Photo from Soh lab
A biosensor designed to detect levels of drug in the bloodstream
New technology could make it easier to ensure patients receive the correct dose of chemotherapy and other drugs, according to research published in Nature Biomedical Engineering.
Researchers developed a closed-loop system that was able to continuously regulate drug levels in rabbits and rats.
“This is the first time anyone has been able to continuously control the drug levels in the body in real time,” said study author H. Tom Soh, PhD, of Stanford University in California.
“This is a novel concept with big implications because we believe we can adapt our technology to control the levels of a wide range of drugs.”
The researchers’ system has 3 basic components: a real-time biosensor to continuously monitor drug levels in the bloodstream, a control system to calculate the right dose, and a programmable pump that delivers just enough medicine to maintain a desired dose.
The sensor contains aptamers that are specially designed to bind a drug of interest. When the drug is present in the bloodstream, the aptamer changes shape, which an electric sensor detects. The more drug, the more aptamers change shape.
That information, captured every few seconds, is routed through software that controls the pump to deliver additional drugs as needed.
Researchers tested the technology by administering the chemotherapy drug doxorubicin to rabbits and rats.
Despite physiological and metabolic differences among individual animals, the team was able to keep a constant dosage in all the animals, something not possible with current drug delivery methods.
The researchers also tested for acute drug-drug interactions and found the system was able to stabilize drug levels to moderate what might otherwise be a dangerous spike or dip.
Dr Soh and his colleagues believe this technology could be particularly useful in treating pediatric cancer patients, who are notoriously difficult to dose because a child’s metabolism is usually different from an adult’s.
The team plans to miniaturize the system so it can be implanted or worn by the patient.
At present, the technology is an external apparatus, like a smart IV drip. The biosensor is a device about the size of a microscope slide.
The current setup might be suitable for a chemotherapy drug but not for continual use.
The researchers are also adapting the system with different aptamers so it can sense and regulate the levels of other biomolecules in the body.
