Molecular Imprinting Technique Research Articles

Functionalized-MXene-based imprinted MOFs composite membranes for the selective separation of ribavirin

The evident decrease for membrane-treated performance in response to multi-component mixture greatly limited its application. Here, we prepared blended nanomolecularly imprinted composite fiber membranes (CXPM-MIMs) with in situ growth of imprinted MOFs on carboxyl functionalized MXene. Through the carboxylate-assisted coordination pathway, a chelation site is provided by the carboxylate-modified MXene to coordinate with NH2-UiO-66, creating a tightly linked NH2-UiO-66/carboxylate-functionalized MXene heterostructure. The key role of the modified carboxyl group can be identified so that it can help to create a strong coordination bond between the two materials. Conventional MOFs typically lack selectivity and specificity. Here, we present a molecularly imprinted nanocomposite MOFs membrane material that exhibits selective adsorption and molecular separation capabilities. Imprinted UiO-66 (Ce) based on diamino-terephthalic acid was synthesized with water as the only solvent without adding any regulator or additive. By adding ribavirin molecules to multicomponent MOFs using a molecular imprinting technique and carrying out adsorption tests (isothermal and kinetic) as well as selectivity testing, we were able to demonstrate this adsorption-separation mechanism. The valuable testing outcomes shown that the as-prepared CXPM-MIMs performed excellently in terms of pemselectivity for ribavirin (RBV) (permselectivity factor β = 4.89, 10.14, 9.23) in addition to exhibiting perfect specific adsorption ability (58.3 mg g−1). The strong permselectivity and particular identification capacity of CXPM-MIMs demonstrated their tremendous potential in the treatment of RBV contamination.

A TALE OF CAPTOPRIL DETECTION BASED ON AN ELECTROCHEMICAL MIP SENSOR

Objective: In this study, it was aimed to develop a voltammetric method using sensors prepared with the molecular imprinting technique for the detection of Captopril, an antihypertensive drug. Material and Method: With the molecular imprinting method, molecularly imprinted polymers were formed on the surfaces of glassy carbon electrodes. The analysis of Captopril was carried out using the differential pulse voltammetry method, and the performance of the sensor was examined. Result and Discussion: A linear analysis was performed up to 50 pM Captopril with a limit of detection value of 2.62 pM. Selectivity studies have shown that Captopril has a higher electrochemical response than other interfering substances, such as paracetamol, ascorbic acid, and L-proline.

Multifunctional Self-Signaling nanoMIP and Its Application for a Washing-Free Assay of Human Angiotensin-Converting Enzyme 2.

Molecular imprinting techniques have attracted a lot of attention as a potential biomimetic technology, but there are still challenges in protein imprinting. Herein, multifunctional nanosized molecularly imprinted polymers (nanoMIPs) for human angiotensin-converting enzyme 2 (ACE2) were prepared by epitope imprinting of magnetic nanoparticles-anchored peptide (magNP-P) templates, which were further applied to construct a competitive displacement fluorescence assay toward ACE2. A cysteine-flanked dodecapeptide sequence was elaborately selected as an epitope for ACE2, which was immobilized onto the surface of magnetic nanoparticles and served as a magNP-P template for imprinting. During polymerization, fluorescent monomers were introduced to endow fluorescence responsiveness to the prepared self-signaling nanoMIPs. A competitive displacement fluorescence assay based on the nanoMIPs was established and operated in a washing-free manner, yielding a wide range for ACE2 (0.1-6.0 pg/mL) and a low detection limit (0.081 pg/mL). This approach offers a promising avenue in the preparation of nanoMIPs for macromolecule recognition and expands potential application of an MIP in the detection of proteins as well as peptides.

