Molecular Imprinting Method Research Articles

Surface-enhanced Raman sensor with molecularly imprinted nanoparticles as highly sensitive recognition material for cancer marker amino acids

Surface-enhanced Raman scattering (SERS) is a powerful technique primarily due to its high sensitivity and signal-enhancing properties, which enable the identification of unique vibrational fingerprints. These fingerprints can be used for the diagnosis and monitoring of diseases such as cancer. It is crucial to selectively identify cancer biomarkers for early diagnosis. A correlation has been established between the reduction in the concentration of specific amino acids and the stage of the disease, particularly tryptophan (TPP) and tyrosine (TRS) in individuals diagnosed with prostate cancer. In this work, we present a strategy to analyze TPP and TRS amino acids using molecularly imprinted polymer nanoparticles (nanoMIPs), which selectively detect target molecules in a SERS sensor. NanoMIPs are synthesized using the solid-phase molecular imprinting method with TPP and TRS as templates. These are then immobilized on a SERS substrate with gold nanoparticles to measure samples prepared from tryptophan and tyrosine in phosphate-buffered saline. The detection and quantification limits of the designed sensor are 7.13 μM and 23.75 μM for TPP, and 22.11 μM and 73.72 μM for TRS, respectively. Our study lays the groundwork for future investigations utilizing nanoMIPs in SERS assessments of TPP and TRS as potential biomarkers for prostate cancer detection.

Application of Biosensors for the Detection of Mycotoxins for the Improvement of Food Safety.

Mycotoxins, secondary metabolites synthesized by various filamentous fungi genera such as Aspergillus, Penicillium, Fusarium, Claviceps, and Alternaria, are potent toxic compounds. Their production is contingent upon specific environmental conditions during fungal growth. Arising as byproducts of fungal metabolic processes, mycotoxins exhibit significant toxicity, posing risks of acute or chronic health complications. Recognized as highly hazardous food contaminants, mycotoxins present a pervasive threat throughout the agricultural and food processing continuum, from plant cultivation to post-harvest stages. The imperative to adhere to principles of good agricultural and industrial practice is underscored to mitigate the risk of mycotoxin contamination in food production. In the domain of food safety, the rapid and efficient detection of mycotoxins holds paramount significance. This paper delineates conventional and commercial methodologies for mycotoxin detection in ensuring food safety, encompassing techniques like liquid chromatography, immunoassays, and test strips, with a significant emphasis on the role of electrochemiluminescence (ECL) biosensors, which are known for their high sensitivity and specificity. These are categorized into antibody-, and aptamer-based, as well as molecular imprinting methods. This paper examines the latest advancements in biosensors for mycotoxin testing, with a particular focus on their amplification strategies and operating mechanisms.

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.

Molecularly Imprinted Macroporous Hydrogel Promotes Bone Regeneration via Osteogenic Induction and Osteoclastic Inhibition.

Macroporous hydrogels offer physical supportive spaces and bio-instructive environment for the seeded cells, where cell-scaffold interactions directly influence cell fates and subsequently affect tissue regeneration post-implantation. Effectively modifying bioactive motifs at the inner pore surface provides appropriate niches for cell-scaffold interactions. A molecular imprinting method and sacrificial templates are introduced to prepare inner pore surface modification in the macroporous hydrogels. In detail, acrylated bisphosphonates (Ac-BPs) chelating to templates (CaCO3 particles) are anchored on the inner pore surface of the methacrylated gelatin (GelMA)-methacrylated hyaluronic acid (HAMA)-poly (ethylene glycol) diacrylate (PEGDA) macroporous hydrogel (GHP) to form a functional hydrogel scaffold (GHP-int-BP). GHP-int-BP, but not GHP, effectively crafts artificial cell niches to substantially alter cell fates, including osteogenic induction and osteoclastic inhibition, and promote in situ bone regeneration. These findings highlight that molecular imprinting on the inner pore surface in the hydrogel efficiently creates orthogonally additive bio-instructive scaffolds for bone regeneration.

