Papers by Keyword: Molecular-Recognition

Abstract: Submicron-sized monodisperse and spherical poly(N-isopropylacrylamide-co-glycidyl methacrylate)-β-cyclodextrin (PNG-CD) microgels with both thermo-responsive and molecular-recognition characteristics have been successfully fabricated via soap-free emulsion polymerization and subsequent chemical modification method. The thermo-responsivity of the microgels is based on the volume phase transition of poly(N-isopropylacrylamide) (PNIPAM) and the molecular-recognition property is based on the host-guest inclusion complexation of β-cyclodextrin (β-CD) units with specific guest molecules. The as-prepared microgels are characterized by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), and dynamic light scattering (DLS) instrument. When β-CD is introduced onto the PNG-CD microgels, the volume phase transition temperature (VPTT) of resultant PNG-CD microgels shifts about 6 °C to a higher temperature in comparison with that of corresponding PNG microgels. When the β-CD units in PNG-CD microgels recognize 8-anilino-1-naphthal-enesulfonic acid ammonium salt (ANS) molecules in aqueous solution, the VPTT of PNG-CD microgels shifts around 3 °C negatively to a lower temperature. PNG-CD microgels present molecular-recognition induced swelling characteristics at fixed temperature. The results in this study provide valuable information for development of monodisperse and spherical dual thermo-responsive and molecular-recognition microgels which have potential applications in the fields of microscale molecular sensors and actuators and so on.

Abstract: We have prepared a variety of biomolecule-responsive hydrogels by using biomolecular complexes as reversible crosslinking points. This paper describes two types of biomolecule-responsive hydrogels that undergo volume changes in response to target biomolecules, which were prepared using biomolecular complexes such as antigen-antibody complexes and saccharide-lectin complexes. One is a biomolecule-crosslinked hydrogel that can swell in response to a target biomolecule and the other is a biomolecule-imprinted hydrogel that can shrink. The antigen-responsive hydrogels as biomolecule-crosslinked hydrogels swelled in the presence of a target antigen due to the dissociation of antigen-antibody complexes that played a role as reversible crosslinking points. On the other hand, the tumor marker glycoprotein-responsive hydrogels as biomolecule-imprinted hydrogels shrank in response to a target glycoprotein due to the complex formation between ligands (lectin and antibody) and the target molecule (saccharide and peptide chains of glycoprotein). This paper focuses on synthetic strategy of the biomolecule-responsive hydrogels and their responsive behavior for target biomolecules.

Abstract: As a basic study to search a molecular recognition site in electron transfer proteins, optically-active ruthenium complexes, [RuII/III(bcmaa)(bpy)] (BCMAA: N,Nbis( carboxymethyl)amino acid, BPY: 2,2’-bipyridine), were designed and prepared. The electron transfer reaction with cytochrome c553 (Alcaligenes xylosoxidans GIFU1051) was kinetically investigated, and its enantio-selectivity was detected. Based on the results of enantio-selective behavior for cytochrome c553, the local structure of molecular recognition site of cytochrome c553 was discussed.