In the paper, Schlenoff and coauthors report investigations into the effects of surface charge and surface hydrophobicity of polyelectrolyte multilayers on the behavior of rat aortic smooth muscle cells cultured on the multilayers. "Substrate properties such as charge and degree of hydrophobicity determine how well smooth muscle cells adhere and spread on the substrate and also affect whether the cells organize their actin filaments in contractile or synthetic smooth muscle cells," Schlenoff explains. In the contractile state, smooth muscle cells use a system based on actins--filamentous proteins--to produce contractile force, but the cells do not crawl or divide. Synthetic smooth muscle cells rearrange the actin filament system to crawl and divide, but they are no longer able to produce contractile force. "In vascular smooth muscle, contractile smooth muscle cells produce force for blood pressure regulation," Schlenoff observes. "When blood vessels are injured, a signal is released that prompts smooth muscle cells to change from the contractile state to the synthetic state. The synthetic smooth muscle cells migrate to the site of injury, where they grow and divide, repairing the damaged blood vessel. The newly formed smooth muscle cells eventually convert back to the contractile state and lose their ability to crawl and divide." HOW SMOOTH MUSCLE cells interact with polyelectrolyte multilayer surfaces has implications for evaluating biocompatibility, according to Schlenoff. For example, the surface properties of stents implanted inside coronary arteries during surgical procedures are thought to play a significant role in the process of restenosis.
by MICHAEL FREEMANTLE, C&EN LONDON |
February 07, 2005