Biosensing Applications of Molecularly Imprinted-Polymer-Based Nanomaterials

In the realm of sensing technologies, the appeal of sensors lies in their exceptional detection ability, high selectivity, sensitivity, cost-effectiveness, and minimal sample usage. Notably, molecularly imprinted polymer (MIP)-based sensors have emerged as focal points of interest spanning from clinical to environmental applications. These sensors offer a promising avenue for rapid, selective, reusable, and real-time screening of diverse molecules. The preparation technologies employed in crafting various polymer formats, ranging from microparticles to nanomaterials, wield a profound influence. These techniques significantly impact the assembly of simplified sensing systems, showcasing remarkable compatibility with other technologies. Moreover, they are poised to play a pivotal role in the realization of next-generation platforms, streamlining the fabrication of sensing systems tailored for diverse objectives. This review serves as a comprehensive exploration, offering concise insights into sensors, the molecular imprinting method, and the burgeoning domain of MIP-based sensors along with their applications. Delving into recent progress, this review provides a detailed summary of advances in imprinted-particle- and gel-based sensors, illuminating the creation of novel sensing systems. Additionally, a thorough examination of the distinctive properties of various types of MIP-based sensors across different applications enriches the understanding of their versatility. In the concluding sections, this review highlights the most recent experiments from cutting-edge studies on MIP-based sensors targeting various molecules. By encapsulating the current state of research, this review acts as a valuable resource, offering a snapshot of the dynamic landscape of MIP-based sensor development and its potential impact on diverse scientific and technological domains.

Microfluidic-based molecularly imprinted polymers-integrated optic sensors

Molecularly imprinted polymers (MIPs) are cheap and easily prepared polymers that have specific recognition sites for the target molecule that suitable for recognition. MIPs are also synthetic materials designed to mimic the recognition properties of natural antibodies or receptors. The development of MIPs in optic sensors has introduced a significant novelty in the field of sensing technology. When integrated into optic sensors, MIPs offer several advantages and novel capabilities including selective recognition, versatility, stability and reusability, signal amplification, and tailored sensor design. Microfluidic systems are enable the control and movement of fluids in small volumes within micro-scale channels. MIPs, optic sensors and microfluidic systems have important superior features such as sensitivity, selectivity and low sample requirement. They are used together in the creation of fast, automated and self-contained systems. The combination of advantages makes microfluidic-based MIPs-integrated optic sensors a promising technology for various applications in analytical sciences, biomedical research, and environmental monitoring.In this review, we first described molecular imprinting method, molecularly imprinted polymers, microfluidic systems, optic sensors and then mentioned different microfluidic-based molecularly imprinted polymers-integrated optic sensors platform for various molecule detection as applications in several working fields.

Efficient and selective extraction of chlorogenic acid in juice samples using magnetic molecularly imprinted polymers

In this study, magnetic molecularly imprinted polymers (Fe3O4@MIPs) were successfully synthesized through surface molecular imprinting method with chlorogenic acid (CGA) as the template molecule. The adsorption properties of Fe3O4@MIPs for CGA were carefully evaluated through adsorption kinetics, adsorption isotherms and selectivity experiments. The obtained Fe3O4@MIPs displayed high adsorption capacity (35.84 mg/g), excellent reusability and significant selectivity for CGA, and the adsorption equilibrium could be achieved within 40 min. Finally, the resulting Fe3O4@MIPs were successfully employed as effective adsorbents combined with high-performance liquid chromatography for the detection of CGA in juice samples with excellent selectivity. A good linear relationship in the range of 0.1–100 μg/mL and the limit of detection (LOD) (0.03 µg/mL) were obtained under the optimized conditions. The satisfactory recoveries of proposed method at three spiked levels analysis were 93.5 %–101.6 % with the relative standard deviation (RSD) less than 5 %.

