Computerized systems can deliver intravenous (IV) medications in precise amounts, but cannot identify or determine concentrations of drugs in the tubing—a fact that sometimes has serious consequences, including incorrect dosage, unintentional substitution of one drug for another, and co-delivery of incompatible drugs. That's why such vulnerability is a major concern in hospitals, according to Brian T. Cunningham, interim director of the Micro and Nanotechnology Laboratory at University of Illinois at Urbana-Champaign (UIUC).
Now, an optical device can overcome this limitation through real-time characterization of fluid in an IV line. The invention of UIUC electrical and computer engineering students led by Cunningham, it uses surface-enhanced Raman scattering (SERS) technology, which boosts sensitivity to molecular signals that can identify chemicals.
To determine the identity of a particular IV medication, the researchers shone laser light onto a nanostructured gold surface that contained millions of tiny "nano-domes" that are separated from each other by as little as 10 nm. The nano-domes were incorporated into the inner surface of IV tubing, where they were exposed to drugs dispersed in liquid. They captured the light scattered from drug molecules in contact with the nano-domes and used SERS to determine the drug's molecular signature. Finally, they matched the captured signature to known signatures of drugs in order to confirm the presence of a specific medication in the IV line.
While other groups have demonstrated excellent nanostructured surfaces for SERS, the researchers' nanostructures are unique because they are inexpensively produced on flexible plastic surfaces by a replica molding process with nanometer-scale accuracy.
Early data show that the system can identify a number of medications in amounts 100 times lower than the clinically delivered drug concentrations commonly used. The system has also proven able to sense a two-drug combination, which has its own unique signature.
The next step is further evaluation for combinations of up to 10 drugs being delivered simultaneously. Computer algorithms are also being developed to automatically interpret the SERS spectra. The researchers are evaluating the system for possible commercialization.
The research was presented during The Optical Society's (OSA's) Frontiers in Optics (FiO) 2013 (presentation LTh3H.4, "Point-of-care Detection and Real-time Monitoring of Intravenously Delivered Drugs via Tubing with an Integrated SERS Sensor").