchange capacity) of the MIPs were studied. The impact of template removal cycle count (from 20 to 35) on the sorption effectivity was studied. Laboratory experiments on selective sorption and separation of samarium and gadolinium from a model solution were carried out.

A novel electrochemical biosensing method with double-layered polymer brush modified electrode

We developed a novel electrochemical biosensor electrode that has a potential to reduce background noise for which we constructed an original conductive substrate modified with a double-layered polymer brush structure that is water impermeable and can control biomolecules adsorption/desorption. In this study, a hydrophobic poly(tert-butyl methacrylate) brush layer was prepared on a gold electrode, and then, the tert-butyl group near the outermost surface was dissociated by the acid treatment to obtain a hydrophilic carboxy group, thereby fabricating a conductive substrate with the double-layered polymer brush structure. Formation of the double-layered polymer brush structure was indicated by surface wettability and optical analyses. The potential difference and hydrogen ion concentration, which is a typical parameter of the surrounding environment, were linearly correlated with the gold electrode having a double-layered polymer brush structure with carboxyl groups. However, there was no correlation on gold electrodes with self-assembled monolayers presenting carboxy groups. It is considered that the pH responsiveness of the carboxy groups on the outermost surface could be exhibited remarkably because the charge state in the vicinity of the surface became constant due to the hydrophobic polymer brush layer having a certain thickness. The target DNA could be captured more efficiently at the probe DNA-immobilized electrode with the double-layered polymer brush structure than when using COOH-SAM. This is the first report of the application of the double-layered polymer brush structure for the electrochemical biosensing, and it will be an excellent surface modification method to reduce background noise.

Epitope imprinted polymeric materials: application in electrochemical detection of disease biomarkers

Epitope imprinting is a promising method for creating specialized recognition sites that resemble natural biorecognition elements. Epitope-imprinted materials have gained a lot of attention recently in a variety of fields, including bioanalysis, drug delivery, and clinical therapy. The vast applications of epitope imprinted polymers are due to the flexibility in choosing monomers, the simplicity in obtaining templates, specificity toward targets, and resistance to harsh environments along with being cost effective in nature. The "epitope imprinting technique," which uses only a tiny subunit of the target as the template during imprinting, offers a way around various drawbacks inherent to biomacromolecule systems i.e., traditional molecular imprinting techniques with regards to the large size of proteins, such as the size, complexity, accessibility, and conformational flexibility of the template. Electrochemical based sensors are proven to be promising tool for the quick, real-time monitoring of biomarkers. This review unravels epitope imprinting techniques, approaches, and strategies and highlights the applicability of these techniques for the electrochemical quantification of biomarkers for timely disease monitoring. In addition, some challenges are discussed along with future prospective developments.

Synthesis of Mesoporous Silica Imprinted Salbutamol with Two TEOS/MTES Ratio Compositions through the Direct Incorporation Method for Salbutamol Separation

Molecularly imprinted mesoporous silica (MIPMS) is one of the methods to improve site accessibility molecule target on molecularly imprinted polymer (MIP) for application in solid-phase extraction (SPE). The MIPMS was prepared using salbutamol sulfate as template molecule, cetyltrimethylammonium bromide as a directing agent, and tetraethyl orthosilicate and methyltriethoxysilane were used as silica precursor and organosilane. In this study, two TEOS : MTES ratios were used. The MIPMS-2 with 3 : 1 ratio of TEOS : MTES has better analytical performance than the MIPMS-1 with 2 : 1 ratio of TEOS : MTES. The adsorption capacity of MIPMS-2 was about 0.0934 mg/g, and it was 0.0407 mg/g for NIPMS-2. The extraction ability of MIPMS-2 was good, with a recovery of about 104.79% ± 1.01% of salbutamol in spiked serum. The imprinting factor (IF) value obtained is 1.2. When serum was spiked with salbutamol and terbutaline, the ability of NIPMS-2 to recognize salbutamol increased. Therefore, optimizing the conditions for the MIPMS synthesis is necessary to produce a sorbent with better selectivity.

Highly Sensitive Molecularly Imprinted Polymer-Based Electrochemical Sensors Enhanced by Gold Nanoparticles for Norfloxacin Detection in Aquaculture Water

The overuse of antibiotics in aquaculture and pharmaceuticals and their subsequent leaking into the environment have been demonstrated to be a potential route for creating antibiotic resistance in bacteria. In order to assess the impact of this problem and take regulatory measures, it is necessary to develop tools that allow for the detection of antibiotics in environmental samples in a routine, low-cost manner. In this study, we integrated gold nanoparticles (AuNPs) into a molecularly imprinted polymer (MIP) membrane to fabricate a new sensor for the detection of norfloxacin in pharmaceuticals and aquaculture samples. The receptor layers were characterized by scanning electron microscopy, electrochemical impedance spectroscopy, and Raman spectroscopy. The results of these studies demonstrate that the addition of AuNPs to the polymer network enhanced the sensor sensitivity by at least a factor of two. The MIP-AuNPs sensor has a low detection limit (0.15 ng/mL, S/N = 3) with a wide linear range and very high sensitivity. The selectivity of the fabricated sensor was measured in the sample containing other antibiotics (like chloramphenicol, ciprofloxacin, and levofloxacin). Rapid and precise norfloxacin detection in pharmaceutical compounds and fishpond water samples indicates that the fabricated sensor has the potential to be used for routine screening of aquacultures and pharmaceutical processes.

