Non-imprinted Polymer Research Articles

Enzyme Activity Inhibition of α-Amylase Using Molecularly Imprinted Polymer (MIP) Hydrogel Microparticles.

Molecularly imprinted polymers (MIPs) are a class of synthetic recognition materials that offer a cost-effective and robust alternative to antibodies. While MIPs have found predominant use in biosensing and diagnostic applications, their potential for alternative uses, such as enzyme inhibition, remains unexplored. In this work, we synthesized a range of acrylamide-based hydrogel MIP microparticles (35 μm) specific for the recognition of α-amylase. These MIPs also showed good selectivity toward the target protein with over 96% binding of the target protein, compared with the control nonimprinted polymer (NIP) counterparts. Specificity of the MIPs was determined with the binding of nontarget proteins, trypsin, human serum albumin (HSA), and bovine serum albumin (BSA). The MIPs were further evaluated for their ability to inhibit α-amylase enzymatic activity, showing a significant decrease in activity. These findings highlight the potential of MIPs as enzyme inhibitors, suggesting an innovative application beyond their conventional use.

Synthesis and characterization of core–shell magnetic molecularly imprinted polymer nanocomposites for the detection of interleukin-6

Interleukin-6 (IL-6) belongs to the cytokine family and plays a vital role in regulating immune response, bone maintenance, body temperature adjustment, and cell growth. The overexpression of IL-6 can indicate various health complications, such as anastomotic leakage, cancer, and chronic diseases. Therefore, the availability of highly sensitive and specific biosensing platforms for IL-6 detection is critical. In this study, for the first time, epitope-mediated IL-6-specific magnetic molecularly imprinted core–shell structures with fluorescent properties were synthesized using a three-step protocol, namely, magnetic nanoparticle functionalization, polymerization, and template removal following thorough optimization studies. The magnetic molecularly imprinted polymers (MMIPs) were characterized using dynamic and electrophoretic light scattering (DLS and ELS), revealing a hydrodynamic size of 169.9 nm and zeta potential of +17.1 mV, while Fourier transform infrared (FTIR) spectroscopy and fluorescence spectroscopy techniques showed characteristic peaks of the polymer and fluorescent tag, respectively. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) investigations confirmed the successful encapsulation of the magnetic core within the ca. 5-nm-thick polymeric shell. The MMIP-based electrochemical sensing platform achieved a limit of detection of 0.38 pM within a linear detection range of 0.38–380 pM, indicating high affinity (dissociation constant KD = 1.6 pM) for IL-6 protein in 50% diluted serum samples. Moreover, comparative investigations with the non-imprinted control polymer demonstrated an imprinting factor of 4, confirming high selectivity. With multifunctional features, including fluorescence, magnetic properties, and target responsiveness, the synthesized MMIPs hold significant potential for application in various sensor techniques as well as imaging.

Molecularly imprinted polymer for the selective removal of direct violet 51 from wastewater: synthesis, characterization, and environmental applications

Abstract Molecularly imprinted polymers (MIPs) are a diverse class of materials designed for selective molecular recognition. These polymers are synthesized with particular binding sites that are suited to a target molecule or a collection of structurally similar molecules through the use of a process called molecular imprinting. MIPs were synthesized in this work to specifically remove direct violet 51 from occupational leachates and aqueous solutions. Methacrylic acid functioned as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, 2,2-azobisisobutyronitrile (AIBN) as the initiator, and alcohol as a porogenic solvent. To improve the dye removal effectiveness, a number of factors were optimized, including time, pH, analyte concentrations, and MIP/NIP dosages. The findings showed that MIPs had a much greater capacity for direct violet 51 adsorption than nonimprinted polymers (NIPs), with MIP adsorption capacity reaching 42.553 mg g−1 and NIP adsorption capacity reaching 7 mg g−1. The pseudo 2nd-order model described the adsorption kinetics, and the rate constant (K 2) for MIPs was found to be 0.00251 mg g−1 min. Furthermore, a high rebinding efficiency of 94 % was observed when the selectivity of MIPs for direct violet 51 was assessed against structurally similar templates.

Synthesis and characterization of molecularly imprinted polymer nanoparticles against porcine circovirus type 2 viral-like particles.

