Sarker, Md, Naghieh, Saman, McInnes, Adam D., Schreyer, David J., and Chen, Xiongbiao
Biotechnology Journal. July 2018, Vol. 13 Issue 7, n/a
Control systems, Biomedical engineering, Rapid prototyping, and College teachers
Byline: Md Sarker, Saman Naghieh, Adam D. McInnes, David J. Schreyer, Xiongbiao Chen Nerve guidance conduits (NGCs) have been drawing considerable attention as an aid to promote regeneration of injured axons across damaged peripheral nerves. Ideally, NGCs should include physical and topographic axon guidance cues embedded as part of their composition. Over the past decades, much progress has been made in the development of NGCs that promote directional axonal regrowth so as to repair severed nerves. This paper briefly reviews the recent designs and fabrication techniques of NGCs for peripheral nerve regeneration. Studies associated with versatile design and preparation of NGCs fabricated with either conventional or rapid prototyping (RP) techniques have been examined and reviewed. The effect of topographic features of the filler material as well as porous structure of NGCs on axonal regeneration has also been examined from the previous studies. While such strategies as macroscale channels, lumen size, groove geometry, use of hydrogel/matrix, and unidirectional freeze-dried surface are seen to promote nerve regeneration, shortcomings such as axonal dispersion and wrong target reinnervation still remain unsolved. On this basis, future research directions are identified and discussed. Biographical information: Md Sarker is currently a Ph.D. student in the Division of Biomedical Engineering at the University of Saskatchewan (Canada). His Ph.D. research focused on the regeneration of damaged peripheral nerve tissue with bioplotted scaffolds. His research interests also include 3D biofabrication with extrusion based technique, evaluation of gelation property of ionic crosslinkers, in vitro study of neuron cells, and covalent binding of peptide molecules with hydrogels. Chen is a Professor with the Department of Mechanical Engineering and Division of Biomedical Engineering, University of Saskatchewan (UofS), Canada. Dr. Chen received his PhD from UofS in 2002; after 1.5 years of PDF at Queen's University, Canada, he joined the UofS as an Assistant Professor, then was promoted to Associate Professor and Full Professor in 2007 and 2010, respectively. During his career, he has conducted research in the interdisciplinary areas of bio-fabrication of scaffolds to replace/repair damaged tissues or organs, and mechatronics to model and control complex systems for improved performance.
Moore, Simon J., Lai, Hung-En, Needham, Hannah, Polizzi, Karen M., and Freemont, Paul S.
Biotechnology Journal. April 2017, Vol. 12 Issue 4, n/a
Fine chemicals, Metabolites, Enzymes, Gene expression, and Codon
Byline: Simon J. Moore, Hung-En Lai, Hannah Needham, Karen M. Polizzi, Paul S. Freemont Keywords: Cell-free; Gene expression; Streptomyces; Synthetic biology; Tetracycline Abstract Streptomyces venezuelae is a promising chassis in synthetic biology for fine chemical and secondary metabolite pathway engineering. The potential of S. venezuelae could be further realized by expanding its capability with the introduction of its own in vitro transcription-translation (TX-TL) system. TX-TL is a fast and expanding technology for bottom-up design of complex gene expression tools, biosensors and protein manufacturing. Herein, we introduce a S. venezuelae TX-TL platform by reporting a streamlined protocol for cell-extract preparation, demonstrating high-yield synthesis of a codon-optimized sfGFP reporter and the prototyping of a synthetic tetracycline-inducible promoter in S. venezuelae TX-TL based on the tetO-TetR repressor system. The aim of this system is to provide a host for the homologous production of exotic enzymes from Actinobacteria secondary metabolism in vitro. As an example, the authors demonstrate the soluble synthesis of a selection of enzymes (12-70 kDa) from the Streptomyces rimosus oxytetracycline pathway. Supporting information: Additional Supporting Information may be found in the online version of this article As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. CAPTION(S): Supporting Information
Soares, Ruben R. G., Silva, Daniel F. C., Fernandes, Pedro, Azevedo, Ana M., Chu, Virginia, Conde, Joao P., and Aires-Barros, M. Raquel
Biotechnology Journal. Dec 2016, Vol. 11 Issue 12, p1498, 15 p.
Byline: Ruben R. G. Soares, Daniel F. C. Silva, Pedro Fernandes, Ana M. Azevedo, Virginia Chu, Joao P. Conde, M. Raquel Aires-Barros Keywords: Aqueous two-phase systems; Microchannel; Microfluidics; Partition; Separation Abstract Aqueous two-phase extraction (ATPE) is a biocompatible liquid-liquid (L-L) separation technique that has been under research for several decades towards the purification of biomolecules, ranging from small metabolites to large animal cells. More recently, with the emergence of rapid-prototyping techniques for fabrication of microfluidic structures with intricate designs, ATPE gained an expanded range of applications utilizing physical phenomena occurring exclusively at the microscale. Today, research is being carried simultaneously in two different volume ranges, mL-scale (microtubes) and nL-scale (microchannels). The objective of this review is to give insight into the state of the art at both microtube and microchannel-scale and to analyze whether miniaturization is currently a competing or divergent technology in a field of applications including bioseparation, bioanalytics, enhanced fermentation processes, catalysis, high-throughput screening and physical/chemical compartmentalization. From our perspective, both approaches are worthy of investigation and, depending on the application, it is likely that either (i) one of the approaches will eventually become obsolete in particular research areas such as purification at the preparative scale or high-throughput screening applications; or (ii) both approaches will function as complementing techniques within the bioanalytics field.
Byline: , , Yang Liu, Haibo Yu, Lianqing Liu, Yang Shi, Yanfeng Li, Jianhua Qin Keywords: Drug screening; Hypoxia-inducible factors (HIFs); Micro-patterning; Multicellular spheroids; Phenotype transition Abstract 3D multicellular spheroid models are of great value in the investigation of tumor biology and tumor responses to chemotherapy and radiation. To establish a mimicking tumor microenvironment in vitro, we developed a straightforward method by patterning hypoxic multicellular spheroids in a 3D matrix. The efficacy of this approach was evaluated by characterizing spheroid formation, invasive capability and phenotypic transition in aggressive human glioma cells. We observed enhanced cell proliferation, spheroid formation and invasive capability in U87 glioma cells transfected with hypoxia-inducible factors (HIFs) compared with non-treated cells. We also demonstrated that the overexpression of HIFs in hypoxic glioma cells may promote cell migration by epithelial-mesenchymal transition within the 3D matrix. Compared with conventional 3D culturing techniques, the simple operation, rapid prototyping, low cost and high throughput format of the micro-patterning method facilitates the characterization of cell proliferation, migration, phenotypic function and drug evaluation in physiologically relevant 3D microenvironments. This in vitro 3D system can recapitulate the physiologically relevant tumor microenvironment and is a promising method for 3D anti-tumor drug screening and the identification of novel targets for tumor invasion and angiogenesis. Article Note: These authors contributed equally to this work.