title: New functional amorphous calcium phosphate nanocomposites by enzyme-assisted biomineralization.
abstract: In the present study, we report on enzyme-assisted formation of biomineralized amorphous calcium phosphate nanocomposites (ACP-NCs). About 100-200 nm sizes of the spherical porous enzyme-assisted ACP-NCs were successfully synthesized via double reverse microemulsion, but no ACP-NCs formed without the enzyme. It is believed that the enzyme was used as an organic template or additive that could regulate the biomineralization process. The enzyme-assisted ACP-NCs were well characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, dynamic light scattering, and Brunauer-Emmett-Teller (BET) criteria. The BET surface area, total pore volume, pore size from adsorption, and pore size from desorption of the ACP-NCs were 163 m(2) g(-1) or 0.37 cm(3) g(-1), 8.87 nm, and 7.48 nm, respectively. The enzyme-assisted ACP-NCs retained about 43% of the catalytic activity of free carboxyl esterase. Furthermore, they preserved their bioactivity even after the 10th reuse and were stable over 10 days even under a stringent shaking conditions. The reported method paves the way for novel biomineralization via enzyme molecules to form functional enzymes containing nanocomposites.
authors.affiliation: College of Life Sciences and Biotechnology, Korea University, Anam-dong, Seongbuk-Gu, Seoul, 136-701, South Korea.
authors.forename: Ee Taek
authors.initials: ET
authors.lastname: Hwang
authors.forename: Rameshwar
authors.initials: R
authors.lastname: Tatavarty
authors.forename: Jinyang
authors.initials: J
authors.lastname: Chung
authors.forename: Man Bock
authors.initials: MB
authors.lastname: Gu
mesh_terms: D000327:Adsorption; D055162:Biocatalysis; D002130:Calcium Phosphates / Q000138:chemical synthesis / Q000737:chemistry*; D004950:Esterases / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D016062:Porosity
chemical_list: D002130:Calcium Phosphates; D011108:Polymers; C519480:amorphous calcium phosphate; D004950:Esterases