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141.
Tang B Cao L Xu K Zhuo L Ge J Li Q Yu L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(12):3637-3644
A novel assembled nanobiosensor QDs-ConA-beta-CDs-AuNPs was designed for the direct determination of glucose in serum with high sensitivity and selectivity. The sensing approach is based on fluorescence resonance energy transfer (FRET) between CdTe quantum dots (QDs) as an energy donor and gold nanoparticles (AuNPs) as an energy acceptor. The specific combination of concanavalin A (ConA)-conjugated QDs and thiolated beta-cyclodextrins (beta-SH-CDs)-modified AuNPs assembles a hyperefficient FRET nanobiosensor. In the presence of glucose, the AuNPs-beta-CDs segment of the nanobiosensor is displaced by glucose which competes with beta-CDs on the binding sites of ConA, resulting in the fluorescence recovery of the quenched QDs. Experimental results show that the increase in fluorescence intensity is proportional to the concentration of glucose within the range of 0.10-50 muM under the optimized experimental conditions. In addition, the nanobiosensor has high sensitivity with a detection limit as low as 50 nM, and has excellent selectivity for glucose over other sugars and most biological species present in serum. The nanobiosensor was applied directly to determine glucose in normal adult human serum, and the recovery and precision of the method were satisfactory. The unique combination of high sensitivity and good selectivity of this biosensor indicates its potential for the clinical determination of glucose directly and simply in serum, and provides the possibility to detect low levels of glucose in single cells or bacterial cultures. Moreover, the designed nanobiosensor achieves direct detection in biological samples, suggesting the use of nanobiotechnology-based assembled sensors for direct analytical applications in vivo or in vitro. 相似文献
142.
羧基功能化的聚[(9,9-二辛基芴基-2,7-二基)-co-(1,4-苯并-{2,1′,3}-噻二唑)]聚合物点(PFBT-COOH)在无外加共反应试剂的条件下具有高的电致化学发光(ECL)信号,且过氧化氢(H2O2)对其ECL具有高效猝灭作用。采用PFBT-COOH修饰玻碳电极,进一步交联葡萄糖氧化酶(GOD)以构建酶传感器(GOD/PFBT-COOH/GCE)。随着检测底液中葡萄糖浓度的增加,葡萄糖在GOD催化下原位产生的H2O2量增加,导致传感器的ECL信号逐渐减弱,从而实现葡萄糖的准确、快速、灵敏检测。此方法测得葡萄糖的线性范围为1.0×10-7~3.0×10-3 mol/L,检出限为3.0×10-8 mol/L。血清样品中葡萄糖的加标回收率为98.5%~106%。该策略为酶传感器的构建提供了新思路,为葡萄糖的检测提供了新方法。 相似文献
143.
In this study, a molecularly imprinted sensor technology is engineered to detect glucose in real blood samples by chronoimpedimetrically. The imprinting process of glucose (Glc) was carried out by electrochemical polymerization of aminophenylboronic acid (APBA) and pyrrole (Py) by performing cyclic voltammetry (CV). Afterwards, glucose molecule was removed from imprinted surface by 5 % acetic acid to reveal glucose imprinted cavities. Electrochemical Impedance Spectroscopy (EIS) was used to characterize sensor modification steps and glucose removal. Glucose monitoring process was carried out chronoimpedimetrically(CI) for the first time in real blood samples. Calibration curve was prepared between 20–800 mg/dL. The standard deviations of the 18 calibration curves R2 were calculated as 0.9866±0.0066 to assess reproducibility. Recovery was calculated by using 105 mg/dL Glc Serum Sample, which was monitored by auto analyzer and into this sample 50 mg/dL Glc added and our sensor response was 147.92±2.43 mg/dL, 98.6±1.62 % (n=5). Non‐imprinted (NIP) sensor gave no signal for the glucose concentration. 相似文献
144.
Dr. Sampa Maiti Dr. Saikat Manna Nicholas Banahene Lucynda Pham Zhijie Liang Jun Wang Yi Xu Reuben Bettinger John Zientko Prof. Dr. Aaron P. Esser-Kahn Prof. Dr. Wenjun Du 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(43):19105-19109
Efforts to synthesize degradable polymers from renewable resources are deterred by technical and economic challenges; especially, the conversion of natural building blocks into polymerizable monomers is inefficient, requiring multistep synthesis and chromatographic purification. Herein we report a chemoenzymatic process to address these challenges. An enzymatic reaction system was designed that allows for regioselective functional group transformation, efficiently converting glucose into a polymerizable monomer in quantitative yield, thus removing the need for chromatographic purification. With this key success, we further designed a continuous, three-step process, which enabled the synthesis of a sugar polymer, sugar poly(orthoester), directly from glucose in high yield (73 % from glucose). This work may provide a proof-of-concept in developing technically and economically viable approaches to address the many issues associated with current petroleum-based polymers. 相似文献
145.
