title: Controlled structure and properties of silicate nanoparticle networks for incorporation of biosystem components.
abstract: Inorganic nanoparticles are of technological interest in many fields. We created silicate nanoparticle hydrogels that effectively incorporated biomolecules that are unstable and involved in complicated reactions. The size of the silicate nanoparticles strongly affected both the physical characteristics of the resulting hydrogel and the activity of biomolecules incorporated within the hydrogel. We used high-resolution transmission electron microscopy (TEM) to analyze in detail the hydrogel network patterns formed by the silicate nanoparticles. We obtained clear nanostructured images of biomolecule-nanoparticle composite hydrogels. The TEM images also showed that larger silicate nanoparticles (22 nm) formed more loosely associated silicate networks than did smaller silicate nanoparticles (7 nm). The loosely associated networks formed from larger silicate nanoparticles might facilitate substrate diffusion through the network, thus promoting the observed increased activity of the entrapped biomolecules. This doubled the activity of the incorporated biosystems compared with that of biosystems prepared by our own previously reported method. We propose a reaction scheme to explain the formation of the silicate nanoparticle networks. The successful incorporation of biomolecules into the nanoparticle hydrogels, along with the high level of activity exhibited by the biomolecules required for complicated reaction within the gels, demonstrates the nanocomposites' potential for use in medical applications.
authors: Division of Drugs, National Institute of Health Sciences, Tokyo, Japan. kumikato@nihs.go.jp
authors: Kumiko
authors: K
authors: Sakai-Kato
authors: Toshiaki
authors: T
authors: Hasegawa
authors: Akio
authors: A
authors: Takaoka
authors: Masaru
authors: M
authors: Kato
authors: Toshimasa
authors: T
authors: Toyo'oka
authors: Naoko
authors: N
authors: Utsunomiya-Tate
authors: Toru
authors: T
authors: Kawanishi
mesh_terms: D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005453:Fluorescence; D006801:Humans; D057446:Hydrodynamics; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry; D008861:Microsomes / Q000201:enzymology; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D017640:Silicates / Q000737:chemistry*; D013997:Time Factors
chemical_list: D017640:Silicates; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D003577:Cytochrome P-450 Enzyme System