Specific Recognition Capability Research Articles

A highly sensitive and selective molecularly imprinted sensor for the determination of atorvastatin

In this study, we developed a highly sensitive carbon paste sensor that combines a molecularly imprinted polymer (MIP) with specific recognition capabilities to monitor atorvastatin (ATV). In the MIP synthesis, designed especially for ATV, ethylene glycol dimethacrylate (EGDMA) was utilized as a cross-linking monomer and methacrylic acid (MAA) as a functional monomer. This non-covalent method made use of polymerization by free radicals. After that, this MIP was added to a carbon paste electrode (CPE), which served as both a selective detection element and a preconcentration agent for ATV analysis. The improved CPE was characterized using scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). To investigate ATV, the anodic peak signal was assessed using square wave stripping voltammetry (SWSV).The calibration curve exhibited two linear regions encompassing dosages from 0.005 to 1 µM and 1 to 20 µM, with a 1.5 nM calculated detection limit. The designed MIP electrode was successfully utilized to assess ATV in tablet and human blood serum samples, demonstrating its usefulness in practical analysis.

Fluorescent probe based on GO/g-C3N4-PEG@Cu NPs/MIP for the detection of dopamine in banana.

Graphene oxide (GO) and copper nanoparticles (Cu NPs) were incorporated to modulate and enhance the fluorescence properties of pegylated graphite phase carbon nitride (g-C3N4-PEG). Combined with the specific recognition capability of a molecular imprinted polymer (MIP), a highly sensitive and selective fluorescent molecular imprinted probe for dopamine detection was developed. The fluorescent g-C3N4-PEG was synthesized from melamine and modified with GO and Cu NPs to obtain GO/g-C3N4-PEG@Cu NPs. Subsequently, MIP was prepared on the surface of GO/g-C3N4-PEG@Cu NPs using dopamine as the template molecule. Upon elution of the template molecule, a dopamine-specific GO/g-C3N4-PEG@Cu NPs/MIP fluorescence probe was obtained. The fluorescence intensity of the probe was quenched through the adsorption of different concentrations of dopamine by the MIP, thus establishing a novel method for the detection of dopamine. The linear range of dopamine detection was from 5 × 10-11 to 6 × 10-8mol L-1, with a detection limit of 2.32 × 10-11mol L-1. The sensor was utilised for the detection of dopamine in bananas, achieving a spiked recovery rate between 90.3% and 101.3%. These results demonstrate that the fluorescence molecular imprinted sensor developed in this study offers a highly sensitive approach for dopamine detection in bananas.

Construction of an Electrochemical Molecularly Imprinted Sensor Based on L-carnitine Doped Polypyrrole for Vibrio Parahaemolyticus Detection

This study addresses the pressing need for rapid detection of pathogenic microorganisms by designing and fabricating an L-carnitine-doped polypyrrole (L-CN/PPy) electrochemical molecularly imprinted sensor, with Vibrio parahaemolyticus as the model target. Employing L-carnitine as a dual-functional dopant and auxiliary recognition element in the electropolymerization process, the sensor not only enhances the conductive properties of polypyrrole but also significantly improves its specific recognition capability towards the target bacteria. The sensor preparation encompasses the electrochemical polymerization of L-CN/PPy composite material, immobilization and elution of template bacteria, followed by bacterial recognition and detection steps. Through systematic optimization of L-CN concentration, polymerization conditions, eluent composition, elution time, and operational parameters, the sensor's performance is maximized. Experimental results confirm the sensor's efficacy in rapidly completing template bacteria elution within just 30 minutes and achieving efficient recognition of Vibrio parahaemolyticus within 20 minutes, demonstrating high sensitivity and selectivity. Moreover, the straightforward and rapid construction method of the sensor introduces a novel technological strategy for practical microbial detection applications, highlighting extensive application prospects.

