Tuning the fluorescence response of surface modified CdSe quantum dots between tyrosine and cysteine by addition of p-sulfonatocalix[4]arene.
A simple identification method of L-tyrosine (Tyr) and L-cysteine (Cys) using gemini surfactant coated CdSe quantum dots by using a fluorescent spectroscopic technique is proposed. The gemini surfactant modified QDs show a selective fluorescence response between Tyr and Cys by addition of p-sulfonatocalix[4]arene (pSCA). The CdSe QDs coated with gemini surfactant [C(12)H(25)N(+)(CH(3))(2)(CH(2))(4)(CH(3))(2)N(+)C(12)H(25)].2Br(-) (GS) obviously responds to Tyr. While in the presence of pSCA, it shows selectivity to Cys due to the cooperation of gemini surfactant coated QDs (GS-QDs) and pSCA. Under optimal conditions, it is found that the luminescence of the GS-QDs enhanced by Tyr in a concentration-dependent fashion is described by a Langmuir binding isotherm equation in the range 5 x 10(-8)-10(-5) M. In the presence of pSCA, the luminescence of the GS-QDs enhanced by Cys in a concentration-dependent fashion can also be described by a Langmuir binding isotherm equation in the range 10(-8)-10(-4) M. The possible mechanism is discussed.
Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China. lhbing@mail.ccnu.edu.cn
Haibing
H
Li
Xiaoqiong
X
Wang
D019187:Cadmium Compounds / Q000737:chemistry*; D047250:Calixarenes / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry*; D005453:Fluorescence; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry*; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013499:Surface Properties; D014443:Tyrosine / Q000737:chemistry*
D019187:Cadmium Compounds; D010636:Phenols; D018036:Selenium Compounds; C511968:p-sulfonatocalix(4)arene; D047250:Calixarenes; D014443:Tyrosine; C058667:cadmium selenide; D003545:Cysteine