Biotechnology and Bioengineering

Cover image for Vol. 110 Issue 3

March 2013

Volume 110, Issue 3

Pages C1–C1, fmi–fmvi, 667–1003

  1. Cover

    1. Top of page
    2. Cover
    3. Contents
    4. Spotlights
    5. Review
    6. Articles
    7. Communication to the Editor
    1. You have free access to this content
      Biotechnology and Bioengineering: Volume 110, Number 3, March 2013 (page C1)

      Version of Record online: 18 JAN 2013 | DOI: 10.1002/bit.24650

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      Cover Legend Targeted, chromosomal double strand breaks made by zinc-finger and TALE nucleases are highly receptive to incorporation of exogenous transgene DNA when the transgene is cleaved in vivo. (Image courtesy of Dr. Gregory J. Cost.)

  2. Contents

    1. Top of page
    2. Cover
    3. Contents
    4. Spotlights
    5. Review
    6. Articles
    7. Communication to the Editor
  3. Spotlights

    1. Top of page
    2. Cover
    3. Contents
    4. Spotlights
    5. Review
    6. Articles
    7. Communication to the Editor
    1. Reliable DFBA simulator (page fmvi)

      Version of Record online: 18 JAN 2013 | DOI: 10.1002/bit.24648

  4. Review

    1. Top of page
    2. Cover
    3. Contents
    4. Spotlights
    5. Review
    6. Articles
    7. Communication to the Editor
    1. Stem cell microencapsulation for phenotypic control, bioprocessing, and transplantation (pages 667–682)

      Jenna L. Wilson and Todd C. McDevitt

      Version of Record online: 17 JAN 2013 | DOI: 10.1002/bit.24802

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      Microencapsulation of stem cells creates a defined microenvironment to modulate stem cell phenotype, protects from hydrodynamic forces and prevents agglomeration during expansion in suspension bioreactors, and is a means to transplant cells behind a semi-permeable barrier, allowing for molecular secretion while avoiding immune reaction. This review will provide an overview of relevant microencapsulation processes and characterization in the context of maintaining stem cell potency, directing differentiation, investigating scalable production methods, and transplanting stem cells for clinically-relevant disorders.

  5. Articles

    1. Top of page
    2. Cover
    3. Contents
    4. Spotlights
    5. Review
    6. Articles
    7. Communication to the Editor
    1. Editors' Choice

      Accurate retention time determination of co-eluting proteins in analytical chromatography by means of spectral data (pages 683–693)

      Florian Dismer, Sigrid Hansen, Stefan Alexander Oelmeier and Jürgen Hubbuch

      Version of Record online: 23 OCT 2012 | DOI: 10.1002/bit.24738

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      Maximizing the information extracted from elution peaks of co-eluting proteins in analytical chromatography can significantly reduce analysis times and help identify proteins in complex mixtures. This can be achieved by looking at spectral changes over elution time measured by standard DAD detectors and a subsequent de-convolution of the elution peaks, yielding the following information: (1) number of components in the peak, (2) accurate retention times, (3) pure component spectra, (4) rough estimate of the peak areas.

    2. Biocatalysis, Protein Engineering, and Nanobiotechnology

      Assessing protein oxidation by inorganic nanoparticles with enzyme-linked immunosorbent assay (ELISA) (pages 694–701)

      Wenjie Sun, Antonia Luna-Velasco, Reyes Sierra-Alvarez and Jim A. Field

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24754

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      Increased application of engineered nanoparticles (NPs) has given rise to concerns about their toxic effects to biological systems. This study assessed the feasibility of utilizing an enzyme-linked immunosorbent assay (ELISA) to measure protein oxidation caused by NPs. The mechanisms involved in the protein oxidation by the reactive NPs (Mn2O3, Cu(0), CuO and Fe(0)) could be attributed to the combined effects of ROS-dependent and direct protein oxidation, providing insights on NP toxicity mechanisms.