PCV2 is a significant epidemic agricultural pathogen that causes a variety of swine diseases. PCV2 infections have significant economic impact on the swine industry, making effective strategies for rapid detection of PCV2 in pigs essential. Herein, we report on the synthesis of the so-called nano-MIPs which can be utilized for molecular recognition of PCV2. The morphology and structure of nano-MIPs were characterized using scanning electron microscopy (SEM). Nano-MIPs are spherical with sizes around 120-150nm. Binding experiments demonstrate that the fluorescence intensity of PCV2 samples decreases proportionally to increasing the concentration of nano-MIPs due to quenching, while non-imprinted polymer nanoparticles (nano-NIPs) do not affect the signal. The Stern-Volmer constant of nano-MIPs binding to PCV2 was 1.3 × 10-3mL/µg, whereas nano-NIPs led to 7 × 10-5mL/µg, i.e., 1.8 orders of magnitude lower. The detection limit for binding MIP particles to PCV2 by fluorescence measurements is 47µg/mL. This affinity test allows for designing both direct and competitive quartz crystal microbalance (QCM) assays for PCV2 leading to QCM measurements. The QCM results show nano-MIPs binding to PCV2 immobilized on the sensor surface with appreciable reproducibility. QCM sensor characteristics reveal signal saturation above around 200µg/mL at a response of - 354Hz and an LOD of approximately 35µg/mL. Nano-MIPs also show selectivity factors of 2-5 for CSFV and PRRSV probably because the three viruses have similar diameters around 50nm.

Preparation of novel semi-covalent molecularly imprinted polymer for highly improved adsorption performance of tetracycline in aqueous medium

In the present study, a novel tetracycline-imprinted polymer for tetracycline (TC) adsorption in an aqueous medium was synthesized using a semi-covalent imprinting method for the first time. In this approach, the template-monomer complex was synthesized by the reaction of 3-isopropenyl-α,α-dimethylbenzyl isocyanate (IPDMBI) as the functional monomer and TC as a template, forming a thermally reversible urethane bond (covalent bond). The polymer was characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), nitrogen adsorption/desorption measurements, and determination of point zero charge (PCZ). The equilibrium time of TC onto MIP was reached in 15 min, which was described by the non-linear pseud second-order kinetic model. Adsorption isotherm was described as a dual-site Langmuir-Freundlich model and the maximum adsorption capacity, determined at pH 5.0, was found to be 76.74 mg g−1 for MIP, exhibiting higher adsorption capacity when compared with other adsorbent materials previously reported in the literature for TC. Based on the increment relative selectivity coefficient the MIP showed higher selectivity towards TC and some structurally similar compounds belonging to the tetracyclines family (oxytetracycline and chlorotetracycline), when compared with NIP (non-imprinted polymer). The obtained outcomes in terms of selectivity, maximum adsorption capacity, and fast kinetic make this imprinted polymer an outstanding material for future application in molecularly imprinted solid phase extraction for analytical purposes.

Photopolymerization of Imprinted Polymer with Dummy Template for the Recognition of Hydroquinone in Aqueous Medium

This study' purposes are to synthesize molecularly imprinted polymer (MIP) with hydroxyethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) using p-xylene under ultraviolet curing at 405 nm for the recognition of hydroquinone (HQ) in aqueous medium. The template was extracted from the polymer with a mixture of methanol and acetic acid (9:1) by volume (v/v). The Fourier transform infrared (FTIR) spectrum of MIP (after wash) showed the absence of peak at the range of 840–860 cm−1, which represented the stretching outside the aromatic plane C–H at the para position (p-xylene). Field emission scanning electron microscope (FESEM) micrograph showed that the MIP had cavities compared to non-imprinted polymer (NIP). The MIP (MIP-Pxy) with ratio (monomer:crosslinker) 0.25 and 1.00% template gave the highest uptake of hydroquinone (HQ) in aqueous solution, which implied more specific recognition (highest KD value). The rebinding of HQ onto MIP-Pxy was best described by both isotherm (Langmuir and Freundlich) and kinetic model (pseudo-first and -second). The MIP was successfully synthesized using p-xylene, able to recognize HQ and was very selective to p-CP. Implication of the study, the synthesized MIP can be used for recognition and sensing materials for HQ and any similar molecules.

Adsorption and detection of praseodymium ion by ion-imprinted polymer with ultra-low sensitivity.

