Toxins as therapeutics with the help of quantum dots
Cone snails found in coastal areas around coral reefs can be rather beautiful in the eye of beholders − with their stripes or speckled shells. But they have teeth like harpoons and their venom can result in death.
Scientists have however, managed to turn the tables and found cures in their venom. Conotoxins obtained from the venom, can be used as an alternative painkiller − especially for patients suffering from severe pain and are dependant on morphine. Once infused into the spine, they attach to the neurons and are able to block off pain signals.
Professor P Gopalakrishnakone, Venom and Toxin Research Programme of the Yong Loo Lin School of Medicine, has discovered some 10 peptides from cone snails which have therapeutic properties. Such research is highly competitive as there is a race round the world now to mine cone snails for their peptides, said Professor Gopalakrishnakone.
Conotoxin is just one of the novel toxins which Professor Gopalakrishnakone and his team are working on. The NUS team is in the forefront in toxin research internationally. In the past decade, they have isolated and characterized several molecules from venoms, such as those from scorpions and snakes. Some of them have been patented. In April 2005, with funding from A*STAR and NUS, ProTherapeutics was launched as Singapore's first biotech company to create drugs from venoms. So far, NUS has licensed to the company an analgesic peptide from the King Cobra patented by Professor Gopalakrishnakone's group to be developed as a therapeutic drug for pain management. It is several times more potent than morphine without addiction or dependence.
"We are also looking for antimicrobial agents from venom. Through the ages, bacteria has become resistant to agents from plants, so we are now looking towards developing drugs from agents found in animals," said Professor Gopalakrishnakone.
Ion channels
Many disorders in our bodies are caused by alterations in the ion channels of our cells. Ion channels are highly specific filters, allowing only desired ions such as calcium and potassium through the cell membrane. Toxins can activate or deactivate these channels. But first, we have to deliver the toxins to these target areas. That's where nanotechnology comes into the picture.
Using quantum dots in toxinology
Professor Gopalakrishnakone and his team have recently started working with the NUS Nanoscience and Nanotechnology Initiative on the use of quantum dots to deliver toxins to target areas. Quantum dot is a nano-scale crystalline structure. When used in medicine and introduced into our bodies, the crystals can be used as probes to track antibodies, viruses, proteins or DNA.
"We intend to link up quantum dots with some of our unique molecules which have very specific actions on cells, organelles, channels and receptors. The quantum dots will allow us to keep track of their progress through imaging. Once they have reached the targets, they can be manipulated to release the toxins at the sites," said Professor Gopalakrishnakone.
The NUS team also intends to see how these toxins will react in animal models of cancer. Through the quantum dots carrying the toxins, the team will be able to see whether the toxins are able to reach target sites.
"We would probably be able to offer some solid findings in three to four years' time," said Professor Gopalakrishnakone.