    3. Tunable nano-oleosomes derived from engineered Yarrowia lipolytica (pages 702–710)

      Zhenlin Han, Catherine Madzak and Wei Wen Su

      Version of Record online: 5 NOV 2012 | DOI: 10.1002/bit.24761

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      This study demonstrates facile biosynthesis of functionalized oleosomes within oleaginous yeast Yarrowia lipolytica, by expressing oleosin fusion proteins which are specifically targeted to and anchored on the surface of the oleosomes. Engineered oleosomes having a mean diameter of 200–300 nm and with both cell-targeting and reporting activities were created and shown to be functional. The Yarrowia oleosome surface display system serves as a simple platform for creating novel “designer” nanoparticles.

    4. Increasing activity and thermal resistance of Bacillus gibsonii alkaline protease (BgAP) by directed evolution (pages 711–720)

      Ronny Martinez, Felix Jakob, Ran Tu, Petra Siegert, Karl-Heinz Maurer and Ulrich Schwaneberg

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24766

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      Directed evolution was used to simultaneously increase the activity and the thermal resistance of Bacillus gibsonii Alkaline Protease (BgAP). Three iterative rounds of directed BgAP evolution yielded a set of BgAP variants with increased specific activity (Kcat) at 15°C and increased thermal resistance. Recombination of both sets of amino acid substitutions resulted in variant MF1 with a 1.5-fold increased specific activity (15°C) and >100 times prolonged half-life at 60°C (224 min compared to 2 min of the WT BgAP). Activity-altering amino acid substitutions were from non-charged to non-charged or from sterically demanding to less demanding. Thermal stability improvements were achieved by substitutions to negatively charged amino acids in loop areas of the BgAP surface which fostered ionic and hydrogen bonds interactions.

    5. Biofuels and Environmental Biotechnology

      Rapid determination of sugar content in biomass hydrolysates using nuclear magnetic resonance spectroscopy (pages 721–728)

      Erica Gjersing, Renee M. Happs, Robert W. Sykes, Crissa Doeppke and Mark F. Davis

      Version of Record online: 18 OCT 2012 | DOI: 10.1002/bit.24741

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      1H NMR spectra can be rapidly collected for biomass hydrolysates but the region from 3.2 to 4.2 ppm contains many overlapping signals from sugars. Data from this region can be regressed with HPLC data to build PLS models in order to predict sugar concentrations for hydrolysates from a variety of biomass feedstocks.

    6. Reconstitution of cellulose and lignin after [C2mim][OAc] pretreatment and its relation to enzymatic hydrolysis (pages 729–736)

      Tong-Qi Yuan, Wei Wang, Li-Ming Zhang, Feng Xu and Run-Cang Sun

      Version of Record online: 18 OCT 2012 | DOI: 10.1002/bit.24743

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      Reconstitution of cellulose and lignin as a function of ionic liquid pretreatment was proposed as a new method to study the effects on enzymatic digestibility. The results showed that the lignin content does not significantly affect the digestibility of cellulose, whereas the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase plays an important role when an ionic liquid pretreatment of biomass was conducted.

    7. Carbohydrate derived-pseudo-lignin can retard cellulose biological conversion (pages 737–753)

      Rajeev Kumar, Fan Hu, Poulomi Sannigrahi, Seokwon Jung, Arthur J. Ragauskas and Charles E. Wyman

      Version of Record online: 18 OCT 2012 | DOI: 10.1002/bit.24744

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      In this study, it was shown that carbohydrate derived pseudo-lignin formed in dilute acid pretreatment can significantly retard cellulose biological conversion through cellulase unproductive binding and/or cellulose reduced accessibility.

    8. Application of high throughput pretreatment and co-hydrolysis system to thermochemical pretreatment. Part 1: Dilute acid (pages 754–762)

      Xiadi Gao, Rajeev Kumar, Jaclyn D. DeMartini, Hongjia Li and Charles E. Wyman

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24751

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      This study extended the application of a recently developed high throughput pretreatment and hydrolysis (HTPH) system originally developed for hydrothermal (water-only) pretreatment to dilute acid pretreatment. To neutralize the whole slurry resulting from dilute acid pretreatment and to maintain the optimum pH required for enzymes maximum activity, a novel single-step neutralization and buffering method was developed, as shown in the image, and was successfully applied for dilute acid pretreatment of several feedstocks at various pretreatment conditions showing the comparable results to conventional method.