A novel kind of carbon dot (CD) was prepared by one-step hydrothermal microwave assisted method using L-tryptophan and L-tartaric acid as raw materials. Monodisperse poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres were utilized as the matrix, with praseodymium (Pr) ion (Pr3+) as the template, methacrylic acid as the functional monomer, and 5-amino-8-hydroxyquinoline (5-AHQ) acts as the ligand. A composite microsphere of ion-imprinted polymer (IIP) and CD (noted CD@IIP) was prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). For comparison, IIP without CD (Pr-IIP) and non-imprinted polymer (NIP) were also prepared. Through static adsorption experiments, it was determined that the saturated adsorption amount of CD@IIP is 47.19mgg-1, that of Pr-IIP is 54.49mgg-1, while that of NIP is only 24.32mgg-1. Dynamic adsorption experiments showed that the equilibrium of three kinds of materials wasreached within 30min. Particularly, CD@IIP could emit two fluorescence peaks at 325nm and 421nm under ultraviolet irradiation, and exhibited excellent selectivity and fluorescence quenching effect on Pr3+. The fluorescence response of Pr3+ in the range 0-400μmol L-1 was determined by ratiometric fluorescence method, offering a two-stage model and robust linear regression coefficient. These results demonstrated that CD@IIP exhibited selective adsorption ability for Pr3+, and a sensitive, rapid and simple method for detection of Pr3+ was successfully developed.

Electrochemical Impedance Spectroscopy-Based Microfluidic Biosensor Using Cell-Imprinted Polymers for Bacteria Detection.

The rapid and sensitive detection of bacterial contaminants using low-cost and portable point-of-need (PoN) biosensors has gained significant interest in water quality monitoring. Cell-imprinted polymers (CIPs) are emerging as effective and inexpensive materials for bacterial detection as they provide specific binding sites designed to capture whole bacterial cells, especially when integrated into PoN microfluidic devices. However, improving the sensitivity and detection limits of these sensors remains challenging. In this study, we integrated CIP-functionalized stainless steel microwires (CIP-MWs) into a microfluidic device for the impedimetric detection of E. coli bacteria. The sensor featured two parallel microchannels with three-electrode configurations that allowed simultaneous control and electrochemical impedance spectroscopy (EIS) measurements. A CIP-MW and a non-imprinted polymer (NIP)-MW suspended perpendicular to the microchannels served as the working electrodes in the test and control channels, respectively. Electrochemical spectra were fitted with equivalent electrical circuits, and the charge transfer resistances of both cells were measured before and after incubation with target bacteria. The charge transfer resistance of the CIP-MWs after 30 min of incubation with bacteria was increased. By normalizing the change in charge transfer resistance and analyzing the dose-response curve for bacterial concentrations ranging from 0 to 107 CFU/mL, we determined the limits of detection and quantification as 2 × 102 CFU/mL and 1.4 × 104 CFU/mL, respectively. The sensor demonstrated a dynamic range of 102 to 107 CFU/mL, where bacterial counts were statistically distinguishable. The proposed sensor offers a sensitive, cost-effective, durable, and rapid solution for on-site identification of waterborne pathogens.

Molecular imprinting based sensor system developed using polymeric nanoparticles for detecting 17β‐estradiol in agricultural wastewater

AbstractMicro pollutants pose a significant issue in water ecosystems. Particularly high concentrations of 17β‐estradiol (E2) have been identified in agricultural wastewater, which poses harmful effects on aquatic organisms and disrupts ecosystem balance. Therefore, effective determination of E2 from water sources is crucial. This study developed a biosensor capable of detecting E2 in wastewater using specific polymer nanoparticle synthesis through molecular imprinting. Est‐imp‐poly(multi‐walled carbon nanotubes‐glycidyl methacrylate [MWCNT‐GMA]) polymer nanoparticles were synthesized using a surfactant‐free emulsion polymerization method, and their characterization was conducted using FTIR and scanning electron microscopy (SEM) technologies. The Qmax value for Est‐imp‐poly(MWCNT‐GMA) nanoparticles in a 1 mg/mL E2 solution was determined to be 140 ppm. Comparing adsorption capacities, the molecularly imprinted nanoparticles (MIP) showed nearly five times higher E2 adsorption compared to non‐imprinted polymers (NIP). The Est‐imp‐poly(MWCNT‐GMA)‐Nafion/screen‐printed electrode (SPE) system was employed for analyzing wastewater samples. The current measurements taken at various concentrations in the wastewater consistently matched the E2 concentration calibration curve. The limit of detection (LoD) and limit of quantification (LoQ) were determined to be 0.042 and 0.12 μM, respectively. The biosensor demonstrated a linear working range from 0.12 to 50 μM, with a high correlation coefficient (R2 = 0.9927). These results highlight the potential of the developed biosensor for detecting E2 in real samples.

