NEWS TRENDS

Certain nanomaterials show strong promise in tissue engineering and orthopedic applications because they appear to promote better tissue regeneration than other methods, according to an engineering and orthopedics expert.

Thomas Webster, PhD, associate professor of engineering and orthopedics at Brown University (Providence, RI), said that nanomaterials might promote tissue regrowth because human tissue is itself nanostructured. Because of that, he said, cells are accustomed to interacting with surfaces that vary on the nanoscale level. Thus, they respond to certain nanomaterials quite well.

He made his remarks in October 2006 at the materials, medicine, and nanotechnology summit sponsored by the Cleveland Clinic and ASM, the materials information society.

“Nanostructured materials possess higher percentages of atoms at the surface, increased portions of surface defects, and greater numbers of material boundaries at the surface that may be influencing protein interactions important for cell function,” Webster explained.

Webster has conducted research showing that nanoscale versions of titania, alumina, and ceramics all attached to bone cells better than their conventional versions. “We are extremely encouraged by how versatile [nanoscale materials are],” he said. “We are also seeing this in animal studies, in multiple labs that have no connection to each other. It raises the question that if you have a material with good properties, can you make it nano?”

There is also evidence, he said, that nanomaterials can reduce bacteria functions while increasing bone cell functions.

Although the conventional definition of nanotechnology is a particle size of 100 nm or smaller, for bone-cell-adhesion purposes, the nanomaterials need to be between 49 and 67 nm, Webster said.

The best manufacturing method for orthopedic implants may be making them out of nanofiber ceramics, because bone is a nanofibered material, Webster said. Nanofibers could also be added to polymers to make coatings for orthopedic implants, he said.

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