The Sensing Application Of Functional Molecules Loaded Mesoporous Silica Nanoprobe In Lysosome

Chemo/biosensing is a crucial technique for in vivo and in real time monitoring biological and pathophysiological processes inside living cells or tissue,and consequently for the advancement of modern medicine.The use of chemo/biosensing is becoming indispensable in modern life science and disease diagnosis field.Fluorescent sensor,now,plays the role of main force in the field of chemo/biosensin g by integrating with the increasingly mature imaging technology.Among which,organic molecular probes have gained great concern in modern life science for its characteristics,such as high sensitivity and broad detection range.With the progress and development of science and technology,it is now a research hot spot as well as a difficult task to expand and promote highly efficient fluorescent probes aiming at subcellular areas,which are more subtle structure in cell.Among various subcellular parts,lysosome is of vital importance.Therefore,it exerts great influence to explore lysosome-related cellular physiological processes to design and develop lysosome-targeted fluorescent probes.However,the characteristics of lysosome including acidic environment and abundant in protein enzymes leaves no way for organic molecular probes to adapt.Traditional methods get exhausted.In order to tackle with the high challenge brought by the new demand,it becomes a possible breakthrough to adapt to the rigorous environment in the lysosome to construct a new platform based on fluorescent probes.In this thesis,the designation of the fluorescent nanoprobe is the major way to solve the shortcomings above and we carried out the following two works by the integration of nanotechnology1.Selective tracking of lysosomal Cu²⁺ions using simultaneous target-and location-activated fluorescent nanoprobes.Copper is an essential element for life and unbalance of Cu²⁺in lysosomes would lead many diseases,such as Wilson dise ase.However,ideal probes for selective tracking Cu²⁺in lysosomes have rarely been reported hitherto because of two reasons.One is that organelle-specific targeting group suffer from non-specific intracellular distribution.The other is poor stability i n in lysosomes.To address these issues,we fabricated a nanoprobe for sensing lysosomal Cu²⁺in living cells based on simultaneous target and low pH-response.On one hand,acid-activated probe circumvent background signal.On the other hand,nanopores provide a stable sensing environment.Besides,MSNs internalize into cells by endocytosis and mainly accumulate in lysosomes.Peptide RGD was used to enhance permeability and retention effect.Baesd on these,Rhod-SP@MSN-CD-RGD has been successfully used for sensitive detection and imaging Cu²⁺in lysosomes as well as in HepG2 and HL-7702 cells.2.Fabrication of a nanolab:A new strategy for detection and imaging of nitric oxide in Lysosome.mesoporous silica nanoparticle?MSN?is charaterized by its multiplepores structure and by making use of this,we loaded the autonomous probe,Rhod-NO,which is fluorescently activated by NO into the pores and conjugated with hydrosolubleb-cyclodextrin??-CD?as gatekeeper to stop the external species.The nanopores are named as nanolab,which allows NO enter the nanopores to react with the fluorescent probe without degradation and interference by physiological environment.Therefore,this strategy has been successfully used for sensitive detection and imaging NO in Lysosomes of HeLa cells.