Preparation of a surface molecularly imprinted thermo-sensitive polymer for selective trypsin capture

Molecularly imprinted polymers (MIPs) are innovative porous materials created through polymerization templating methods for highly selective, sensitive detection and separation of the desired chemical species, known as template molecules. Surface imprinting over nano-sized substrates with special functional groups is an effective approach for improving the mass transfer and rebinding capacity. In this study, we successfully performed surface imprinting using methacrylic acid (MAA) and thermoresponsive N-isopropyl acrylamide (NIPAm) as functional monomers on acrylic-functionalized silica nanoparticles and served as a Trypsin artificial receptor. The resulting Trypsin imprinted polymer exhibited a binding capacity of 1022.44 mg/g, surpassing the non-imprinted polymer’s capacity of 292.41 mg/g within 45 min. Moreover, the imprinting factor, the main influence factor in MIP performance, was 3.5, demonstrating the significant selectivity of the polymeric products. In addition, due to the temperature sensitivity of NIPAm the template removing process was simply done by changing pore size. The silica nanoparticles and the synthesized MIP particles had diameters of approximately 95 nm and 105 nm, respectively, with the polymer layer thickness being around 5 nm. The MIP adsorption model followed the Freundlich isotherm and pseudo-second-order kinetics resulting in efficiencies of 93.0 % and 95.4 %, respectively. The developed Trypsin imprinted polymer was reusable for four consecutive uses,demonstrating both resilience and selectivity towards Trypsin.

Selective and sensitive detection of dimethyl phthalate in water using ferromagnetic nanomaterial-based molecularly imprinted polymers and SERS

To overcome the complicated pretreatment, low selectivity and low sensitivity detection associated with the detection of dimethyl phthalate (DMP), this study synthesized ferromagnetic nanomaterials that coupled with surface enhanced Raman scattering (SERS) and molecular imprinting polymers (MIPs). The pretreatment process can be simplified by ferromagnetic nanomaterials, then Fe3O4@SiO2@Ag@MIPs selectively adsorbing DMP can be achieved, and SERS can be applied for DMP detection with high sensitivity. As a control, the non-imprinted polymers (NIPs) Fe3O4@SiO2@Ag@NIPs were synthesized. Adsorption experiments results showed that the saturation adsorption amounts of Fe3O4@SiO2@Ag@MIPs is 36.74 mg/g with 40 mg/L DMP and Fe3O4@SiO2@Ag@NIPs is 17.45 mg/g. For DMP, Fe3O4@SiO2@Ag@MIPs have a greater affinity. In addition, after seven adsorption-desorption cycles the Fe3O4@SiO2@Ag@MIPs are reusable with approximately a 9.8 % loss in adsorption capacity. With an 8.7 × 10−9 M detection limit, DMP detection was performed by SERS, which revealed that the Raman intensities of the associated characteristic peak were linearly proportional to the DMP concentrations. As a result, the recovery rate of the testing artificial water varied from 87.9 % to 117 %. These outcomes show that the suggested technique for finding DMP in actual water samples is practical.

Targeted microorganism detection with molecularly imprinted polymer biosensors

In this article, a molecularly imprinted polymer (MIP)-based electrochemical biosensor was developed for the detection of Enterococcus faecium, demonstrating exceptional selectivity and sensitivity in real urine samples. Our approach involved fabricating electrodes coated with bacteria-imprinted polypyrrole through electropolymerization. The surface characteristics of the molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) coated electrodes were thoroughly characterized using cyclic voltammetry and electrochemical impedance spectroscopy. Remarkably, the MIP-coated electrodes exhibited superior conductivity, highlighting their efficacy in capturing Enterococcus faecium. By subjecting the MIP-based biosensor to Enterococcus faecium incubation, we successfully monitored impedance changes, enabling the detection of minute quantities of the bacteria with a limit of detection of 9 CFU/mL. The technology could successfully distinguish Enterococcus faecium from Enterococcus faecalis, a related bacteria species within the same genus, marking a significant advancement in clinical differentiation. Additionally, the biosensor selectively captured Enterococcus faecium and discriminated it from other common bacteria, including Proteus mirabilis, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. This research underscores the utility of MIP-based electrochemical biosensors for the rapid and selective detection of Enterococcus faecium in clinical settings, with implications for targeted antibiotic therapy and infection control.

