Newswise — Research by a multidisciplinary group at the University of California at Santa Barbara suggests that nanostructured titania (NST) is a better material to interface M/NEMS devices with biological systems than traditional materials such as dense silicon nitride or silicon oxide. This research is reported in Nanotechnology ( http://www.iop.org/EJ/journal/Nano ), published by Institute of Physics (IOP) Publishing.

Silicon based micro (and nano) electromechanical systems (M/NEMS) have potential applications in the life sciences. M/NEMS devices are usually fabricated using conventional microelectronics processing techniques; hence, the passivation or outermost layer of these devices is either dense silicon nitride or silicon oxide layers, as these are the traditional materials of choice. Nanomaterials such as porous silicon and assemblies of functionalized carbon nanotubes are currently being explored as substrates to interface electronic devices with biological systems.

In this work, we proposed a simple technique to form integrated micrometer scale features of porous nanostructured titania (NST) on Si-chips. When mouse fibroblast cells were cultured on different surfaces, these cells attached faster on NST relative to dense silicon nitride or silicon dioxide layers. This enhanced attachment clearly suggests that NST is a better material to interface M/NEMS devices with biological systems.

One advantage of the technique used to form the NST is its compatibility with existing process tools and material systems being used in the microelectronics industry. In this technique, Ti film is oxidized in aqueous hydrogen peroxide to form a hydrated titania gel, and porous NST is formed after heating this gel at a few hundred degrees Celcius. As a continuation of this work, Noel MacDonald and his students at the University of California at Santa Barbara are using this technique to form integrated NST in M/NEMS devices fabricated from bulk Ti.Notes to editors:

The paper was published online on December 21, 2005 in Nanotechnology ( http://www.iop.org/EJ/journal/Nano ). The paper can be downloaded free of charge from http://www.iop.org/EJ/abstract/0957-4484/17/2/032 . The paper will also be available in the print version of the journal: Volume 17, Issue 2, January 28, 2006.

The Institute of Physics is a leading international professional body and learned society with over 37,000 members, which promotes the advancement and dissemination of a knowledge of and education in the science of physics, pure and applied. It has a world-wide membership and is a major international player in:
• scientific publishing and electronic dissemination of physics;
• setting professional standards for physicists and awarding professional qualifications;
• promoting physics through scientific conferences, education and science policy advice.