A Review on Bio- and Chemosensors for the Detection of Biogenic Amines in Food Safety Applications: The Status in 2022

This article provides an overview on the broad topic of biogenic amines (BAs) that are a persistent concern in the context of food quality and safety. They emerge mainly from the decomposition of amino acids in protein-rich food due to enzymes excreted by pathogenic bacteria that infect food under inappropriate storage conditions. While there are food authority regulations on the maximum allowed amounts of, e.g., histamine in fish, sensitive individuals can still suffer from medical conditions triggered by biogenic amines, and mass outbreaks of scombroid poisoning are reported regularly. We review first the classical techniques used for selective BA detection and quantification in analytical laboratories and focus then on sensor-based solutions aiming at on-site BA detection throughout the food chain. There are receptor-free chemosensors for BA detection and a vastly growing range of bio- and biomimetic sensors that employ receptors to enable selective molecular recognition. Regarding the receptors, we address enzymes, antibodies, molecularly imprinted polymers (MIPs), and aptamers as the most recent class of BA receptors. Furthermore, we address the underlying transducer technologies, including optical, electrochemical, mass-sensitive, and thermal-based sensing principles. The review concludes with an assessment on the persistent limitations of BA sensors, a technological forecast, and thoughts on short-term solutions.

Recent Advances in Molecularly Imprinted Polymers for Antibiotic Analysis

The abuse and residues of antibiotics have a great impact on the environment and organisms, and their determination has become very important. Due to their low contents, varieties and complex matrices, effective recognition, separation and enrichment are usually required prior to determination. Molecularly imprinted polymers (MIPs), a kind of highly selective polymer prepared via molecular imprinting technology (MIT), are used widely in the analytical detection of antibiotics, as adsorbents of solid-phase extraction (SPE) and as recognition elements of sensors. Herein, recent advances in MIPs for antibiotic residue analysis are reviewed. Firstly, several new preparation techniques of MIPs for detecting antibiotics are briefly introduced, including surface imprinting, nanoimprinting, living/controlled radical polymerization, and multi-template imprinting, multi-functional monomer imprinting and dummy template imprinting. Secondly, several SPE modes based on MIPs are summarized, namely packed SPE, magnetic SPE, dispersive SPE, matrix solid-phase dispersive extraction, solid-phase microextraction, stir-bar sorptive extraction and pipette-tip SPE. Thirdly, the basic principles of MIP-based sensors and three sensing modes, including electrochemical sensing, optical sensing and mass sensing, are also outlined. Fourthly, the research progress on molecularly imprinted SPEs (MISPEs) and MIP-based electrochemical/optical/mass sensors for the detection of various antibiotic residues in environmental and food samples since 2018 are comprehensively reviewed, including sulfonamides, quinolones, β-lactams and so on. Finally, the preparation and application prospects of MIPs for detecting antibiotics are outlined.

Application of molecular imprinting polymers in separation of active compounds from plants

Molecular imprinting technique is becoming an appealing and prominent strategy to synthesize materials for target recognition and rapid separation. In recent years, it has been applied in separation of active compounds from various plants and has achieved satisfying results. This review aims to make a brief introduction of molecular imprinting polymers and their efficient application in the separation of various active components from plants, including flavonoids, organic acids, alkaloids, phenylpropanoids, anthraquinones, phenolics, terpenes, steroids, and diketones, which will provide some clues to help stimulating research into this fascinating and useful area.

Biofunctionalization of Multiplexed Silicon Photonic Biosensors

Silicon photonic (SiP) sensors offer a promising platform for robust and low-cost decentralized diagnostics due to their high scalability, low limit of detection, and ability to integrate multiple sensors for multiplexed analyte detection. Their CMOS-compatible fabrication enables chip-scale miniaturization, high scalability, and low-cost mass production. Sensitive, specific detection with silicon photonic sensors is afforded through biofunctionalization of the sensor surface; consequently, this functionalization chemistry is inextricably linked to sensor performance. In this review, we first highlight the biofunctionalization needs for SiP biosensors, including sensitivity, specificity, cost, shelf-stability, and replicability and establish a set of performance criteria. We then benchmark biofunctionalization strategies for SiP biosensors against these criteria, organizing the review around three key aspects: bioreceptor selection, immobilization strategies, and patterning techniques. First, we evaluate bioreceptors, including antibodies, aptamers, nucleic acid probes, molecularly imprinted polymers, peptides, glycans, and lectins. We then compare adsorption, bioaffinity, and covalent chemistries for immobilizing bioreceptors on SiP surfaces. Finally, we compare biopatterning techniques for spatially controlling and multiplexing the biofunctionalization of SiP sensors, including microcontact printing, pin- and pipette-based spotting, microfluidic patterning in channels, inkjet printing, and microfluidic probes.

Review: 3-Aminopropyltriethoxysilane (APTES) Deposition Methods on Oxide Surfaces in Solution and Vapor Phases for Biosensing Applications

Surface functionalization and bioreceptor immobilization are critical processes in developing a highly sensitive and selective biosensor. The silanization process with 3-aminopropyltriethoxysilane (APTES) on oxide surfaces is frequently used for surface functionalization because of beneficial characteristics such as its bifunctional nature and low cost. Optimizing the deposition process of the APTES layer to obtain a monolayer is crucial to having a stable surface and effectively immobilizing the bioreceptors, which leads to the improved repeatability and sensitivity of the biosensor. This review provides an overview of APTES deposition methods, categorized into the solution-phase and vapor-phase, and a comprehensive summary and guide for creating stable APTES monolayers on oxide surfaces for biosensing applications. A brief explanation of APTES is introduced, and the APTES deposition methods with their pre/post-treatments and characterization results are discussed. Lastly, APTES deposition methods on nanoparticles used for biosensors are briefly described.