    9. A biofilm model to understand the onset of sulfate reduction in denitrifying membrane biofilm reactors (pages 763–772)

      Youneng Tang, Aura Ontiveros-Valencia, Liang Feng, Chen Zhou, Rosa Krajmalnik-Brown and Bruce E. Rittmann

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24755

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      Engineers usually want to maximize nitrate reduction while suppressing sulfate reduction in a H2-based membrane biofilm reactor used for water or wastewater treatment. To achieve this objective, it is important to know that the onset of sulfate reduction occurs only when the nitrate concentration at the fiber's outer surface is low enough so that the growth rate of the denitrifying bacteria is at least equal to that of the sulfate-reducing bacteria.

    10. Quantitative proteomic profiling reveals photosynthesis responsible for inoculum size dependent variation in Chlorella sorokiniana (pages 773–784)

      Qian Ma, Jiangxin Wang, Shuhuan Lu, Yajin Lv and Yingjin Yuan

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24762

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      To figure out the main limit factor in high inoculum cultivation, the authors performed proteomic analyses of Chlorella sorokiniana under different inoculum sizes. Proteins in photosynthesis and Calvin cycle showed significant variations, and canonical correlation analysis of the photosynthesis-related proteins and metabolite biomarkers showed a good correlation. Subsequent proteomic analysis of C. sorokiniana under different illuminations suggested that by elegantly adjusting light conditions, high cell density cultivation and high biodiesel production might be achieved.

    11. Enhanced nitrogen removal in single-chamber microbial fuel cells with increased gas diffusion areas (pages 785–791)

      Hengjing Yan and John M. Regan

      Version of Record online: 23 NOV 2012 | DOI: 10.1002/bit.24769

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      Enhanced nitrogen removal and power densities were achieved in single-chamber microbial fuel cells (MFCs) with increased gas diffusion areas. Single-chamber air-cathode MFCs were assembled with an extra air cathode or an identical area nonplatinized diffusion cloth to double gas diffusion areas.

    12. Bioprocess Engineering and Supporting Technologies

      A reliable simulator for dynamic flux balance analysis (pages 792–802)

      K. Höffner, S. M. Harwood and P. I. Barton

      Version of Record online: 18 OCT 2012 | DOI: 10.1002/bit.24748

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      Dynamic flux balance analysis (DFBA) provides a platform for detailed design, control and optimization of biochemical process technologies. The numerical tool presented here accurately and efficiently simulates large-scale dynamic flux balance models. The main advantages of this approach are that the linear program only has to be solved when qualitative changes in the optimal flux distribution of the metabolic network occur and that it can reliably simulate behavior near the boundary of the domain where the model is defined.

    13. Bacteriophage-induced aggregation of oil sands tailings (pages 803–811)

      Susan B. Curtis, W. Scott Dunbar and Ross T.A. MacGillivray

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24745

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      Filamentous bacteriophage displaying the sequence DSQKTNPS on the pVIII coat protein induced rapid settling of diluted oil sands tailings. Genetic engineering of the displayed pVIII peptide identified the contributions of individual side chains to the aggregation process. Both the nature of the chemical side chains and the conformation that is adopted by the variable pVIII peptide appear to be important for phage-induced aggregation. These observations may be useful in the design of synthetic polymers for aggregation of oil sands tailings.

    14. Cell mass and cell cycle dynamics of an asynchronous budding yeast population: Experimental observations, flow cytometry data analysis, and multi-scale modeling (pages 812–826)

      Rita Lencastre Fernandes, Magnus Carlquist, Luisa Lundin, Anna-Lena Heins, Abhishek Dutta, Søren J. Sørensen, Anker D. Jensen, Ingmar Nopens, Anna Eliasson Lantz and Krist V. Gernaey

      Version of Record online: 12 NOV 2012 | DOI: 10.1002/bit.24749

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      In this paper, the experimentally observed dynamics of cell size and cell cycle position distributions, for a batch cultivation of Saccharomyces cerevisiae, are described using a 2-stage population balance model (PBM). Furthermore, the segregated model is coupled to a simple kinetic model describing the varying extracellular environment. The good agreement between the model predictions and the experimental observations confirms the potential of using PBM for describing dynamic microbial populations, subject to a changing extracellular environment.

