Research On The In-situ Monitoring Methods Of Reactive Oxygen Species Produced By Biological Systems Under Stress Based On Noble Metal Nanoparticles Hybrid Sensing Interface

Obtaining stress information of biological system is of great significance for crop yields,pathological and pharmacological research,and understanding the complex physiological activities.Monitoring the concentration variations of ROS(reactive oxygen species),the most common chemical signals of biologycal systems,is more effective to obtain stress information.However,recent detection methods of ROS in biological systems show obvious disadvantages,including limited application area,irreversible damage to the biological system,unresponsive information acquisition,and the difficulty in achieving on-site detection.Based on this,the main goal of this project is to realize the in-situ real-time monitoring of ROS in biological systems.Our research starts from the following four parts:constructing sensing interface,fabricating flexible sensors for ROS detection,the application in biological system ROS sensing,and the in-situ real-time monitoring.First of all,the hybrid noble metal nanoparticles-based sensing interface was established for detecting ROS with high sensitivity,biocompatibility,and selectivity.Then a flexible sensing device was fabricated based on the proposed sensing interface to explore the sensing performance in real-time moniotoring of ROS in biological systems.The main research contents and results are as follows:(1)Due to the demand for high catalytic activity sensing interface for ROS detection,this project designed and constructed a hybrid sensing interface based on noble metal nanoparticles-two-dimensional(2D)nanomaterial-based paper.The 2D nanosheets of typical transition metal dichalcogenides(TMDs)and transition metal nitrides/carbonitrides(MXene)(Mo S₂,WS₂,Ti₃C₂T_x)were self-assembled to prepare a paper-like film as the basic interface.By exploring the energy level distribution of prepared paper-like film,a strategy of spontaneous growth of noble metal nanoparticles on paper-like film surface is proposed.Compared with the traditional construction method,this method does not need to use toxic reagents and reducing agents.It can realize the uniform nucleation of noble metal nanoparticles(gold,palladium)in only 3 seconds under normal temperature and pressure,and has the huge advantages of simplicity,efficiency,and green environmental protection.The mechanism of spontaneous construction of the noble metal nanoparticles-based hybrid sensing interface was explored,and a strategy of mixing noble metal precursors was further proposed to achieve effective control of the composition and growth morphology of noble metal nanoparticles(platinum,silver)at the interface.The method of constructing and controlling the sensing interface based on the spontaneous growth strategy provides a new path for the later preparation of high-performance sensing devices.(2)Heretofore the preparation process of ROS sensing devices based on noble metal nanoparticles is hindered from the tedious procedures.Based on this,the spontaneous growth strategy for constructing noble metal particles-based hybrid sensing interfaces is applied to flexible TMDs(Mo S₂,WS₂)and MXene paper electrodes to prepare ROS sensing device with high activity.The Mo S₂ paper electrode and the MXene paper electrode modified with gold-platinum nanoparticles were developed respectively,and the detection performance of ROS was explored.For the detection of ROS-H₂O₂ by gold-platinum nanoparticles modified Mo S₂ paper electrode,the detection sensitivity can reach 111?A cm^-2 m M^-1(R²=0.9910)in the range of0.05?1.05 m M,and the detection limit(S/N=3)is 0.01 m M.For the gold-platinum nanoparticles-modified MXene paper electrode used for ROS-O₂^·-detection,the linear detection range is0.4?9.5?M(R²=0.9962),and the sensitivity is 172?A cm^-2 m M^-1,the detection limit is 0.2?M.In addition,the sensing devices exhibit good selectivity,stability,repeatability and flexibility.The results show that the noble metal nanoparticles-based sensing interface hold great application potential in the construction of flexible ROS sensing devices.(3)In order to further explore the performance of proposed flexible ROS sensors with hybrid noble metal nanoparticles-based sensing interfaces for ROS detection in biological systems,we applied the flexible devices into the detection of ROS in plant and cells.In the experiment,Au Pt NPs/Mo S₂ paper electrode was used for detecting ROS in plant,relative ROS detection model in plant systems was established.The results of standard recovery experiments for verifing the accuracy of established model shows that a recovery efficiency higher than 82%could be obtained.In addition,Au Pd Pt NPs/Mo S₂ paper electrodes with higher biocompatibility were constructed based on the proposed strategy for ROS monitoring in cell system.The results shows that the cells(human liver cancer cell,Hep-G2)remain?100%activity after being incubated on the sensing interface for 4 hours,which demonstrates that the propsoed sensing interface has low cytotoxicity to cells system.Based on this,the ROS detection model of cells system was established,and the prepared ROS sensor was able to realized the real-time monitoring of released ROS molecules from cells under drug stimulation.(4)In order to realize the in-situ monitoring of stress signals in biological systems,a minimally invasive implantable detection method is proposed to achieve in-situ sensing of ROS in plants.Because the traditional sensing device is limited by structure and principle,it will greatly affect the detection performance after miniaturization,and it is difficlut to maintain high detection sensitivity while achieving minimally invasiveness.Based on this,the noble metal nanoparticles-based hybrid sensing interface is combined with organic electrochemical transistors to prepare high-performance flexible sensing devices.Taking advantage of the small size,signal amplification,and biocompatibility of organic electrochemical transistors,the device is fabricated on a flexible polyimide film(25?m),and a needle-shaped detection area(length:4 mm)is designed,which is effective in reducing damage to the plant caused by implanted monitoring.In addition,the construction of the noble metal nanoparticles-based hybrid sensing interface further enhances the current response signal of the device to ROS,and ensures the sensitivity of minimally invasive detection in plants.Through the establishment of a ROS detection model and simulated in-situ sensing experiments,it is proved that the device has a high feasibility in the in-situ sensing of reactive oxygen in plant systems.