Bioimaging Study Of Tumor Markers In Living Cell

In recent years,It is of great significance to explore early diagnosis and prognostic monitoring new methods for major diseases(such as cancer,cardiovascular disease,etc.),especially develop real-time and in situ imaging and characterization of important biomolecule molecules to reveal its biological function and to further understand the process of occurrence of relevant mechanisms and laws at deeper cellular levels,which is also favorable for the understandability the nature of life and early diagnosis of disease at the cellular level.Nanobiosensors was applied to many other interdisciplinary involving chemical,biological and nanoscience,in particular,with the nanotechnology and life science of the continuous cross-integration,the development of cell imaging and characterization new methods for biomolecule provide a lot of innovation thoughts.On the one hand,Nanomaterials with adjustable nano-size structure,good biocompatibility,the surface can modify a variety of biological molecules and other special physical and chemical properties.The functionalized nanomaterials with unique signal generation and enhancement properties,at the same time,nanomaterials can serve as an excellent carrier for cell delivery,which can afford a great potential to provide the biomarker and detection of functional molecules at cellular level.On the other hand,nucleic acid probes are easy to design and modify,and nucleic acid sequence specific recognition can be achieved by specialized design.Furthermore,the application of nucleic acid signal amplification technology can further enriche and improve the many superior properties of nucleic acid probes.Based on the nucleic acid molecule of the fluorescent probe,the organic molecular probe established a biosensor method for the biomechanics of intracellular and disease related substances.The details are as follows:The expression level of certain mRNAs in the cells is closely related to the disease,and abnormal expression of intracellular mRNA can lead to a variety of serious diseases such as neurological diseases or cancer.However,the intracellular mRNA concentration is usually low,moreover,the occurrence of the same disease may be the result of many mRNA co-regulate,therefore,it is of great significance to achieve highly sensitive mRNA multiple detection at the cellular level.In Chapter 2,we used manganese dioxide(MnO2)nanosheets as cell carrier to develop an isothermal enzyme-free nucleic acid amplification technique-catalytic hairpin assembly(CHA)for intracellular mRNA dual-color fluorescence imaging.First,four pairs hairpin probes were assembled on the MnO2 nanosheet,when enter into the cells,the intracellular glutathione(GSH)reduced the MnO2 nanosheets to Mn2+,the four hairpin probes released and then interacted with the corresponding cancer-related mRNA to produce the activated fluorescence signal,moreover,the target mRNA initiate CHA reaction,would further enhance the fluorescence signal.This strategy was demonstrated to provide excellent selectivity and superior sensitivity two kinds of mRNA(TK1 mRNA and survivin mRNA).Therefore,the developed approach is expected to be used for the analysis of mRNA expression levels and early diagnosis of related diseases.Nitroreductase is a class of cytokine reductase containing single nucleotide or adenine dinucleotide unit,which is an important indicator of the state of hypoxia in cells or organisms.The level of nitroreductase is closely related to hypoxia tumor occurrence,development and migration.In Chapter 3,based on nitroreductase-triggered domino cascade reaction,we have developed a novel activatable fluorescent probe for intracellular nitroreductase imaging.The as-prepared fluorescent probe offer several favorable attributes including low-toxic,low background fluorescence,high selectivity and promise good responsiveness for nitroreductase detection,and it was estimated that the detection limit was as low as 26 ng/mL,moreover,fluorescence imaging showed that the probe could be successfully applied to activatable imaging of nitroreductase in tumor cells under hypoxic conditions.