In situ detection of biological membrane structure and permeability under pulse electric fields via second harmonic generation and two-photon fluorescence method

Pulse electric fields (PEF) have promising application prospects in fields such as drug absorption and vesicle synthesis. This study employs surface-sensitive second harmonic generation (SHG) and two-photon fluorescence (TPF) techniques to analyze the behavior of doxorubicin (DOX), a widely used anticancer drug with a positively charged side chain, at the phospholipid membrane interface, as well as the structural change of the vesicles under PEF. An effective method is proposed for real-time observation of biological membrane structure under the action of PEF. It is found that under the action of PEF, the interfacial structure of vesicles is partially destroyed. When the processing time reaches a threshold, vesicles undergo extensive rupture, forming smaller vesicles. At the same time, doxorubicin was not observed to enter the vesicle intima under the influence of electric field. These experimental results provide valuable insights for dosage guiding the real-time control of electric field strength in applications such as drug preparation and drug delivery.