Chiral octahedral cobalt(III) complex immobilized on Carboblack C as a novel robust and readily available enantioselective voltammetric sensor for the recognition of tryptophan enantiomers in real samples

Enantioselective voltammetric sensors (EVSs) have significant interest in analytical and medicinal chemistry, as they allow for the express analysis and recognition of pharmacologically active components in drugs, as well as the establishment of the enantiopurity of compounds. The most common methods of modifying the electrode surface are through molecular imprinting techniques and the addition of a non-electroactive chiral modifier to the electrode composition. By varying the structure and properties of the chiral modifier, the sensor can be designed to have the highest enantioselectivity for a chosen chiral analyte. In this study, we describe the development of a new type of EVS based on a Carboblack C paste electrode modified with a chiral octahedral cobalt(III) complex for use as a selective enantioselector. It was found that the EVS, prepared from enantiopure Co(III) complexes, can selectively recognize L- and D-tryptophan (Trp) in phosphate buffer solution (PBS) with pH = 6.86. The peak current ratio (iD/iL) between the two enantiomers reached 1.36, demonstrating the effectiveness of the sensor. The experimental results indicate a linear correlation between the peak currents of Trp enantiomers and their concentration in the range from 1.00·10−6 to 5.00·10−4 М, leading to a detection limit of 2.42 µM and 3.30 µM for D- and L-Trp, respectively, when using chiral octahedral Co(III) complex with chloride counter-anion. Next, the EVSs developed demonstrated practical applicability in measuring the concentration of Trp in pharmaceutical samples and human urine and blood plasma. An important advantage of these sensors is the difference in the oxidation potentials between Trp enantiomers (ΔEp=35 mV), which makes it possible to determine Trp enantiomers in their mixtures. Quantum chemical calculations and experimental data show that the octahedral Co(III) complex binds to one of the Trp enantiomers with a stronger affinity, thus increasing its concentration at the electrode surface and promoting its oxidation. The easy preparation of the chiral Co(III) complex from inexpensive commercial materials, its high stability and insolubility in water make it a promising selector for the creation of efficient multifunctional EVSs for the analysis of various aqueous solutions.

Preparation of styrene-based imprinted polymer for the adsorption of hazardous bromocresol green dye: Equilibrium, kinetics and thermodynamics study

In this study, styrene was used as a functional monomer for the production of molecularly imprinted polymer (MIP) via free radical  polymerization method, using bromocresol green dye (BCG) as template. A non-imprinted polymer (NIP), that excluded the template,  was also synthesized. Both polymers were applied for the removal of BCG from aqueous medium. The synthesized polymers were  characterized with Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray powder diffraction spectroscopic  techniques. The effect of operating variables, such as pH, contact time, initial dye concentration and process temperature, on the efficiencies of the polymers in removing the dye were evaluated. Equilibrium time of BCG adsorption onto the  MIP was reached within  40 min, with adsorption capacity of 49.68 mg g-1 . The adsorption process followed the pseudo-second-order kinetic and Freundlich  isotherm models, while chemisorption mechanism was predicted. The adsorption process was spontaneous and exothermic in nature,  with DH values of -140.03 and -25.01 kJ/mol-1 recorded for BCG removal by MIP and NIP, respectively. The styrene-based MIP showed  good mechanical stability, and retained up to about 99% of its adsorption capacity after six sequential cycles of   regeneration.  Comparatively, the MIP (99.81mg g-1 ) performed considerably better than its NIP (59.00 mg g-1 ) analogue in the removal of BCG from  aqueous medium, thus affirming the potentials of the molecular imprinting technique in the production of efficient adsorbents for  adsorption of toxic dyes from industrial effluents. 

High-sensitivity concentration detection of trace doxycycline in solution by molecular imprinting based on surface plasmon resonance technology

The abuse of doxycycline (DC) will lead to the presence of its residues in animals and water environments, which threatens human health. It is of great significance to detect the micro-content of DC in solution. Based on surface plasmon resonance (SPR) technology, we develop a detection method for trace DC in solution by modifying the SPR sensor chip with a molecular imprinting technique. The results show that the SPR sensor could specifically recognize DC in solution, and the detection limit of this method reaches 10−6µg/mL, which is 100 times lower than that of the ELISA method. The detection signal has good linearity in the concentration range of 10−6−10µg/mL. This method has the advantages of a low detection limit, large linear range, and high specificity for DC detection.

