Abstract：
This study details the preparation and investigation of molecular nanogels formed by the self-assembly of bolaamphiphilic dipeptide derivatives containing a reduction-sensitive disulfide unit. The described bolaamphiphiles, featuring amino acid terminal groups, generate cationic vesicles at pH 4, which evolve into gel-like nanoparticles at pH 7. The critical aggregation concentration has been determined, and the nanogels\' size and morphology have been characterized through Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Circular Dichroism (CD) spectroscopy reveals substantial molecular reconfigurations accompanying the pH shift. These nanogels enhance the in vitro cellular uptake of the lipophilic dye Nile Red and the ionic photosensitizer Rose Bengal into Human colon adenocarcinoma (HT-29) cells, eliminating the need for organic co-solvents in the former case. Fluorescence measurements with Nile Red as a probe indicate the reduction-sensitive disassembly of the nanogels. In photodynamic therapy (PDT) applications, Rose Bengal-loaded nanogels demonstrate notable improvements, with flow cytometry analysis evidencing increased apoptotic activity in the study with HT-29 cells.
摘要：
这项研究详细介绍了通过包含还原敏感性二硫化物单元的两亲性二肽衍生物的自组装形成的分子纳米凝胶的制备和研究。所描述的两亲动物，具有氨基酸末端基团，在pH4时产生阳离子囊泡，在pH7时演变成凝胶状纳米颗粒。临界聚集浓度已经确定，纳米凝胶的尺寸和形态已通过动态光散射（DLS）和透射电子显微镜（TEM）进行了表征。圆二色性（CD）光谱揭示了伴随pH变化的大量分子重排。这些纳米凝胶增强亲脂性染料尼罗红和离子光敏剂玫瑰红的体外细胞摄取到人结肠腺癌（HT-29）细胞中，在前一种情况下消除了对有机共溶剂的需要。用尼罗红作为探针的荧光测量表明纳米凝胶的还原敏感分解。在光动力疗法（PDT）应用中，载有玫瑰红的纳米凝胶表现出显著的改进，流式细胞术分析证明在HT-29细胞的研究中凋亡活性增加。
