Park S.,50 Yonsei ro |
Kwon T.-G.,50 Yonsei ro |
Lee S.-Y.,50 Yonsei ro
Powder Technology | Year: 2013
Growth control and alignment of rod-like self-assemblies have been studied widely since rod-like particulates have enormous potential as components of modern devices. In this study, size-controlled magnetic microrods were prepared by evaporation-induced self-assembly (EISA) from the self-assembling organic molecule and a magnetic γ-Fe2O3 nanoparticle mixture. Sizes of the magnetic microrods were controlled by adjusting solvent evaporation temperature to produce magnetic microrods in hundreds of micrometers with high aspect ratio. Thin microrods with an aspect ratio of 129.6 were obtained by lowering the temperature to at -20°C. The prepared magnetic microrods showed superparamagnetic properties similar to that of γ-Fe2O3 nanoparticles, while the pristine microrods showed diamagnetism. Unidirectional alignment of the magnetic microrods was achieved by applying an external magnetic field. Further, the prepared magnetic microrods had different refractive indices in the axial and radial directions, which is due to the alignment of chemical bonds of the building block molecules during self-assembly. The practical outcome of this study is that fabricating self-assembled structures into ordered structures with controlled sizes is readily achievable. © 2013 Elsevier B.V.
Kim E.-J.,50 Yonsei ro |
Kim P.,50 Yonsei ro |
Lee C.-H.,50 Yonsei ro |
Sung J.,50 Yonsei ro |
And 3 more authors.
Chemical Communications | Year: 2012
A new type of porphyrin ligand bearing four triazole groups at the ortho-positions of phenyl rings in tetraphenylporphyrin was synthesized for the formation of monoporphyrinate lanthanide complexes without ancillary ligands. © 2012 The Royal Society of Chemistry.
PubMed | 50 Yonsei ro
Type: | Journal: Colloids and surfaces. B, Biointerfaces | Year: 2016
In this study, a novel cysteinyl bolaamphiphilic molecule was synthesized and its self-assembled planar suprastructure was applied as a biomimetic matrix to create a hemoglobin-mimetic oxygen adsorbent that exploits the ability of cysteine thiols to bind hemin. Self-assembly of the cysteinyl bolaamphiphilic molecule exposed cysteine thiols on its surface in the presence of -mercaptoethanol, known to reduce disulfide bonds, without which, helically coiled structures were generated. The self-assembled planar structure was used as a soft matrix to create a hemoglobin-mimetic oxygen adsorbent. The surface-exposed cysteine thiols were used to attach hemin, producing a hemin-bound, planar structure mimicking hemoglobin. This hemoglobin mimic strongly adsorbed oxygen and remained stable up to 50C. The cysteinyl bolaamphiphile self-assembled structure provided a biomimetic platform that allowed for the association of biological substances in a manner similar to natural proteins.
PubMed | 50 Yonsei ro
Type: | Journal: Colloids and surfaces. B, Biointerfaces | Year: 2012
A novel bolaamphiphile molecule exploiting biochemical functionality was synthesized and self-assembled to form a spherical reactive template for the preparation of composite metallic nanoshells. A tyrosine-containing bolaamphiphile, bis(N-alpha-amido-tyrosine)-1,7-heptane dicarboxylate, self-assembles instantaneously in an aqueous solution forming nanoscaled spheres. Instantaneous assembly of the prepared bolaamphiphile is driven by the polarity and stacking of phenol moiety in tyrosine. Through spectroscopic investigations, molecular interactions such as hydrogen bonding and - stacking of aromatic rings were found to induce the self-assembly of the molecule. The phenol moiety of tyrosine is exposed to the surface of the spherical assembly due to its polarity. Under basic conditions, the spherical assembly was used as a reactive template on which metal clusters were deposited. The surface-exposed phenol group reduced the silver ions to solid clusters, and these clusters were further exploited as catalysts for the gold layer deposition. This study illustrates that the bolaamphiphilic molecule with designed biochemical functionality provides a facile way to prepare supramolecular structures with chemical activity.
PubMed | 50 Yonsei ro
Type: | Journal: Colloids and surfaces. B, Biointerfaces | Year: 2015
Adopting the strong metal binding moiety of a mussel protein, a novel bolaamphiphile molecule was prepared and applied to the fabrication of magnetic core-shell nanoparticles. The novel bolaamphiphile molecule with 3,4-dihydroxyphenylalanine (DOPA) end groups was synthesized and its self-assembly was used as a template to adsorb metal ions and subsequently to produce magnetic nanoparticles. The DOPA bolaamphiphile molecule self-assembled in aqueous solution to produce nanospherical structures that exposed the catechol moiety of DOPA to the outer surface. The catechol groups adsorbed cobalt and iron ions to create magnetic metal oxide clusters on the self-assembly. Spectroscopic analysis showed that the cobalt and iron ions were coordinated with quinone, an oxidized form of the catechol. Exploiting the strong metal-adsorbing and binding properties of DOPA, dense cobalt oxide and iron oxide shell layers were created on the nanospherical self-assembly to produce magnetic core-shell nanoparticles. This study demonstrated a simple method for creating magnetic metal oxide nanoparticles that exploits the molecular binding forces and self-assembly property of DOPA.