Mar 21, 2003
Gold nanoparticles could boost biosensors
Scientists at the Hebrew University of Jerusalem, Israel, and Brookhaven National Laboratory, US, have used gold nanoparticles to attach glucose-oxidizing enzymes to electrodes. These enzyme-electrodes could ultimately be used as miniaturized biosensors inside the body that measure blood glucose.
"A single gold particle that is implanted into the protein acts as an electrical contacting point between the redox-centre and the electrode," Itamar Willner of the Hebrew University of Jerusalem told nanotechweb.org. "The resulting enzyme reveals an electron-transfer exchange rate with the electrode of about 5000 per second, whereas in nature its electron-transfer exchange rate is only about 700 per second."
The gold nanoparticle both orients the binding of the enzyme to the electrode and provides an electrical pathway. When the enzyme oxidizes glucose, electrons flow through the nanoparticle and into the electrode - the amount of current indicates the level of glucose present.
This more efficient electrical communication should lead to electrodes with better specificity and sensitivity. "The improved sensitivity will allow the use of miniaturized implanted electrodes as sensing devices," explained Willner. "The enhanced specificity would enable the operation of the electrodes without disturbing effects of interfering reagents in the analyzed samples."
The nanoengineered electrodes could also have applications in bionanoelectronic devices such as biofuel cells. "By the fabrication of implanted biofuel cell devices, one will be able to use glucose in blood as the fuel source for the generation of electricity," said Willner. "Such implanted biofuel cells would generate electricity from body fluids and the electrical power could activate pacemakers, insulin pumps or prosthetic units."
The researchers reported their work in Science.
About the author
Liz Kalaugher is editor of nanotechweb.org.