Low voltage electric-double-layer transistor nonenzymic erythromycin sensors based on molecularly imprinted polymers

Erythromycin (Ery) is a commonly used antibiotic that can be found ubiquitously in water bodies. The increasing apprehension over the adverse effects of antibiotic remnants in aquatic environments necessitates the prompt advancement of erythromycin detection techniques that are both highly sensitive and compact. Here, we propose a non-enzyme Ery sensor that integrates a mesoporous SiO2-based low-voltage oxide electric-double-layer transistor (EDLT) with a molecular imprinting technique, featuring a molecularly imprinted polymers (MIP) functionalized gate electrode. The mesoporous SiO2-based oxide transistor exhibits excellent electrical characteristics, including an operating voltage of small than 1.0 V, an on/off ratio exceeding 106 and a mobility of 14.95 cm2V−1s−1. At an ultra-low operating voltage within 0.5 V, the sensor exhibits a linear response to the concentration range of 1 nM–10 μM of Ery, with a detection limit of 0.22 nM and a sensitivity of 23.3 mV dec−1. Besides, the single-spike dynamic sensing mode effectively reduces the power consumption of the detection. The proposed sensor provides a rapid and convenient approach to detect Ery in aqueous environments, with benefits such as miniaturization, high sensitivity, and simplicity.

Self‐assembly imprinting fabrication of shell‐crosslinking fluorescent nanoparticles for the detection of sialic acid

AbstractA new strategy for preparing sialic acid (SA)‐quenching fluorescent nanoparticles by macromolecular self‐assembly and molecular imprinting technique is suggested. An amphiphilic block copolymer polystyrene‐b‐poly(glycidyl methacrylate) (PS‐b‐PGMA) was designed and synthesized. After functionalization, PS‐b‐PGMA was co‐assembled with the template molecule SA to prepare SA‐imprinted fluorescent nanoparticles, named as nano‐FMIPs. In this process, the shell layers of nanoparticles were photo‐crosslinked upon 365 nm UV light to stabilize the recognition site. The size of the crosslinked shell was found to be increased to 420 ± 5 nm by TEM and DLS measurements. After extraction of SA, recognition cavities complementary in shape, size, and chemical function toward the template SA were left on the surface of nano‐FMIPs, which can selectively rebind the target SA in a mixture of structurally similar compounds. It is found that SA can significantly quench the fluorescence intensity of nano‐FMIPs linearly within a concentration range of 1 × 10−2 ~ 2 × 10−6 mol L−1 and a detection limit of 1.55 × 10−6 mol L−1. This strategy provides a new approach for preparing surface‐imprinted nano‐FMIPs for the quantitative detection of SA, and the nano‐FMIPs may have great potential for biomedical application.

Rational design of MIPs for the detection of Myxovirus resistance protein A (MxA), a biomarker for viral infection

Accurate diagnosis is crucial for effective patient care and the containment of antimicrobial resistance outbreaks. The intricate challenge of distinguishing bacterial from viral infections, coupled with limited diagnostic tools and overlapping symptoms has driven the utilization of molecular imprinting techniques. This study focuses on developing cost-effective, chemically stable antibody analogs for the interferon-induced protein myxovirus resistance protein A (MxA). MxA is an intracellular, cytoplasmic GTPase having activity against a wide range of viruses and serves as a distinctive biomarker for viral infections. We utilized computational design to guide the polymer assembly, centering on epitope imprinting to target MxA-specific regions crucial for interaction. Molecular docking calculations, alongside a pioneering multi-monomer simultaneous docking (MMSD) protocol, efficiently elucidate cooperativity during pre-polymerization. Monomer binding affinity scores, such as for APTMS, exhibited notable increase, ranging from −3.11 to −13.03 kcal/mol across various MMSD combinations compared to a maximum of −2.78 kcal/mol in single monomer docking, highlighting the capacity of MMSD in elucidating crucial monomer-monomer interactions. This computational approach provides a theoretical alternative to labor-intensive experimental optimization, streamlining the development process for synthetic receptors. Simulations reveal unique interactions enhancing MIP-peptide complementarity, yielding optimized receptors selectively binding to MxA epitopes. The obtained MIPs demonstrated a maximum adsorption capacity of approximately 12 mg/g and captured 1.6 times more epitope and 2.6 times more epitope containing MxA protein than corresponding NIPs. A proof-of-concept study demonstrates MxA protein binding to synthetic receptors, highlighting the potential of MIPs, analogous to antibodies, in overcoming current diagnostic challenges for precise detection of viral infection.