Porous boronate imprinted microsphere prepared based on new RAFT functioned cellulose nanocrystalline with multiple H-bonding at the emulsion droplet interface for highly specific separation of Naringin

For porous molecular imprinted polymers (MIPs), introduction of special functional groups and integration porous structure support will endow the MIPs with tunable surface properties and specific affinity performance. Herein, by combination of RAFT molecular imprinting, Pickering emulsion, and boronate affinity methods, a new kind of porous imprinted microspheres (BA-HPMIPs) using the low pKa value of APBA (1-allylpyridinium-3-boronic acid, pKa = 7.4) as functional monomer was prepared for specific molecular recognition and separation of NRG. Meanwhile, the novel RAFT functioned surfactants with dual amide multiple H-bonds were designed as stabilized particles was used to promote sustainability, which further confer them multifunctionality and/or by polymerizing the Pickering emulsion itself. Equilibrium adsorption was reached rapidly within 360 min, and the maximum equilibrium binding capacities of BA-HPMIPs were found to be 118.32 µmol g−1 for NRG. Furthermore, they had a stronger selectivity towards NRG than other competitive target (i.e rutin, catechol, ARS, o-nitrophenol). Moreover, BA-HPMIPs have shown outstanding reusability of 8.63 % loss in enrichment performance after five times repeatedly. As a proof of this concept, a commercially avaliable NRG with purity could be effectively extracted and concentrated to 96.75 % purity. These results demonstrated that, a new kind of porous imprinted microsphere with abundant porous structure and boronic acid recognizing sites has great potential for separation and purification of industrial samples under neutral conditions.

Molecular imprinted polymer with dorzolamide for contact lens applications assisted by computational and experimental design

The main aim of the present study was to prepare a molecularly imprinting polymer for dorzolamide as a potential soft contact lens. A computational protocol was used for molecular imprinting polymers (MIP) and Non-molecular imprinting polymers (NIP) preparation. Physicochemical characteristics of MIP and NIP were determined by using Fourier transform infrared spectroscopy analysis (FTIR), Scanning electron microscopy (SEM), Differential scanning calorimetry (DSC) and Brunauer–emmett–teller (BET). Release profile studies were done by using Franz™ Diffusion Cell. Five isotherm models, including Langmuir, Freundlich, Dubinin-Radushkevich (D-R), Temkin and Hill deboer, were investigated to study adsorption equilibrium. Kinetic parameters were evaluated using the Zero-order model, Pseudo-first order and Pseudo-second order. Results revealed that hydroxyethyl methacrylate (HEMA), methacrylic acid (MAA) and methyl methacrylate (MMA) could be considered suitable monomers to form the elastic network. The molecular imprinting technique increased the loading capacity of hydrogels. The optimized imprinted hydrogels were prepared in 1:3:2:1:34 M ratios of DZD, HEMA, MAA, MMA, and EGDMA, respectively. This molar ratio was obtained with a computational method. SEM, FTIR, DSC and BET of MIP confirmed a high degree of polymerization. The adsorption information was essentially fitted on the Hill DeBoer model (R2 = 0.9997); maximum sorption capacity was 187.8 mg/g of DZD for MIP and occurred at the weight of the polymer; 50 mg, temperature; of 25 °C and concentration of DZD solution; of 100 mg/L. maximum sorption capacity was 128.4 mg/g of DZD for NIP and occurred at the weight of the polymer; 50 mg, temperature; of 25 °C and concentration of DZD solution; of 30 mg/L. Release profile analysis showed that MIP has a superior control to release DZD, and the release mechanism fits the Peppas model (R2 = 0.9911). The molecular imprinting method had a substantial impact on loading and releasing DZD from hydrogels.

