Construction Of The Quantum Dots Test Strips And Their Applications In Biomolecules Detection

Biomolecules,such as small biomolecules,nucleic acids and proteins,as important components of organisms,play vital roles in the process of life activities.The concentrations and form of biomolecules are associated with many diseases and directly reflect the health of organisms.Therefore,the detection of biomolecules have great significance in reveals and illuminates life process,achieve the prevention and treatment of major diseases,and screen and develop drugs.Compared with the reported methods,lateral flow chromatography test strip?LFTS?has its unique advantages.LFTS has been a rapid analysis detection technology developed in recent years.Compared with the traditional laboratory testing methods,LFTS has obvious advantages,including rapid,simple,portable,sensitive and economic.In addition,the greatest advantage of LFTS is that it can measure outside of testing room or laboratory without any professional facilities.In this thesis,a series of strip detection methods for the qualitative and quantitative analysis of glutathione?GSH?and alkaline phosphatase?ALP?were established by combining LFTS and fluorescent quantum dots?QDs?with excellent optical properties.The main research contents are described as follows:1.The sensitive detection of GSH based on a fluorescent test strip mediated by silver ionIn this work,based on the quenching ability of Ag⁺and the stronger binding force between Ag⁺and GSH,a new fluorescence enhanced strip sensing system for detection of GSH was developed.In this design,bovine serum albumin?BSA?functionalized QDs were chosen as signal reporter and modified on the test line of the LFTS.In the presence of Ag⁺,the fluorescence of QDs can be quenched efficiently owing to the electron transfer from QDs to Ag⁺.In the presence of GSH,due to the much stronger affinity between Ag⁺and GSH,Ag⁺preferred to bind with GSH to form Ag-S bond,the chelate can not quench the fluorescence of QDs.With the increase of GSH,the fluorescence of QDs on the test line recovered gradually.By monitoring the changes of fluorescent intensity on the test line,GSH was successfully detected in buffer with a detection limit of 25 nM.In addition,the proposed detection platform was used for GSH detection in real samples.2.The rapid detection of ALP based on a fluorescent test strip mediated by Ce?IV?Herein in this work,using ATP as substrate,a portable and rapid method for detecting the concentration of ALP was developed based on QDs fluorescent test strip.In this design,Ce?IV?ion can efficiently quench the fluorescence of QDs.However,in the presence of ALP,ALP can catalyze the hydrolysis of ATP to generate phosphate ion,Ce?IV?was combined with phosphate ion and the fluorescence of the system was restored.Based on this principle,we successfully and rapidly detected ALP in buffers with a detection limit of 1.1 U/L.In addition,this method was used for ALP detection in real samples.3.The sensitive and portable detection of ALP based on a colorimetric/fluorescent dual-readout LFTS mediated by manganese dioxide nanosheetsHerein in this work,based on the quenching effect of manganese dioxide?MnO₂?nanosheetsonQDsandconbinedwithfluorescentteststrip,a colorimetric/fluorescent dual-readout LFTS platform for ALP determination has been developed.In this design,bovine serum albumin?BSA?functionalized QDs were chosen as signal reporter and modified on the test line of the LFTS.In the absence of ALP,MnO₂ nanosheets aggregated on the test line and exhibited an obvious brown color,which can be observed by the naked eye to use as a qualitative signal.Meanwhile,the fluorescence of QDs on the test line can also be effectively quenched by MnO₂ nanosheets due to inner-filter effect of fluorescence.However,in the presence of ALP,ALP can catalyze the hydrolysis of L-ascorbic acid 2-phosphate?AAP?to generate L-ascorbic acid?AA?,which can reduce MnO₂ into Mn²⁺and trigger the decomposition of MnO₂ nanosheets,accompanying with the fluorescence recovery of the QDs.By monitoring the changes of colorimetric and fluorescent intensity on the test line,ALP was successfully detected with a detection limit of 0.7U/L.At last,this colorimetric/fluorescent assay was successfully applied to determination of ALP in human serum with satisfactory results.