Monitoring the response of a model protocell to dye and surfactant molecules through second harmonic generation and fluorescence imaging

Bifei Li; Jianhui Li; Shujiao Chen; Qunhui Yuan; Chao Fang; Wei Gan

doi:10.1039/d4cp00009a

Monitoring the response of a model protocell to dye and surfactant molecules through second harmonic generation and fluorescence imaging

Phys Chem Chem Phys. 2024 Mar 6;26(10):8148-8157. doi: 10.1039/d4cp00009a.

Authors

Bifei Li^{1

2}, Jianhui Li^{1

2}, Shujiao Chen^{1

2}, Qunhui Yuan³, Chao Fang^{1

2}, Wei Gan^{1

2}

Affiliations

¹ Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China. fangchao@hit.edu.cn.
² School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China.
³ Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China. yuanqunhui@hit.edu.cn.

PMID: 38380536
DOI: 10.1039/d4cp00009a

Abstract

Probing the interaction between molecules and protocells is crucial for understanding the passive transport of functional molecules in and out of artificial and real cells. Second-harmonic generation (SHG) has been proven to be a powerful method for analyzing the adsorption and cross-membrane transport of molecules on lipid bilayers. In this study, we used SHG and two-photon fluorescence (TPF) imaging to study the interaction of charged dye molecules (D289) with a lipid vesicle. Unexpectedly, it was observed that the transport of D289 at a relatively high concentration is not as efficient as that at a lower dye concentration. Periodic shrinking of the model protocell and discharging of D289 out from the vesicle were revealed by combined analyses of SHG and TPF images. The response of the vesicle to a surfactant was also analyzed with D289 as a probe. This work demonstrates that the combined SHG and TPF imaging method is a unique approach that can provide detailed information on the interaction of molecules and lipids (both morphology and molecular kinetics). Determining these subtle interfacial kinetics in molecules is important for understanding the mechanism of many biophysical processes occurring on lipids.