SYNTHESIS OF TETRACYCLINE IMPRINTED POLYMERS WITH METHACRYLIC ACID AS FUNCTIONAL MONOMER IN METHANOL-CHLOROFORM MIXTURE USING BULK AND PRECIPITATION POLYMERIZATION METHOD

The content of tetracycline residues in poultry meat products can cause antibiotic resistance in humans who consume these products, so it is necessary to develop sensitive analytical techniques to determine the levels of tetracycline residues to assess the safety of these products for consumption. The molecular imprinting technique is a method to produce sorbents with molecular recognition capability of target compounds that can be used to increase the selectivity of solid phase extraction to extract tetracycline residues for further analysis. This study aimed to obtain a sorbent synthesized by molecular imprinting technique to analyze tetracycline in poultry meat products. The stages of the research began with the study of the interaction of functional monomers with template molecules, determining the association constants of functional monomers with template molecules, synthesis of imprinted polymer molecules using bulk and precipitation methods, evaluating the ability and adsorption capacity of the synthesized polymers, assess the selectivity of polymers for analog structures and physical characteristics with FTIR. The research showed that methacrylic acid was the best functional monomer with a binding energy value of -27.3776 kcal/mol. The higher adsorption capacity was achieved by Molecularly Imprinted Polymer (MIP) that was synthesized by precipitation method (MIP2) than the other MIP synthesized by bulk polymerization (MIP1) with a value of 0.8748 mg/g and 0.4077 mg/g, respectively. The analogous compounds' imprinting factor values for each MIP were 1.197 and 1.1272. The polymer synthesized by molecular imprinting technique is selective for extracting and analyzing tetracycline from poultry meat matrix.

Bidirectional Regulation of Intracellular Enzyme Activity Using Light-Driven Nano-Inhibitors.

Photochemical regulation provides precise control over enzyme activities with high spatiotemporal resolution. A promising approach involves anchoring "photoswitches" at enzyme active sites to modulate substrate recognition. However, current methods often require genetic mutations and irreversible enzyme modifications for the site-specific anchoring of "photoswitches", potentially compromising the enzyme activities. Herein, we present a pioneering reversible nano-inhibitor based on molecular imprinting technique for bidirectional regulation of intracellular enzyme activity. The nano-inhibitor employs a molecularly imprinted polymer nanoparticle as its body and azobenzene-modified inhibitors ("photoswitches") as the arms. By using a target enzyme as the molecular template, the nano-inhibitor acquires oriented binding sites on its surface, resulting in a high affinity for the target enzyme and non-covalently firm anchoring of the azobenzene-modified inhibitor to the enzyme active site. Harnessing the reversible isomerization of azobenzene units upon exposure to ultraviolet and visible light, the nano-inhibitor achieves bidirectional enzyme activity regulation by precisely docking and undocking inhibitor at the active site. Notably, this innovative approach enables the facile in situ regulation of intracellular endogenous enzymes, such as carbonic anhydrase. Our results represent a practical and versatile tool for precise enzyme activity regulation in complex intracellular environments.

Bidirectional Regulation of Intracellular Enzyme Activity Using Light‐Driven Nano‐Inhibitors

