Biosensor Detects Brain Injuries During Heart Surgery

The organic thin film transistor design has a sensing area that is one centimeter square in size. On the surface of the sensor is a layer of antibodies that attract GFAP; when this occurs, it changes the physics of other material layers within the sensor, altering the amount of electrical current that is passing through the device. These electrical changes can be monitored, enabling the user to know when GFAP is present.

The researchers suggest that the testing takes place during surgery itself, by placing a drop of the patient’s blood on the sensor, which could activate a sound, light, or numeric display if the protein is present. By alerting the surgical team to an ongoing injury, better therapies could be developed, including improved control of blood pressure. The information obtained could also be used to redesign cardiopulmonary bypass machines, optimize cooling and rewarming procedures, and establish benchmarks for the developing and testing of new protective medications. The study was published in the November 11, 2013, issue of Chemical Science.

“This sensor proved to be extremely sensitive,” said senior author Howard E. Katz, PhD, of the JHU Whiting School of Engineering. “It recognized GFAP even when there were many other protein molecules nearby. As far as we’ve been able to determine, this is the most sensitive protein detector based on organic thin film transistors.”

Recent studies have found that after heart surgery about 40% of infant patients suffer brain abnormalities that show up in magnetic resonance imaging (MRI) scans. The damage is most often caused by strokes, which can be triggered and aggravated by multiple events during surgery and recovery, when the brain is most susceptible to injury. These brain injuries can lead to deficiencies in the child’s mental development and motor skills, as well as hyperactivity and speech delay.

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