Shenzhen Key Laboratory of Flexible Printed Electronics Technology, also School of Science, Harbin Institute of Technology (Shenzhen), University Town, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Shenzhen 518055, Guangdong, Harbin 150001, Heilongjiang, China.
Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Province, Shantou University, Shantou 515063, Guangdong, China.
Phys Chem Chem Phys. 2022 May 25;24(20):12465-12475. doi: 10.1039/d2cp01183b.
The investigation of the self-assembly of amphiphilic molecules and the formation of micelles/vesicles has attracted significant attention. However, and real-time methods for such studies are rare. Here, a surface-sensitive second harmonic generation (SHG) technique was applied to study the formation of vesicles in solutions of an anti-cancer drug, doxorubicin (DOX), and a generally used surfactant (sodium bis (2-ethylhexyl) sulfosuccinate, AOT). With the aid of two-photon fluorescence (TPF), Rayleigh scattering and TEM, we revealed the structural evolution of the aggregated micelles/vesicles. It was found that AOT and DOX molecules rapidly aggregated and formed micelles in the solution. The residual DOX then acted as a "glue" that induced the aggregating/growing of the micelles and the transformation from aggregates to vesicles. The existence of lipid films, which was considered as the necessary intermediate state for vesicle formation, was excluded the SHG observations, indicating that hollow shells may be directly transformed from solid aggregated micelles in the self-assembly formation of complex vesicles. The combined spectroscopic methods were also used to investigate the formation of vesicles from a commonly used lipid (, 1,2-dioleoyl--3-phospho-rac-(1-glycerol) sodium salt, DOPG) from its stacked bilayers. The swelling, curving and sealing of the DOPG bilayers for vesicle formation was monitored and clear dynamics were revealed. This work shows that the vesicle formation mechanism varies with the initial state of the surfactant/lipid molecules. It not only demonstrates the capability of the combined spectroscopic methods in investigating the aggregated systems but also provides new insight for understanding the formation of vesicles.
两亲分子的自组装和胶束/囊泡的形成的研究引起了人们的极大关注。然而，用于此类研究的实时方法却很少见。在这里，我们应用了一种表面敏感的二次谐波产生（SHG）技术来研究抗癌药物阿霉素（DOX）和一种常用表面活性剂（双（2-乙基己基）磺基琥珀酸钠，AOT）在溶液中囊泡的形成。借助双光子荧光（TPF）、瑞利散射和 TEM，我们揭示了聚集胶束/囊泡的结构演变。结果发现，AOT 和 DOX 分子在溶液中迅速聚集并形成胶束。然后，残留的 DOX 充当“胶”，诱导胶束的聚集/生长以及从聚集物到囊泡的转变。在 SHG 观察中排除了脂质膜的存在，这被认为是囊泡形成的必要中间状态，表明中空壳可能直接从复杂囊泡自组装形成的固体聚集胶束转化而来。还使用组合光谱方法研究了常用脂质（1,2-二油酰基-sn-甘油-3-磷酸-rac-（1-甘油）钠盐，DOPG）从其堆叠双层形成囊泡的过程。监测了 DOPG 双层囊泡形成的肿胀、弯曲和密封过程，并揭示了清晰的动力学。这项工作表明，囊泡形成机制随表面活性剂/脂质分子的初始状态而变化。它不仅展示了组合光谱方法在研究聚集体系方面的能力，还为理解囊泡的形成提供了新的见解。