Simultaneous synthesis of carbon quantum dots and hydrothermal biochar from corn straw through hydrothermal treatment

In the realm of efficient agricultural production, the conversion of large volumes of agroforestry waste into sustainable, high-value materials is imperative to address pollution, curb carbon dioxide emissions, and alleviate the burden of costly waste disposal. This study endeavored to address these challenges by concurrently synthesizing carbon quantum dots fluorescent nanomaterials and hydrothermal biochar through hydrothermal carbonization (HTC), employing corn straw (CS) as the primary precursor material. The synthesized CS-based carbon quantum dots (CS-CDs) exhibited a typical graphite structure, with a uniform particle size distribution and a particle size average of 2.28 ± 0.5 nm. Notably, CS-CDs displayed excitation-dependent photoluminescence (PL) behavior, remarkable water solubility, high fluorescence stability, and specific recognition capabilities for Fe3+ detection. The detection range of CS-CDs for Fe3+ spanned from 50 to 2000 μM, with a limit of detection (LOD) of 5.32 μM. Meanwhile, during the HTC process, the solid fraction yielded hydrothermal biochar (HC) at a rate of 57.60 %. HC was enriched with essential elements and held promise as an organic carbon fertilizer or premium-quality fuel, thereby realizing the multifaceted utilization potential of CS resources. This study offers valuable insights and innovative strategies for the high-value and multifunctional utilization of agroforestry resources, contributing to the promotion of sustainable agricultural practices.

Convenient and highly efficient adsorption of diosmetin from lemon peel by magnetic surface molecularly imprinted polymers

As a typical bioflavonoid, diosmetin is desirable in the field of natural medicine, healthy food, and cosmetics by anti-cancer, antibacterial, antioxidant, estrogen-like and anti-inflammatory activities, and it comes from a wide range of sources in traditional Chinese medicine like spider fragrance, spearmint and chrysanthemum, as well as in Citrus fruit. However, traditional analytical methods such as silica gel column chromatography face multiple challenges in the selective extraction of diosmetin from biological materials and traditional Chinese medicinal materials. Therefore, it is urgent to develop a new type of absorbent with high efficiency, recyclability and good specificity to diosmetin. In this investigation, a magnetic surface molecularly imprinted polymer (labeled as Diosmetin/SMIPs) was synthesized employing magnetic nanoparticles as the carrier and 4-vinylpyridinyl (4-VP) as the functional monomer by surface imprinting technology. The functional monomer was screened by the binding energy (ΔE) between functional monomers and template molecules via computational simulation. The Diosmetin/SMIPs had a high level of specific recognition and adsorption capability towards diosmetin with a 20.25 mg g-1 adsorption capacity and an imprinting factor (IF) of 2.28. Additionally, it demonstrated excellent regeneration performance with 8 adsorption/desorption cycles. In addition, 91.20 %–94.16 % of spiked diosmetin was recovered from the lemon peel samples. The strategy of constructing Diosmetin/SMIPs based on computational simulation can effectively enhance the specific adsorption performance of diosmetin. Meanwhile, Diosmetin/SMIPs synthesized by imprinting polymerization showed excellent anti-interference and reusability, and realized efficient targeted extraction of diosmetin from lemon peel samples. The results of this investigation provide a promising adsorbent for selective enrichment of diosmetin from Citrus fruit and complicated materials.

Genetically programmable cell membrane-camouflaged nanoparticles for targeted combination therapy of colorectal cancer

Cell membrane-camouflaged nanoparticles possess inherent advantages derived from their membrane structure and surface antigens, including prolonged circulation in the bloodstream, specific cell recognition and targeting capabilities, and potential for immunotherapy. Herein, we introduce a cell membrane biomimetic nanodrug platform termed MPB-3BP@CM NPs. Comprising microporous Prussian blue nanoparticles (MPB NPs) serving as both a photothermal sensitizer and carrier for 3-bromopyruvate (3BP), these nanoparticles are cloaked in a genetically programmable cell membrane displaying variants of signal regulatory protein α (SIRPα) with enhanced affinity to CD47. As a result, MPB-3BP@CM NPs inherit the characteristics of the original cell membrane, exhibiting an extended circulation time in the bloodstream and effectively targeting CD47 on the cytomembrane of colorectal cancer (CRC) cells. Notably, blocking CD47 with MPB-3BP@CM NPs enhances the phagocytosis of CRC cells by macrophages. Additionally, 3BP, an inhibitor of hexokinase II (HK2), suppresses glycolysis, leading to a reduction in adenosine triphosphate (ATP) levels and lactate production. Besides, it promotes the polarization of tumor-associated macrophages (TAMs) towards an anti-tumor M1 phenotype. Furthermore, integration with MPB NPs-mediated photothermal therapy (PTT) enhances the therapeutic efficacy against tumors. These advantages make MPB-3BP@CM NPs an attractive platform for the future development of innovative therapeutic approaches for CRC. Concurrently, it introduces a universal approach for engineering disease-tailored cell membranes for tumor therapy.

