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Ma X.,East China University of Science and Technology | Xiao Y.,East China University of Science and Technology | Xu H.,Collaborative Innovation Center for Petrochemical New Materials | Lei K.,East China University of Science and Technology | And 2 more authors.
Materials Science and Engineering C | Year: 2016

Drug-eluting stents with biodegradable polymers as reservoirs have shown great potential in the application of interventional therapy due to their capability of local drug delivery. Herein, poly(l-lactide-co-ϵ-caprolactone) (PLCL) with three different compositions as carriers for ciprofloxacin lactate (CIP) was coated on ureteral stents by the dipping method. To simulate a body environment, degradation behavior of PLCL as both the bulk film and the stent coating was evaluated in artificial urine (AU, pH 6.20) respectively at 37 °C for 120 days by tracing their weight/Mn loss, water absorption and surface morphologies. Furthermore, the release profile of the eluting drug CIP on each stent exhibited a three-stage pattern, which was greatly affected by the degradation behavior of PLCL except for the burst stage. Interestingly, the degradation results on both macroscopic and molecular level indicated that the release mechanism at stage I was mainly controlled by chain scission instead of the weight loss or morphological changes of the coatings. While for stage II, the release profile was dominated by erosion resulting from the hydrolysis reaction autocatalyzed by acidic degradation residues. In addition, ciprofloxacin-loaded coatings displayed a significant bacterial resistance against E. coli and S. aureus without obvious cytotoxicity to Human foreskin fibroblasts (HFFs). Our results suggested that PLCL copolymers with tunable degradation rate as carriers for ciprofloxacin lactate could be used as a promising long-term antibacterial coating for ureteral stents. © 2016 Elsevier B.V. All rights reserved. Source


Zhang X.,East China University of Science and Technology | He H.,East China University of Science and Technology | Yin Y.,East China University of Science and Technology | Zhou W.,East China University of Science and Technology | And 4 more authors.
Journal of Biotechnology | Year: 2016

Light, as an important environmental signal, generally brings about a broad regulation in fungal metabolism. In this work, we aim to explore the light-responded metabolic rules so as to further develop a feasible and effective light regulation strategy for production of anticancer polyketide 1403C by marine fungus Halorosellinia sp.. Light derived production enhancement of polyketides was first found in shake flask. To further understand this well working black box, light-responded cell growth, polyketides biosynthesis, metabolic behaviors (enzymes activities and organic acids levels) and mycelia morphology were then investigated in 5-L bioreactor. By comparing cultures under constant irradiation and dark conditions, the entire bioprocess was divided into two phases. During 0-60. h, light presumably stimulated relevant metabolism to generate sufficient energy, NADPH and carbon skeleton, particularly malonyl-CoA, which was favorable for mycelia growth and polyketides accumulation. After 60. h, light did harm to biomass and polyketides production. Consequently, a light-dark shift strategy was proposed and verified in 5-L bioreactor. It led to a maximal 1403C production of 1.67. g/L, which was 24% and 74% higher than those obtained under constant irradiation and dark conditions, respectively. © 2016 Elsevier B.V. Source


Wang M.,East China University of Science and Technology | He H.,East China University of Science and Technology | Na K.,Shanghai Institute of Pharmaceutical Industry | Cai M.,East China University of Science and Technology | And 4 more authors.
Process Biochemistry | Year: 2015

