An older method involves the reduction of copper hydrazine carboxylate in an aqueous solution using reflux or by heating through ultrasound under an inert argon atmosphere.
The reduction of copper(II) acetylacetonate in organic solvent with oleyl amine and oleic acid causes the formation of rod and cube-shaped nanoparticles while variations in reaction temperature affect the size of the synthesized particles.
[6] Another method of synthesis involves using copper (II) hydrazine carboxylate salt with ultrasound or heat in water to generate a radical reaction, as shown in the figure to the right.
[9] As the nanoparticles oxidize slowly in solutions, cupric ions are released from them and they can create toxic hydroxyl free radicals when the lipid membrane is nearby.
Redox reactions utilized in those sensors are generally irreversible and also require high overpotentials (more energy) to run.
In fact, the nanoparticles have the ability to make the redox reactions reversible and to lower the overpotentials when applied to the sensors.
[12] In fact, the nanoparticles enable the sensor to be more stable at high temperatures and varying pH, and more resistant to toxic chemicals.
[13] A copper nanoparticle-plated screen-printed carbon electrode functions as a stable and effective sensing system for all 20 amino acid detection.