Electrochemical detection of carbohydrates using copper nanoparticles and carbon nanotubes

Copper (Cu) nanoparticles (4-8 nm in diameter), prepared by using sodium borohydride to reduce copper dodecyl sulfate (Cu(DS)₂), were used with single-wall carbon nanotubes (SWCNTs) to fabricate electrochemical sensors. Nafion, a perfluorosulfonated polymer, was able to solubilize SWCNTs and displayed interactions with Cu nanoparticles to form a network, connecting Cu nanoparticles to a glassy carbon (GC) or Cu electrode surface. Cyclic voltammetry confirmed an electrical contact through SWCNTs between Cu nanoparticles and the GC backing whereas TEM micrographs illustrated the deposition of Cu nanoparticles on the carbon nanotubes. The response time and the detection limit (S/N=3) of the sensor for glucose were 10 s and 250 nM, respectively, i.e. a four-fold increase in the sensitivity compared to a bare Cu disk electrode. The response to interferents, such as acetaminophen, ascorbic acid and uric acid was suppressed in the presence of the SWCNT/Cu nanoparticle composite.