The Preparation And Modification Of Si-B-doped Carbon Dots And The Application In Sensing Hemoglobin

Fluorescent carbon dots（CDs）are a new type of carbon nanomaterials with sizes of less than 10 nm.Due to their outstanding optical properties,such as adjustable luminous range,chemical stability,low cytotoxicity,good biocompatibility,high photostability,easy functionalization and so on,CDs are become focused the interest of the researchers.In chapter 1,the properties,preparation methods and the modifications of CDs were introduced,as well as their applications in the fields of sensing and bio-imaging.In chapter 2,a microwave oven one-pot approach for the synthesis of Si-B-CDs had been proposed by using citric acid（C6H8O7）,boric acid（H3BO3）and（3-Aminopropyl）triethoxy sliane（APTES）as source materials.Si-B-CDs was characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）and fourier transform infrared spectra（FT-IR）,respectively,confirmed the resulting product is amorphous CDs,with small amount of Si and B;The transmission electron microscopy（TEM）results indicated that the synthesized Si-B-CDs had good monodispersity,with a size of ca.4～8 nm.The obtained Si-B-CDs showed excitation-independent PL behavior in a certain range,and the excitation/emission maximum was 350 nm/445 nm,respectively.The quantum yield of Si-B-CDs was 20.1%.The interaction of CDs with hemoglobin（Hb）had been detailedly studied by fluorescence spectroscopy in combination with circular dichroism（CD）spectroscopy and UV-vis absorption spectroscopy.The results showed that Si-B-CDs interacted with the heme prosthetic group of Hb and formation of static complexes results in fluorescence quenching of Si-B-CDs,so,a new method for detecting Hb was established.Under the optimum experimental conditions,the method for Hb sensing using Si-B-CDs as fluorescence probe was developed,with the linear range from 0.45 to 3.73 μmol L-1 with a correlation coefficient of 0.9971,and the limit of detection was 0.14 μmol L-1.The method was successfully applied to the determination of Hb in human blood samples.In chapter 3,Polyacrylic acid sodium（PAAS）surface contains a large number of carboxyl,not only enhancing the water-soluble Si-B-CDs,but also improving the sensitivity of detection of Hb.A microwave oven one-pot approach for the synthesis of PAAS-CDs had been proposed using a passivating PAAS,and it was applied for fluorescent probe of Hemoglobin（Hb）.The quantum yield of PAAS-CDs was 34.6%.Under the optimum experimental conditions,when PAAS-CDs was employed as fluorescence probe,the the limit of detection for sensing of Hb was 0.06 μmol L-1,with a linear range of 0.21 to 5.22 μmol L^-1.