Amoebae Assemble Synthetic Spherical Particles To Form Reproducible Constructs.

Difflugia are testate amoebae that use particulate inorganic matter to build a protective shell (generally called a test or theca). Difflugia globulosa were grown both in culture containing only naturally occurring theca-building materials and under conditions where synthetic particles were present also. The presence of monodisperse Stöber silica microspheres of 1, 3, and 6 μm in diameter or 4 μm polystyrene spheres dramatically increased the rate of Difflugia growth, and foreign microspheres became the overwhelmingly dominant construction material.

Lipase catalyzed synthesis of silicone polyesters.

Immobilized Candida antarctica lipase B (CALB) was successfully employed as a catalyst to synthesize silicone aromatic polyesters by the transesterification of dimethyl terephthalate with alpha,omega-bis(hydroxyalkyl)-terminated poly(dimethylsiloxane) in toluene under mild reaction conditions.

Fiber technology for reliable repair of skeletal muscle.

Conventional soft-tissue reclosure methods-sutures and staples-require substantial organized-collagen content. Some tissues lack extensive intrinsic collagenous content. Wound disruption consequences range from newly closed abdominal wounds bursting open, to post-cesarean wombs splitting at delivery, to heart valves loosening.

Conformation and assembly of polypeptide scaffolds in templating the synthesis of silica: an example of a polylysine macromolecular "switch".

Although the role of polycationic macromolecules in catalyzing the synthesis of silica structures is well established, detailed understanding of the mechanisms behind the production of silica structures of controlled morphologies remains unclear. In this study, we have used both poly-L-lysine (PLL) and/or poly-D-lysine (PDL) for silica synthesis to investigate mechanisms controlling inorganic morphologies. The formation of both spherical silica particles and hexagonal plates was observed.

On the role(s) of additives in bioinspired silicification.

Biological organisms are able to direct the formation of patterned and hierarchical biomineral structures. Extractable organic materials have been found entrapped in diatom, sponge and plant biosilica, some of which have been isolated by selective chemical dissolution methods and their composition and structure studied. Information gained from the bioextracts has inspired materials chemists to design biomimetic analogues and develop bioinspired synthetic schemes for silica formation.

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.

A durable load bearing muscle to prosthetic coupling.

Skeletal muscles have been successfully linked to power mechanical support devices acutely. However, the required load bearing muscle to prosthetic interfaces have not been consistently durable. Tissue simply may not tolerate the repetitive pressure generated, ranging to 40,000 mm Hg, when necessary forces meet the crosssectional areas accessible by suture or clamp fixation.

Bioinspired synthesis of new silica structures.

Silicon and oxygen are the two most abundant elements in the Earth's crust but despite the vast scientific literature on crystalline and amorphous silica, new chemistries, structures and applications continue to be discovered for compounds formed from these elements--thus we present here for the first time the formation of new amorphous silica structures that were uniquely synthesized by a bioinspired synthetic system.

Controlled formation of biosilica structures in vitro.

Herein we describe the controlled formation of biosilica structures by manipulation of the physical reaction environment; we were able to synthesize arched and elongated silica structures using a synthetic peptide; the results presented here are evidence that in vitro biocatalysis may be controlled in order to form desired silica structures.

Distribution of silicon/e in tissues of mice of different fibrinogen genotypes following intraperitoneal administration of emulsified poly(dimethylsiloxane) [correction of poly(dimethysiloxane)].

Following injection into the abdominal cavity of a C57BL/6 mouse, droplets of emulsified PDMS visible by light microscopy (diameter > or = 1 microm) disseminate to multiple organs of the animal. Because fibrinogen may facilitate dissemination, we compared histologically the accumulation of PDMS droplets in lymph nodes, lungs, spleen, liver, and left kidney of Fib +/+, Fib +/-, and Fib -/- mice of C57BL/6 background 35 and 75 days after intraperitoneal injection of an emulsion of the polymer. We also used ICP-AES to assess the accumulation of silicon in the lymph nodes, livers, and spleens of the animals.

Ultrafast holographic nanopatterning of biocatalytically formed silica.

Diatoms are of interest to the materials research community because of their ability to create highly complex and intricate silica structures under physiological conditions: what these single-cell organisms accomplish so elegantly in nature requires extreme laboratory conditions to duplicate-this is true for even the simplest of structures. Following the identification of polycationic peptides from the diatom Cylindrotheca fusiformis, simple silica nanospheres can now be synthesized in vitro from silanes at nearly neutral pH and at ambient temperatures and pressures. Here we describe a method for creating a hybrid organic/inorganic ordered nanostructure of silica spheres through the incorporation of a polycationic peptide (derived from the C.

Fibrinogen adsorbs from aqueous media to microscopic droplets of poly(dimethylsiloxane) and remains coagulable.

Fibrinogen binds from aqueous media containing it to droplets of linear trimethylsilyl-terminated poly(dimethylsiloxane) (PDMS) dispersed in those same media. Once bound, fibrinogen elutes from emulsified droplets of PDMS only very slowly, even when incubated in buffer that contains a physiologic concentration of the protein. The bound fibrinogen is coagulable, as indicated by the thrombin-dependent agglutination of droplets.