Determination of sulfonamides in meat with dummy-template molecularly imprinted polymer-based chemiluminescence sensor.

In this study, a molecularly imprinted polymer capable of recognizing 15 sulfonamides was first synthesized with sulfabenz as the dummy template. The calculation results from computation simulation showed that the specific 3D conformation of the template had an important influence on the polymer's recognition ability. Then, the polymer was used as recognition reagent to prepare a chemiluminescence sensor on a conventional 96-well microplate for the determination of the residues of 15 sulfonamides in meat (chicken and pork). Due to the 4-(imidazol-1-yl)phenol-enhanced luminol-H2O2 system, the limits of detection for the 15 analytes were in the range of 1.0-12 pg/mL. The recoveries from the standard fortified blank samples were in the range of 72.7-99%. Furthermore, one assay could be finished within 30 min, and the sensor could be reused 4 times. Therefore, this sensor could be used as a very useful tool for routine screening of residues of sulfonamides in meat samples. Graphical abstract Assay procedures of the molecularly imprinted polymer-based chemiluminescence sensor for determination of sulfonamides.

Immunosensor interface based on physical and chemical immunoglobulin G adsorption onto mixed self-assembled monolayers.

An immunosensor interface based on mixed hydrophobic self-assembled monolayers (SAMs) of methyl and carboxylic acid terminated thiols with covalently attached human Immunoglobulin G (hIgG), is investigated. The densely packed and organised SAMs were characterised by contact angle measurements and cyclic voltammetry. The effect of the non-ionic surfactant, Tween 20, in preventing nonspecific adsorption is addressed by ellipsometry during physical and covalent hIgG immobilization on pure and mixed SAMs, respectively. It is clearly demonstrated that nonspecific adsorption due to hydrophobic interactions of hIgG on methyl ended groups is totally inhibited, whereas electrostatic/hydrogen bonding interactions with the exposed carboxylic groups prevail in the presence of surfactant. Results of ellipsometry and Atomic Force Microscopy, reveal that the surface concentration of covalently immobilized hIgG is determined by the ratio of COOH / CH(3)-terminated thiols in SAM forming solution. Moreover, the ellipsometric data demonstrates that the ratio of bound anti-hIgG / hIgG depends on the density of hIgG on the surface and that the highest ratio is close to three. We also report the selectivity and high sensitivity achieved by chronoamperometry in the detection of adsorbed hIgG and the reaction with its antibody.

[Influences of the genotypes of HBV and HBeAg regarding their response to PEG-IFN in chronic hepatitis B patients].

OBJECTIVE: To study the effects of genotypes of HBV and HBeAg on the response to PEG-interferon alpha (PEG-IFN) in chronic hepatitis B (CHB) patients. METHODS: PCR-RFLP and S gene sequencing were conducted in 42 CHB patients. RESULTS: The sustained response (SR) rates were 66.7% in genotype B and 27.3% in genotype C group. The P value was 0.039 by the Pearson Chi-square test, while it was 0.06 by the Fisher's exact test. The results suggested a trend that patients with genotype B HBV compared to genotype C had better SR to PEG-IFN therapy, although the difference was not significant. Results also showed that SR rate in patients with HBeAg-negative CHB (7/8 87.5%) was significantly higher than that in HBe+ CHB patients (8/21 38.1%, P < 0.05). CONCLUSION: Our results indicate that HBV genotype and HBeAg, especially the later, are main factors for predicting PEG-IFN therapy response in CHB patients.