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양병선(Byeongseon Yang),윤진영(Jin Young Yun),차형준(Hyung Joon Cha) 한국해양바이오학회 2018 한국해양바이오학회지 Vol.10 No.2
Silicon has become of increasing importance as the basic element of many high-technology products. Its synthesis is very difficult requiring high temperature solid-state reactions (>100 0℃) or lower temperature methods (100-200℃) involving hydrothermal and solvothermal reactions under extreme pH conditions. In nature, on the other hand, a wide range of living organisms have collectively evolved the means of biosilicification at the astounding rate of gigatons/year. This is impressive because biosilicification in these organisms occurs under mild physiological conditions. Marine sponges possess the ability to sequester soluble silicon sources from their environments and assemble them into intricate 3D architecture. The advent of molecular biology has recently made it possible to glean molecular information about biosilicification from these systems and it turned out that enzyme silicatein is the core of biosilicification. In this review, biosilicification regulated by silicatein and its mechanism are described. Also, production of silicatein through recombinant technology and several applications of recombinant silicatein are described including immobilization of silicatein, formation of Au or Ag nanoparticles on nanowires, nanolithography approaches, core-shell materials, encapsulation, bone replacement materials, and microstructured optical fibers.
Synthesis of silica nanoparticles using biomimetic mineralization with polyallylamine hydrochloride
Kang, Kyoung-Ku,Oh, Hyun-Seok,Kim, Dong-Young,Shim, Gyurak,Lee, Chang-Soo Elsevier 2017 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.507 No.-
<P><B>Abstract</B></P> <P>To synthesize silica particles under mild conditions, we proposed a biomimetic synthesis method. The synthesis process was carried out based on a biphasic sol-gel synthesis method using TEOS (tetraethyl orthosilicate) as a silica source and PAH (polyallylamine) as a substitute for proteins of marine microorganisms for biosilicification. The function and activity of the PAH, used as a replacement for bioactive substances, were confirmed through comparisons between control experiments and designed experiments. The PAH exhibited the ability accelerate condensation with hydrolyzed TEOS in aqueous solutions. The PAH also exhibited high condensation activity in acidic and neutral conditions to produce silica particles. Moreover, PAH also created the nuclei of the silica particles, and the number of nuclei could be controlled by the concentration of PAH. In addition to exhibiting these unique capabilities, PAH did not generate any complexes or composites with the silica species. Depending on the synthesis conditions, the synthesized silica particles exhibited various shapes, such as sponge-like, self-assembled, irregular spherical and completely spherical shapes. The sizes of the primary particles were diverse, with a range from 10nm to 50nm. In particular, by adjusting the PAH concentration, it was possible to obtain nearly perfect spherical-shaped silica nanoparticles with uniform sizes, which has rarely been reported. Above all, using this paper, we can get closer to understanding the principles of silica formation using PAH as a replacement for the bioactive proteins of microorganisms.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spherical and monodispersed silica nanoparticles were synthesized by using PAH. </LI> <LI> PAH is strongly involved in nucleation and condensation reactions of silica. </LI> <LI> PAH can accelerate the nucleation and condensation of the hydrolyzed TEOS. </LI> <LI> PAH has a relatively very weak interaction with aqueous silicates. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Bioinspired Synthesis of Micelle-templated Silica Nanocapsules for Biocatalysts
Ae Sol LEE,Chang Sup KIM 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Enzymes have various advantages compared to chemical catalysts, including their high selectivity to a substrate and less production of byproducts. However, it remains a challenge to use enzymes in practical applications due to their low stability under harsh conditions. In this study, we developed biocatalytic silica nanoparticles templated from R5 peptide- and enzyme-functionalized micelle using two-phase biosilicification. Carbonic anhydrase (CA) was used as a target enzyme, which catalyzes a hydration reaction of carbon dioxide. Each CA and silica forming peptide R5 was covalently conjugated with NHS-ester functionalized hydrophilic ends of triblock copolymer F127 (F127-CA and F127-R5). CA- and R5 peptide-functionalized micelles (F127-CA/R5 micelle) were prepared by controlling a molar ratio of F127-CA and F127-R5. Biocatalytic silica nanoparticles (F127-CA/R5 micelle@SiNP) were synthesized from F127-CA/R5 micelles using the two-phase biosilicification method. F127-CA/R5 micelle@SiNP showed a porous structure with a thin silica layer. Furthermore, it showed enhanced thermal and storage stability compared to the free enzymes without a reduction in activity. We expected that this proposed method would present a direction for the use of enzymes as biocatalysts in practical applications.
