Method for detecting polyelectrolyte conformation transformation in flow field

Abstract

The invention discloses a method for detecting polyelectrolyte conformation transformation in a flow field. The method comprises the following steps of: marking a to-be-detected polyelectrolyte by adopting a fluorescent dye capable of reflecting local environmental change; constructing a micro-fluidic channel; measuring the sizes of excitation spaces of the fluorescent dye with the known diffusioncoefficient at different positions in the micro-fluidic channel in the longitudinal height direction by adopting a fluorescence correlation spectrum; determining flow field flow velocities at different positions of the micro-fluidic channel when an external injection pump provides different apparent flows by adopting fluorescence correlation spectroscopy; taking a dilute solution of polyelectrolyte as a flowing medium, and determining spectra of the dilute solution at different positions in the micro-fluidic channel by adopting a single-molecule fluorescence spectrum; obtaining the local environment change of the polyelectrolyte according to the fluorescence intensity of the fluorescent dye marked on the polyelectrolyte, reflecting the concentration change of the counter ions according tothe local environment change, and obtaining the polyelectrolyte conformation transformation information according to the concentration change of the counter ions. The method is suitable for researching the influence on the polyelectrolyte conformation when a flow field and other factors coexist.

Description

technical field [0001] The invention relates to a method for detecting conformational transition of polyelectrolytes in a flow field, belonging to the fields of polymer chemistry and polymer physics. Background technique [0002] Electrolyte, as a multi-charged macromolecule, can dissociate counter ions and charged main chains in polar solvents. It is used in sewage treatment, drug delivery, anti-adhesion on the surface of solid materials, preparation of functional composite membrane materials and intelligent biosensors. Has a wide range of applications. Understanding the conformation of polyelectrolytes and the distribution of counter ions around the main chain has always been a very important basic issue in the field of polymer physics research. For example, polyelectrolytes will be sheared due to the non-uniform distribution of flow velocity in the channel during transportation or filtration purification. Stress, the existence of this kind of flow shear will have a certa...

AI Technical Summary

Problems solved by technology

Fluorescence imaging is the most intuitive method in the previous in situ study of the conformation of polyelectrolytes in the flow field, but this method is limited by the optical diffraction limit, requiring that the polyelectrolyte to be studied must be long enough, and the flow rate in the flow field should not be too high

In practice, only a small number of proteins and DNA are relatively large in size, and most polyelectrolytes are not suitable for fluorescence imaging to study their conformation

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