Stretchable Electrochemiluminescence Sensors For Monitoring Of Hydrogen Peroxide Released In Endothelial Cells

Endothelial cells are constantly stimulated by cyclic stretch and dynamic shear stress of blood flow in blood vessels.Meanwhile,mechanotransduction of endothelial cells is a process that converts mechanical signals of such physical stimulus into biochemical signals.Reactive oxygen species（ROS）is a representative products of mechanotransduction,and the released level of ROS is closely related to vascular REDOX homeostasis,which is essential for regulating vascular function.Specifically,as one of the ROS species,,hydrogen peroxide（H₂O₂）not only participates in maintaining REDOX homeostasis of cells,but also affects physiological processes such as cell growth and proliferation and other pathophysiological processes as a second message,which regulating the life activities of the body.Therefore,highly sensitive and quantitative monitoring of H₂O₂levels released by endothelial cells during mechanotransduction is a key step to understand its pathological,physiological and biomedical functions,which is expected to provide theoretical guidance for health monitoring and disease diagnosis.Electrochemiluminescence（ECL）is a process in which photons were emitted when the material on the electrode surface forms a high-energy excited state through electron transfer reaction and returns to the ground state.ECL is widely used in various biosensing fields due to its ultra-high sensitivity,zero optical background,wide dynamic detection range,excellent controllability and anti-interference of electroactive substances.At present,the ECL sensing platforms for monitoring H₂O₂are mostly based on the traditional rigid electrode,which is difficult to monitor the released of signal molecules under the mechanical force stimulation of cell deformation.Therefore,it is important to innovate and develop flexible ECL sensors that can adapt to the structural deformation of cells and thus capture various biological signals directly from the target location.And effective conversion of biological signals into readable optical signals is of great significance for highly sensitive in-situ monitoring of H₂O₂produced by mechanical force signal transduction of endothelial cells.Based on this,we synthesized electrochemiluminescence luminophor of Au-L012 NSs,and prepared stretchable ECL sensor combined with the flexible electrode,which was successfully used to monitor the level of H₂O₂released by mechanotransduction in human umbilical vein endothelial cells（HUVECs）.The research content carried out in this thesis mainly includes the following two parts:（1）Preparation of Au-L012 NSs electrochemiluminescence luminophor and construction of stretchable electrochemiluminescence sensor.The L012 of luminol derivative was used as ECL luminophor,ans Au-L012nanomaterials（Au-L012 NSs）were successfully prepared by a simple chemical reduction method to reduce chloroauric acid to prepare gold nanoparticles while functionalizing L012.Then,a flexible stretchable ECL electrode was constructed by modified Au-L012 NSs onto the surface of Au nanotubes（Au NTs）/PDMS electrode.Naturally,it was proved that the sensor has excellent mechanical stability and good biocompatibility by exploring it’s structure and performance.At the same time,the sensor has high selectivity response to H₂O₂because H₂O₂can be used as a specific coreactive agent of L012.（2）Stretchable ECL sensors for monitoring of H₂O₂levels released by HUVECs.We used the above constructed sensor to detect the ECL signal responses with a series of standard concentrations of H₂O₂solutions.The Au-L012 NSs/Au NTs/PDMS sensor exhibited linear response,high sensitivity and excellent stability to H₂O₂.On this basis,HUVECs were cultured on the surface of the Au-L012 NSs/Au NTs/PDMS sensors and then the cells could grow a good spindle shape.In addition,the pseudopods of cells were fully attached and extended,achieving synchronous deformation with the flexible electrode while maintaining stable ECL response.The ECL sensor monitored the signal response under two different conditions of applied external stimulation induction and tensile stress induction.The sensor quantitatively evaluated the H₂O₂released level of cells under different stretching amplitude,realizing the detection of H₂O₂changed in the signal transduction process of HUVECs subjected to mechanical force stimulation.These studies provided a technical support for directed transduction of cellular mechanics and functional monitoring.