Anionic Ln-MOF with tunable emission for heavy metal ion capture and -cysteine sensing in serum

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-03, Vol.8 (11), p.5587-5594
• Main Authors: Sun, Tiancheng, Fan, Ruiqing, Xiao, Rui, Xing, Tingfeng, Qin, Mingyue, Liu, Yaqi, Hao, Sue, Chen, Wei, Yang, Yulin
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c9ta13932j

As important biomarkers, the levels of essential amino acids in serum are of vital importance for human health. Here, we reported two sensitive luminescent probes based on a novel heterometallic anionic MOF, Eu-K-bpda (H 2 bpda = 2,2′-bipyridine-6,6′-dicarboxylic acid), for wide-range l -cysteine detection in serum. Notably, the connected K + ions enlarged the distance between Ln 3+ ions and resulted in a more controllable illuminating color related to the Eu 3+ /Tb 3+ ratio via limiting Tb 3+ -Eu 3+ energy transfer, which has been rarely reported. Benefitting from an anionic framework, MOF exhibited significant adsorption for two heavy metal ions, namely, Fe 3+ (105.15 mg g −1 ) and Cu 2+ (143.88 mg g −1 ) as common toxicant ions with a luminescence response. Therefore, based on the strong affinity between metal ions and l -cysteine, the two designed Fe 3+ @Eu-K-bpda and Cu 2+ @Eu-K-bpda could act as efficient turn-on luminescent probes for detecting l -cysteine with high sensitivity (LOD = 0.149 μM) and a wide detection range (0-100 μM). Meanwhile, the luminescent platform demonstrated good water, pH, and thermal stability for recycling. The combination of adsorption and luminescence properties makes Eu-K-bpda a potential functional material for pollution control and biomarker detection. Efficient turn-on luminescent probes for l -cysteine sensing in serum are designed and synthesized based on an anionic Ln-K-MOF with tunable emission color and heavy metal ion adsorption capacity.