Biosensor Allows Real-Time Monitoring of Blood Chemicals

Biosensor Allows Real-Time Monitoring of Blood Chemicals

A research team at Stanford University has developed a biosensor that allows real-time monitoring of blood chemicals. Not only is the device able to constantly monitor the presence of chemicals in the blood, it also allows clinicians to control levels of those chemicals accurately in real-time.

The biosensor system can be configured to monitor levels of a wide range of different molecules such as drugs, and it is believed the system can also be used to monitor for the presence of certain proteins such as enzymes.

Biosensor systems are nothing new, although until now they have only been used to monitor levels of chemicals and biological compounds every few minutes. Recently, the Food and Drug Administration (FDA) in the United States approved an artificial pancreas which is capable of monitoring blood glucose levels and administering a dose of insulin to bring glucose levels back to a desirable level. However, the device only measures glucose every few minutes. The Stanford system offers blood chemical monitoring in real-time.

The potential applications are considerable. Certain diseases and medical conditions require antibiotics or drugs to be administered slowly to ensure the concentration in the blood is kept within a very narrow range. If the concentration of those drugs exceeds a certain limit, patients may experience dangerous side effects. If the concentration falls too much the treatment becomes ineffective. The new biosensor could ensure clinicians always hit the sweet spot. The researchers also believe that by configuring the system to monitor for specific proteins it may be possible to predict the onset of an infection or an impending heart attack.

The research was led by H. Tom Soh. In 2013, Soh and his team said they had successfully used the biosensor to measure concentrations of chemotherapy drugs and antibiotics in rats and humans; however, the system has now been tweaked and the device can now send data faster with less of a lag between taking and reporting measurements. Peter Mage, a postdoctoral researcher in the team, recently tested a new closed-loop system that enabled the team to control concentrations of blood chemicals in live animals.

The system was tested using doxorubicin; a drug commonly used in chemotherapy. While the drug is effective, it is difficult to accurately control the dose. The team was able to accurately monitor the dose in a test rabbit by drawing blood from the animal’s ear and passing it through the sensor. The sensor measured the concentration of the drug, passed that information to a computerized feedback system, which then administered more doxorubicin into the animal’s other ear using a programmable drug pump.

Sensor systems do not tend to work well on whole blood as they get clogged, but an innovative design allowed the researchers to filter large particles out of the blood to let smaller molecules reach the electrodes used to measure chemical concentrations.

The device only works for a few hours, although the team believe that by developing disposable sensor elements – which can be changed every few hours – it will be possible to use the system for long-term monitoring of patients.