    15. Evaluation of the feasibility of alcohols serving as external carbon sources for biological phosphorus removal induced by the oxic/extended-idle regime (pages 827–837)

      Dongbo Wang, Wei Zheng, Xiaoming Li, Qi Yang, Dexiang Liao and Guangming Zeng

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24753

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      This study showed that ethanol was a favorable external substrate to the oxic extended-idle regime for EBPR enhancement, and the oxic extended-idle regime can drive a better EBPR than the conventional aerobic/oxic regime when using ethonal as the sole substrate.

    16. Dye free automated cell counting and analysis (pages 838–847)

      Dietrich Dehlinger, Lynn Suer, Maher Elsheikh, José Peña and Pejman Naraghi-Arani

      Version of Record online: 7 JAN 2013 | DOI: 10.1002/bit.24757

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      We have developed an automated cell counting algorithm for the enumeration and analysis of confluent cell populations in situ. Using this method we monitor both the cell population and the state of cell infection through changes in population level shape in an automated, consistent and nondestructive, manner.

    17. Bioseparations and Downstream Processing

      Development of a platform process for adenovirus purification that removes human set and nucleolin and provides high purity vector for gene delivery (pages 848–856)

      Frank Riske, Nicole Berard, Karen Albee, Peng Pan, Mike Henderson, Kris Adams, Simon Godwin and Sherri Spear

      Version of Record online: 18 OCT 2012 | DOI: 10.1002/bit.24742

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      A robust manufacturable platform process for Adenovirus (Ad) gene vector purification is presented. The process provides highly purified Ad with very low host cell proteins including SET and nucleolin.

    18. mRNA display selection and solid-phase synthesis of Fc-binding cyclic peptide affinity ligands (pages 857–870)

      Stefano Menegatti, Mahmud Hussain, Amith D. Naik, Ruben G. Carbonell and Balaji M. Rao

      Version of Record online: 19 NOV 2012 | DOI: 10.1002/bit.24760

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      A novel method is presented for the synthesis of mRNA-display libraries of cyclic peptides by reversible library adsorption and solid-phase peptide cyclization. Peptide ligands identified through library screening have been used to purify immunoglobulins from cell culture supernatants with high yield and purity. The approach presented herein can be used to generate and evaluate cyclic peptide affinity ligands for a broad spectrum of targets.

    19. Cellular and Metabolic Engineering

      In vivo cleavage of transgene donors promotes nuclease-mediated targeted integration (pages 871–880)

      Sandra Cristea, Yevgeniy Freyvert, Yolanda Santiago, Michael C. Holmes, Fyodor D. Urnov, Philip D. Gregory and Gregory J. Cost

      Version of Record online: 23 OCT 2012 | DOI: 10.1002/bit.24733

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      Targeted transgene integration is a critical tool for genome engineering. Unfortunately some organisms (including CHO and plant cells) are refractory to targeted transgenesis due to deficits in homology-based DNA repair. In this paper, Cristea and Freyvert, and coworkers develop a homology-independent targeted DNA integration technique based on zinc-finger nucleases that should allow for efficient targeted DNA integration in all organisms. Key to the method's success is linearization of the donor DNA in vivo by the zinc-finger nucleases.

    20. Ultrahigh frequency lensless ultrasonic transducers for acoustic tweezers application (pages 881–886)

      Kwok Ho Lam, Hsiu-Sheng Hsu, Ying Li, Changyang Lee, Anderson Lin, Qifa Zhou, Eun Sok Kim and Kirk Koping Shung

      Version of Record online: 16 OCT 2012 | DOI: 10.1002/bit.24735

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      Two types of 200-MHz lensless transducer design, LiNbO3 single crystal press-focused and ZnO self-focused transducers, were developed as an ultrasound microbeam device for an acoustic tweezers application. Tightly focused acoustic beams produced by these transducers were shown to be capable of manipulating single microspheres as small as 5 µm two-dimensionally within a range of hundreds of micrometers in distilled water. The results suggest that acoustic tweezers may be a useful tool to manipulate a single cell or molecule for biomedical applications.

    21. Thiolase engineering for enhanced butanol production in Clostridium acetobutylicum (pages 887–897)

      Miriam S. Mann and Tina Lütke-Eversloh

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24758

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      A new combinatorial metabolic engineering approach to optimize biosynthetic pathways involving thiolase-dependent carbon flux limitations was developed. This strategy was employed to engineer the thiolase of Clostridium acetobutylicum for reduced sensitivity towards its physiological inhibitor, free coenzyme A, and expression of the optimized thiolase derivative was demonstrated to increase clostridial butanol production.

