Amine-functionalized UiO-66 as a fluorescent sensor for highly selective detecting volatile organic compound biomarker of lung cancer

The analysis of breath VOC biomarkers is an efficient method for the early diagnosis of lung cancer. In this work, the zirconium UiO-66 was post-synthetically modified by using methylamine (MA), ethylenediamine (ED) and N,N′-dimethylethylenediamine (MMEN), respectively. The modified UiO-66 materials were thoroughly characterized, including PXRD, FTIR, TGA, physical adsorption at 77 ​K by nitrogen and photoluminescence analysis. The sensing properties of the modified UiO-66 materials toward the selected five potential breath VOC biomarkers were investigated. Results showed that after modification, the BET surface area and total pore volume all decreased, and followed the order: UiO-66 ​> ​UiO-66-MA ​> ​UiO-66-MMEN ​> ​UiO-66-ED. Furthermore, the N–H group was successfully grafted into the modified UiO-66 samples. In comparison with UiO-66, the fluorescence intensities of UiO-66-MA, UiO-66-ED and UiO-66-MMEN toward hexanal, styrene and isoprene all obviously increased, while the fluorescence intensities of the modified UiO-66 materials toward 1-propanol and ethylbenzene all decreased a lot, accompanied by the frequency shift. In addition, the LOD of hexanal on UiO-66-MA was calculated to be as low as 12 ​ppm, which was obviously lower than that of UiO-66 (31 ​ppm). The fluorescence quenching of hexanal was mainly due to the FRET mechanism. The results of this study would provide information for the development of early breath diagnosis of lung cancer.