Categories: MRS 2009 Boston | 1 Comment
Tuesday saw me submerge myself in a number of sessions on biomaterials research, an area I’ve been fascinated by since my days on the Journal of Materials Chemistry editorial team. And as expected I wasn’t disappointed.
My favourite talk of the day was an overview of the use of state-of-the-art nanotechnology in biomedical implants given by Thomas Webster at Brown University, US. During his presentation we were told about a recent ‘happiness’ survey of army amputees, where one group was given replacement prosthetic limbs and the other group was not. The survey found that soldiers who received prosthetics were less happy than those that did not, citing reasons such as problems cleaning them and loose fits. Some researchers might have been discouraged that huge amount of reserach that has gone into this field in recent years is going unappreciated, but not Webster – he sees it as a challenge to do better.
One of the topics he touched upon was ‘scratching’ nanosized groves into the surface of implants so that they more closely mimic the surfaces of natural materials such as bone. Researchers have found that proteins absorb, and therefore tissues grow (what is needed for a prosthetic implant to bed into a body), better on synthetic materials with these nanogroves than those with smoother surfaces.
Amazingly these nanogroves also seem to have antibacterial properties. For example, Webster has shown that fewer bacteria grow on PVC (polyvinylchloride) with nanofeatures on their surface than those without. He suggested that this might be the key to overcoming bacterial infections that are developing resistance to current approaches.
Webster is also concerned with improving current clinical approaches to assessing whether prosthetics are functioning properly once fitted, namely imaging (e.g. x-ray) the patient a few months after implantation. His approach is to develop an in situ nanomaterial-based coating that sits between the implant and the tissues and can tell you what is happening there in real time. He envisages a sensor that works based on conductivity, as a biofilm (growing as a result of an infection) for example will have a different conductivity to bone and tissue. This change is conductivity will then be communicated with a device outside of the body.
Excited? Well it gets one step cleverer – this coating will be biodegradable under higher currents (biofilms are more conducting than tissue, you see) and degradation will release an infection-fighting drug imbedded within the coating. So………when the area between the implant and the tissue gets infected, the coating will automatically release a drug to treat the offending bugs. See I told you it was good!
Another noteworthy talk from yesterday was Peng Chen from Cornell University, US, talking about the use of his single-molecule imaging technique to ‘watch’ individual molecules undergoing electrochemical reactions on the surface of single walled carbon nanotubes. Chen found the reactions occur at discrete reactive sites (largely the ends of the tubes or where there are defects on the surface) – rather than along the whole of the nanotube walls. These hotspots of catalytic activity have been hypothesised, but never ‘seen’ before. I covered this research on this blog earlier this year (and also Chen’s previous work on nanoparticle catalysis in a news article), but I think it provides such an insight into fantastic fundamental science that it is worth another mention.