Electrochemical Detection of Pseudomonas aeruginosa Quorum Sensing Molecule (S)-N-Butyryl Homoserine Lactone Using Molecularly Imprinted Polymers.

Pseudomonas aeruginosa is a multidrug-resistant Gram-negative bacterium that poses a significant threat to public health, necessitating rapid and on-site detection methods for rapid recognition. The goal of the project is therefore to indirectly detect the presence of P. aeruginosa in environmental water samples targeting one of its quorum-sensing molecules, namely, (S)-N-butyryl homoserine lactone (BHL). To this aim, molecularly imprinted polymers (MIPs) were synthesized via bulk free-radical polymerization using BHL as a template molecule. The obtained MIP particles were immobilized onto screen-printed electrodes (MIP-SPEs), and the BHL rebinding was analyzed via electrochemical impedance spectroscopy (EIS). To study the specificity of the synthesized MIPs, isotherm curves were built after on-point rebinding analysis performed via LC-MS measurements for both MIPs and NIPs (nonimprinted polymers, used as a negative control), obtaining an imprinting factor (IF) of 2.8 (at C f = 0.4 mM). The MIP-SPEs were integrated into an electrochemical biosensor with a linear range of 1 × 101-1 × 103 nM and a limit of detection (LoD) of 31.78 ± 4.08 nM. Selectivity measurements were also performed after choosing specific interferent molecules, such as structural analogs and potential interferents, followed by on-point analysis performed in spiked tap water to prove the sensor's potential to detect the presence of the quorum-sensing molecule in environmentally related real-life samples.

Molecularly imprinted Ag2S quantum dots with high photocatalytic activity for dye removal: Experimental and DFT insights

Molecular imprinted polymers (MIPs) were developed by carrying out the cocktail solution of Template ((Salata, 2004)-Gingerol), monomer, crosslinker, and Ag2S Quantum Dots (QDs) by ex-situ dissolved in an appropriate solvent, resulting in an efficient crosslinked polymer composite. Degradation of Alizarin red S (ARS) dye and yellowish sunset (SY) azo dye under visible light irradiation was reported first time by the introduction of prepared MIPs composite. In this research, the result shows efficient photocatalyt activity of Ag2S-MIPs composite for the degradation of AR and SY dye with degradation% (80%) and (84%) in the aqueous wastewater. The degradation efficiency of the Ag2S-MIPs composite and the Ag2S QD associated with non-imprinted polymers (NIPs) (i.e.Ag2S-NIPs composite) were calculated by using different parameters such as catalyst dose, pH value, optimum time and concentration variation and the observations are evocative. Moreover, the density functional theory (DFT) approach was also used to analyze the structural, stability/energetics, and electronic features of the organic-inorganic hybrid composites of the Ag2S QD with the MIPs based on (Salata, 2004)-gingerol extract. The proposed QD and MIPs (EGDMA and (Salata, 2004)-Gingerol) composite model has been detected to be the most stable because it shows the largest binding energy (BE) among the three chosen composite models. It was found out that imprinted polymers were superior in enhancing the degradation of dyes when compared to non imprinted polymers. Introducing MIPs into the valence band accelerates the catalysis properties to stabilize newly fashioned excitons that are basically generated as a result of light excitation in presence of Ag2S Quantum Dots (QDs) and molecular imprinted polymer (MIPs). Motivation behind this work is to address the challenges related to environmental pollution causing by organic dyes. These toxins are known to cause diverse symptoms (e.g., skin irritation, eye infection, respiratory disorders, and even cancer) once exposed through ingestion and inhalation. Through incorporation of Ag2S QD into MIP,the purpose of this research is to enhance the selectivity, specificity and photocatalytic activity for dyes and that work holds a potential towards environmental remediation by developing a cost effective and sustainable method for controlling pollution in water.

Detection and adsorption of florfenicol in milk using bifunctional carbon dot-doped molecularly imprinted polymers.