Surface imprinted upconversion nanoparticles for selective albumin recognition

Upconversion nanoparticles (UCNPs) have attracted researchers’ attention because these particles transform two or more low-energy infrared (IR) photons into high-energy visible photons via a sequential absorption process. The molecular imprinting method, one of the biomimicking approaches, has remarkable advantages for creating synthetic receptors for molecules of interest. In this study, we have focused our attention on developing novel selective materials simultaneously having upconversion and biorecognition abilities to form a supramolecular complex. We proposed a new approach to synthesize silica-based UCNPs via surface imprinting of albumin that was chosen as a model biomolecule. In the first step, synthesis of surface imprinted upconversion silica nanoparticles and template removal processes were performed. FTIR, SEM, fluorimetry / UV-Vis spectrophotometry, zeta-size / potential measurements and BET (surface area measurements) were performed for the characterization. Biorecognition conditions were optimized and the optimum BSA recognition conditions were determined as BSA initial concentration, interaction time, pH, and temperature as 0.5 mg/mL, 15 min, 4.5, and 25 oC, respectively. The relative selectivity coefficients, designating the selectivity gained by the imprinting process for BSA/hemoglobin, BSA/ovalbumin, and BSA/γ-globulin pairs were calculated as 4.69, 38.37, and 9.66, respectively. In the second step, the synthesis of the magnetic nanoparticles and antibody immobilization onto these particles were investigated. At the final step, sandwich-like supramolecular complex with magnetic nanoparticles (MNPs) and upconversion silica nanoparticles (UC-SiNPs) were done and characterized with UV-Vis spectroscopy, fluorescent spectrometry, and zeta size and potential measurements. In a conclusion, developed molecular imprinted upconversion supramolecular complex will be an alternative and intriguing approach where sandwich-like recognition, detection, and selective adsorption properties are simultaneously required.

A High-Luminescence Biomimetic Nanosensor Based on N, S-GQDs-Embedded Zinc-Based Metal-Organic Framework@Molecularly Imprinted Polymer for Sensitive Detection of Octopamine in Fermented Foods.

In this study, a novel fluorescent molecularly imprinted nanosensor (N, S-GQDs@ZIF-8@MIP) based on the nitrogen and sulfur co-doped graphene quantum dots decorated zeolitic imidazolate framework-8 was constructed for the detection of octopamine (OA). Herein, ZIF-8 with a large surface area was introduced as a supporter of the sensing system, which effectively shortened the response time of the sensor. Meanwhile, high green luminescent N, S-GQDs and a maximum emission wavelength of 520 nm under 460 nm excitation and a 12.5% quantum yield were modified on the surface of ZIF-8 as a signal tag that can convert the interactions between the sensor and OA into detectable fluorescent signals. Finally, N, S-GQDs@ZIF-8@MIP was acquired through the surface molecular imprinting method. Due to the synergy of N, S-GQDs, ZIF-8, and MIP, the obtained sensor not only demonstrated higher selectivity and sensitivity than N, S-GQDs@ZIF-8@NIP, but also displayed faster fluorescence response than N, S-GQDs@MIP. Under optimal conditions, the developed sensor presented a favorable linear relationship in the range of 0.1–10 mg L−1 with a detection limit of 0.062 mg L−1. Additionally, the proposed N, S-GQDs@ZIF-8@MIP strategy was effectively applied to the detection of OA in fermented samples, and the obtained results had a satisfactory correlation with those of HPLC.

Selective Recognition of Kanamycin via Molecularly Imprinted Nanosensor

Herein, the molecular recognition sites on the surface of the chip were created by the molecular imprinting method to produce the surface plasmon resonance (SPR) based nanosensor for the real-time kanamycin (KAN) detection. Firstly, kanamycin imprinted nanofilm, which has specific recognition cavities for kanamycin were synthesized by in-situ radical polymerization. Fabricated nanofilm for the detection of kanamycin was characterized with FTIR, ellipsometer, and atomic force microscope by the means of structurally and morphologically. The mean thickness values were determined for the imprinted and non-imprinted nanofilms as 102.4±3.1 nm and 101.8±4.7, respectively. The sensitivity performance of imprinted nanosensor was investigated by using the KAN solutions at different concentrations (25-200 ng/mL). The refractive index and the KAN concentration were found to be in perfect agreement with a regression coefficient (R2, 0.992). The detection limit was calculated as 0.40±0.05 ng/mL by using the equation in the calibration curve. The response of imprinted and nonimprinted nanosensors towards the chemical analogs of KAN (NEO and SPM) were investigated to prove the selectivity of KAN imprinted nanosensors. The reusability performance of imprinted nanosensor was investigated by spiking 25 ng/mL KAN solution with three replicates. When the kinetic analyzes were examined, high sensitivity real-time kanamycin analysis was performed at very low concentrations with good reusability.

