New form of silicon opens up range of applications beyond high-tech

Out of all of the materials indispensable to the high-tech industry, silicon is arguably the most important. In everything from computers to telephones and radios, silicon-based semiconductors act as driving forces behind the technology.

Yet the full potential of silicon remained unknown until a series of breakthroughs over the past two decades by British inventor Leigh Canham. He not only developed a method to manufacture porous silicon (pSi) inexpensively; he also discovered the biodegradability and biocompatibility of pSi - opening possibilities for the use of silicon in a wide range of new applications and industries. 

Canham nano-engineered a new form of pSi called BioSilicon, which features a honeycomb structure with nano-sized pockets. These pockets can be filled with a range of compounds: drugs, genes, proteins, peptides, radionuclides, and other therapeutics and vaccines. Medical professionals can also take advantage of BioSilicon's semiconductor properties to dissolve the honeycomb at a controlled rate, effectively regulating drug dosages for patients over the course of days, months or even years. 

The most promising application to come out of Canham's work so far has been a new treatment for pancreatic cancer called BrachySil. This is a new form of brachytherapy, also known as internal radiotherapy, which acts as a complement to chemotherapy. BrachySil has successfully completed phase II trials and is set to begin phase III - the final testing before actual marketing can begin for the treatment. Up to this point, there has been a 100% response rate of tumours in pancreatic cancer to BrachySil. As of 2006, pSivida believed the global market size for this application to be $600 million per annum with eventual growth to $1 billion.

For his pioneering work in implementing pSi in areas such as controlled-release drug delivery, targeted cancer therapy, tissue engineering, and improved health and beauty products, Canham has been nominated for a 2011 European Inventor of the Year Award. He is being recognised in the category of Small and Medium-sized Enterprises (SMEs). The award will be presented on 19 May at a ceremony in Budapest. 

Tapping unidentified potential

The road to discovering the full extent of pSi's abilities began in 1986. That year, Canham became intrigued by the potential of nano-engineered silicon as a semiconductor and began working on the electroluminescent properties of the substance. His first major breakthrough came in 1990 when he successfully engineered the semiconductor to emit red, orange, yellow and green light, bringing pSi attention on an international scale.

He followed this achievement with discoveries in the mid-1990s that pSi is both biodegradable and biocompatible (non-toxic), meaning that the substance could now be used in a wide range of new fields such as the medical field and consumer health care markets.

pSi had in fact been discovered entirely by accident in 1956 when scientists began exploring how to polish the surfaces of two semiconductors: germanium and silicon. Their endeavour almost failed due to a thick, dark film on the surface of the two materials. Eventually the team of scientists successfully removed the film and continued with their work - never knowing that unearthing this film was the first discovery of pSi.

Entering the market

To develop new medical uses for pSi, Canham helped found pSiMedic Ltd. and became the company's Chief Scientific Officer to oversee two products: BioSilicon and Durasert.

Besides BioSilicon, Canham's second product, Durasert, is a polymer-based technology for use in drug delivery that also offers new opportunities in medical industries.

Canham's pSiMedic Ltd. later became a subsidiary of pSivida Corporation - a company with operations in five continents and a consolidated net income of $8.8 million in 2010. 

Canham then left the company in order to found IntrinsiQ Materials, which focuses on further developing pSi technology for use in nutritional and consumer care products.  

On the edge of a breakthrough

So far pSivida has secured licensing deals for Durasert with Bausch & Lomb - one of the world's leading suppliers of eye health products - as well as an AUD 203 million deal with pharma giant Pfizer. Although a similar deal is yet to materialise for BioSilicon, interest regarding the pSi technology is strong in both the medical devices and electronics industries. Meanwhile, the industry is also financially supporting clinical trials for products from IntrinsiQ Materials. 

For all of Canham's pSi products, potential is high - especially with regards the drug delivery market and BrachySil, the new treatment for pancreatic cancer, based on Canham's work. The effectiveness this treatment method combined with its minimally invasive, relatively painless nature could transform cancer treatment.

A wide range of uses

Besides medical applications, Canham's pSi technology is also being explored for use as an abrasive in toothpaste. The global market was expected to reach $12.6 billion in 2010. Vitamin technology is another area where pSi has begun to be utilised, with a global market predicted to be $3.3 billion by 2015. In addition to all of these, pSi is also being explored for implementation in bubblegum. 

Canham's pSi technology is not only being developed by pSivida and his IntrinsiQ Materials; it has also been licensed to Beijing Med-Pharma to develop BrachySil for the Chinese market and to Aion Diagnostics for development in the diagnostics market.