Bioelectronic sensor hunts, IDs chemicals
Researchers foresee a multitude of uses for biosensors.
Durham, N.C.—A new bioelectronic sensor detects a specific chemical in a complex mixture and then produces an electric signal that shows its identity and concentration.
Researchers already demonstrated they can engineer proteins to detect glucose in blood serum and the sugar maltose in beer, showing that these protein sensors can pick specific molecules out of complex mixtures without interference or fouling from other constituents.
“Since these engineered proteins are robust and potentially miniaturizable, we believe they will provide a basis for a vast array of chemical sensors,” said Duke University Medical Center biochemist Homme Hellinga. “For medical applications, you could imagine a multitude of sensors on a tiny chip that physicians could use at the patient’s bedside to immediately determine from a drop of blood the concentrations of drugs or metabolites, such as glucose.
Anesthesiologists could use such biosensors to instantly measure during surgery the concentration of anesthetic or key metabolites, such as epinephrine, in a patient’s body rather than relying on less accurate monitoring of vital signs. Thus, with these biosensors, in many cases you would no longer need expensive chemical laboratories and time-consuming clinical analysis.
Also, said Hellinga, an implantable glucose sensor would enable constant monitoring of blood glucose in people with diabetes and could also provide a long-term sensor as the basis for an artificial pancreas.
In other applications, Hellinga said, he foresees use of the biosensors to monitor pollutants and chemical and biowarfare agents. He emphasized the adaptability of the system. “These engineered proteins are based on proteins that bacteria use to sense their chemical environment, and since there are perhaps hundreds or thousands that exist, they provide a basis for a vast array of chemical sensors,” he said. “Using powerful computational design tools that we have developed, it is possible to engineer these candidates to dramatically alter their specificity and sensitivity.”
Hellinga and his colleagues described how they started with natural bacterial proteins called “bacterial periplasmic binding proteins.” These proteins constitute a large “superfamily” of proteins on the bacterial surface that the organisms use to sense food sources such as sugars and avoid toxic chemicals.