Fungi fibrinolytic compound 1 (FGFC1) is a potential fibrinolytic drug candidate produced by the marine fungus Stachybotrys longispora FG216. FGFC1 has an interesting chemical structure, with two symmetrical carbon-chains connected by ornithine. This study demonstrated that the carbon skeleton of FGFC1 was synthesized in a mixed biosynthetic mode based on pathway inhibitor and precursor regulation; the process involves the shikimate and mevalonate pathways. Moreover, the key precursor ornithine was directly integrated into the molecule. Through ornithine regulation, two critical intermediates of FGFC1 were then detected and designated as FGFC2 and FGFC3. The chemical structures of FGFC2 and FGFC3 and their relationships among the four compounds were inferred. We then derived that one molecule of l-ornithine and one molecule of FGFC3 synthesized one molecule of FGFC2; one molecule of l-ornithine and two molecules of FGFC3 synthesized one molecule of FGFC1. Based on bioprocess features, the full fermentation process was divided into four specific phases. Accordingly, feeding of cells with different concentrations of glucose and ornithine showed that FGFC1 production reached 9.92 and 9.6 g/L, respectively, which were increases of 16.3% and 9.6% compared to the control. © 2015 Elsevier Ltd. All rights reserved. Source


Cao Y.-D.,East China University of Science and Technology | He Y.-C.,Changzhou University | Li H.,East China University of Science and Technology | Kai G.-Y.,Shanghai Normal University | And 4 more authors.
Journal of Biotechnology | Year: 2015

Hyoscyamine 6β-hydroxylase (H6H, EC 1.14.11.11), an α-ketoglutarate dependent dioxygenase catalyzes the hydroxylation of (-)-hyoscyamine and the subsequent epoxidation of 6β-hydroxyhyoscyamine to form scopolamine, a valuable natural alkaloid. In this study, random mutagenesis and site-directed saturation mutagenesis were used to enhance the hydroxylation activity of H6H from Anisodus acutangulus (AaH6H). A double mutant, AaH6HM1 (S14P/K97A), showed a 3.4-fold improved hydroxylation activity compared with the wild-type enzyme, and the in vivo epoxidation activity was also improved by 2.3 times. After 34h cultivation of Escherichia coli cells harboring Aah6hm1 in a 5-L bioreactor with a working volume of 3L, scopolamine was produced via a single-enzyme-mediated two-step transformation from 500mgL-1 (-)-hyoscyamine in 97% conversion, and 1.068g of the product were isolated, corresponding to a space-time yield of 251mgL-1d-1. This study shows that the protein engineering of some key enzymes is a promising and effective way for improving the production of rare natural products such as scopolamine. © 2015 Elsevier B.V. Source


Zhang J.,Shanghai Key Laboratory of Advanced Polymeric Materials | Xiao Y.,Shanghai Key Laboratory of Advanced Polymeric Materials | Xiao Y.,Shanghai Collaborative Innovation Center for Biomanufacturing | Xu H.,Collaborative Innovation Center for Petrochemical New Materials | And 3 more authors.
Polymer Chemistry | Year: 2016

The introduction of reactive groups such as -NH2, -COOH etc. onto a poly(ϵ-caprolactone) (PCL) backbone was necessary for further modification but a well-controlled approach remains a challenge for synthetic chemistry. Carboxyl functionalized PCL was typically prepared via three steps involving the synthesis of the corresponding monomer with a carboxyl-protecting group, polymerization and the removal of the protection. Except for obtaining purified monomers and a decent polymerization, the most critical step in carboxyl PCL synthesis was the deprotection from the degradable main chain. Therefore, electronic effects and steric hindrance of the protecting group were taken into account with the aim for controllable polymerization and feasible deprotection. Substituents including -CH3, H and NO2 with discriminative electronegativity on the para position of the benzyl protecting group have been selected to investigate their behavior in monomer preparation, polymerization and deprotection, respectively. It turned out that the electron donating group (-CH3) displayed the highest selectivity in the monomer preparation, excellent control over the polymerization degree and the most efficient removal of the protecting groups without degradation of the backbone. In addition, the reactivity of the pendant carboxyl groups on PCL was demonstrated by amidation with 4-amino-2,2,6,6-tetramethylpiperidinyloxy (4-amino-TEMPO). Our results also provide guidance information on preparing well-defined biodegradable polymers with pendant reactive groups such as polypeptides, expanding the library of novel biomaterials. © 2016 The Royal Society of Chemistry. Source

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