Research And Application Of Gold Nanorod Rotation Tracking Technology In Polymer Gel Phase Transition

In recent years,polymer gels have attracted widespread attention for their unique physical and chemical properties and broad prospects for biological and medical applications.The applications are determined by the properties,which are fundamentally determined by the structures.Analysis and characterization of the phase transition including the formation,decomposition,spatiotemporal characteristics,and dynamic evolution of polymer gels have a great significance for deep understanding of their properties and further development of their rational application.Single Particle Tracking(SPT),with its unique advantages such as high sensitivity,high spatiotemporal resolution,and low sample loss,is gradually becoming a powerful tool for the analysis and study of the spatiotemporal properties of chemical reactions,dynamic processes of biological and physical systems,and microrheology.In combination with SPT,it is helpful to trace the origin and explore the microstructural properties and dynamic characteristics of polymer gels and their phase transition.To this end,we focus on the research and application of single gold nanorods(AuNRs)rotational tracking in the phase transition of polymer gels.The main contents are as follows.A solution characterization method based on SPT has been established.Using a DualChannel Polarized Dark Field Microscope(DPDFM),and imaging and tracking of single AuNRs in glycerol,polyethylene glycol,hyaluronic acid,and droplets,we have explored a research strategy for different liquid substances based on single AuNRs rotational tracking.By comparing translational tracking and rotational tracking,lowfrequency rotational tracking and high-frequency rotational tracking,it has been proved that the high spatiotemporal resolution and high-frequency single AuNRs rotational tracking is applicable in different solution,which lays a practical foundation for the study of single AuNRs rotational tracking in various systems such as polymer solutions,gels,and soft matter solutions.The dynamic rotation information of single AuNRs during the gelation process and the sol-gel process have been studied,and the phase transition process have been characterized and applied to the actual sample evaluation.Through identification and detailed analysis of three different rotation states of single AuNRs in polyacrylamide(PAAm)gel after losing translational motion,the dynamic,progressive,and anisotropic interactions of PAAm gel clusters during deep crosslinking have been revealed.Through the analysis of the behaviors of single AuNRs during the phase transition of Chitosan-Polyethylene Glycol Gel(Chi-PEG Gel)and Hyaluronic acid-Polyethyleneimine Gel(HA-PEI Gel),the microscopic sol-gel strategy based on SPT for the detection of Hyaluronidase(HAase)has been successfully established.In general,we have established a set of advanced strategies and methods to study the phase transition process of polymer gels,and the single AuNRs rotational tracking technology could be applied to more extensive physical and chemical reactions,life activities,and condensed matter systems.