Modern and Dedicated Methods for Producing Molecularly Imprinted Polymer Layers in Sensing Applications

Molecular imprinting (MI) is the most available and known method to produce artificial recognition sites, similar to antibodies, inside or at the surface of a polymeric material. For this reason, scholars all over the world have found MI appealing, thus developing, in this past period, various types of molecularly imprinted polymers (MIPs) that can be applied to a wide range of applications, including catalysis, separation sciences and monitoring/diagnostic devices for chemicals, biochemicals and pharmaceuticals. For instance, the advantages brought by the use of MIPs in the sensing and analytics field refer to higher selectivity, sensitivity and low detection limits, but also to higher chemical and thermal stability as well as reusability. In light of recent literature findings, this review presents both modern and dedicated methods applied to produce MIP layers that can be integrated with existent detection systems. In this respect, the following MI methods to produce sensing layers are presented and discussed: surface polymerization, electropolymerization, sol–gel derived techniques, phase inversionand deposition of electroactive pastes/inks that include MIP particles.

Preparation and Investigation of Antibacterial Activities of Ciprofloxacin Imprinted p(HEMAH) Cryogels

Staphylococcus aureus, Enterococcus faecalis and Escherichia coli are the common causes of wound infections. For the treatment of these infections, ciprofloxacin can be recommended as a broad-spectrum antibiotic that acts on both Gram-negative and Gram-positive microorganisms. Besides, antimicrobial agents could be integrated into polymeric materials. Cryogels, one of these polymeric materials, are spongy polymers showing high macroporosity. In addition to their attractive usage as affinity support materials and scaffolds, they also appear as drug carrier materials in recent years. Molecular imprinting method is a recognition technique prepared by forming a polymeric network around the template. Although this method has been used in purification and separation processes for more than thirty years, it has gained great interest as a new approach that provides an advantage in drug release studies in terms of high drug loading capacity and long-term release.
 In this study, ciprofloxacin (CIP) imprinted 2-Hydroxyethyl methacrylate (HEMA) based N-methacryloyl-(L)-histidine methyl ester (MAH) containing [CIP-p(HEMAH)] cryogels was prepared and characterized. CIP releasing experiments were performed, and then, antimicrobial activities of CIP p(HEMAH) cryogels were examined against S. aureus, E. faecalis and E. coli. It can be concluded that CIP-p(HEMAH) cryogels could be proposed as promising polymeric materials for wound healing applications.

Bovine serum albumin detection by using molecularly imprinted surface plasmon resonance sensors

Molecular imprinted polymers (MIP) have key-lock pattern binding properties specific to the size and shape of target molecules. In this study, we have prepared detection platforms based on a molecularly imprinted surface plasmon resonance (SPR) sensor that can detect bovine serum albumin (BSA) sensitively, selectively, quickly, and in real time. The polymeric film prepared on the SPR sensor surface by molecular imprinting method was obtained by selecting the N-methacryloyl-(L)-glutamic acid molecule as a suitable functional monomer using ultraviolet polymerization. Three different imprinting methods, such as epitope, bulk, and surface imprinting methods, were used to examine the imprinting efficiency. Real-time measurements were performed with BSA imprinted SPR sensor provide linearity in the concentration range from 0.10 to 7.50 nM and indicate a detection limit value of 0.015 nM. Furthermore, we performed the selectivity experiments, where transferrin and hemoglobin were chosen as competitor agents. Overall, the SPR sensor prepared by the epitope imprinting approach has been found to be highly selective and sensitive for bovine serum albumin. To statistically assess the reusability of the sensor, intraday experiments were tested three times with five replicates. The RSD% value less than

Nanoscale SPR sensor for the ultrasensitive detection of the ovarian cancer marker carbohydrate antigen 125

In this study, a nanoscale surface plasmon resonance (SPR) sensor was developed to determine the ovarian cancer marker carbohydrate antigen (CA) 125 level in serum utilizing the molecular imprinting method.

Analysis of heterocyclic aromatic amines using selective extraction by magnetic molecularly imprinted polymers coupled with liquid chromatography - Mass spectrometry.

