Candida antarctica lipase B chemically immobilized on epoxy-activated micro- and nanobeads: catalysts for polyester synthesis.


:Candida antarctica Lipase B (CALB) was covalently immobilized onto epoxy-activated macroporous poly(methyl methacrylate) Amberzyme beads (235 microm particle size, 220 A pore size) and nanoparticles (nanoPSG, diameter 68 nm) with a poly(glycidyl methacrylate) outer region. Amberzyme beads allowed CALB loading up to 0.16 g of enzyme per gram of support. IR microspectroscopy generated images of Amberzyme-CALB beads showed CALB is localized within a 50 microm thick loading front. IR microspectroscopy images, recorded prior to and after treatment of Amberzyme-CALB with DMSO/aqueous Triton X-100, are similar, confirming that CALB is largely chemically linked to Amberzyme. The activity of CALB immobilized on Amberzyme, Lewatit (i.e., Novozym 435 catalyst), and nanoPSG was assessed for lactone ring-opening and step-condensation polymerizations. For example, the percent conversion of -caprolactone using the same amount of enzyme catalyzed by Amberzym-CALB, Novozym 435, and nanoPSG-CALB for 20 min was 7.0, 16, and 65%, respectively. Differences in CALB reactivity were discussed based on resin physical parameters and availability of active sites determined by active site titrations. Regardless of the matrix used and chemical versus physical immobilization, -CL ring-opening polymerizations occur by a chain growth mechanism without chain termination. To test Amberzyme-CALB stability, the catalyst was reused over three reaction cycles for -CL ring-opening polymerization (70 degrees C, 70 min reactions) and glycerol/1,8-octanediol/adipic acid polycondensation reactions (90 degrees C, 64 h). Amberzyme-CALB was found to have far better stability for reuse relative to Novozym 435 for the polycondensation reaction.






Chen B,Hu J,Miller EM,Xie W,Cai M,Gross RA




Has Abstract


2008-02-01 00:00:00












  • Injectable and Self-Healing Dynamic Hydrogels Based on Metal(I)-Thiolate/Disulfide Exchange as Biomaterials with Tunable Mechanical Properties.

    abstract::Despite numerous strategies involving dynamic covalent bonds to produce self-healing hydrogels with similar frequency-dependent stiffness to native tissues, it remains challenging to use biologically relevant thiol/disulfide exchange to confer such properties to polymeric networks. Herein, we report a new method based...


    pub_type: 杂志文章


    authors: Casuso P,Odriozola I,Pérez-San Vicente A,Loinaz I,Cabañero G,Grande HJ,Dupin D

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  • Shear-induced self-assembly of native silk proteins into fibrils studied by atomic force microscopy.

    abstract::Noncontact mode atomic force microscopy was used to investigate native silk proteins prepared in different ways. Low protein concentrations revealed that single protein molecules exhibit a simple, round shape with apparent diameters of 20-25 nm. Shearing the native protein solutions after extraction from the gland and...


    pub_type: 杂志文章


    authors: Greving I,Cai M,Vollrath F,Schniepp HC

    更新日期:2012-03-12 00:00:00

  • Injectable Shape-Holding Collagen Hydrogel for Cell Encapsulation and Delivery Cross-linked Using Thiol-Michael Addition Click Reaction.

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    pub_type: 杂志文章


    authors: Pupkaite J,Rosenquist J,Hilborn J,Samanta A

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    pub_type: 杂志文章


    authors: Riemer T,Nimptsch A,Nimptsch K,Schiller J

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    pub_type: 杂志文章


    authors: Suarez S,Grover GN,Braden RL,Christman KL,Almutairi A

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    pub_type: 杂志文章


    authors: George KA,Wentrup-Byrne E,Hill DJ,Whittaker AK

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  • Dual-Cross-Linked Network Hydrogels with Multiresponsive, Self-Healing, and Shear Strengthening Properties.

