Investigation of different temperatures-modified cysteine/gold nanoparticles film applied for copper ions sensing

In this study, the cysteine (Cys) modified gold nanoparticles (AuNPs) film on glass substrate was used for copper ions sensing. AuNPs were prepared by using photochemical method, which were modified on glass substrate by using self-assembly method, and then followed by modifying Cys on AuNPs film at various temperatures of 0 °C, 25 °C and 50 °C. Cys can help AuNPs to capture copper ions and cause the aggregation of AuNPs, which were due to the chelation effect, so that the absorption peak of Cys/AuNPs film exhibited a red-shift phenomenon. And the surface morphology of the film at various temperatures was observed using SEM. Finally, the sensitivity for the detection of copper ions using Cys/AuNPs modified films at various temperatures was investigated in this paper. The results indicated that Cys modified on AuNPs film at 25°C showed the optimal copper ions detection with a red-shift of absorbance wavelength of 2 nm.