New way to embed proteins in polymers.The age of plastics arrived decades ago, when chemists learned to string together chemical units, called monomers, to make polymers. Today, scientists endow en·dow tr.v. en·dowed, en·dow·ing, en·dows 1. To provide with property, income, or a source of income. 2. a. these materials with biological talents - for use primarily in chemical separation and sensing devices -- by attaching proteins to them. A new technique for building proteins directly into polymers now promises to expand the variety of biologically active materials that can be synthesized. Researchers might one day use the method to make an artificial heart from materials containing an enzyme that prevents blood clotting blood clotting, process by which the blood coagulates to form solid masses, or clots. In minor injuries, small oval bodies called platelets, or thrombocytes, tend to collect and form plugs in blood vessel openings. , for example, or to develop a hormone-containing polymeric glue that encourages bone deposition while keeping artificial hips fixed in place. "This strategy opens up whole new vistas for incorporating proteins into different materials," says Alan Russell, one of the chemical engineers who developed the method at the University of Pittsburgh. Many of the most commonly used polymers -- such as the acrylates used to make Plexiglas, contact lenses contact lenses contact npl → verres mpl de contact contact lenses contact npl → Kontaktlinsen pl contact lenses npl , and materials that can control the release of drugs - must be synthesized in organic solvents. Because proteins don't dissolve in these solvents, chemists who combine proteins with polymers have had to use polymers that can be made in water. The Pittsburgh team has now removed this limitation by finding a way to incorporate proteins into polymers that can be made in organic solvents. Russell and co-worker Darrell Williams converted the enzyme subtilisin sub·til·i·sin n. An extracellular enzyme produced by certain strains of a soil bacterium (Bacillus amyloliquefaciens) that catalyzes the breakdown of proteins into polypeptides and resembles trypsin in its action. into a "biomonomer" that can link up with other monomers. As a first step, they attached a chemical group called polyethylene glycol polyethylene glycol (PEG): see glycol. to the enzyme. This made it soluble in organic solvents. Then they hooked this unit to a methyl methacrylate methyl methacrylate (meth´il methak´rilāt), n an acrylic resin, CH2 = C(CH3)COOCH3, derived from methyl acrylic acid. Monomer is the single molecule and polymer is the polymerization product. monomer monomer (mŏn`əmər): see polymer. monomer Molecule of any of a class of mostly organic compounds that can react with other molecules of the same or other compounds to form very large molecules (polymers). . Working with several common organic solvents, they polymerized these biomonomers into a material that looks and feels just like polymethylmethacrylate but has subtilisin's catalytic ability. Because the enzyme is chemically bound to the material, it remains stable and can't be leached out. The team is now eager to try the technique with other enzymes and polymers. |
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