Orientationally immobilized enzyme microreactors (OIMERs), embedded in microfluidic paper-based analytical devices (mu PADs) were developed for improved detection of pesticide residues in food. Acetylcholinesterase (AChE) was orientationally immobilized on the reusable Part I of the mu PADs, using the specific affinity binding of concanavalin A (Con A) to a glycosyl group on AChE. Using the disposable Part II, facile colorimetric quantification was performed with a smartphone and software, or qualitative detection by a naked-eye visual test. The AChE immobilized in OIMERs not only had improved activity and stability, but also high sensitivity, with a limit of detection as low as (0.007 +/- 0.003) mu g/mL. The method was used to detect pesticides residues in real vegetable samples; the recovery (88.6-102.7%) showed high reliability for pesticide residues detection in foods. A molecular docking study and an enzyme kinetic analysis were conducted to characterize the mechanism of action of the OIMERs.

A facial and rapid method for glycoproteins enrichment by capillary electrophoresis was developed. The 3-aminophenylboronic acid-functionalized poly(glycidyl methacrylate) microparticles (PGMA@APBA) were attached to the capillary inlet (length of similar to 1.5 cm) by electrostatic self-assemble action to prepare a partially coated capillary column. The process is simple and reversible, allowing for easy renewal of the PGMA@APBA coating when its enrichment efficiency decreases. By utilizing the coated column, glycoproteins can be enriched within 2 min. The column exhibits a specific enrichment for glycoproteins and can be consecutively used for approximately 60 runs. The relative standard deviations (RSDs) of peak area of run-to-run (n = 5) and batch-to-batch (n = 3) were 1.5 % and 1.0%, respectively. The method was successfully applied to enrich glycoproteins from 1 x 10(12)-fold diluted real egg white sample, indicating its practical applicability.

利用相溶解度曲线研究不同浓度的羟丙基-β-环糊精(HP-β-CD)与布洛芬(BF)的超分子相互作用.采用高效液相色谱法(HPLC)建立布洛芬的标准工作曲线.配制系列浓度的HP-β-CD溶液,加入过量的布洛芬,采用HPLC法测定布洛芬的溶解度,绘制相溶解度图.结果显示,HP-β-CD与布洛芬的相溶解度曲线为线性关系,说明两者之间包合模型为AL型,布洛芬与HP-β-CD以1:1包合,其包合常数K为7.23×103 L/mol.羟丙基-β-环糊精对布洛芬形成的超分子化合物均有较好的增溶作用.

An open-tubular capillary electrochromatography method has been developed for the determination of binding constants between beta(2)-adrenergic receptor (beta(2)-AR) and seven drugs. beta(2)-AR was oriented immobilized onto one part of inner surface of capillary via microwave-assisted technical synthesis. According to the linear relationship between coating length and the apparent mobility of analyte, the binding constant (K-b) can be obtained by related theories and equations. The order of K-b values between drugs such as adrenaline hydrochloride, norepinephrine bitartrate, and propranolol hydrochloride with beta(2)-AR is well consistent with that reported in the literature. By the method, K-b values between four extracts of Radix Paeoniae Rubra and beta(2)-AR were also successfully obtained. Subsequently, computer models were applied to interpret the CEC experiments. And the results proved to be in good agreement with the method. The work, herein, demonstrates the potential of the method in drug-receptor affinity interactions evaluation and screening of lead compounds from natural sources.

Oriented covalent immobilized β2‐adrenergic receptor (β2‐AR) CE (OIRCE) was developed to determine the interactions between a set of natural extracts of Radix Paeoniae Rubra (NERPR) and β2‐AR, and to predict the activity of NERPR. The inner capillary surface is chemically bonded with stable β2‐AR coating via microwave‐assisted technical synthesis. The modified capillaries were characterized via infrared spectroscopy and fluorescence microscopy. Furthermore, the bonding amounts of β2‐AR were first obtained via fluorescence spectroscopy method. In determining the amount of bonded β2‐AR, the regression equation A = 576 707C + 35.449 and the correlation coefficient 0.9995 were obtained. This result revealed an excellent linear relationship in the range of 2 × 10−4 mg/mL to 1 × 10−3 mg/mL. The normalized capacity factor (KRCE) was obtained using OIRCE in evaluating drug–receptor interactions. Related theories and equations were used to calculate KRCE values from apparent migration times of a solute and EOF. The order of KRCE and the binding constant (Kb) values between drugs and β2‐AR was well consistent. The results confirmed that the OIRCE and KRCE values can be effectually used to investigate drug‐receptor interactions, and OIRCE has the potential to predict drug activity and to select leading compounds from natural chemicals.