Heterocyclic aromatic amines (HCAs) are highly carcinogenic and mutagenic chemicals. This study reports on the development of magnetic molecularly imprinted polymers (MMIPs) for the purification and quantification of HCAs. A novel magnetic molecularly imprinted polymer was successfully prepared using a surface molecular imprinting method using functionalized Fe particles as the magnetic cores. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) was used as a molecular template; methacrylic acid (MAA), ethylene glycol dimethyl acrylate (EGDMA), 2, 2'-Azobis (2-methylpropionitrile) were used as the functional monomer, crosslinker, and initiator, respectively. The use of the template/functional monomer/crosslinking agent at a ratio of 1:4:20 resulted in a product with better adsorption properties (3.24 mg/g). The HCAs were successfully detected and quantified in processed meat samples by MISPE and LC-MS/MS. Under the final optimized detection conditions, the proposed method offered good linearity (R > 0.995) for the five HCAs with an acceptable level of precision, and an LOQ of 0.05 ng/g was successfully achieved.

Investigation of polyacrylamide hydrogel-based molecularly imprinted polymers using protein gel electrophoresis.

In conjunction with polyacrylamide gel electrophoresis (PAGE), molecular imprinting methods have been applied to produce a multilayer mini-slab in order to evaluate how selectively and specifically a hydrogel-based molecularly imprinted polymer (MIP) binds bovine haemoglobin (BHb, ~64.5 kDa). A three-layer mini-slab comprising an upper and lower layer and a MIP, or a non-imprinted control polymer dispersion middle layer has been investigated. The discriminating MIP layer, also based on polyacrylamide, was able to specifically bind BHb molecules in preference to a protein similar in molecular weight such as bovine serum albumin (BSA, ~66 kDa). Protein staining allowed us to visualise the protein retention strength of the MIP layer under the influence of an electric field. This method could be applied to other proteins with implications in effective protein capture, disease diagnostics, and protein analysis.

Preparation of molecularly imprinted Ag-TiO2 for photocatalytic removal of ethyl paraben.

Herein, MI-Ag-TiO2 was prepared by one-step sol-gel method, and its photocatalytic and characterization performance were fully analyzed. Within 120 min, the photocatalytic degradation rate of MI-Ag-TiO2 to ethyl paraben was 93.4%, which was 1.48 times that of naked TiO2. Compared with Ag-TiO2, MI-TiO2, and TiO2, the photocatalytic selectivity of MI-Ag-TiO2 to target pollutants increased by 24.5%, 31.5%, and 100%, respectively. Hence, the one-step molecular imprinting method can simply and quickly improve the photocatalytic performance of TiO2. This research may help to further promote the practical application of molecularly imprinted photocatalysts in the future.

S‐citalopram imprinted monolithic columns for capillary electrochromatography enantioseparations

In this study, the molecular imprinting method was used to separate enantiomeric forms of chiral antidepressant drug, R,S-citalopram (R,S-CIT) in aqueous solution by CEC system combining the advantages of capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC). For that, an amino acid-based molecularly imprinted monolithic capillary column was designed and used as a stationary phase for selective separation of S-citalopram (S-CIT) for the first time. S-CIT was selectively separated from the aqueous solution containing the other enantiomeric form of R-CIT, which is the same in size and shape as the template molecule. Morphology of the molecularly imprinted (MIP S-CIT) and non-imprinted (NIP S-CIT) monolithic capillary columns was observed by scanning electron microscopy. Imprinting efficiency of MIP S-CIT monolithic capillary column used for selective S-CIT separation was verified by comparing with NIP S-CIT and calculated imprinting factor (I.F:1.81) proved the high selectivity of the MIP S-CIT for S-CIT. Cavities formed for S-CIT form enabled selective (α = 2.08) separation of the target molecule from the other enantiomeric R-CIT form. Separation was achieved in a short period of 10 min, with the electrophoretic mobility of 7.68 × 10-6 m2 /Vs for R,S-CIT at pH 7.0 10mM PB and 50% ACN ratio. The performance of both MIP S-CIT and NIP S-CIT columns was estimated by repeating the R,S-CIT separations with intra-batch and inter-batch studies for reproducibility of retention times of R,S-CITs. Estimated RSD values that are lower than 2% suggest that the monolithic columns separate R,S-CIT enantiomers without losing separation efficiency.