Based On Carbon Nanomaterials And Enzymatic Assisted Cycle Signal Amplification Detection Of Heavy Metal Ions

BackgroundHeavy metals are one of the most important causes of environmental pollution.Heavy metals can accumulate in the human body along with the circulation of the food chain,thus damaging the normal physiological and metabolic activities of organisms and causing a great threat to human health.Heavy metal ions can cause serious damage to human brain cells,kidney function and central nervous system.Therefore,we constructed a fluorescence sensor that can detect Hg2+ or Ag+ rapidly and sensitively.In addition,Exo ?has been utilized to make the analyte recyclable,thus further improving the sensitivity of the detection method.Objectives(1)A fluorescence sensor based on CNMs and enzyme-assisted cyclic signal amplification was constructed to detect Hg2+;(2)A fluorescence sensor based on GO and enzyme-assisted cyclic signal amplification was constructed to detect Ag+.Methods(1)Based on the fact that Hg2+and two thymine can combine to form stable T-Hg2+-T complex and Ag+ and two cytosine can combine to form stable C-Ag+-C complex,'the detection of Hg2+ and Ag+by using oligonucleotides is realized.(2)Carbon nanomaterials can adsorb dye-labeled oligonucleotides,which quenches the fluorescence signal and greatly reduces the fluorescence background signal.(3)By using Exo IID as an auxiliary circulator,the target Hg2+or Ag+can be recycled and reused,so as to realize the purpose of fluorescent signal amplification.Results(1)Fluorescence sensor based on CNTs and enzyme-assisted cyclic signal amplification showed a good linear relationship when detecting Hg2+in the concentration range of 50-1000 nM;(2)Fluorescence sensor based on GO and enzyme-assisted cyclic signal amplification showed a good linear relationship when detecting Hg2 in the concentration range of 20?500 nM.Compare with CNTs,GO had stronger fluorescence quenching efficiency and lower background noise for FAM-ssDNA;(3)Fluorescence sensor based on GO and enzyme-assisted cyclic signal amplification showed a good linear relationship when detecting Ag in the concentration range of 50?500 nM.Conclusions(1)Fluorescence sensor based on GO and enzyme-assisted cyclic signal amplification can quickly and sensitively detect the content of Hg2+and show good selectivity and specificity for Hg2+;(2)Fluorescence sensor based on CNTs and enzyme-assisted cyclic signal amplification can quickly and sensitively detect the content of Hg2+ and show good selectivity and specificity for Hg2+;(3)The sensitivity of the fluorescence sensor constructed with CNTs or GO to detect Hg2+ was similar;(4)whether CNTs or GO was used as the fluorescence quenching agent,the fluorescence sensor can achieve the specific detection of Hg2+;(5)The principle of this method could be used for the detection of Ag+and showed good selectivity and specificity for Ag+.