Their proposed bio-sensor involves a nanocomposite, consisting of functionalized carbon nanotubes and magnetic iron oxide nanoparticles, used in a process which led to the production of a sensitive electro-catalytic system.
Dehydrogenase enzymes form the most extensive category of known enzymes which includes more than 300 different types. Lactate dehygroenases (LDHs) are a group of enzymes found in the cytoplasm of almost all body tissues. The LDH content in the body increases in case of various diseases. Thus, LDH measurement has been proved to serve as a tool for preliminary diagnosis of renal infraction, renal cell carcinoma, skeletal muscle disease, etc.
In this context, the measurement of very low substrate concentrations of the mentioned enzyme (lactate) is of practical importance. The proposed "functionalized carbon nanotubes - Fe3O4 magnetic nanoparticles" nanocomposite enables the oxidative elecrocatalysis of NADH at very low potentials. Finally, the covalent bonding of the NAD+ cofactor and the lactate dehygroenase enzyme upon the synthesized nanocomposite led to the production of a fully integrated bio-sensor for lactate analysis.
"The catalytic property of the invented nanocomposite at very low potentials is due the synergism arising from the combination of the two involved nanostructures (functionalized carbon nanotubes and Fe3O4 magnetic nanoparticles). In addition, another advantage of our proposed system lies in the biocompatibility of the nanocomposite which is in favor of protecting the lactate dehygroenase," Dr. Salimi, a member of the research group, explained.