Kirsten Berger Johanna Josefine Ostberg-Potthoff Tamara Bakuradze Peter Winterhalter Elke Richling 《Molecules (Basel, Switzerland)》2020,25(22)
Red fruits and their juices are rich sources of polyphenols, especially anthocyanins. Some studies have shown that such polyphenols can inhibit enzymes of the carbohydrate metabolism, such as α-amylase and α-glucosidase, that indirectly regulate blood sugar levels. The presented study examined the in vitro inhibitory activity against α-amylase and α-glucosidase of various phenolic extracts prepared from direct juices, concentrates, and purees of nine different berries which differ in their anthocyanin and copigment profile. Generally, the extracts with the highest phenolic content—aronia (67.7 ± 3.2 g GAE/100 g; cyanidin 3-galactoside; chlorogenic acid), pomegranate (65.7 ± 7.9 g GAE/100 g; cyanidin 3,5-diglucoside; punicalin), and red grape (59.6 ± 2.5 g GAE/100 g; malvidin 3-glucoside; quercetin 3-glucuronide)—showed also one of the highest inhibitory activities against α-amylase (326.9 ± 75.8 μg/mL; 789.7 ± 220.9 μg/mL; 646.1 ± 81.8 μg/mL) and α-glucosidase (115.6 ± 32.5 μg/mL; 127.8 ± 20.1 μg/mL; 160.6 ± 68.4 μg/mL) and, partially, were even more potent inhibitors than acarbose (441 ± 30 μg/mL; 1439 ± 85 μg/mL). Additionally, the investigation of single anthocyanins and glycosylated flavonoids demonstrated a structure- and size-dependent inhibitory activity. In the future in vivo studies are envisaged. 相似文献
146.
Yang X Lee MC Sartain F Pan X Lowe CR 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(33):8491-8497
In this study, 2-acrylamidophenylboronate (2-APB) was synthesised and its ability to bind with glucose was investigated both in solution and when integrated into a holographic sensor. Multiple forms of 2-APB, resulting from the neighbouring effect of the amido group with the boronic acid through an intramolecular B--O-coordinated interaction, were shown to exist in solution by using multinuclear NMR spectrometry. It was found that 2-APB predominantly adopts a zwitterionic tetrahedral form at physiological pH values. The complex formation of 2-APB with glucose and lactate was investigated in DMSO; 2-APB favours binding with glucose rather than lactate and generates a five-membered-ring complex. Furthermore, a 2-APB-based holographic sensor displayed a significant response to glucose with little interference from lactate, and with no dependence on pH in the physiological pH range. These features suggest that the new ligand 2-APB is a potential candidate for the development of glucose-selective sensors. 相似文献
147.
Engström HA Johansson R Koch-Schmidt P Gregorius K Ohlson S Bergström M 《Biomedical chromatography : BMC》2008,22(3):272-277
Continuous monitoring of drug levels and endogenous molecules in biological fluids is a developing research area with many applications. One example is the need to improve life for millions of diabetes mellitus patients by continuously monitoring the glucose level. In order to have a dynamic response, the recognition molecule in a continuous sensor should preferentially have a fast dissociation rate and a dissociation constant in the millimolar range. We have evaluated the monoclonal antibody (mAb) 3F1E8-A2 for its potential to be used in a future glucose sensor application. The mAb was generated from hybridomas by immunizing mice with 10 kDa dextran (an alpha1,6-glucose polymer) with the aim of obtaining mAbs that can recognize the glucose monomer. The mAb was immobilized to macroporous silica and the interaction with dextran-derived oligosaccharides was evaluated with weak affinity chromatography (WAC). To measure the low affinities between the mAb 3F1E8-A2 and different monosaccharides, a competitive weak affinity chromatography approach was employed. It was found that the mAb had a higher specificity for glucose compared with other monosaccharides and the dissociation constant (K(d)) towards glucose was determined as 18.8 +/- 2.6 mm. 相似文献
148.
149.
150.
A surface-renewable glucose biosensor is reported. The glucose biosensor is developed using glucose oxidase (GOD) encapsulated in organically modified solgel glass (ORMOSIL) network in the composite matetial. The organic group in the ORMOSIL network controls the hydrophobicity of the electrode surface and thus limits the wettability of the electrode surface. The graphite powder provides the conductivity for the electrode.Ferrocenecarboxylic acid in phosphate buffer solution (pH 7.0) transfers electron between enzyme and electrode. Cyclic volammetry and amperometric measurements have been used to exmine the electrochemical behavior of glucose biosensor as shown in Fig. 1 and Fig.2. The electrode gives a linear response range of 1 -20mM glucose with a sensitivity of 3.26 μA· mM-1. The electrode can be renewed easily in reproducible manner by a simple polishing step. 相似文献