ブックタイトル高分子　POLYMERS　62巻12月号

概要

高分子　POLYMERS　62巻12月号

高分子科学最近の進歩Front-Line Polymer ScienceThis type of material could be used as a colorimetricglucose sensor that can provide the desired monitoringof glucose levels using simple macroscopic visualobservation.（Fig.3d）3.2.3.2 EnzymeAmong studies of smart hydrogels, a relatively newarea is the use of selective enzyme-catalyzed reactionsfor hydrogel design. Typically, an enzyme-responsivehydrogel is composed of an enzyme substrate and asensitive component that can trigger a macroscopicstimulus response of the hydrogel. The enzymaticreaction will directly result in changes in the swellingof the hydrogel（see II）. Sailor et al. 53）prepared anenvironmentally benign two-layer porous silicon PhCnanostructure by electrochemical etching for sensingby enzymes（Fig.4）. The upper layer contained largepores that trapped a protease and acted as a reactor.The lower layer had smaller pores that could excludethe proteases and other large proteins. Infiltrationof protease-digested fragments into the lower layerchanged the refractive index of the sensor and produceda measurable change in optical reflectivity. Comparedwith its refractive index, the lattice change caused astop-band shift by the responsive PhCs that could bebetter recognized and could sometimes even coverthe entire visible spectrum. To improve sensitivityof detection, inverse opals that possess greaterdiscrimination enabling the diffusion of biomoleculesthrough the pores were covalently immobilized withenzymes. The porosity serves both as the source of theiridescent color and as a facilitator of the diffusion.3.2.3.3 Antigen?antibodyTaking advantage of the specific binding reactionbetween an antigen and its corresponding antibody,one can obtain an antigen-responsive hydrogel byusing antigen?antibody binding to cross-link polymersin the hydrogels. Miyata et al. 54）were the first tocombine antibodies with smart hydrogels to prepareantigen-responsive smart hydrogels（Fig.5a, I I）.Kang et al. 55）,56）combined such smart hydrogels withblock copolymer PhCs. They self-assembled the blockcopolymer to form a layered structure. As shown inthe schematic in Fig.5b, the block copolymer had aperiodic layered structure. They modified the antipathogen-specificantibodies on the hydrophilic layerby chemical modification and achieved a visuallydetectable response to the presence of the pathogen.Our group has done extensive work in the field ofsmart PhC hydrogels. We developed inverse-opal PhCmicroparticles for label-free multiplex bioassays based＊は、e！高分子のSupporting Informationにハイパーリンクされています。高分子62巻12月号（2013年）Fig.4Schematic illustration of a double-layer porous siliconphotonic crystal used for protein sensing. 53）Fig.5（a）Antigen-antibody-responsive hydrogel；（b）Pathogenresponsive block copolymer PhC.54）, 55）on antigen?antibody recognition. 57）The microparticleswere formed by droplet crystallization of a suspensionof silica nanoparticles and polystyrene spheres insilicone oil. The polystyrene spheres were removedby high-temperature calcination, leaving an orderednetwork of interconnected macropores in inverse opalPhC microparticles. The reflection position of thispeak, which can be varied by changing the size of thepolystyrene spheres, was used as the encoding element.Through the selective recognition of antigens by theantibodies, label-free multiplex biorecognition can beobserved based on a shift of reflection spectra, whichresults from specific analyte binding causing changesin the average refractive index of the microparticles.3.2.3.4 DNADeoxyribonucleic acid（DNA）is composed of the fourbases A, T, C and G. According to the complementarybase principle, smart hydrogels with single-strandedDNA as their cross-linking agent could specificallyrecognize free complementary single-stranded DNAand could result in some physicochemical propertychange in the hydrogels（Fig.6a, I I）.58）Basedon this principle, we have developed a new type ofDNA-responsive PhC microparticle using acrylamidemonomer bound to DNA cross-linkers as essentialmaterials. 59）In a solution of matching DNA, specificc2013 The Society of Polymer Science, Japan747