Specific, sensitive, and reliable sensing of cancer cells based on quantum dot/hydrogel-coated double optical fiber ball

For clinical applications, a sensor of cancer cells should exhibit high sensitivity, have a small and robust sensing structure, and exhibit good anti-interference. This paper presents a novel biosensor for the recognition and concentration detection of biotin receptor (BR)-overexpressed cancer cells. This biosensor uses a hydrogel composed of biotin-quantum dots (BQDs) grafted onto oxidized sodium alginate with carboxymethyl chitosan (BQDs-g-OSA/CMCS) and a double optical fiber ball (DOFB) sensing structure. The developed BQDs-g-QSA/CMCS hydrogel exhibited specific recognition capabilities for cancer cells and an excellent fluorescence stability. Meanwhile, the proposed DOFB structure was small and presented a strong robustness and integrated fluorescence excitation and reception, which are favorable for in vivo sensing. In addition, in-depth study of the sensing performance of the sensor was conducted by utilizing streptavidin (SV) protein and BR-overexpressed cancer cells (leukemia cells, K562). The experimental results revealed a linear relationship between the photoluminescence intensity of the sensor and concentrations of SV and K562, with minimum detection concentrations of 1.62 nM and 1.0 × 103 cells/mL, respectively. In addition, the specificity of the sensor was confirmed through investigation of the its response to another BR-overexpressed cancer cell type (lung cancer cells, A549) and normal cells (human gastric mucosal epithelial, GES-1). The sensor exhibited similar responses to A549 as to K562 cells but not to GES-1 cells, which indicates its specificity toward cancer cells with BR overexpression. In summary, the proposed sensor offers important potential for applications in cancer diagnosis and treatment.

CsPbBr3 PQDs in EuAPO-5 zeolite: Highly stable fluorescent-traffic-light sensor for point-of-care response of tetracycline and temperature

Fluorescent point-of-care (POC) sensors with specific target recognition capability through signaling mechanisms have promising applications in areas such as environmental monitoring and food detection. Herein, a solvent-free method was developed to prepare a novel POC sensor based on dual-luminescent CsPbBr3@EuAPO-5 composite that enabled the multiple sensing of tetracycline (TC) and temperature in a unique fluorescent-traffic-light manner. Benefiting from the confinement effect of EuAPO-5 zeolite, the CsPbBr3 perovskite quantum dots (PQDs) exhibits extraordinary luminescent stability even soaking in water for 30 days. During TC detection, the effective absorbed energy transfer from TC to Eu3+ in EuAPO-5 zeolite through the antenna effect enhances the red emission of Eu3+, and meanwhile a internal filtering effect (IFE) between the TC molecule and CsPbBr3 PQDs results in the green emission quenching of CsPbBr3. Combining the colorimetric determination using a smartphone-based analysis application (APP), the CsPbBr3@EuAPO-5 can serve as a portable POC sensor for TC monitoring in aqueous solution with a low detection limit of 0.013 µM in a linear range of 0–140 µM. Besides, ratiometric temperature sensing behavior of CsPbBr3@EuAPO-5 for high temperature warning in a fluorescent-traffic-light manner was also achieved, boosting a high sensitivity of 27.63 % K-1 (at 383 K) and a temperature resolution greater than 0.0035 K in 293–383 K. This work provides a novel bifunctional CsPbBr3 PQDs based sensor for reliable and visual detection of TC concentration and temperature, laying the foundation for the development of high-quality POC sensors with exceptional sensitivity and practicality.

Research Progress on Molecularly Imprinted Materials for the Screening and Identification of Organic Pollutants

Organic pollutants, distinguished by their persistence and bioaccumulation in the environment, pose significant ecological and health threats that surpass those of traditional pollutants. Crucial to understanding their environmental behavior, health risks, and mitigation strategies, is the screening and identification of these pollutants. This process indispensably employs functional materials, among which molecularly imprinted polymers (MIPs) prove to be particularly advantageous because of their specific recognition capabilities and extensive application range. This review presents cutting-edge techniques and strategies for the fabrication of MIPs, including surface imprinting techniques and dummy molecular strategies. It encapsulates the last five years’ advancements in MIP research within the domains of sample pretreatment, as well as optical and electrochemical sensing analysis. The objective of this discourse is to potentially foster the evolution of MIP technology and establish the groundwork for its transition from lab-scale to commercial production.

Interplay of graphene-DNA interactions: Unveiling sensing potential of graphene materials.

