Computerized smart systems can deliver drugs intravenously in exact volumes to hospital patients. However, the systems do not recognize which medications are in the tubing, nor can they determine the concentration of the drug in the tubing. This can lead to medication errors including incorrect dosage, unintentional substitution of one drug for another, and co-delivery of incompatible drugs.
A new optical device, developed by a team of electrical and computer engineering students at the University of Illinois at Urbana-Champaign, can identify the contents of the fluid in an intravenous (IV) line in real-time, offering a new way to improve the safety of IV drug delivery.
To approach this problem, the researchers turned to the nanoscale and used a technology called Surface-Enhanced Raman Scattering (SERS), which can obtain extremely sensitive molecular signals to identify chemicals.
Researchers shone laser light onto a nanostructured gold surface containing millions of tiny “nano-domes” that are separated from each other by as little as 10 nanometers in order to determine the identity of a particular IV medication. The nano-domes are incorporated into the inner surface of IV tubing, where they are exposed to drugs that are dispersed in liquid. They captured the light scattered from drug molecules that are in contact with the nano-domes and used SERS to determine the drug’s molecular signature. Finally, they matched the signature to known signatures for the drug in order to confirm the presence of a specific medication in the IV line.
These nanostructured surfaces are inexpensively produced on flexible plastic surfaces by a replica molding process with nanometer scale accuracy. The system has been able to identify morphine, methadone, phenobarbital, the sedative promethazine, and mitoxantrone, which is used to treat multiple sclerosis. The system is extremely sensitive: it can detect drugs in amounts 100 times lower than the clinically delivered drug concentrations commonly used. So far, the researchers have also shown their system can sense a two-drug combination, which has its own unique signature.
