The Study Of Multidimensional Optical Probes And Their Applications

A lectin is a saccharide-binding protein or glycoprotein of non-immune origin widespreading in nature which agglutinates cells and/or precipitates glycoconjugates.The specific interactions between lectins and saccharides involve various physiological and pathological processes,such as inflammatory responses,cancer metastasis and cell-cell interaction.Therefore,the qualitative and quantitative analysis of lectins plays an integral role in understanding and exploring important biological behaviors.We designed and built multidimensional optical probes.Compared with the traditional optical probes which are limited to transducting a single kind of signal,the multidimensional optical ones have following advantages.First,with more than single transduction channel the multidimensional optical probes offer improved discrimination accuracy and sensibility.Second,they are general for analysis on lectins hence expand the diversity.Finally,they extract four dimensional information in situ from a single sample system without separate measurements which provide convenience and accuracy.In a word,the simplicity and effectiveness of the multidimensional optical probes not only helps the development of the new strategies of the detection of biomolecular,but also provide a potential way forward for clinical diagnosis,antibiotic discovery,and therapeutic monitoring.This dissertation is separated into following four chapters.Chapter one:overview of the concept and relevent related researches and mainly introduce the multidimensional optical probes and their applications on the detection of the biomolecules.Chapter two:The lectin recognizable saccharides D-mannopyranose?Man?,D-galactopyranose?Gal?and D-N-acetyl glucosamine?GlcNac?were first thiolated and then grafted onto the surface of QDs via the formation of sulfur–sulfur bonds.The thiolated productions 3-mercaptopropyl glycosides were characterized by NMR and MS.The glycosylated QDs were prepared via phase transfer reactions between a chloroform phase and an aqueous phase.As a result,ligand exchange of hydrophobic octylamine on QDs with Man-SH,Gal-SH and GlcNac-SH was carried out respectively,and the glycosylated QDs were dispersible in water.The success of the synthesis of the multidimensional optical probes was characterized through FT-IR and TEM.Chapater three:We took excitation wavelength,incubation time and temperature into consideration to optimize the reaction conditions.In the optimized conditions,we collected the optical signals induced by lectin-saccharide interactions.The differences of optical signals induced by different properties and concentrations of lectins were expected to discriminate lectins via linear discriminant analysis?LDA?and hierarchical cluster analysis?HCA?.For qualitative analysis,being non-saccharide binding proteins,both bovine serum albumin?BSA?and hemoglobin?HGB?induced negligible signals,revealing the specificity of the probes for lectins only and a methodological feasibility to multiplexed analysis of lectins.As for quantitative analysis,a canonical score plot for the multidimensional signal as obtained from the multidimensional optical probes,and the limit of detection?LOD?was then obtained.The quantitative analysis of Concanavalin A?Con A?,Wheat germ agglutinin?WGA?,Peanut agglutinin?PNA?,Ricinus communis agglutinin(RCA₁₂₀)and Pisum sativum agglutinin?PSA?based on this multidimensional optical probes was also performed satisfactorily with LODs of nM concentrations.In addition,the quantitative accuracy for each lectin in human serum was satisfactory.We designed and built multidimensional optical probes based on fluorescence and Resonance Rayleigh Scattering?RRS?providing a potential way forward for fields of biological science,chemical analysis and health care.