Graphene-based materials and DNA probes/nanostructures have emerged as building blocks for constructing powerful biosensors. Graphene-based materials possess exceptional properties, including two-dimensional atomically flat basal planes for biomolecule binding. DNA probes serve as excellent selective probes, exhibiting specific recognition capabilities toward diverse target analytes. Meanwhile, DNA nanostructures function as placement scaffolds, enabling the precise organization of molecular species at nanoscale and the positioning of complex biomolecular assays. The interplay of DNA probes/nanostructures and graphene-based materials has fostered the creation of intricate hybrid materials with user-defined architectures. This advancement has resulted in significant progress in developing novel biosensors for detecting DNA, RNA, small molecules, and proteins, as well as for DNA sequencing. Consequently, a profound understanding of the interactions between DNA and graphene-based materials is key to developing these biological devices. In this review, we systematically discussed the current comprehension of the interaction between DNA probes and graphene-based materials, and elucidated the latest advancements in DNA probe-graphene-based biosensors. Additionally, we concisely summarized recent research endeavors involving the deposition of DNA nanostructures on graphene-based materials and explored imminent biosensing applications by seamlessly integrating DNA nanostructures with graphene-based materials. Finally, we delineated the primary challenges and provided prospective insights into this rapidly developing field. We envision that this review will aid researchers in understanding the interactions between DNA and graphene-based materials, gaining deeper insight into the biosensing mechanisms of DNA-graphene-based biosensors, and designing novel biosensors for desired applications.

A label-free ratiometric fluorescent aptasensor based on a peroxidase-mimetic multifunctional ZrFe-MOF for the determination of tetrodotoxin.

A Fe/Zr bimetal-organic framework (ZrFe-MOF) is utilized to establish a ratiometric fluorescent aptasensor for the determination of tetrodotoxin (TTX). The multifunctional ZrFe-MOF possesses inherent fluorescence at 445nm wavelength, peroxidase-mimetic activity, and specific recognition and adsorption capabilities for aptamers, owing to its organic ligand, and Fe and Zr nodes. The peroxidation of o-phenylenediamine (OPD) substrate generates fluorescent 2,3-diaminophenazine (OPDox) at 555nm wavelength, thus quenching the inherent fluorescence of ZrFe-MOF because of the fluorescence resonance energy transfer (FRET) effect. TTX aptamers, which are absorbed on the material surface without immobilization or fluorescent labeling, inhibit the peroxidase-mimetic activity of ZrFe-MOF. It causes the decreased OPDox fluorescence at 555nm wavelength and the inverse restoration of ZrFe-MOF fluorescence at 445nm wavelength. With TTX, the aptamers specifically bind to TTX, triggering rigid complex release from ZrFe-MOF surface and reactivating its peroxidase-mimetic activity. Consequently, the two fluorescence signals exhibit opposite changes. Employing this ratiometric strategy, the determination of TTX is achieved with a detection limit of 0.027ng/mL and a linear range of 0.05-500ng/mL. This aptasensor also successfully determines TTX concentrations in puffer fish and clam samples, demonstrating its promising application for monitoring trace TTX in food safety.

Preparation of an imprinted monolith for field simultaneously selective separation and enrichment of nitrophenols and lead (II) ion in water samples

Imprinted materials have gained significant attention due to its highly specific recognition performance. However, there is no study that using molecule and ion as mixed templates to prepare hybrid imprinted material for simultaneously selective separation and enrichment of molecules and ion. Here, a new strategy employing organic molecule and heavy metal ion as mixed templates to prepare imprinted material was proposed. 2,4-Dinitrophenol (2,4-DNP) and Pb2+ were selected as model templates to in-situ synthesize adsorbent based on imprinted monolith (AIM) in pipette tip. The obtained AIMs were used as the extraction medium of home-made multiple channels in-tip microextraction device (MCMD) for field simultaneously selective entrapment of nitrophenols (NPs) and Pb2+. The selection of functional monomers was well verified with Density function theory. Under the optimal fabrication conditions, the AIM displayed high specific recognition capability towards 2,4-DNP and Pb2+ with imprinted factors 7.31 and 5.20, respectively, and corresponding adsorption capacities were as high as 27.8 mg/g and 20.3 mg/g, respectively. The practicality of proposed AIM/MCMD was evaluated by simultaneously on-site selective capture of NPs and Pb2+ in various environmental waters prior to quantification with HPLC (for NPs) and atomic absorption spectrometry (for Pb2+). Results well evidence that the proposed strategy is feasible in the preparation of imprinted polymer for simultaneously specific extraction of molecules and metal ion, and the developed AIM/MCMD is a useful field sample preparation method for reliable quantification of NPs and Pb2+ in aqueous samples.

