Surface Enhanced Raman Detection And Cell Imaging Analysis Of Tumor Related Mirnas

Recently,with the increasing of cancer-related mortality,cancer has become a serious threat to human life and health.Early diagnosis and treatment of cancer remains a great challenge that human faced in the field of medical health.Along with the rapid development of nanotechnology,nanomaterials have been widely used for tumor imaging,early-stage diagnosis and treatment of cancer.Given all these considerations,a highly sensitive and specific nanoprobe was designed to detect miRNA and fluorescence imaging and surface enhanced Raman scattering(SERS)imaging.This thesis mainly includes two aspects as follows:(1)A simple,rapid yet,sensitive SERS method for target miRNA detection was developed on the basis of an enzyme-free DNA machine signal amplification.The method is sensitive and feasible without the need of bioactive enzymes,thus representing an excellent isothermal cycling signal-amplification protocol,with a detection limit toward miRNA as low as 0.17 fM.In contrast to enzyme-based amplification methods,like polymerase chain reaction(PCR)and isothermal DNA recycling reaction,which usually are time-consuming and limited to a thermostable enzyme and a laboratory setting,this method exhibited distinct advantages of simplicity in probe design and rapidness in the detection process(within 2 h).Furthermore,the assay was highly selective and capable of detecting miRNAs in complex biological media.Thus,this method offers a highly sensitive and selective platform for the early diagnosis of cancer,and also opens a promising avenue to develop other enzyme-free SERS biosensing systems.(2)A self-delivering DSS probe for the simultaneous intracellular imaging and quantification of miRNAs with significantly different expression levels.Combined with the complementary advantages of the fluorescence and SERS techniques,the method achieved in situ tracking of the intracellular behavior of the probe with good performance and could quantitatively determine multiple mi RNAs using SERS ratiometric detection.Moreover,the accurate detection of multiple miRNAs withsignificantly different expression levels in living cells was successfully achieved via an asymmetric amplification mode.This novel method could offer a powerful approach for the simultaneous imaging and detection of other biomolecules in living cells.