New 3-D test method for biomaterials 'flat o...( A novel three-dimensional (3-D) scre...)

A novel, three-dimensional (3-D) screening method for analyzing interactions between cells and new biomaterials could cut initial search times by more than half, researchers from the National Institute of Standards and Technology (NIST) and Rutgers University report in the new issue of Advanced Materials.* The technique, an advance over flat, two-dimensional screening methods, enables rapid assessment of the biocompatibility and other properties of materials designed for repairingor even rebuildingdamaged tissues and organs.

In what may be a first, the team demonstrated how to screen cellmaterial interactions in a biologically representative, but systematically altered, 3-D environment. The pivotal step in the experiment was the collaborators success in making so-called libraries of miniature porous scaffolds that are bone-like in structure but vary incrementally in chemical composition. Knowing how changes in scaffold ingredients influence cell responses, researchers can devise strategies for developing biomaterials optimized for particular therapies and treatments.

Until now, attempts to accelerate screening of candidate biomaterials have used flat films and surfaces. (See, for example, Designer Gradients Speed Surface Science Experiments, Tech Beat June 8, 2006. http://www.nist.gov/public_affairs/techbeat/tb2006_0608.htm#designer ) Along with other shortcomings, these two-dimensional substrates are neither consistent with cells normal 3-D environment inside the body nor with the most common intended use of biomaterials: creating scaffolds to encourage the growth of cells into functional 3-D tissues and organs.

Cells are very sensitive to the texture, shapes, and other three-dimensional features of their local environment inside the body, explains NIST biomaterial scientist Carl Simon. The large difference in structure between 2-D films and 3-D scaffolds should be considered when screening new materials.

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