4차화된 2-(디메틸아미노)에틸메타크릴레이트 고분자에 의한 실리카 박막의 생체모방 합성
정영환(Young-Hwan Jung) 산업기술교육훈련학회 2008 산업기술연구논문지 (JITR) Vol.13 No.1
Biosilicification in diatoms is achieved by specific interactions between silaffins, composed of polypeptides and long-chain polyamines, and silicic acid derivatives. The polycondensation of silicic acids is reported to be catalyzed by the long-chain polyamines that mainly contain tertiary N -methylpropyleneimine moieties. In this paper, we utilized a quaternized poly(2-(dimethylamino)ethyl methacrylates) (PDMAEMA) as a surface-grafted, biomimetic counterpart of the long-chain polyamines in silaffins and demonstrated that the surface-initiated polycondensation of silicic acids, leading to the formation of silica thin films. The formed silica thin films were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM).
Choi, O.,Kim, B.C.,An, J.H.,Min, K.,Kim, Y.H.,Um, Y.,Oh, M.K.,Sang, B.I. IPC Science and Technology Press ; Elsevier Scienc 2011 Enzyme and microbial technology Vol.49 No.5
We constructed a fusion protein (GOx-R5) consisting of R5 (a polypeptide component of silaffin) and glucose oxidase (GOx) that was expressed in Pichia pastoris. Silaffin proteins are responsible for the formation of a silica-based cell matrix of diatoms, and synthetic variants of the R5 protein can perform silicification in vitro[1]. GOx secreted by P. pastoris was self-immobilized (biosilicification) in a pH 5 citric buffer using 0.1M tetramethoxysilane as a silica source. This self-entrapment property of GOx-R5 was used to immobilize GOx on a graphite rod electrode. An electric cell designed as a biosensor was prepared to monitor the glucose concentrations. The electric cell consisted of an Ag/AgCl reference electrode, a platinum counter electrode, and a working electrode modified with poly(neutral red) (PNR)/GOx/Nafion. Glucose oxidase was immobilized by fused protein on poly(neutral red) and covered by Nafion to protect diffusion to the solution. The morphology of the resulting composite PNR/GOx/Nafion material was analyzed by scanning electron microscopy (SEM). This amperometric transducer was characterized electrochemically using cyclic voltammetry and amperometry in the presence of glucose. An image produced by scanning electron microscopy supported the formation of a PNR/GOx complex and the current was increased to 1.58μAcm<SUP>-1</SUP> by adding 1mM glucose at an applied potential of -0.5V. The current was detected by way of PNR-reduced hydrogen peroxide, a product of the glucose oxidation by GOx. The detection limit was 0.67mM (S/N=3). The biosensor containing the graphite rod/PNR/GOx/Nafion detected glucose at various concentrations in mixed samples, which contained interfering molecules. In this study, we report the first expression of R5 fused to glucose oxidase in eukaryotic cells and demonstrate an application of self-entrapped GOx to a glucose biosensor.
Yang, Sung Ho,Park, Ji Hun,Cho, Woo Kyung,Lee, Hee-Seung,Choi, Insung S. WILEY-VCH Verlag 2009 Small Vol.5 No.17
<B>Graphic Abstract</B> <P>A simple change of counteranions in catalytic templates for biomimetic silicification on surfaces dictates the size of silica nanostructures formed. It is found that the charge density of the counteranions plays an important role in controlling the structures of both templates and silica in the biomimetic silicification on surfaces (see image; scale bar = 500 nm). <img src='wiley_img/16136810-2009-5-17-SMLL200900440-content.gif' alt='wiley_img/16136810-2009-5-17-SMLL200900440-content'> </P>