    22. Engineering Science of Biological Systems

      Recombinant tagging system using ribosomal frameshifting to monitor protein expression (pages 898–904)

      Se Jong Han, Sayeon Cho, Ky Lowehhaupt, So-Young Park, Sang Jun Sim and Yang-Gyun Kim

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24740

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      Rapid and accurate measurement of expressed recombinant protein: The target gene was fused to the enhanced green fluorescent protein (EGFP) gene with a -1 ribosomal frame shifting (-1RFS) element. The unfused target and the target-EGFP fusion proteins were produced at a fixed ratio showing high enzymatic activity without a large metabolic burden. Furthermore, the expression ratio between unfused and fused forms was adjustable simply by exchanging -1RFS signals. This method would be useful for the real-time monitoring of recombinant protein expression.

    23. Synthetic Biology

      In vitro selection of sialic acid specific RNA aptamer and its application to the rapid sensing of sialic acid modified sugars (pages 905–913)

      Suhyung Cho, Bo-Rahm Lee, Byung-Kwan Cho, June-Hyung Kim and Byung-Gee Kim

      Version of Record online: 5 NOV 2012 | DOI: 10.1002/bit.24737

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      The RNA aptamer showing high affinity and specificity against N-acetyl neuraminic acid, the most common member of sialic acids, was screened and engineered to the aptazyme by coupling with the ribozyme. The aptazyme displayed distinguishable activity to the sialic acid modified sugars from other sugars without the tedious process such as releasing from linked sugars, purification, and modification. This work may be very useful for the diagnosis and the rapid sensing of sialic acid modified molecules.

    24. Systems Biotechnology

      Development of thermodynamic optimum searching (TOS) to improve the prediction accuracy of flux balance analysis (pages 914–923)

      Yan Zhu, Jiangning Song, Zixiang Xu, Jibin Sun, Yanping Zhang, Yin Li and Yanhe Ma

      Version of Record online: 18 OCT 2012 | DOI: 10.1002/bit.24739

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      A novel optimization method TOS was developed to calculate the thermodynamically optimal solution, based on the energy conservation, the second law of thermodynamics, the minimum magnitude of the Gibbs free energy change and the maximum entropy production principle (MEPP). TOS was applied to five physiological conditions of E. coli and the resulting prediction accuracy was found significantly improved (10.7–48.5%), indicating that TOS can be considered an advanced calculation and prediction tool in metabolic engineering.

    25. Analyzing the effect of decreasing cytosolic triosephosphate isomerase on Solanum tuberosum hairy root cells using a kinetic–metabolic model (pages 924–935)

      Alexandre Valancin, Balasubrahmanyan Srinivasan, Jean Rivoal and Mario Jolicoeur

      Version of Record online: 18 OCT 2012 | DOI: 10.1002/bit.24747

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      In this work, the authors studied the effects of a 90% decrease in cytosolic triosephosphate isomerase expression in Solanum tuberosum hairy roots engineered with a constitutively expressed antisense RNA. Experimental data and simulations from a kinetic-metabolic model were used to demontrate that antisense roots showed increased exchanges between the pentose phosphate and the glycolytic pathways, as well as increased oxygen uptake and growth rate.

    26. Tissue Engineering and Delivery Systems

      Enhanced cell viability via strain stimulus and fluid flow in magnetically actuated scaffolds (pages 936–946)

      Julia J. Mack, Abigail A. Corrin, Sergio L. dos Santos e Lucato, James C.Y. Dunn, Benjamin W. Wu and Brian N. Cox

      Version of Record online: 11 OCT 2012 | DOI: 10.1002/bit.24736

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      A non-contact actuation system was used to explore the effects of strain stimulus on the proliferation and spatial distribution of smooth muscle cells in tubular scaffolds. Magnetically actuable scaffolds were fabricated by winding electrospun sheets of a biodegradable polymer functionalized with magnetic nanoparticles. The tubular scaffolds were actuated by a magnetic field to induce a cyclic crimping deformation, which applies strain stimulus to the cells and pumps nutrient fluid through the porous tube walls.

