A factory built of gel does not sound very durable. But the new type of micro-factories invented by researchers at Aarhus University do not have to last.
They will actually be placed inside a patient's body - exactly where the medicine is required - and they will gradually dissolve and disappear in the patient's urine once their mission is accomplished.
The prospects are so enormous that Associate Professor of Chemistry Alexander Zelikin, Aarhus University, has just been granted EUR 2 million to boost research and development in this field. The European Research Council (ERC) has awarded him an ERC Consolidator Grant.
Very advanced gel
The tiny factories consist of hydrogel, which is fundamentally a mixture of water and polymers with characteristics similar to gelatine. In this case we deal with some advanced variants of hydrogels: They must simultaneously be able to function as material for the small factories and contain the enzymes needed to produce medicine while the raw material is arriving at the factories.
There is basically nothing new in allowing enzymes to be in charge of the medical production - plenty of drugs are made of inactive substances which are not converted into active drugs until the liver or enzymes elsewhere in the body begins to break them down. They are called prodrugs.
An ordinary prodrug is, for example acetylsalicylic acid, which is the main ingredient in the common types of pain-relieving drug. They will not work until your liver has converted them into alicylic acid.
"The problem with this type of prodrugs is, however, that after the conversion they are typically sent into the blood in the intire body, so that only a fraction reaches the place which hurts. This problem can be solved in the process by creating prodrugs, which can only be transformed by specific enzymes - and then placing these enzymes in th eparticular part of the body which needs the drugs," explains Alexander Zelikin.
He will spend the EUR 2 million on developing two types of biodegradable factories:
Stents and particles
One of them is a new kind of stent which, among other things, is a term for the small metal meshes, which is operated into patients suffering from blockage of their coronary artery to keep it open after an angioplasty.
Alexander Zelikin's stents will be made of hydrogel instead of metal, because their primary purpose is not to keep a vein open, but to deliver medicine: the doctor injects a prodrug into the patient's vein, after which the enzymes in the stent convert it to, for example, a medicine against arteriosclerosis.
"The same enzymes will also be able to transform other sorts of prodrugs, so if one medicine doesn't work, you can switch to another without having to call the patient in for a new treatment," says Alexander Zelikin and continues:
"Metal stents coated with medicine are already in use - they just do not have the flexibility, that treatment which the enzymatic medicine factories have."
The second sort will consist of small particles, which initially can be used for the treatment of diseases such as cancer. The particles must be able to submit both medicine and for example contrast agents, so that they can be used simultaneously for treatment and diagnosis.
More specifically, the ERC grant will result in the employment of four PhD students and a postdoc.