Design Of Organic Fluorescent Nanoprobe And Application Of Biomarker Detection

Organic fluorescent materials are increasingly favored by scientific researchers due to their advantages such as a wide variety of materials,low cost,fast response,and high sensitivity.The fluorescent probes designed based on organic fluorescent materials have been widely used in human health,environmental detection,food safety and other fields.In recent years,with the improvement of people's living standards,social problems have occurred frequently.The detection of environmental pollution and food safety issues have always been the focus of scientific research.At the same time,environmental pollutions,food safety problems,and unhealthy eating habits have also led to the occurrence of some diseases.Many diseases have no obvious symptoms in the early diagnosis,and cannot be detected early by people,which greatly increases the incidence of diseases and the difficulty of curing.However,some endogenous volatile organic compounds(VOCs)in the exhaled breath of the human body are closely related to certain diseases of the body.Therefore,these endogenous VOCs can be used as biomarkers for the assessment of various diseases and health warnings.This thesis uses a smartphone sensor platform based on the organic hybrid ratiometric fluorescent probe combined with a smartphone device to achieve sensitive,convenient,reliable and visual detection of biomarkers.The designed method provides effective sensing strategies for health warning,environmental pollution,food safety and other fields.The main research contents are as follows:(1)The portable smartphone device based on 3D printing technology uses visual detection of acetone to make the initial diagnosis of the disease.The key part of the device consists of red carbon dots(RCDs),which used as internal standard and a sensing part(3-N,N-(Diacethydrazide)-9-Ethylcarbazole(2-HCA))for acetone.Under the excitation wavelength of 360nm,the emission wavelengths of 2-HCA and RCDs are 443nm and 619nm,respectively.2-HCA can effectively capture acetone to form non-fluorescent acylhydrazone by condensation reaction in aqueous solution,showing obvious color changes from blue-violet to dark red.The detection limit for acetone is 2.62 ?M(?0.24 ppm).It is far lower than normal human blood ketone content(?0.50 mM)and human respiratory gas acetone content(?1.80 ppm).The portable smartphone devices based on 3D printing technology has good recovery rates for acetone detection in blood and exhaled breath,which for 90.56-109.98%(RSD ?5.48)and 92.80-108.00%(RSD?5.07),respectively.The method designed here provide a reliable way for health warning by visually detecting marker of ke-tosis/diabetes in blood or exhaled breath.(2)The components in exhaled breath have been confirmed to be related to certain diseases,especially studies have shown that isopropanol(IPA)might closely relate with illnesses such as lung cancer.Herein,we designed a portable smartphone platform based on chemically synthesized ratiometric fluorescent probe for real-time/on-site,sensitive,and semi-quantitatively visual detection of IPA in exhaled breath.The fluorescent probe was fabricated by nicotinamide adenine dinucleotide(NAD+)functional modified onto the fluorescent internal standard red carbon dots(RCDs).While IPA can convert NAD+into reduced nicotinamide adenine dinucleotide(NADH)though enzymatic reaction of secondary alcohol dehydrogenase(S-ADH).The electron transfer from IPA to NAD+emitted the blue emission of NADH,which displaying consecutive color changes from red to light blue.Under optimum conditions,the fluorescent probe shows sensitive responses to IPA with a detection limit as low as 4.45 nM.Moreover,combined with the smartphone color recognizer application(APP),the color information(RGB value)of the fluorescent photo is converted into data information for the visual quantitative determination of IPA,which has been employed for visual quantitative determination of IPA with detection limit of 8.34 nM,and the recovery rate of 91.62-110.09%(RSD?4.71).The method reported here provides a convenient pathway for real-time/on-site and visual detection of IPA in exhaled air,and expected to extend application of investigation of potential volatile biomarkers for preliminary monitoring and clinical diagnosis.(3)The ratiometric fluorescence probes also have important development prospects in environmental monitoring and food safety.By preparing a new compound based on Cyclen and Nile blue(NB).mixed with blue carbon dots to form a ratiometric fluorescent probe solution,it can be used to detect Cu2+ in water.Using the principle that paramagletic Cu2+ and Cyclen can form a metal complex to quench the fluorescence of the composite,a new type of smartphone fluorescence sensor system is constructed.With the addition of Cu2+,the red fluorescence in the system gradually weakened,while the blue fluorescence remained unchanged,thus showing a series of fluorescence changes from purple to blue.The designed fluorescence system provides a new fluorescence strategy for rapid detection of Cu2+ in water.This fluorescence strategy has very good application value in environmental detection,and also has great potential in the field of rapid detection.In terms of food safety,ratiometric fluorescence probes also have very good application value.Using the blue fluorescence of tea oil and CdTe QDs,a ratiometric fluorescence probe with purple fluorescence was constructed.When Hg2+ in tea oil contacts CdTe QDs,the fluorescence of QDs is quenched,and then the blue fluorescence of tea oil is not affected by Hg2+,so it shows a wide range of fluorescence variation.The ratiometric fluorescence sensing system based on detecting its Hg2+ in tea oil not only has a detection limit as low as 6.04 nM,but is also convenient and quick,simple to operate,time-saving,fast and cost-effective.The designed ratiometric fluorescence fluorescence sensing system provides a new strategy for the rapid detection of heavy metals in actual camellia oil samples.