    27. Gene delivery to overcome astrocyte inhibition of axonal growth: An in vitro Model of the glial scar (pages 947–957)

      Hannah M. Tuinstra, Melissa M. Ducommun, William E. Briley and Lonnie D. Shea

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24750

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      An in vitro neuronal co-culture model was developed to simulate the glial scar observed in vivo, which physically and biochemically inhibits axon growth. The authors investigated gene therapy approaches to overcome this inhibition, which included miRNA to reduce deposition of chondroitin sulfate proteoglycans and expression of the enzyme chondroitinase to degrade the inhibitory ECM.

    28. Co-culture with mesenchymal stem cells enhances metabolic functions of liver cells in bioartificial liver system (pages 958–968)

      Ying Yang, Jianzhou Li, Xiaoping Pan, Pengcheng Zhou, Xiaopeng Yu, Hongcui Cao, Yingjie Wang and Lanjuan Li

      Version of Record online: 1 NOV 2012 | DOI: 10.1002/bit.24752

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      In this study, the authors developed a novel liver cell co-culture system. C3A cells were co-cultured with human placental mesenchymal stem cells (hPMSC) in microspheres placed in a fluidized bioreactor. Their results suggest that this culture system significantly improved the preservation of liver cells'metabolic functions which may greatly enhance the efficacy of bioartificial liver treatment.

    29. Covalently grafted BMP-7 peptide to reduce macrophage/monocyte activity: An in vitro study on cobalt chromium alloy (pages 969–979)

      Hark Chuan Tan, Chye Khoon Poh, Yanli Cai, Min Thun Soe and Wilson Wang

      Version of Record online: 2 NOV 2012 | DOI: 10.1002/bit.24756

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      Pristine cobalt chromium (CoCr) surfaces are doped with polydopamine. BMP-7 peptides are then covalently bound to the polydopamine coated CoCr. This modified CoCr surface with BMP-7 peptides helps reduce monocyte/macrophage-induced inflammation.

    30. Helical spring template fabrication of cell-laden microfluidic hydrogels for tissue engineering (pages 980–989)

      Guoyou Huang, Senhao Wang, Xiang He, Xiaohui Zhang, Tian Jian Lu and Feng Xu

      Version of Record online: 12 NOV 2012 | DOI: 10.1002/bit.24764

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      This work developed a simple method to fabricate microfluidic hydrogels with helical microchannels based on a helical spring template. Results from both experimental investigation and numerical modeling revealed a significant enhancement on the perfusion ability and cell viability of helical microfluidic hydrogels compared to those with straight microchannels. The feasibility of such a helical spring template method was also demonstrated for microfluidic hydrogels with complex three-dimensional channel networks such as branched helical microchannels.

    31. Bioreducible poly(amido amine)s with different branching degrees as gene delivery vectors (pages 990–998)

      Bo Zhang, Xinpeng Ma, William Murdoch, Maciej Radosz and Youqing Shen

      Version of Record online: 23 NOV 2012 | DOI: 10.1002/bit.24772

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      The branching degree of reducible PAA strongly affects its DNA binding ability, polyplexe cellular uptake and thereby gene delivery efficiency. Low branched PAA is the best in terms of these abilities.

  6. Communication to the Editor

    1. Top of page
    2. Cover
    3. Contents
    4. Spotlights
    5. Review
    6. Articles
    7. Communication to the Editor
    1. Tissue Engineering and Delivery Systems

      Laminar shear stress elicit distinct endothelial cell e-selectin expression pattern via TNFα and IL-1β activation (pages 999–1003)

      Ryan B. Huang, Anjelica L. Gonzalez and Omolola Eniola-Adefeso

      Version of Record online: 18 OCT 2012 | DOI: 10.1002/bit.24746

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      Naïve or shear-preconditioned endothelial cell (EC) monolayers were exposed to TNFα or IL-1β in static or in the presence of high laminar shear. Simultaneous presence of shear generally enhanced E-selectin expression relative to static activation in naïve ECs in response to either TNFα or IL-1β stimulation. Prior exposure to shear preconditioning mutes E-selectin expression with shear-TNFα activation, while enhancing or down-regulating shear-IL-1b induced expression, dependent on the activation period.

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