Design And Application Of Peptide-based Metal Ions Fluorescence Sensor

Metal ions play a vital role in maintaining the normal physiological function of human body,but their extensive application in industrial and agricultural production has brought serious metal ion pollution problems.Because metal ions are toxic and difficult to degrade,they may cause certain damage to human health and environmental protection.The traditional metal ions detection methods have some shortcomings,such as expensive instruments,tedious detection steps and long detection time.Therefore,it is very necessary to study a new technology which can realize the rapid and effective detection of metal ions.Peptide are widely used in the detection of metal ions because of their high selectivity,high water solubility and good biocompatibility.In this paper,four different types of fluorescence sensors were constructed on the basis of peptide to investigate their specific ability to detect metal ions,and explore their application in the detection of tap water samples.The main contents are as follows:1.based on Zn²⁺photoinduced electron transfer and Cu²⁺paramagnetic quenching effect,a bidirectional peptide fluorescence sensor L1（WHEPGH）was designed.The addition of Zn²⁺resulted in the enhancement of L1 fluorescence.The addition of Cu²⁺can cause fluorescence quenching of L1.The fluorescence sensing results showed that the binding ratio of L1 to Zn²⁺and Cu²⁺was 2:1,and the binding constants were0.22774×10¹² M^-2 and 0.21731×10¹² M^-2.The detection limit of Zn²⁺and Cu²⁺were75.0 n M and 79.8 n M,respectively.2.L1 and Au NCs were combined to form a peptide-Au nanoclusters fluorescence sensor L1-Au NCs,which has excellent fluorescence properties,good water solubility and emitd red fluorescence,L1-Au NCs showed excellent selectivity and sensitivity to Zn²⁺.When the concentration of Zn²⁺was in the range of 0～50μM,the fluorescence intensity of L1-Au NCs showed a good linear relationship with the concentration of Zn²⁺,and the detection limit was 25.2 n M.In addition,L1-Au NCs showed excellent ability to detect Zn²⁺in tap water samples.3.based on the peptide sequence of L1,a novel peptide fluorescence sensor L2（YCPGHPGE）was optimized,the addition of Cu²⁺can cause the quenching of the fluorescence peak of L2,which showd excellent specific binding ability to Cu²⁺,and other metal ions did not interfere with the detection of Cu²⁺.The binding ratio of L2 to Cu²⁺was 2:1,the binding constants was 1.45×10¹¹ M^-2,and the detection limit of Cu²⁺was 51.9 n M.In addition,L2 has been successfully applied to the quantitative determination of Cu²⁺in tap water samples.4.a novel fluorescence sensor L3（CCYCPGHPGEE）with strong Cu²⁺recognition ability was designed by optimizing the sequence of L2,which is combined with Au NCs to form a red peptide-Au nanoclusters fluorescence sensor L3-Au NCs.It had good fluorescence stability.The introduction of Cu²⁺can significantly reduce the fluorescence intensity of L3-Au NCs,and realize sensitive detection of Cu²⁺,with the lowest detection limit of 14.9 n M.In addition,L3-Au NCs have been successfully applied to the determination of Cu²⁺in tap water samples.