Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata-700009, India.
Department of Life Science & Biotechnology, Jadavpur University, Kolkata-700032, India.
Biomater Sci. 2023 Aug 8;11(16):5549-5559. doi: 10.1039/d3bm00491k.
A β-thioester and tertiary amine based covalently cross-linked nanoassembly coined as a nanonetwork (NN) endowed with dual pH responsive features (tumor acidity induced surface charge modulation and endosomal pH triggered controlled degradation) has been designed and synthesized for stable sequestration and sustained release of drug molecules in response to endosomal pH. An amphiphile integrated with tertiary amine and acrylate (ATA) functionalities was synthesized to fabricate the nanonetwork. This amphiphile showed entropically driven self-assembly and micellar nanostructures (nanoassemblies), which can sequester hydrophobic drug molecules at neutral pH. To further stabilize the nanoassemblies and the sequestered drug molecules even below its critical aggregation concentration (CAC), the micellar core was cross-linked the thiol-acrylate Michael addition click reaction to generate multiple copies of acid labile β-thioester functionalities in the core, which undergo slow hydrolysis at endosomal pH (∼5.0), thus enabling sustained release of the anti-cancer drug doxorubicin at endosomal pH. The nanonetworks showed a significant decrease in drug leakage compared to the nanoassemblies (NAs), which was also justified by a low leakage coefficient calculated from the fluorescence resonance energy transfer experiment. The NN also exhibited dilution insensitivity and high serum stability, whereas the NA disassembled upon dilution and during serum treatment. The biological evaluation revealed tumor extracellular matrix pH (∼6.4-6.8) induced surface charge modulation and cancer cell (HeLa) selective activated cellular uptake of the doxorubicin loaded nanonetwork (NN-DOX). In contrast, the benign nature of NN-DOX towards normal cells (H9c2) suggests excellent cell specificity. Thus, we believe that the ease of synthesis, nanonetwork fabrication reproducibility, robust stability, smart nature of tumor microenvironment sensitive surface charge modulation, boosted tumoral-cell uptake, and triggered drug release will make this system a potential nanomedicine for chemotherapeutic treatments.
一种基于β-硫酯和叔胺的共价交联纳米组装体，被称为纳米网络（NN），具有双重 pH 响应特性（肿瘤酸度诱导的表面电荷调制和内涵体 pH 触发的控制降解），被设计并合成用于药物分子的稳定隔离和持续释放，以响应内涵体 pH。一种整合了叔胺和丙烯酰胺（ATA）功能的两亲分子被合成来制备纳米网络。这种两亲分子表现出熵驱动的自组装和胶束纳米结构（纳米组装体），可以在中性 pH 下隔离疏水性药物分子。为了进一步稳定纳米组装体和隔离的药物分子，甚至在其临界聚集浓度（CAC）以下，胶束核心通过硫醇-丙烯酰基迈克尔加成点击反应交联，在核心中产生多个酸不稳定的β-硫酯官能团，在内涵体 pH（约 5.0）下缓慢水解，从而使阿霉素等抗癌药物能够在内涵体 pH 下持续释放。与纳米组装体（NA）相比，纳米网络显示出药物泄漏显著减少，这也可以通过荧光共振能量转移实验计算出的低泄漏系数来证明。NN 还表现出稀释不敏感性和高血清稳定性，而 NA 在稀释和血清处理过程中会解体。生物学评价表明，肿瘤细胞外基质 pH（约 6.4-6.8）诱导表面电荷调制和阿霉素负载的纳米网络（NN-DOX）对癌细胞（HeLa）的选择性激活细胞摄取。相比之下，NN-DOX 对正常细胞（H9c2）的良性性质表明其具有优异的细胞特异性。因此，我们相信该系统易于合成、纳米网络制备重现性、稳健的稳定性、肿瘤微环境敏感表面电荷调制的智能性质、增强的肿瘤细胞摄取和触发的药物释放，将使其成为一种有潜力的用于化疗治疗的纳米药物。
