ZnO-Salen NPs Employed as Chemosensor for Detection of Al3+ and K+ in Aqueous Medium, Developing Human Cell Images

ZnO nanoparticles (NPs) were prepared and characterized by different analytical methods and then they were used to decorate with N, N´-bis(salicylidene)ethylenediamine (salen) in order to perform as receptor for the metal ions in an aqueous medium. The results show that ZnO-salen selectively detects Al³⁺ ions in aqueous medium since the intensity of fluorescence has been enhanced significantly. However, the presence of K⁺ in the medium further intensified the fluorescence emission for the [ZnO-salen-Al³⁺] system. The above system has been applied to recognize Al³⁺ and K⁺ in cells by developing the cell images, for which, the fluorescence image is brightened if a human glioblastoma U251 cell contains [ZnO-salen-Al³⁺] + K⁺ ions, consisting of the fluorescence titration. The binding global constant for Al³⁺ and the subsequent recognition of K⁺ by ZnO-salen resulted in β₂(Al³⁺) = 6.61 × 10³ and β₂(K⁺) = 3.71 × 10³ with a detection limit of 36.51 µM for Al³⁺ and 17.39 µM for K⁺. In the cell toxicity analysis, the cell viability was over 85% for the ZnO-salen even in the concentration as high as 100 mM.