Microreaction technology is an interdisciplinary area of science and engineering. It has attracted the attention of researchers from different fields in the past few years and consequently, several microreactors have been developed. Enzymes are organic catalysts used for the production useful substances in an environmentally friendly way, and have high potential for analytical applications. However, relatively few enzymatic processes have been commercialized because of problems in the stability of enzyme molecule, and the cost and efficiency of the reactions. Thus, there have been demands for innovation in process engineering particularly for enzymatic reactions, and microreaction devices can serve as efficient tools for the development of enzyme processes. In this review, we summarize the recent advances of microchannel reaction technologies and focus our discussion on enzyme microreactors. We discuss the manufacturing process of microreaction devices and the advantages of microreactors compared with the conventional reactors. Fundamental techniques for enzyme microreactors and important applications of this multidisciplinary technology in chemical processing are also included in our topics. Biotechnology and Genetic Engineering Reviews -Vol. 25, 405-428 (2008) *To whom correspondence may be addressed (m.miyazaki@aist.go.jp or maeda-h@aist.go.jp) #Present address: Department of Pharmacology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan Abbreviations: NTA, N,N-bis(carboxymethyl)glycine, which binds Nickel (II) ion, and usually applied for identification/purification of histidine tag of the engineered enzyme molecule; LIGA, Lithography, Electroplating, and Molding; PEEK, poly(ether ether ketone).
Elastin, one of the extracellular matrix components, is present in tissues requiring extensibility and resilience such as the aorta, lungs, ligaments and skin. Degradation of elastin is observed in diseases such as atherosclerosis, emphysema and metastasis. It has been suggested that degraded elastin-derived peptides interact with a variety of cell types and are involved in development of diseases. Two nonapeptides, Ala-Gly-Val-Pro-Gly-Leu-Gly-Val-Gly (AGVPGFGVG) and Ala-Gly-Val-Pro-Gly-Phe-Gly-Val-Gly (AGVPGFGVG), exist in hydrophobic regions of elastin. In this paper, we characterized these elastin-derived nonapeptides by macrophage migration assay. Both nonapeptides induced a maximal migration at 10(-8) M and elicited the same degree of responsiveness. To investigate the role of the sixth residue of the nonapeptides, seven analog peptides in which Leu or Phe is substituted by Ile, Val, Ala, Gly, Pro, Lys or Glu were synthesized and their macrophage migration activity tested. Among the nonapeptide analogs, only Ala-Gly-Val-Pro-Gly-Ile-Gly-Val-Gly induced the migration of macrophages at the optimal concentration of 10(-9) M and its responsiveness was the same as that of parent nonapeptide AGVPGFGVG. Results of the deactivation tests and the effect of lactose on macrophage migration showed that a lactose-insensitive receptor which mainly recognizes Ala-Gly-Val-Pro-Gly-Ile-Gly-Val-Gly is presumably present on the membrane of macrophages in addition to the elastin-binding protein (EBP) sensitive to lactose. These results suggest that Leu, Phe and Ile residues at the sixth position of elastin-derived nonapeptides are crucial for inducing macrophage migration and in particular, Ile residue is important for the recognition by receptor insensitive to lactose.
We developed a simple immobilisation method for His-tagged enzymes on a microchannel surface. It facilitates immobilisation of protein molecule on microchannel surface through Ni-complex, using crude or purified protein solutions. By this method, we could immobilize proteins on microcapillary constantly. This method might be useful for further development of microreactor with reversibly immobilized enzymes.
A microchannel forms a laminar flow if the fluid velocity is sufficiently slow. It is important to clarify the effect of gravity on laminar flow, since several microsystems require side-by-side laminar flow, which does not possess an interfacial tension. In this work, the influence of gravity on side-by-side laminar flow was quantitatively investigated using a computational fluid dynamics (CFD) simulation. As a result, a dimensionless parameter related to side-by-side laminar flow interfacial tilting was derived. Using this parameter, it was possible to estimate the interfacial tilting angle. The results reported here will be useful for microdevice design for chemical analysis, mixing, and chemical reactions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.