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Vanillic acid (4-hydroxy-3-methoxybenzoic acid) is a phenolic acid found in many plant extracts. It is used as aflavoring and scent agent and produces a pleasant, creamy odor. It is widely used in many applications for therapeuticpurposes to flavoring agent. Molecularly imprinted polymers of vanillic acid were synthesized by precipitationpolymerization with a noncovalent approach for the extraction from blood serum. Three different imprinted polymershave been synthesized with varying molar ratio of monomer. The synthesized polymer particles were characterizedusing Fourier-transform infrared spectroscopy and scanning electron microscopy. The extraction efficiency of highlyselected imprinted polymer of vanillic acid from spiked blood serum was about 80%.
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Objective: The molecularly imprinted osthole on surface-modified quartz sand was prepared and characterized by SEM and FT-IR. The adsorption properties of molecularly imprinted materials were investigated. Methods: The morphology of MIP was prepared using N-(β-aminoethyl)-γ-aminopropylmethylbimethoxy silane (KH-602) modified quartz sand as supporter, osthole as template, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker, axodiisobutyronitrile (AIBN) as initiator, and methanol as porogen, observed by SEM, and the chemical structure of MIP was characterized by FT-IR. Results: The dynamic adsorption experiment showed that the adsorption capacity of molecularly imprinted materials to osthole gradually reached saturation with the increase of time. The maximum adsorption capacity of molecularly imprinted materials for osthole was studied by static adsorption experiment. The selective adsorption experiment was adopted to study the binding properties and molecule recognition characters of molecularly imprinted materials for osthole. Conclusion: The experimental results showed that MIP had specific recognition selectivity, excellent binding affinity and elution property for ractopamine. The MIP on the adsorption ability of osthole was significantly better than xanthotoxin and imperatorin.
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Eighty percent of bacterial infections are related to the formation of bacterial biofilm. Compared with planktonic bacteria, bacterial biofilm is 10-1 000 times more resistant to antibiotics, which is the main cause of current bacterial drug resistance. A comprehensive understanding of the characteristics and resistance mechanisms of bacteria biofilm will help us treat the stubborn infections caused by the bacterial biofilm better and solve the problem of bacterial drug resistance. In this review, the composition and quorum sensing of bacterial biofilm, two major patterns of biofilm formation and drug resistance mechanisms were presented. Furthermore, representative compounds with anti-biofilm activity and compounds synergistic with antibiotics in anti-biofilm actions were introduced. Nano drug delivery strategies used for anti-biofilm in recent years as well as a novel drug delivery system-molecularly imprinted polymer was also introduced.
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OBJECTIVE:To synthesize 4-hydroxyphenylacetic acid(PHPAA)molecular imprinted polymers(MIPs),and to provide reference for separation and enrichment of PHPAA in urine of cancer patients. METHODS:With PHPAA as template molecule and azobisisobutyronitrile as evocating agent,MIPs was synthesized by precipitation polymerization using 4-vinyl pyridine(4-V),acrylamide(AM),1-vinyl imidazole(1-V)and o-diaminobenzene as functional monomers,ethylene glycol dimethacrylate(EGDMA)and trimethylolpropane trimethacrylate(TRIM)as crosslinking agent. Using scanning electron microscope,infrared spectrum,static adsorption test and molecular recognition performance test used adopted to characterize the structure and performance of MIPs. RESULTS:MIPs1(4-V,EGDMA)microspheres adhered seriously,and MIPs2(AM, EGDMA)microspheres are aggregated. MIPs3(1-V,TRIM),MIPs4(o-diaminobenzene,TRIM)microspheresare were dispersed and had good sphericity. Characteristic absorption peak of PHPAA was not found in infrared spectrum of MIPs. The adsorption capacity of each MIPs was higher than that of blank imprinted polymer without the template molecule,and increased as the increase of template molecular concentration. The adsorption capacity of MIPs3 was significantly higher than that of other MIPs,and its static distribution coefficient(0.14)of PHPAA was higher than that of other structural analogues [PHPA(0.06),TA(0.01)],selective separation factors of PHPAA to PHPA,PHPAA to TA were 2.3,11.5,respectively. CONCLUSIONS:MIPs synthesized with 1-V as functional monomer and TRIM as crosslinking agent has the ability of specific adsorption and selective recognition. It can used as solid phase extractant to separate and enrich low content of PHPAA in the urine of tumor patients.
