BIO profile: The hope beyond the hype

It might seem a bit of a leap to make from researching biofouling and bacterial surface interactions to working in tissue engineering and biomaterials, or to some even a yawning gulf. However, that's the road taken by Dr Keith McLean, who now leads a large team at CSIRO Molecular and Health Technologies in the stimulating but not uncontroversial field of biomaterials and regenerative medicine.

While the idea of tissue engineering has been around for 20 or 30 years, there is a lingering feeling within the scientific community that it has not quite lived up to the hype, particularly in getting actual products to market. The emergence of tissue engineered skin therapies and orthopaedic materials, both bone and cartilage, and model demonstrations in other applications, however, might point the way towards a more hopeful future.

"I think it is likely there will be progress [in the near future] but it's still an emerging technology area," McLean says. "We still need new materials for scaffolding that have appropriate mechanical properties and these require the incorporation of biological signals in a way that directs tissues to do what you want, in a temporal as well as a spatial dimension. It is a field that has tremendous potential but there are still a lot of obstacles to overcome before we are doing this in a big way."

CSIRO's team is working to overcome some of those obstacles in a number of areas. McLean's team concentrates on ophthalmic biomaterials, novel biomedical adhesives, bioactive scaffolds for cell therapy and platforms for the propagation of stem cells. McLean has intimate knowledge of the ophthalmic area, having worked for a number of years with the Cooperative Research Centre (CRC) for Eye Research and Technology, now known as the Vision CRC, on surface coatings for an implantable contact lens.

One of CSIRO's roles in the project is the development of a biocompatible polymer for the lens, which is implanted in the cornea to correct refractive errors. "We do have that material in human eyes with collaborators with the Vision CRC in India and the results from that are very encouraging," McLean says.

"The initial concept was the development of an artificial cornea, so it would be for people who had corneal problems, but while it potentially could still be used for that it is now intended as a method to correct refractive error and to compete with conventional contact lenses and laser surgery. Approximately 60 per cent of the population require vision correction and don't like the inconvenience of either lenses or glasses or are unwilling to undergo laser surgery."

Surgical adhesives

While McLean is still involved in this project, there are a number of other projects his multi-disciplinary team is working on. A very interesting area is surgical adhesives, which his team has been involved in for a number of years.

"It started off originally with some work looking at a protein that was produced by an Australian frog, which was done in conjunction with the University of Adelaide. We are no longer directly involved in that [particular project] but based on that, we've been looking to exploit marine resources, so we are looking natural bioadhesives from marine organisms, trying to understand how they work and since they are natural products we are looking at making these recombinantly or make synthetic variants.

"Some of the problems with current surgical adhesives is that they are either very high bond strength but they have poor biological compatibility or they are protein-based products that are biologically accepted but there's not much strength. We also have some work using purely synthetic chemistry and we have a couple of approaches that are close to filing for patents."

The CSIRO has also developed a method to produce recombinant proteins, including resilin and collagen, and to rapidly crosslink them into biomaterial scaffolds. These materials could open new doors in medical product applications, ranging from spinal disc implants to scaffolds for tissue engineering as well as drug delivery vehicles.

One of CSIRO's success stories of the last couple of years has been a spin-off company, PolyNovo Biomaterials, which is based at CSIRO Molecular & Health Technologies' campus in Melbourne's Clayton. This company has successfully developed and is now commercialising NovoSorb, a biodegradable polymer for use in medical devices. It is also being tailored as a scaffolding material for the regrowth of chondrocytes for cartilage repair.

"We are working with PolyNovo, Bionic Technologies Australia, which is a Victorian Government science, technology and innovation (STI) initiative, and the University of Wollongong looking at developing the same family of materials as the scaffold for directed repair of peripheral nerves," McLean says.

At BIO2007, McLean will address the session on differentiated cell therapies as one of the two research providers. The other is Robert Langer's group from MIT, considered the world's leading research group for materials for tissue engineering. In addition, there will be speakers from two companies with experience in taking cell therapies to market. These are Organogenesis, a Massachusetts company involved in products for wound healing and tissue repair; and Genzyme, which among other things works on cell therapies to repair damaged heart tissue.

Regenerative medicine is a very exciting and competitive field with great potential but there remain a number of hurdles to jump before it becomes mainstream, McLean says. "Next generation material scaffolds able to provide physical, chemical and biological signals are needed and will be required to overcome regulatory hurdles. Increasingly, stem cell biology will play an important role in the replacement and repair of damaged tissue."