AbstractPhotochemical regulation provides precise control over enzyme activities with high spatiotemporal resolution. A promising approach involves anchoring “photoswitches” at enzyme active sites to modulate substrate recognition. However, current methods often require genetic mutations and irreversible enzyme modifications for the site‐specific anchoring of “photoswitches”, potentially compromising the enzyme activities. Herein, we present a pioneering reversible nano‐inhibitor based on molecular imprinting technique for bidirectional regulation of intracellular enzyme activity. The nano‐inhibitor employs a molecularly imprinted polymer nanoparticle as its body and azobenzene‐modified inhibitors (“photoswitches”) as the arms. By using a target enzyme as the molecular template, the nano‐inhibitor acquires oriented binding sites on its surface, resulting in a high affinity for the target enzyme and non‐covalently firm anchoring of the azobenzene‐modified inhibitor to the enzyme active site. Harnessing the reversible isomerization of azobenzene units upon exposure to ultraviolet and visible light, the nano‐inhibitor achieves bidirectional enzyme activity regulation by precisely docking and undocking inhibitor at the active site. Notably, this innovative approach enables the facile in situ regulation of intracellular endogenous enzymes, such as carbonic anhydrase. Our results represent a practical and versatile tool for precise enzyme activity regulation in complex intracellular environments.

Fluorescent Probes Based on Ag NPs@N/GQDs and Molecularly Imprinted Polymer for Sensitive Detection of Noradrenaline in Bananas.

Fluorescence intensity and selective recognition ability are crucial factors in determining the analytical techniques for fluorescent probes. In this study, a core-shell fluorescent material, composed of silver nanoparticles@nitrogen-doped graphene quantum dots (Ag NPs@N/GQDs), was synthesised using mango leaves as the raw material through a thermal cracking method, resulting in strong fluorescence luminescence intensity. By employing noradrenaline as a template molecule and using a surface molecular imprinting technique, a molecularly imprinted membrane (MIP) was formed on the surface of the fluorescent material, that was subsequently eluted to obtain a highly specific, fluorescent probe capable of recognising noradrenaline. The probe captured various concentrations of noradrenaline using the MIP, which decreased the fluorescence intensity. Then a method for detecting trace amounts of noradrenaline was established. This method exhibited a linear range from 0.5 -700pM with a detection limit of 0.154pM. The proposed method was implemented in banana samples. Satisfactory recoveries were confirmed at four different concentrations. The method presented a relative standard deviation (RSD) of less than 5.0%.

Multifunctional molecularly imprinted nanozymes with improved enrichment and specificity for organic and inorganic trace compounds.

Although nanozymes exhibit properties superior to those of natural enzymes and conventional engineered enzymes, the development of highly specific nanozymes remains a challenge. New yolk-shell Fe3O4 molecularly imprinted (MIP@void@Fe3O4) nanozymes with peroxidase-like activity were developed by modelling the substrate channels of natural enzymes through molecular imprinting techniques and interfacial affinity modifications in this study. To establish a platform technology for the adsorption and determination of inorganic and organic contaminants, lead ion (Pb2+) and diazinon (DIZ), respectively, were selected as imprinting templates, and a hollow mesoporous shell was synthesized. The as-prepared MIP@void@Fe3O4 nanozymes, characterized using TEM, HRTEM, SEM, FT-IR, TGA, VSM and XPS, not only affirmed the successful fabrication of a magnetic nanoparticle with a unique hollow core-shell structure but also facilitated an exploration of the interfacial bonding mechanisms between Fe3O4 and other shell layers. The enrichment of the MIP@void@Fe3O4 nanozymes due to imprinting was approximately 5 times higher than the local substrate concentration and contributed to the increased activity. Based on selective and competitive recognition experiments, the synthesized nanozymes could selectively recognize organic and inorganic targets with the lowest detection limits (LOD) of 6.6 × 10-9 ppm for Pb2+ and 5.13 × 10-11 M for DIZ. Therefore, the proposed biosensor is expected to be a potent tool for trace pollutant detection, which provides a rational design for more advanced and subtle methods to bridge the activity gap between natural enzymes and nanozymes.

