Preparation Of Fluorescent Carbon Quantum Dots And Its Application In NO Detection

Carbon quantum dots illustrates broader development prospects in the fields of fluorescent labeling,bio-imaging,bioanalysis and medical diagnosis than traditional semiconductor quantum dots because of their advantages of nano-sized particle size,extremely strong fluorescence,good electron conductivity,photo bleaching and high biocompatibility.Nitric oxide(NO),as an important active nitrogen and signaling molecule,has a wide range of physiological functions,and its activity changes are closely related to many diseases.Its online detection in organisms is expected to achieve the early diagnosis of related diseases and efficient treatment.However,NO display unstable chemical stability,short half-life,low concentration and difficult to separate in organisms,.Therefore,scientists have been exploring more selective,specific,and sensitive methods to achieve NO detection in real time,Which could provide significant guidance for the early diagnosis of related diseases.In this study,o-phenylenediamine and thiourea were utilized as raw materials to prepare carbon quantum dots(NO-CDs)with specific response to NO by one-step hydrothermal method.Ultraviolet,infrared,transmission electron microscopy and dynamic light scattering were performed to characterize NO-CDs.The relationship between the excitation and emission light of carbon quantum dots was studied,the concentration of carbon quantum dots,the p H of the buffer solution,the illumination time,the storage time and the effects of various metal and nonmetal ions on the fluorescence intensity were also study to explore the optimal detection conditions.The following conclusions were obtained through the research of this thesis:(1)A large amount of o-phenylenediamine was introduced on the surface of the synthesized carbon quantum dots by the raw material of o-phenylenediamine,and the specific reaction between o-phenylenediamine and NO was used to achieve NO Selective detection(2)Carbon quantum dots have strong chemical stability and light stability,and their fluorescence intensity does not change with the exposure time,storage time and interference of other ions,reflecting strong anti-interference ability,which is more suitable for NO detection.(3)NO can selectively quench the fluorescence of NO-CDs,which is linearly correlated with the concentration of sodium nitroprusside(SND,NO donor)in a certain range.(4)NO-CDs have strong specificity and sensitivity to NO,and the lowest detection concentration is 10nmol/L,demonstrating that NO-CDs have great potential to realize the real-time monitoring of NO in various tissues and organs in the body.This study lays an important foundation for the selective and real-time detection of NO in vivo.Later work is expected to discuss the online detection of NO by NO-CDs at the cellular and living levels,which is expected to provide important guidance for the early diagnosis and treatment of related diseases.