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Objective: To prepare rutin-Cu2+ complex imprinted polymer and study its adsorption ability. Methods: The polymer was prepared in mixed poler solvent, using α-methacrylic acid as functional monomer. The structure and preparation mechanism were studied by UV-vis spectroscopy and IR spectroscopy. Results: The polymer and rutin-Cu2+ complex were combined by coordinate bond and intermolecular force, the polymer had remarkably specific adsorption to complex of rutin-Cu2+. Conclusion: Rutin-Cu2+ complex molecularly imprinted polymer has great adsorption and specific identification to rutin-Cu2+, and can be used in extraction and separation of Chinese medicine effective constituent rutin.
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An electrochemical sensor has been developed for the selective determination of chlortetracycline ( CTC) using the molecularly imprinted technique. A molecular imprinted polymer ( MIP) on the surface of a glassy carbon electrode ( GCE ) was prepared by electropolymerization of o-aminophenol ( OAP ) in the presence of CTC in the sodium perchlorate ( NaClO4 ) solution using cyclic voltammetry ( CV ) . The electrochemical performance of the sensor was studied by using differential pulse voltammetry ( DPV ) . A linear relationship between the peak current difference and the CTC concentration was found in the range of 2. 0×10-8-6. 1×10-7 mol/L with the detection limit of 1. 5×10-8 mol/L (3σ). After regeneration by washing with the mixture of methanol and sulfuric acid, the sensor showed excellent reproducibility and good stability. The MIP electrode exhibited almost no response to chloramphenicol and penicillin, and very weak responses to tetracycline and oxytetracycline, proving a good selectivity. Recoveries of standard addition measured in the actual samples of milk and chicken meat were between 86 . 4% -96 . 9%. Compared with the reported methods, this sensor showed a low detection limit, simple operation without derivatization, rapid response and low cost.
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Objective: To investigate the specific molecular recognition ability for galangin molecular imprinting polymer (GMIP). Methods: GMIP was prepared through the method of thermal polymerization with galangin as template molecular, acrylamide (AM) as functional monomer, ethyleneglycol dimethacrylate (EGDMA) as cross-linker, and tetrahydrofuran, acetonitrile, and acetone as pore forming agents, respectively. The GMIP was characterized by infrared spectroscopy and scanning electron microscopy (SEM). In addition, the GMIP was investigated in equilibrium binding experiment to evaluate its adsorption property and selective recognition. Results: The Scathard model analysis showed that two kinds of binding sites existed in the GMIP. The dissociation constant (Kd) and apparent maximum binding constant (Qmax) were Kd1 = 0.961 mmol/L, Qmax1 = 19.79 μmol/g for high affinity binding sites and Kd2 = 0.101 mmol/L, Qmax2 = 51.09 μmol/g for low affinity binding sites, respectively. Conclusion: GMIP has the specific adsorption and recognition capabilities to the galangin molecules. It can be a novel material for the separation and purification of the active ingredients from natural products.
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Objective: To snythesize theophylline molecular imprinted polymer (MIP) microspheres. The influences of reaction conditions, including the category of solvent, reaction time, and the ratio of template to the cross-linking agent on the morphology and adsorption properties of MIP microspheres were studied. Methods: Theophylline MIP microspheres were prepared by precipitation polymerization with theophylline as template and ethyleneglycol dimethacrylate (EGDMA) as cross-linker. The microspheres were characterized by static adsorption and scanning electron microscopy (SEM). Results: The ratio of template to the cross-linking agent was 1:16, reaction time was 24 h, and acetontrile was the solvent. The theophylline MIP microspheres were regular microspheres. The MIP microspheres showed the high adsorption capacity and the partition coefficient of the microspheres adsorbing theophylline was 1.74. Conclusion: Theophylline MIP microspheres have the specific adsorption and recognition capabilities to the theophylline molecules.
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Molecular imprinted film modified glassy carbon electrode was prepared by electrochemical polymerization of pyrrole with the cyclic voltammetry in the presence of template molecular, salicylic acid. The template molecules were removed from the modified electrode surface by over-oxidized at 1.3V in the solution of 0.2 mol/L Na2HPO4 for 10 min. The modified electrodes can effectively promote electrochemical oxidation process of salicylic acid in the surface of electrode and avoid interference of structural similar substance such as benzoic acid. Cyclic voltammetry was employed in the electrochemical measurements. The experimental results show that the optimum acidity of background solution is pH 6.86 and the optimum incubation is 10 min. The linear response curve was obtained from 1.0×10-6 mol/L to 2.0×10-3 mol/L, with the detection limit of 8.0×10-7 mol/L. The imprinted electrode has been applied to the analysis of salicylic acid in the simulated samples with recovery rates ranging from 94.6% to 103.4%.