Molecularly imprinted polymers by reflux precipitation polymerization for selective solid-phase extraction of quinolone antibiotics from urine

Molecularly imprinted polymers (MIPs) possess high specific cavities towards the template molecules, thus solid-phase extraction (SPE) based on MIPs using the target as the template has been widely used for selective extraction. However, the performance of SPE depends strongly on the shape and the distribution of the MIP sorbents, and rapid synthesis of MIPs with uniform particles remains a challenge. Our previous studies have shown that reflux precipitation polymerization (RPP) was a simple and rapid method for the synthesis of uniform MIPs. However, synthesis of MIPs by RPP for a group of targets using only one of the targets as the template has rarely been reported. In this work, MIPs with specific recognition capability for a group of quinolone antibiotics were synthesized for the first time via RPP with only ofloxacin as the template. The synthesized MIPs displayed good adsorption performance and selectivity (IF > 3.5) towards five quinolones, and subsequently were used as SPE adsorbents. Based on this MIPs-SPE, after systematic optimization of the SPE operation parameters during loading, washing and elution, an efficient and sensitive enough SPE method for separation and enrichment of the five quinolones in urine was developed and evaluated in combination with LC-MS/MS. The results showed that MIPs-SPE-LC-MS/MS has a good correlation (R2 ≥ 0.9961) in the linear range of 1–500 μg L−1. The limit of detection (LOD) and limit of quantification (LOQ) for the five quinolones were 0.10–0.14 μg L−1 and 0.32–0.48 μg L−1, respectively. In addition, the proposed method demonstrated good reproducibility (≤ 13 %) and high accuracy (92 %–113 %). We are confident that this method holds significant promise for the analysis of quinolones within the contexts of forensic medicine, epidemiology, and environmental chemistry.

Hairpin/DNA Ring Ternary Complex Initiated Rolling Circle Amplification for an Elevated Accuracy and Its Application in Analyzing Let-7a.

Rolling circle amplification (RCA) is an attractive isothermal nucleic acid amplification approach and has been widely applied in constructing a variety of biosensors. However, the inevitable drawbacks of lacking enough selectivity greatly hindered further applications of RCA-based approaches. Here, we develop a novel RCA-based approach by integrating the specific target recognition capability of the hairpin/DNA ring ternary complex and multiple signal amplification and successfully applied it for let-7a detection. In this method, let-7a specifically unfolds the hairpin probe (Hp probe) in the ternary complex to induce target recycle and RCA- and DNAzyme-based signal generation. Based on this, the established approach exhibits a high selectivity to let-7a, and the response of the approach to one base pair mismatched sequences was 24.9%, indicating a significantly improved specificity. Meanwhile, the limit of detection is as low as 342 aM, which can meet the high requirement for a trace amount of miRNA detection. In all, we believe that the established approach can offer a new avenue for miRNA detection and post-tumor care.

A multifunctional Tb-MOF luminescent probe: Synthesis, characterization and mechanism exploration

A multifunctional lanthanide metal–organic framework: Tb(cpioa) was successfully obtained by a facile hydrothermal method. Based on the single-crystalline XRD, BET and FT-IR characterizations, it’s found that Tb(cpioa) has a porous 3D networks crystal structure. Luminescent characteristics and sensing properties of Tb(cpioa) were investigated in details. Tb(cpioa) has a specific and sensitive recognition capability of acetone, Fe3+ and Cr2O72- in water. Based on detailed characterizations and theoretical computations, the luminescence quenching mechanism is found complicated and composed of four quenching processes: the competition of UV–vis absorption, the weak interactions between ligand and analytes, and two dynamic transfer processes: the fluorescence resonance energy transfer (FRET) and the photo-induced electron transfer (PET).

Employment of the Phage Cocktail as a Species-Specific Recognition Agent for Wide-Spectrum Detection of Bacterial Strains.

