A Biocompatible Bottom-Up Route for the Preparation

MARÍA C. GUTIÉRREZ; MATÍAS JOBBÁGY; NOELIA RAPÚN; MARÍA L. FERRER; FRANCISCO DEL MONTE

ADVANCED MATERIALS

WILEY-V C H VERLAG GMBH

Lugar: WEINHEIM, GERMANY; Año: 2006 vol. 18 p. 1137 - 1140

0935-9648

Structurally organized inorganic materials[1] are attracting much attention for emerging applications (e.g., catalysis, storage- and controlled-release systems, smart fillers, and biotechnologies), since they offer the desirable combination of high internal reactive surface area, produced by narrow nanopores, and facile molecular transport possible through broad “highways” leading to and from these pores.[2] The incorporation of biomolecules within such organized materials with full preservation of their native structures would result in the achievement of functional materials with increased levels of spatial organization, that is, in hierarchically organized functional materials. Since the discovery of mesoporous materials,[3] the most widely used strategy, which provides control of the scale and degree of porosity in silica-based materials, is template-directed assembly. This method basically consists of using alkoxide precursors and molecular, supramolecular, or colloidal-crystal templates to prepare microporous, mesoporous, or macroporous materials, respectively.[4] Moreover, the combined use of different templates has recently facilitated the achievement of materials with bimodal and even trimodal pore structures.[5][1] are attracting much attention for emerging applications (e.g., catalysis, storage- and controlled-release systems, smart fillers, and biotechnologies), since they offer the desirable combination of high internal reactive surface area, produced by narrow nanopores, and facile molecular transport possible through broad “highways” leading to and from these pores.[2] The incorporation of biomolecules within such organized materials with full preservation of their native structures would result in the achievement of functional materials with increased levels of spatial organization, that is, in hierarchically organized functional materials. Since the discovery of mesoporous materials,[3] the most widely used strategy, which provides control of the scale and degree of porosity in silica-based materials, is template-directed assembly. This method basically consists of using alkoxide precursors and molecular, supramolecular, or colloidal-crystal templates to prepare microporous, mesoporous, or macroporous materials, respectively.[4] Moreover, the combined use of different templates has recently facilitated the achievement of materials with bimodal and even trimodal pore structures.[5][2] The incorporation of biomolecules within such organized materials with full preservation of their native structures would result in the achievement of functional materials with increased levels of spatial organization, that is, in hierarchically organized functional materials. Since the discovery of mesoporous materials,[3] the most widely used strategy, which provides control of the scale and degree of porosity in silica-based materials, is template-directed assembly. This method basically consists of using alkoxide precursors and molecular, supramolecular, or colloidal-crystal templates to prepare microporous, mesoporous, or macroporous materials, respectively.[4] Moreover, the combined use of different templates has recently facilitated the achievement of materials with bimodal and even trimodal pore structures.[5][3] the most widely used strategy, which provides control of the scale and degree of porosity in silica-based materials, is template-directed assembly. This method basically consists of using alkoxide precursors and molecular, supramolecular, or colloidal-crystal templates to prepare microporous, mesoporous, or macroporous materials, respectively.[4] Moreover, the combined use of different templates has recently facilitated the achievement of materials with bimodal and even trimodal pore structures.[5][4] Moreover, the combined use of different templates has recently facilitated the achievement of materials with bimodal and even trimodal pore structures.[5][5] Template removal (e.g., by thermal or dissolution treatments) yields a hierarchically organized material with a structure that is a replica of the original template. Even though the application of these processes is widespread, the synthesis of hierarchical biohybrid materials is rare. This is most likely because of the chemical nature of the templates employed and/or the processes used for their removal, which, in practice, have limited the composition of the resulting bimodal/ trimodal pore structures to inorganic ones. More usual are hierarchical hybrid materials based on polymer networks and inorganic nanoparticles.[6] Zhang et al. recently reported on the preparation of aligned 2D and 3D structures of polymers and inorganic nanoparticles following a similar synthetic approach to that reported by Mukai et al. for the preparation of microhoneycombed silica macrostructures.[ 7,8] The process involves the submission of an aqueous gel to liquid-nitrogen temperatures. The rapid ice formation (hexagonal form) causes every solute originally dispersed in the aqueous gel to be segregated from the ice phase, giving rise to a hierarchical assembly characterized by “fences” of matter enclosing empty areas where the ice originally resided. Note that one of the main interests of this ice-segregation-induced self-assembly (ISISA) process for the preparation of hierarchical assemblies resides in its highly biocompatible character, as pointed out recently by our group.[9] More recently, McCann et al. and Deville et al. also applied the ISISA process for the preparation of highly porous polymer fibers[10] and hydroxyapatite scaffolds with nacreous architectures,[ 11] respectively.[6] Zhang et al. recently reported on the preparation of aligned 2D and 3D structures of polymers and inorganic nanoparticles following a similar synthetic approach to that reported by Mukai et al. for the preparation of microhoneycombed silica macrostructures.[ 7,8] The process involves the submission of an aqueous gel to liquid-nitrogen temperatures. The rapid ice formation (hexagonal form) causes every solute originally dispersed in the aqueous gel to be segregated from the ice phase, giving rise to a hierarchical assembly characterized by “fences” of matter enclosing empty areas where the ice originally resided. Note that one of the main interests of this ice-segregation-induced self-assembly (ISISA) process for the preparation of hierarchical assemblies resides in its highly biocompatible character, as pointed out recently by our group.[9] More recently, McCann et al. and Deville et al. also applied the ISISA process for the preparation of highly porous polymer fibers[10] and hydroxyapatite scaffolds with nacreous architectures,[ 11] respectively.[ 7,8] The process involves the submission of an aqueous gel to liquid-nitrogen temperatures. The rapid ice formation (hexagonal form) causes every solute originally dispersed in the aqueous gel to be segregated from the ice phase, giving rise to a hierarchical assembly characterized by “fences” of matter enclosing empty areas where the ice originally resided. Note that one of the main interests of this ice-segregation-induced self-assembly (ISISA) process for the preparation of hierarchical assemblies resides in its highly biocompatible character, as pointed out recently by our group.[9] More recently, McCann et al. and Deville et al. also applied the ISISA process for the preparation of highly porous polymer fibers[10] and hydroxyapatite scaffolds with nacreous architectures,[ 11] respectively.The process involves the submission of an aqueous gel to liquid-nitrogen temperatures. The rapid ice formation (hexagonal form) causes every solute originally dispersed in the aqueous gel to be segregated from the ice phase, giving rise to a hierarchical assembly characterized by “fences” of matter enclosing empty areas where the ice originally resided. Note that one of the main interests of this ice-segregation-induced self-assembly (ISISA) process for the preparation of hierarchical assemblies resides in its highly biocompatible character, as pointed out recently by our group.[9] More recently, McCann et al. and Deville et al. also applied the ISISA process for the preparation of highly porous polymer fibers[10] and hydroxyapatite scaffolds with nacreous architectures,[ 11] respectively.[9] More recently, McCann et al. and Deville et al. also applied the ISISA process for the preparation of highly porous polymer fibers[10] and hydroxyapatite scaffolds with nacreous architectures,[ 11] respectively.[10] and hydroxyapatite scaffolds with nacreous architectures,[ 11] respectively.respectively.