Drug‐delivery contact lenses

The prevalence of ocular chronic diseases, like those associated to diabetes (diabetic retinopathy, macular edema and glaucoma), has increased significantly in the last years. They affect quite negatively people's quality of life, leading to extremely high economic costs both for patients and society. Recent advances in pharmacotherapy have greatly improved their prognosis. However, the efficacy and safety of the treatments currently available are still a concern. Topical drug delivery (DD) is useful to treat diseases of the anterior segment of the eye, but new strategies are needed to increase drug's bioavailability, which is quite low, and to overcome the difficulties that e.g. elderly people face in topical administration. Regarding the posterior segment, the challenge is to reach the target tissues due to the eye's natural barriers. Topical treatments are generally useless in this case. Systemic administration requires large doses to achieve local therapeutic levels and may induce undesirable side effects. Intravitreal route provides direct access to the intraocular environment and is highly effective, but is rather invasive and may origin serious complications, such as endophthalmitis, retinal detachment, intravitreal haemorrhage and cataract. In BioMat Research Group of IST, and within the frame of ORBITAL and SOL projects, we are making efforts to develop and optimize new DD systems for the treatment of diabetic ocular diseases that use noninvasive routes and present sustained drug release capabilities, increasing the drug's bioavailability at the target tissues. We propose the use of soft contact lenses (SCLs) as DD vehicles, due to their high biocompatibility and prolonged contact with the eye. Being frequently replaced, SCLs may be used as drug reservoirs for continued treatments, not only of diseases of the anterior part of the eye, but also of the posterior, using innovative techniques that enhance the drug penetration in the eye. Although in the last years much research has been done on this type of devices, they are still not available in the market due to a number of reasons, such as the need of improving systems efficiency, the difficulty in transposing to industry the preparation methodologies, issues related with sterilization/storage or lack of in vivo and clinical tests. In our studies, we have used different strategies to increase the bioavailability of the drugs and achieve adequate drug release profiles. Besides applying coatings and molecular imprinting techniques, we investigated the formation of prodrugs and drug inclusion in nanostructures that protect them in the biological medium. The incorporation in SCLs of cell penetrating peptides (CPP) that increase drug's ability to cross the corneal epithelium and reach the back of the eye, also led to to promising results. Ex‐vivo tests and mathematical modelling were used to predict the biological performance of the drug‐loaded devices in vivo before performing tests with animal models. Finally, alternative sterilization techniques which allow to process such challenging systems were explored.The obtained results shall contribute for the development of new forms of treatment of ocular diseases that are more predictable, safe and effective, giving response to an unmet clinical need.

Selective extraction and quantitative analysis of pyrroloquinoline quinone from food.

Pyrroloquinoline quinone (PQQ) is a bioactive compound that has attracted significant attention due to its potential health benefits. In this study, we developed a new magnetic molecularly imprinted nanoparticle (MMIN) for the selective extraction and determination of PQQ from food samples. The MMIN was synthesized using a surface molecular imprinting technique with PQQ as the template molecule, Fe3O4 nanoparticles as the magnetic core, and methacrylic acid as the functional monomer. The MMIN exhibited high selectivity and affinity towards PQQ, allowing for efficient extraction and preconcentration of PQQ from complex food matrices. The extracted PQQ was then quantified using HPLC-DAD. The developed method showed good linearity (R2 = 0.9985) and low limits of detection (0.03 μg L-1). The accuracy and precision of the method were evaluated by analyzing spiked food samples, with average recoveries close to 89.8%. The MMIN also demonstrated good reusability, with negligible decrease in extraction efficiency after five cycles of use. Overall, the developed MMIN-based method provides a reliable and efficient approach for the analysis of PQQ in food samples.

In2O3/Bi2S3 S-scheme Heterojunction-Driven Molecularly Imprinted Photoelectrochemical Sensor for Ultrasensitive Detection of Florfenicol.

Florfenicol (FF) raises significant human health and environmental concerns due to its toxicity to the hematology system and the potential spread of antibiotic-resistant genes. Here, a highly sensitive molecularly imprinted photoelectrochemical (PEC) sensor, featuring an In2O3/Bi2S3 S-scheme heterojunction, is proposed to detect FF without an external voltage supply. Compared with conventional II-type heterojunctions, S-scheme heterojunctions efficiently promote carrier separation and enhance the redox capability of the photocatalytic system. This allows more dissolved O2 and H2O molecules to participate in the redox reaction, resulting in an amplified and stabilized photocurrent response. The electron transfer in the S-scheme heterojunction is confirmed via electron spin resonance (ESR). With the molecular imprinting technique, this PEC platform exhibits exceptional selectivity, wide linear range (1.0 × 10-4-1.0 × 104 ng mL-1), low detection limit (6.4 × 10-5 ng mL-1), and applicability in real milk and chicken samples. This work not only showcases a PEC platform for accurately and portably detecting drugs but also proposes a viable approach for designing S-scheme heterojunctions in sensing analysis.

