Supramolecular hydrogels formed by cyclodextrins and polymers have been widely investigated as a biocompatible, biodegradable and controllable drug delivery system. In this study, a supramolecular hydrogel based on biodegradable poly(caprolactone)–poly(ethylene glycol)–poly(caprolactone) (PCL-PEG-PCL) triblock copolymers and γ-cyclodextrin (γ-CD) was prepared through inclusion complexation as an injectable, sustained-release vehicle for insulin. The triblock copolymer PCL-PEG-PCL was synthesised by the ring-opening polymerisation method, using microwave irradiation. The polymerisation reaction and the copolymer structures were evaluated by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The supramolecular hydrogel was prepared in aqueous solution by blending an aqueous γ-CD solution with an aqueous solution of PCL-PEG-PCL triblock copolymer at room temperature. In vitro insulin release through the hydrogel system was studied. The relative surface hydrophobicity of standard and released insulin from the SMGel was estimated using 8-anilino-1-naphthalene sulfonic acid (ANS). Results of 1HNMR and gel permeation chromatography revealed that microwave irradiation is a simple and reliable method for synthesis of PCL-PEG-PCL copolymer. Gelation occurred within a minute. The supramolecular hydrogel obtained by mixing 10.54% (w/v) γ-CD and 2.5% (w/v) copolymer had an excellent syringeability. Insulin was released up to 80% over a period of 20 days. Insulin kept its initial folding after formulating and releasing from SMGel. A supramolecular hydrogel based on complexation of triblock PCL-PEG-PCL copolymer with γ-cyclodextrin is a suitable system for providing sustained release of therapeutic proteins, with desirable flow behaviour.Key words: insulin, PCL-PEG-PCL, supramolecular hydrogel, triblock copolymer, γ-CD相似文献
In the present study, a sensitive and competitive chemiluminescence immunoassay (CLIA) was developed in order to detect human serum albumin (HSA) in urine specimen. The method utilizes a home-made monoclonal anti-albumin antibody conjugated to horseradish peroxidase enzyme (mAb-HRP). Sensitivity, specificity and linearity of the assay were evaluated. According to the results, the proper concentration of HSA and mAb-HRP conjugates was 800?ng/100?μl and 1:200 respectively. In optimal conditions, this method could detect HSA in a high linear range of 10–200?μg?ml?1 with the low detection limit of 0.025?μg?ml?1. No evidence of interference with presence of probable substances in the urine samples indicated its high specificity and selectivity. Moreover, high reproducibility as well as high sensitivity and specificity of the test were confirmed using diabetic and non-diabetic samples. Significant concordance was observed between CLIA and immunoturbidimetry assay regarding detection of HSA. The results of the present study can be considered in accordance with the current demands such as reliability, accuracy, convenience and high speed of performance for a precise protein detection method. Furthermore, it may be regarded as a more rapid, simpler and cheaper alternative compared to other sophisticated assays. 相似文献
Caspase 8 (CASP8) gene plays a key role in the regulation of apoptotic cell death. Expression variation in this gene has been associated with the risk of breast cancer. The aim of this study was to investigate the association of rs3834129 and rs3769821, as functional variants, and their haplotypes with molecular profile as well as the risk of breast cancer in an Iranian population. A case-control study was conducted on 812 participants including 293 breast cancer patients and 519 healthy controls. Genotyping was performed by polymerase chain reaction–based methods. Statistical analysis was performed using SPSS Ver16. The association between polymorphisms and haplotypes with the risk of breast cancer was estimated by calculating odds ratios (OR) and chi-square (χ2) tests. In comparison with ins allele (I) of rs3834129, carriers of del allele (D) showed a lower risk of breast cancer (OR, 0.65; 95% confidence interval [CI], 0.49-0.87; P = 0.004). The multivariate logistic regression model indicated DD genotype as an independent factor for a decreased risk of breast cancer in our population (OR, 0.18; 95% CI, 0.06-0.58; P = 0.004). Also, the C allele of rs3769821 was associated with a 43% increased risk of breast cancer (P = 0.005); however, after adjustment for confounding factors, no association with rs3769821 and breast cancer was observed. In addition, D-T haplotype and diplotype presented protective effects (P < 0.05). Our results indicate that genetic variations in the promoter region of CASP8 gene, especially rs3834129, may serve as a genetic risk factor for breast cancer in an Iranian population. 相似文献
Xylose reductase (XR) and xylitol dehydrogenase (XDH) are the key enzymes for xylose fermentation and have been widely used for construction of a recombinant xylose fermenting yeast. The effective recycling of cofactors between XR and XDH has been thought to be important to achieve effective xylose fermentation. Efforts to alter the coenzyme specificity of XR and HDX by site-directed mutagenesis have been widely made for improvement of efficiency of xylose fermentation. We previously succeeded by protein engineering to improve ethanol production by reversing XDH dependency from NAD+ to NADP+. In this study, we applied protein engineering to construct a novel strictly NADPH-dependent XR from Pichia stipitis by site-directed mutagenesis, in order to recycle NADPH between XR and XDH effectively. One double mutant, E223A/S271A showing strict NADPH dependency with 106% activity of wild-type was generated. A second double mutant, E223D/S271A, showed a 1.27-fold increased activity compared to the wild-type XR with NADPH and almost negligible activity with NADH. 相似文献
Since global warming affects wheat cropping systems, more has yet to be indicated on the parameters, which control terminal heat tolerance, and severely influence wheat (Triticum aestivum L.) productivity. Identification of tolerant wheat genotypes by heat tolerance-linked molecular markers is a rapid and cost-effective screening tool in plant breeding. Accordingly, in a four-year field experiment (2015–2019), 44 wheat genotypes were selected out of 100 genotypes, and were examined in timely and late planting (mid-January resulting in heat stress). Stress decreased yield components, including 1000-kernel weight (TKW), grains per spike, and plants per square meter, and the physiological traits, including days to heading and days to maturity, grain filling duration, and greenness, and eventually decreased grain yield up to?~?28%. The early maturity genotypes resulted in higher yields under stress conditions by a stress-avoidance mechanism. Among 14 SSR markers, GWM577 was positively correlated with yield, and WMS3062, GWM261, and WMS1025 had positive correlations with longevity under stress. Accordingly, WMS3062 and GWM261 can be used to determine high yield and early maturity genotypes. Furthermore, GWM114 showed a positive correlation with TKW, indicating their usefulness for grouping wheat genotypes and for identifying heat-related markers. Since the crossing of the genetically distant genotypes can create more diverse populations, the results could be applied to plan breeding projects to establish more diverse populations for different chromosomal locations and traits under heat stress conditions. Moreover, our findings demonstrated that the morphological and molecular analyses could be useful for describing wheat genetic variation of heat tolerance.