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    pub_type: 杂志文章


    authors: Zhao J,Diaz-Dussan D,Wu M,Peng YY,Wang J,Zeng H,Duan W,Kong L,Hao X,Narain R

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    authors: Pechar M,Pola R,Laga R,Ulbrich K,Bednárová L,Maloň P,Sieglová I,Král V,Fábry M,Vaněk O

    更新日期:2011-10-10 00:00:00

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    pub_type: 杂志文章


    authors: Lam AK,Wouters CL,Moen EL,Pusavat J,Rice CV

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    pub_type: 杂志文章


    authors: Chnari E,Nikitczuk JS,Wang J,Uhrich KE,Moghe PV

    更新日期:2006-06-01 00:00:00

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    pub_type: 杂志文章


    authors: Zagami R,Rapozzi V,Piperno A,Scala A,Triolo C,Trapani M,Xodo LE,Monsù Scolaro L,Mazzaglia A

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    pub_type: 杂志文章


    authors: Nordmark EL,Yang Z,Huttunen E,Widmalm G

    更新日期:2005-01-01 00:00:00

  • Galactose-decorated cross-linked biodegradable poly(ethylene glycol)-b-poly(ε-caprolactone) block copolymer micelles for enhanced hepatoma-targeting delivery of paclitaxel.

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    pub_type: 杂志文章


    authors: Yang R,Meng F,Ma S,Huang F,Liu H,Zhong Z

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    pub_type: 杂志文章


    authors: Taglienti A,Valentini M,Sequi P,Crescenzi V

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  • Mild and selective oxidation of cellulose fibers in the presence of N-hydroxyphthalimide.

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    authors: Coseri S,Nistor G,Fras L,Strnad S,Harabagiu V,Simionescu BC

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    pub_type: 杂志文章


    authors: Torrent M,Odorizzi F,Nogués MV,Boix E

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    pub_type: 杂志文章


    authors: Sashiwa H,Yajima H,Aiba S

    更新日期:2003-09-01 00:00:00

  • Specific Drug Formulation Additives: Revealing the Impact of Architecture and Block Length Ratio.

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    pub_type: 杂志文章


    authors: Wieczorek S,Schwaar T,Senge MO,Börner HG

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    pub_type: 杂志文章


    authors: Singh S,Papareddy P,Mörgelin M,Schmidtchen A,Malmsten M

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    abstract::Type I collagen is explored heavily for use in biomaterials, but the role of other extracellular matrix components in regulating collagen organization is gaining attention. We show that as the ratio of type III to type I collagen increases, fibril diameter decreases. A mixture of the two collagen types results in a mo...


    pub_type: 杂志文章


    authors: Stuart K,Panitch A

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  • Fluorescent conjugated polyfluorene with pendant lactopyranosyl ligands for studies of Ca(2+)-mediated carbohydrate-carbohydrate interaction.

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    pub_type: 杂志文章


    authors: Chen Q,Cui Y,Zhang TL,Cao J,Han BH

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  • Click-Chemistry Approach toward Antibacterial and Degradable Hybrid Hydrogels Based on Octa-Betaine Ester Polyhedral Oligomeric Silsesquioxane.

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    authors: Han J,Chen Q,Shen Y,Liu Z,Hao X,Zhong M,Zhao Z,Bockstaller MR

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    pub_type: 杂志文章


    authors: Soltantabar P,Calubaquib EL,Mostafavi E,Biewer MC,Stefan MC

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    pub_type: 杂志文章


    authors: Baier G,Cavallaro A,Vasilev K,Mailänder V,Musyanovych A,Landfester K

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    pub_type: 杂志文章


    authors: Zhang Y,Zheng M,Kissel T,Agarwal S

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    pub_type: 杂志文章


    authors: Liu Y,Li H,Yan S,Wei J,Li X

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    pub_type: 杂志文章


    authors: Walters CM,Boott CE,Nguyen TD,Hamad WY,MacLachlan MJ

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    pub_type: 杂志文章


    authors: Liu S,Wang W,Moos Ev,Jackman J,Mealing G,Monette R,Ben RN

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    pub_type: 杂志文章


    authors: Malmo J,Vårum KM,Strand SP

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    pub_type: 杂志文章


    authors: Jadhav V,Maiti S,Dasgupta A,Das PK,Dias RS,Miguel MG,Lindman B

    更新日期:2008-07-01 00:00:00