Preparation Of Doped Carbon Quantum Dots And Their Analytical Application In Drug Detection

Fluorescent carbon QDs are a new type of carbon nanomaterials with a size of<10 nm.Due to their excellent optical properties and good biocompatibility,they have attracted the interest of researchers.Studies have shown that the cytotoxicity does not change significantly after the doping of the fluorescent carbon dots compared with the undoped carbon dots,but the doped carbon dots have stronger luminescence properties.Therefore,doped fluorescent carbon dots have become a research hotspot in the field of biological and pharmaceutical analysis.In this dissertation,two kinds of doped fluorescent carbon dots were prepared.Based on this,the analysis and detection of curcumin,manganese?VII?and ascorbic acid in actual samples,and cell imaging applications were achieved.Chapter 1:The first chapter mainly summarizes the properties of fluorescent carbon dots and their research progress in preparation and application.Chapter 2:A simple and rapid preparation of nitrogen and phosphorus dual-doped carbon dots?NP-Cdots?using glucose,1,2-ethanediamine and concentrated phosphoric acid as carbon sources,N-dopant and P-dopant,respectively.Based on this,a novel label-free fluorescence sensor with detection of curcumin was constructed.Based on the inner filter effect?IFE?,Cur strongly quenches the fluorescence of NP-Cdots.The constructed sensor is used for sensitive detection of Cur in aqueous solution with a linear range of 0.5-20?mol/L and a limit of detection of 21 nmol/L.Common amino acids and other drugs do not interfere with the detection of Cur,with good selectivity and anti-interference.The sensor was successfully applied to the detection of Cur in drinking water and urine with satisfactory results.The RSDs and recoveries were 0.08%-5.39%and 95.2%-105.2%,respectively.More importantly,the prepared NP-Cdots act as a cellular imaging fluorescent reagent without significant cytotoxicity.The constructed fluorescence sensor is simple and practical,indicating that NP-Cdots has potential application value in biosensing,cell labeling and imaging,and biological monitoring.Chapter 3:Microorganism consists of abundant amino acids,?-vitamins,and adenosine triphosphates.It can be used as a potential precursor for the fabrication of CNDs.Herein,waste microorganisms as precursors were used to synthesize nitrogen,phosphorous,and sulfur co-doped carbon nanodots?CNDs?,which not only reduces the experimental costs,but also avoids the secondary pollution of microorganisms.In this chapter,N-,S-,and P-co-doped carbon nanodots(N,S,P-CND_Sac)were prepared by one-step hydrothermal method using S.cerevisiae as a reaction precursor.Using modern analytical methods,N,S,P-CND_Sac were characterized in detail to understand the properties of N,S,P-CND_Sac,and for further application.Chapter 4:N,S,P co-doped carbon nanodots(N,S,P-CND_Sac)prepared based on the third chapter,and the construction of label-free detection of manganese?VII?and antimony-ascorbic acid??-AA?Fluorescent probes.Based on the inner filtration effect?IFE?,Mn?VII?can effectively quench the fluorescence of N,S,P-CND_Sac,thereby constructing a fluorescent probe for the detection of Mn?VII?.By addition of L-AA,Mn?VII?is reduced to Mn?IV?,Mn?II?and Mn?0?,thereby enabling the detection of L-AA.The probe has high sensitivity and selectivity for Mn?VII?and L-AA,with the lowest detection limits of 50nmol/L and 1.2?mol/L,respectively.According to this phenomenon,an"AND"logic gate based on the new N,S,P-CNDSac has been constructed.More importantly,the as-proposed fluorescent probe was extended to detect Mn?VII?and?-AA in biosystem.Furthermore,the as-constructed fluorescent probe system was successfully applied to the analyses of Mn?VII?in Tap water,Fenhe river and Medicinal herbs samples with satisfactory results.The proposed method was simple and ease of operation,which demonstrated the great potential of N,S,P-CNDSac in bio-sensing,disease diagnosis,cellular labelling and environmental monitoring.