Chemistry

Gelling Cells

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Science  21 Nov 2003:
Vol. 302, Issue 5649, pp. 1295
DOI: 10.1126/science.302.5649.1295a

Hydrogels, which consist of water-filled, highly cross-linked polymer networks, are under consideration as a means of drug or cell delivery. Usually, the polymer networks incorporate physical or chemical cross-links, and the cells are immobilized within this network. Lee et al. consider the case in which the cells themselves are one of the components cross-linked. They started with alginate, a biopolymer that does not appreciably adsorb proteins or cells, and attached a small number of arginine-glycine-aspartic acid (RGD) peptides. When cells were mixed with these modified polymers, a network formed due to the cell surface expression of RGD-binding integrins. The resulting gel was found to be shear-reversible, meaning that its viscosity decreased significantly when subjected to a shear flow, which disrupted the RGD-integrin interactions, yet the gel reformed within 10 min after shearing. Thus, it would potentially be feasible to inject the gel into a patient with a standard syringe for medical applications. — MSL

Adv. Mater. 15, 1829 (2003).

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