Detection of florfenicol (FF) residues in animal-derived foods, as one of the most widely used antibiotics, is critically important to food safety. The fluorescent molecularly imprinted polymer (MIP) was synthesized by surface-initiated atom transfer radical polymerization technique with poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres, 4-vinylpyridine, ethylene glycol dimethacrylate, and FF as the matrix, functional monomer, crosslinker, and template molecule, respectively. Meanwhile, N-S co-doped carbon dot (CD) was synthesized with triammonium citrate and thiourea as precursors under microwave irradiation at 400W for 2.5min and then integrated into FF-MIP to obtain CD@FF-MIP. For comparison, non-imprinted polymer (NIP) without FF was also prepared. The adsorption capacity of CD@FF-MIP to FF reached 53.1mgg-1, which was higher than that of FF-MIP (34.7mgg-1), whereas the adsorption capacity of NIP was only 17.3mgg-1. The adsorption equilibrium of three materials was reached within 50min. Particularly, CD@FF-MIP exhibited an excellent fluorescence quenching response to FF in the concentration range of 3-50 µmolL-1. As a result, CD@FF-MIP was successfully utilized to extract FF in milk samples, which were analyzed by high-performance liquid chromatography. The standard recoveries were 95.8%-98.2%, and the relative standard deviation was 1.6%-4.2%. The method showed the advantages of simple operation, high sensitivity, excellent selectivity, and low cost, and also demonstrated a great application prospect in food detection.

Magnetic multi-template molecularly imprinted polymers for selective simultaneous extraction of chlorophenols followed by determination using HPLC

Magnetic multi-template molecularly imprinted polymers (M-mt-MIPs) were successfully synthesized by surface imprinting and multi-template imprinting strategy, using polydopamine coated magnetic multi-walled carbon nanotubes as supporting materials, five typical chlorophenols (CPs) as templates, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker. Compared to non-imprinted polymers (NIPs), the as-prepared M-mt-MIPs showed high adsorption capacity (32.58‒80.63 mg g−1), rapid mass transfer and specific selectivity for the five targeted CPs, which were applied as magnetic solid-phase extraction (MSPE) adsorbents. Parameters affecting MSPE efficiency were detailed investigated, such as adsorbents dosage, sample pH, extraction time, type and volume of desorption solvent and salt effect. Combined with HPLC-DAD, a simple, rapid and sensitive method was established, showing good linearity (2‒200 μg L−1), low limits of detection (0.32‒0.49 μg L−1), and high enrichment factors (35.2‒108). The developed M-mt-MIPs-MSPE-HPLC method was applied to enrich and determine CPs in tannery wastewater, wet-blue and crust leather, and satisfactory spiking recoveries were attained in the range of 73.95‒109.7% with relative standard deviations (RSDs) of 2.13–8.48%. This study provided a new alternative material and method to rapid simultaneously extract and analyze low concentration of typical CPs in complicated matrices.

Microwave-assisted synthesis of molecularly imprinted polymers for smartphone-based luminescent hemoglobin one-pot detection

This work introduces a novel strategy to selectively and sensitively determine Hemoglobin (Hb) using a microwave-synthesized molecularly imprinted polymer (MIP) and chemiluminescence (CL) as the detection method. Studies conducted on both MIP and non-imprinted polymer (NIP) evidenced that the MIP material exhibits a high adsorption capacity (48 µg/mg) and an imprinted factor of about 3, in addition to a selective adsorption property towards Hb in the presence of other proteins, whose structures are very similar to that of Hb. The high selectivity and sensitivity of the proposed biosensor were also assured by the CL detection, whose mechanism is based on Hb's ability to enhance luminol oxidation in an alkaline medium in the presence of hydrogen peroxide, emitting a blue light whose intensity is related to the Hb concentration. The emitted light intensities from the CL reaction, directly proportional to Hb concentration, were captured and analyzed using a smartphone and RGB Color application, avoiding the use of sophisticated equipment and facilitating the measurement process. In order to streamline and speed up the detection process, all the experimental steps including Hb adsorption on MIPHb, supernatant removal, CL reaction, and smartphone readout occur in a single 8-well strip. Therefore, the proposed approach offers one-pot detection for the sensitive (LOD = 0.03 µg.mL−1, equivalent to 1.5 nmol.L−1) and selective determination of Hb in blood samples, for biomedical or forensic applications, through a rapid, low-cost, simple, and affordable approach.

