Built-in microscale electrostatic fields induced by anatase-rutile-phase transition in selective areas promote osteogenesis

Titanium implants with built-in electric fields that assist bone regeneration have been made by a team of researchers in China and the USA. The polymer collagen makes up about 90% of the organic matrix of bones. Mechanical stresses generated during movement cause collagen to generate electric fields, which promote bone formation. In the past, externally applied fields have generally been used to mimic this effect, but now Chuanbin Mao of the University of Oklahoma and Zhejiang University and co-workers have made implants with built-in electric fields. They used selective laser irradiation to produce alternating strips of two phases of titanium oxide, which have low and high electron densities; this variation in the electron density gives rise to internal electric fields. The researchers found that bone regeneration was promoted near the implants.