Phages have already been employed to detect bacteria because of their specific recognition capability and strong infectious activity toward their host. However, the reported single-phage-based techniques are inevitably restricted by false negative results that arose from extremely high strain specificity of phages. In this study, a cocktail composed of three Klebsiella pneumoniae (K. pneumoniae) phages was prepared as a recognition agent to broaden the recognition spectrum for detecting this bacterial species. A total of 155 clinically isolated strains of K. pneumoniae collected from four hospitals were adopted to test its recognition spectrum. A superior recognition rate of 91.6% for the strains was achieved due to the complementarity of the recognition spectra of the three phages composed of the cocktail. However, the recognition rate is as low as 42.3-62.2% if a single phage is employed. Based on the wide-spectrum recognition capability of the phage cocktail, a fluorescence resonance energy transfer method was established for detecting K. pneumoniae strains by employing fluorescein isothiocyanate labeled to the phage cocktail and Au nanoparticles labeled to p-mercaptophenylboronic acid as energy donors and acceptors, respectively. The detection process can be completed within 35 min, with a wide dynamic range of 5.0 × 102-1.0 × 107 CFU/mL. The application potential was verified by applying it to quantitate K. pneumoniae in different sample matrixes. This pioneer work opens an avenue for achieving wide-spectrum detection of different strains belonging to the same bacterial species with the phage cocktail.

A point-of-care detection platform for Escherichia coli O157:H7 by integration of smartphone and the structural colour of photonic microsphere

A smartphone-based sensitive, rapid, label-free and high-throughput detection platform for Escherichia coli O157:H7 was established. The specific recognition capability of this platform was dependent of the aptamer modified on the silica photonic microsphere (SPM), whose structural colour was utilized for the quantification of the target bacterium. Gold nanoparticles and silver staining technique were employed to improve the sensitivity of the detection platform. Such smartphone-based detection platform gave a wide linear detection range of 102 ∼ 108 CFU/mL with a low limit of detection (LOD) of 68 CFU/mL and high specificity for Escherichia coli O157:H7. Moreover, the recovery rates of the detection method were measured in the range of 99 ∼ 108% in the milk, pork and purified water samples. Furthermore, the developed detection platform did not require complex sample pretreatment and could be easily manipulated, displaying great application potential in the fields of food safety, environmental monitoring and disease diagnosis.

Development of Levo-Lansoprazole Chiral Molecularly Imprinted Polymer Sensor Based on the Polylysine-Phenylalanine Complex Framework Conformational Separation.

The efficacies and toxicities of chiral drug enantiomers are often dissimilar, necessitating chiral recognition methods. Herein, a polylysine-phenylalanine complex framework was used to prepare molecularly imprinted polymers (MIPs) as sensors with enhanced specific recognition capabilities for levo-lansoprazole. The properties of the MIP sensor were investigated using Fourier-transform infrared spectroscopy and electrochemical methods. The optimal sensor performance was achieved by applying self-assembly times of 30.0 and 25.0 min for the complex framework and levo-lansoprazole, respectively, eight electropolymerization cycles with o-phenylenediamine as the functional monomer, an elution time of 5.0 min using an ethanol/acetic acid/H2O mixture (2/3/8, V/V/V) as the eluent, and a rebound time of 10.0 min. A linear relationship was observed between the sensor response intensity (ΔI) and logarithm of the levo-lansoprazole concentration (l-g C) in the range of 1.0 × 10-13-3.0 × 10-11 mol/L. Compared with a conventional MIP sensor, the proposed sensor showed more efficient enantiomeric recognition, with high selectivity and specificity for levo-lansoprazole. The sensor was successfully applied to levo-lansoprazole detection in enteric-coated lansoprazole tablets, thus demonstrating its suitability for practical applications.

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)%.

Step-Growth Glycopolymers with a Defined Tacticity for Selective Carbohydrate-Lectin Recognition.

Glycopolymers are potent candidates for biomedical applications by exploiting multivalent carbohydrate-lectin interactions. Owing to their specific recognition capabilities, glycosylated polymers can be utilized for targeted drug delivery to certain cell types bearing the corresponding lectin receptors. A fundamental challenge in glycopolymer research, however, is the specificity of recognition to receptors binding to the same sugar unit (e.g., mannose). Variation of polymer backbone chirality has emerged as an effective method to distinguish between lectins on a molecular level. Herein, we present a facile route toward producing glycopolymers with a defined tacticity based on a step-growth polymerization technique using click chemistry. A set of polymers have been fabricated and further functionalized with mannose moieties to enable lectin binding to receptors relevant to the immune system (mannose-binding lectin, dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin, and dendritic and thymic epithelial cell-205). Surface plasmon resonance spectrometry was employed to determine the kinetic parameters of the step-growth glycopolymers. The results highlight the importance of structural complexity in advancing glycopolymer synthesis, yet multivalency remains a main driving force in lectin recognition.