(Ti,Sn)O₂ Solid Solution Self‐Aligned into “Sandwich” Array on Grafted Modification Collagen Matrix

Abstract

Monolayer and multilayer films with morphology-controllable structures are promising for applications in building novel sensor devices, light-emitting diodes, biomedical coatings, and in creating organically based nonlinear optical materials. [1] Various approaches, including spin-coating, the Langmuir± Blodgett technique, electrostatic adsorption of oppositely charged polyelectrolytes, and covalent attachment of polymers using conventional coupling chemistry, have been used to produce complex nanostructures and have been developed for preparing different hybrids with diversified morphologies.[2] The general utility of these methods has been further extended by incorporating nanocrystals into polymer matrices.[3] The versatility and complexity of these polymeric composites provide new opportunities in the semiconductor, photovoltaic, and molecular electronic fields. [4] However, it is still important to study thin-film preparation in various media and with a variety of modification agents.[5]Incorporating metal nanocrystals in biological systems is a widespread, yet incompletely understood, procedure, involving complex interactions at the biomacromolecule±metal nucleus interface.[6] Studying this process may help us to understand and control the formation of metal nanocrystals in a generalized peptide±amphiphile chain system. Two major approaches have been developed to organize metal nanoparticles into polymer substrates.[7±12] The first method involves the self-coding of nanoparticle building blocks that can be coupled via interparticle connectors with specific recognition properties based on, for example, DNA duplex formation, [7] antibody±antigen specificity, [8] streptavidin±biotin coupling, [9] electrostatic matching, [10] or shape-directed hydrophobic forces.[11]Another method, the template-directed approach, [12] utilizes porous solid substrates or discrete liquid droplets as patterned or shaped interfaces for the assembly of preformed nanoparticles. In this process capillary, drying, and swelling forces, or other chemical interactions, are used to implant, position, and immobilize nanoparticles irreversibly within the template or around the surface of individual latex beads pre-coated with a layer-by-layer shell of oppositely charged polyelectrolyte macromolecules. However, to the best of our knowledge, there has been no previous example of incorporating bimetal solid solutions into a biological system in order to form a well-defined morphology without using any template or specific recognition interparticle connectors.Herein, we present a versatile procedure, based on the selfassembly process, for preparing a large-area nanoscale ªsand-wichº layer array of tailored composition, with a controllable crystalline phase and defined morphology. The idea for creating this composite film was stimulated by Yang and Rubner, [13] who developed a novel assembly method by using hydrogen-bonding interactions to fabricate a polyelectrolyte multilayer film. Differing from their work, we employed a protein with a unique...

One‐Dimensional Assemblies of Nanoparticles: Preparation, Properties, and Promise

“…[33] Cao et al reported that TiO 2 and SnO 2 NPs self-assembled onto linear collagen peptides to form 1D aggregates. [34] Biotemplates of greater complexity have also been employed. [35] Dujardin et al [36] and Mann and co-workers [36±38] used the tobacco mosaic virus, which has the shape of a linear tube, for assembly of various kinds of NPs inside and outside the tubes.…”

Self‐Assembling Nanoparticles at Surfaces and Interfaces

“…Nanoparticles also arrange on fibrous peptides [157] or dextran [158] templates to form metal or metal oxide 1D nanoparticle assemblies such as double helical arrays of Au, Pd, TiO 2 , and SnO 2 . [159,160] Moreover, other biological templates such as viruses, polypeptide nanotubes are also attractive. [161][162][163] Figure 11.…”

Triple‐Helix Scaffolds of Grafted Collagen Reinforced by Al2O3–ZrO2 Nanoparticles

“…In contrast, at higher particle concentrations, more binding sites on the peptide chains are anchored by hydrogen bonding to the nanoparticles, and thus no agglomeration of grafted collagen is observed. For even higher particle loadings, the excess nanoparticles cannot be immobilized or anchored, [16] and thus are not able to further enhance the mechanical properties of the hybrid material. The thermal behavior of the hybrid nanocomposites has been investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA).…”

“…Therefore, the DTA curve provides indirect evidence of the strong interactions between the grafted collagen matrix and Al 2 O 3 -ZrO 2 composite nanoparticles. [16] A schematic model for spatial interactions existing in this system is shown in Scheme 1. Hydrogen bonds may be formed between the oxygen atom of the bimetallic oxide nanoparticles and the -OH or -NH 2 groups on the grafted collagen (blue line); additionally, covalent bonds can link adjacent Al 2 O 3 (violet) and ZrO 2 (blue) species (red line), [16] resulting in the formation of the composite nanoparticles shown in Figure 3A.…”

“…[16] A schematic model for spatial interactions existing in this system is shown in Scheme 1. Hydrogen bonds may be formed between the oxygen atom of the bimetallic oxide nanoparticles and the -OH or -NH 2 groups on the grafted collagen (blue line); additionally, covalent bonds can link adjacent Al 2 O 3 (violet) and ZrO 2 (blue) species (red line), [16] resulting in the formation of the composite nanoparticles shown in Figure 3A. The resulting hybrid nanocomposites reduce the exposure of the collagen to collagenase, and are thus expected to significantly increase the resistance against collagenase degradation.…”