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Biocatalytic synthesis of highly ordered degradable dextran-based hydrogels
Ferreira, Lino; Gil, Maria H.; Cabrita, António M. S.; Dordick, Jonathan S.We have prepared unique macroporous and ordered dextran-based hydrogels using a single-step biocatalytic transesterification reaction between dextran and divinyladipate in neat dimethylsulfoxide. These hydrogels show a unimodal distribution of interconnected pores with average diameters from 0.4 to 2.0 [mu]m depending on the degree of substitution. In addition, the hydrogels show a higher elastic modulus for a ...
Biocompatibility of chemoenzymatically derived dextran-acrylate hydrogels
Ferreira, Lino; Rafael, Ana; Lamghari, Meriem; Barbosa, Mario A.; Gil, Maria H.; Cabrita, António M. S.; Dordick, Jonathan S.The biocompatibility of chemoenzymatically generated dextran-acrylate hydrogels has been evaluated in vitro, using human foreskin fibroblasts, and in vivo, by subcutaneous and intramuscular implantation in Wistar rats for up to 40 days. In vitro tests show that hydrogel extracts only minimally reduced (<10%) the mitochondrial metabolic activity of fibroblasts. Direct contact of the hydrogels with cells induced ...
Enzymatic synthesis of dextran-containing hydrogels
Ferreira, Lino; Gil, Maria H.; Dordick, Jonathan S.Dextran, a natural glucose-containing polysaccharide, has been acylated by Proleather FG-F and lipase AY, a protease and lipase from Bacillus sp. and Candida rugosa, respectively, in anhydrous dimethylsulfoxide in the presence of vinyl acrylate (VA). The efficiency of the reaction in the presence of Proleather FG-F and the isolated yields were ca. 71% and 45%, respectively. Dextran derivatized with VA (dexT70-V...
Biocatalytic Polytransesterification of Inulin with Divinyladipate
Ferreira, Lino; Gil, Maria H.; Carvalho, Rui; Geraldes, Carlos F. G. C.; Kim, Dae-Yun; Dordick, Jonathan S.http://dx.doi.org/10.1021/cm020393w
Enzymatic Synthesis of Inulin-Containing Hydrogels
Ferreira, Lino; Carvalho, Rui; Gil, Maria H.; Dordick, Jonathan S.The Bacillus subtilis protease Proleather FG-F catalyzed the transesterification of inulin with vinyl acrylate (VA) in dimethylformamide (DMF). The reaction conversion for different VA concentrations was greater than 57% after 96 h at 50 °C. The degree of substitution (DS, defined as the amount of acrylate groups per 100 inulin fructofuranoside residues) with acrylate moieties can be controlled by varying the m...
Exquisite Regioselectivity and Increased Transesterification Activity of an Imm...
Ferreira, Lino; Ramos, M. A.; Gil, Maria Helena; Dordick, Jonathan S.Commercially available proteases and lipases were screened for their ability to acylate regioselectively sucrose with divinyladipate either in pyridine or dimethylformamide (DMF). The protease (EC 3.4.21.62) from Bacillus subtilis (Proleather FG-F) exhibited the highest conversion (100% in 24 h of reaction in DMF) yielding sucrose 2- O-vinyladipate as main product. The enzyme preference for a secondary hydroxyl...
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