Synthesis, Characterization and Application of New Polymers Imprinted with Zinc (II) Ions

In this work, molecularly imprinted polymers with zinc imprints and their comparison polymers without imprints were synthesized. A comparative characterization of the physical parameters of the synthesized zinc-imprinted (ZnIP) and non-imprinted (NIP) polymers was carried out using the methods of elemental analysis, conductometry, scanning electron microscopy, and IR-Fourier spectroscopy. The ability of the resulting polymers to molecularly recognize zinc was evaluated. Based on experimental data on static adsorption, the adsorption capacity of ZnIP and NIP was determined using an atomic emission spectrometer. It was found that ZnIP is characterized by better physical parameters and a higher ability for molecular recognition of zinc compared to NIP. ZnIP with zinc imprints were found to have better sorption capacity for zinc than their reference polymers. The sorption of zinc by molecular imprinted ZnIP is mainly due to the complex formation and pores of the initial carbon product. The synthesized ZnIP have increased porosity. The presence of pores with a diameter <50 nm in ZnIP is associated with voids formed after acid hydrolysis, which is clearly visible in images recorded by scanning electron microscopy. Thus, the possibility of using ZnIP as a selective sorbent has been established.

Molecularly imprinted polymer-based extended-gate field-effect transistor chemosensors for selective determination of antiepileptic drug.

Ultrathin molecularly imprinted polymer (MIP) films were deposited on the surfaces of ZnO nanorods (ZNRs) and nanosheets (ZNSs) by electropolymerization to afford extended-gate field-effect transistor sensors for detecting phenytoin (PHT) in plasma. Molecular imprinting efficiency was optimized by controlling the contents of functional monomers and the template in the precursor solution. PHT sensing was performed in plasma solutions with various concentrations by monitoring the drain current as a function of drain voltage under an applied gate voltage of 1.5V. The reliability and reproducibility of the fabricated sensors were evaluated through a solution treatment process for complete PHT removal and PHT adsorption-removal cycling, while selectivity was examined by analyzing responses to chemicals with structures analogous to that of PHT. Compared withthe ZNS/extracted-MIP sensor and sensors with non-imprinted polymer (NIP) films, the ZNR/extracted-MIP sensor showed superior responses to PHT-containing plasma due to selective PHT adsorption, achieving an imprinting factor of 4.23, detection limit of 12.9ng/mL, quantitation limit of 53.0ng/mL, and selectivity coefficients of 3-4 (against tramadol) and ~ 5 (against diphenhydramine). Therefore, we believe that the MIP-based ZNR sensing platform is promising for the practical detection of PHT and other drugs and evaluation of their proper dosages.

Template bacteria-free fabrication of surface imprinted polymer-based biosensor for E. coli detection using photolithographic mimics: Hacking bacterial adhesion

As one class of molecular imprinted polymers (MIPs), surface imprinted polymer (SIP)-based biosensors show great potential in direct whole-bacteria detection. Micro-contact imprinting, that involves stamping the template bacteria immobilized on a substrate into a pre-polymerized polymer matrix, is the most straightforward and prominent method to obtain SIP-based biosensors. However, the major drawbacks of the method arise from the requirement for fresh template bacteria and often non-reproducible bacteria distribution on the stamp substrate. Herein, we developed a positive master stamp containing photolithographic mimics of the template bacteria (E. coli) enabling reproducible fabrication of biomimetic SIP-based biosensors without the need for the “real” bacteria cells. By using atomic force and scanning electron microscopy imaging techniques, respectively, the E. coli-capturing ability of the SIP samples was tested, and compared with non-imprinted polymer (NIP)-based samples and control SIP samples, in which the cavity geometry does not match with E. coli cells. It was revealed that the presence of the biomimetic E. coli imprints with a specifically designed geometry increases the sensor E. coli-capturing ability by an “imprinting factor” of about 3. These findings show the importance of geometry-guided physical recognition in bacterial detection using SIP-based biosensors. In addition, this imprinting strategy was employed to interdigitated electrodes and QCM (quartz crystal microbalance) chips. E. coli detection performance of the sensors was demonstrated with electrochemical impedance spectroscopy (EIS) and QCM measurements with dissipation monitoring technique (QCM-D).