Biomedical subjects

Morley O Stone

Publications and source records attributed to Morley O Stone.

22 records · Page 2Linked to original sources

PubMed2002

Biomimetic synthesis and patterning of silver nanoparticles.

The creation of nanoscale materials for advanced structures has led to a growing interest in the area of biomineralization. Numerous microorganisms are capable of synthesizing inorganic-based structures. For example, diatoms use amorphous silica as a structural material, bacteria synthesize magnetite (Fe3O4) particles and form silver nanoparticles, and yeast cells synthesize cadmium sulphide nanoparticles. The process of biomineralization and assembly of nanostructured inorganic components into hierarchical structures has led to the development of a variety of approaches that mimic the recognition and nucleation capabilities found in biomolecules for inorganic material synthesis. In this report, we describe the in vitro biosynthesis of silver nanoparticles using silver-binding peptides identified from a combinatorial phage display peptide library.

Amino Acid Sequence↗

PubMed2002

Silica-precipitating peptides isolated from a combinatorial phage display peptide library.

Many biological organisms contain specialized structures composed of inorganic materials. Cellular processes in vivo facilitate the organized assembly of mineral building blocks into complex structures. The structural hierarchy and complexity across a range of length scales are providing new ideas and concepts for materials chemistry. Proteins that direct biomineralization can be used to control the production of nanostructured materials and facilitate the fabrication of new structures. Here, we demonstrate that some of the silica-binding peptides isolated from a combinatorial phage peptide display library can be used in precipitating silica from a solution of silicic acid. The results described in this report demonstrate that peptides displayed by phages act as templates in inorganic material synthesis and provide a means of understanding how some of the biological systems may be carrying out materials chemistry in vivo.

Biomimetic Materials↗

PubMedDate not supplied

Study of the chemical and physical influences upon in vitro peptide-mediated silica formation.

Herein, we report on the ability to create complex 2-D and 3-D silica networks in vitro via polycationic peptide-mediated biosilicification under experimentally altered chemical and physical influences. These structures differ from the sphere-like silica network of particles obtained in vitro under static conditions. Under chemical influences, overall morphologies were observed to shift from a characteristic network of sphere-like silica particles to a sheetlike structure in the presence of -OH groups from additives and to sharp-edged, platelike structures in the presence of larger polycationic peptide matrixes. Under physical influences, using externally applied force fields, overall silica morphologies were observed to transition from sphere-like to fiberlike and dendrite-like structures. These findings could lead to the future development of bio-inspired complex 2-D and 3-D silica micro- and nano-devices.

Amino Acid Sequence↗

PubMedDate not supplied

Thermally induced alpha-helix to beta-sheet transition in regenerated silk fibers and films.

The structure of thin films cast from regenerated solutions of Bombyx mori cocoon silk in hexafluoroisopropyl alcohol (HFIP) was studied by synchrotron X-ray diffraction during heating. A solid-state conformational transition from an alpha-helical structure to the well-known beta-sheet silk II structure occurred at a temperature of approximately 140 degrees C. The transition appeared to be homogeneous, as both phases do not coexist within the resolution of the current study. Modulated differential scanning calorimetry (DSC) of the films showed an endothermic melting peak followed by an exothermic crystallization peak, both occurring near 140 degrees C. Oriented fibers were also produced that displayed this helical molecular conformation. Subsequent heating above the structural transition temperature produced oriented beta-sheet fibers very similar in structure to B. mori cocoon fibers. Heat treatment of silk films at temperatures well below their degradation temperature offers a controllable route to materials with well-defined structures and mechanical behavior.

Animals↗