Dual improvement in sensitivity and selectivity of SnO2 nanospheres for formaldehyde sensing based on molecular imprinting and Ag doping

In order to develop a gas sensitive material with both high sensitivity and good selectivity, Ag–SnO2 MIPs were designed and synthesized by adopting molecular imprinting technique. Specifically, SnO2 nanospheres synthesized through hydrothermal method were used as substrate. Then, Ag–SnO2 was assembled by decorating nano-sized Ag on the surface of SnO2 nanospheres. Molecular imprinting modification with formaldehyde as template molecules was in next conducted to get Ag–SnO2 MIPs. The morphology, valence and crystal structure of the samples were characterized using SEM, XRD, TEM and XPS. The characterization results showed that uniform SnO2 nanospheres were successfully synthesized with metallic Ag distributed on the surface, and the molecular imprinting process did not change the morphology of the material. According to gas sensing measurement results, it was found that the sensor based on Ag–SnO2 MIPs exhibited superior formaldehyde sensing performance. The molecular imprinting modification effectively improved the sensor's selectivity towards formaldehyde gas. Owning to the catalytic property of Ag, the sensing response of sensor was greatly enhanced. Additionally, Ag–SnO2 MIPs also exhibits high reproducibility and long-term stability.

The Role of Molecularly Imprinted Polymers In Sensor Technology: Electrochemical, Optical and Piezoelectric Sensor Applications

With the help of molecular imprinting technology, artificial receptors can be made and used for identification. This technique's limitless application increases polymer technology and makes it adaptable to other technologies. In this study, examples of sensor applications are used to explain molecular imprinting technology (MIT) and its brief history. MIT can be used to create polymer-based artificial receptors with remarkable selectivity and affinity to detect any target molecules that can be imprinted on a polymer. A monomer is synthesized around a template molecule to create a selective cavity that serves as an artificial receptor. Molecularly imprinted polymers (MIP) offer a wide range of uses and have recently garnered much attention. These polymers' production methods, production kinds, and molecular imprinting techniques are all thoroughly detailed. The outstanding properties of MIPs make a crucial contribution to sensor applications offering selective, fast, easy, and cost-effective analysis, which became very popular after Clark published his first biosensor study. Apart from the biological recognition receptors, MIPs have the advantage that they are not affected by physical conditions of the environment, such as temperature, pH, and ion strength. To overcome the biological recognition receptors' disadvantages, molecularly imprinted polymers can be used for sensor development. From the point of view of the review, the combination of MIPs and sensors was explained and proposed as an informative paper.

Microfluidic synthesis of pH-responsive molecularly imprinted silica nanospheres for fluorescence sensing target glycoprotein.

Here, fluorescent artificial antibodies for sensing ovalbumin in food were synthesized by molecular imprinting technique in a microfluidic reactor. A phenylboronic acid-functionalized silane was employed as the functional monomer to enable the polymer has pH-responsive property. Fluorescent molecularly imprinted polymers (FMIPs) could be produced continuously in a short time. Both fluorescein isothiocyanate (FITC) and rhodamine B isothiocyanate (RB)-based FMIPs can specifically recognize the target ovalbumin, particularly FITC-based FMIP, giving an imprinting factor of 2.5 and cross-reactivity factors of 2.7 (ovotransferrin), 2.8 (β-lactoglobulin) and 3.4 (bovine serum albumin), and was applied for the detection of ovalbumin in milk powder with recovery rates of 93-110%; moreover, the FMIP can be reused at least four times. Such FMIPs have promising future in replacing the fluorophore-labelled antibodies to fabricate fluorescent sensing devices or establish immunoassay methods, which have extra merits of low-cost, high stability and recyclability, easy to carry and store at ambient environments.