Date Published: 7 July 2011
Nanocomposite material used in artificial windpipe transplant
Professor Seifalian, a medical scientist from University College London (UCL) and his team designed and built the synthetic windpipe 'scaffold' used in an operation in Sweden - recently announced by the Karolinska University Hospital and Karolinska Institutet.
The windpipe (trachea) implanted into the patient was developed using nanocomposite materials which were developed and patented by Professor Alexander Seifalian of the UCL Division of Surgery & Interventional Science, whose labs are based at the Royal Free Hospital, London.
A nanocomposite is a material containing some components that are less than 100 nanometres (nm) in size. To give a sense of scale, a human hair is about 60,000 nanometres in thickness - click for more about scientific numbers. A polymer is a repeating chain of small, identical molecules (called monomers) which are linked together. Polymers are already used in medical devices, but the properties of these novel polymers reduce the risk of rejection, rupture, or the need for repeat surgery. They have better elasticity, strength and versatility and are formulated to encourage cell growth.
Professor Seifalian has worked closely with UCL Business, which is responsible for technology development and commercial transactions at UCL, to patent these materials and develop their use in medical devices. As well as being used for biological tissue scaffolds, the materials have other potential uses such as coronary stents and grafts.
A full size 'y-shaped' trachea scaffold was manufactured in Professor Seifalian's labs. This was achieved using a CT (computerised tomography) scan of the patient as a guide, to create the exact shape and dimension needed. A mould was then made using glass. When the polymer scaffold had been made, it was taken to Karolinska where the patient's stem cells were incorporated to it (or 'seeded') by Professor Paolo Macchiarini's team at Karolinska, and the full biological trachea was grown in a bioreactor - a device designed for the procedure by Harvard Bioscience which provides the correct environment for the tissue to grow. This process means the trachea very effectively simulates natural tissue and has the same properties as a 'real' trachea.
Professor Seifalian said:
" Professor Macchiarini has previously performed successful transplants of tissue engineered tracheas, but on those occasions the tracheas used were taken from organ donors and then reseeded with the patient's own stem cells.
_ What makes this procedure different is it's the first time that a wholly tissue engineered synthetic windpipe has been made and successfully transplanted, making it an important milestone for regenerative medicine. We expect there to be many more exciting applications for the novel polymers we have developed."
Source: UCL, http://www.ucl.ac.uk