Research On The Design,Synthesis And Application Of Peptide-based Fluorescence Quantum Dots

Peptides are short chains of amino acid monomers linked by amide bonds.Polypeptides with simple structure,good activity and strong specificity are synthesized according to the functional properties and specific sequence of amino acids.These polypeptides can be directly used or coupled with fluorescent quantum dots to realize rapid and effective detection of heavy copper ions,highly toxic ions such as cyanide ions,biotin dopamine,etc.It has certain significance for ecological environmol/Lent,chemical research,life science research and so on.Nowadays,with the rapid development of agriculture,copper and cyanide preparations are widely used in pesticides,which leads to the problem that the contents of copper and cyanide ions in food exceed the standard.The detection of these two substances is of great significance for the healthy development of food.Based on the principle of fluorescence quantum dots,three kinds of polypeptide fluorescence quantum dots were designed and synthesized.The fluorescence responses of copper ion,cyanide ion and dopamine were studied respectively.The main contents are as follows:1.Decapeptide CHGWDAHSS fluorescent probe was used to detect copper ions.CHGGWDAHSS,a decapeptide fluorescent probe,was synthesized by indole groups on tryptophan as fluorescent groups,functional polypeptide sequences DAH and GGH.When copper ions are added to the probe system,the probe fluorescence quenching will occur.The experimental results showed that the probe had a strong selectivity for copper ions.Under the optimum detection conditions,the linear relationship between copper ion concentration and fluorescence intensity is good in the range of 0.2-8.0?mol/L.The regression equation is y=-84.309x+933.34,the linear correlation coefficient R²=0.995,and the detection limit is 45 nmol/L.2.Tetrapeptide WHKR fluorescent probe was used to detect cyanide ion.The tetrapeptide fluorescence probe WHKR was synthesized by introducing the tripeptide sequence of HKR into the probe system,and the fluorescence of the probe was enhanced by adding cyanide ion.The experimental results showed that the probe had a strong selectivity for cyanide ion,and the fluorescence intensity increased rapidly after adding cyanide ion.Under the optimum detection conditions,the concentration of cyanide ion has a good linear relationship with fluorescence intensity in the range of 0.1-6.0?mol/L.The regression equation is y=84.175x+347.49,the linear correlation coefficient is 0.993,and the minimum detection limit is 16 nmol/L.3 Polypeptide-gold nanocluster fluorescence sensor was used to detect copper ion.Gold nanoclusters were synthesized using bovine serum albumin as the template and successfully coupled with polypeptide CCYWDAHRDY.When copper ions were added to the probe system,the fluorescence of the probe was quenched.The experimental results show that the probe can detect copper ions more sensitively.Under the optimum detection conditions,the linear relationship between copper ion concentration and fluorescence intensity is good in the range of 0.1-4.2?mol/L.The regression equation is y=-105.9x+693.68,the linear correlation coefficient is 0.997,and the minimum detection limit is 52 nmol/L.4."Turn on"fluorescent probe based on Cu²⁺@polypeptide-AuNCs fluorescence system was used to detect dopamine.A fluorescent probe based on the fluorescent system of copper ion polypeptide gold nanoclusters was constructed and used to detect dopamine.The experimental results showed that the method had good specificity for the detection of dopamine.Under the optimal detection conditions,the linear relationship between dopamine concentration and fluorescence intensity is good in the range of 0.2-30?mol/L.The regression equation is y=16.217x+247.03,and the correlation coefficient R2=0.999.The detection limit of this method is 19 nmol/L.The method has been successfully applied to the determination of dopamine in human urine.The recovery of the standard addition is 98.2%-102.15%,and the RSD is 1.5³.2.