Fischell Department of Bioengineering, University of Maryland , College Park, Maryland 20742, United States.
Department of Chemistry, University of British Columbia , Vancouver, British Columbia Canada V6T 1Z1.
Bioconjug Chem. 2018 Jan 17;29(1):136-148. doi: 10.1021/acs.bioconjchem.7b00658. Epub 2017 Dec 21.
Nanoparticle (NP)-mediated drug delivery (NMDD) has emerged as a novel method to overcome the limitations of traditional systemic delivery of therapeutics, including the controlled release of the NP-associated drug cargo. Currently, our most advanced understanding of how to control NP-associated cargos is in the context of soft nanoparticles (e.g., liposomes), but less is known about controlling the release of cargos from the surface of hard NPs (e.g., gold NPs). Here we employ a semiconductor quantum dot (QD) as a prototypical hard NP platform and use intracellularly triggered actuation to achieve spatiotemporal control of drug release and modulation of drug efficacy. Conjugated to the QD are two peptides: (1) a cell-penetrating peptide (CPP) that facilitates uptake of the conjugate into the endocytic pathway and (2) a display peptide conjugated to doxorubicin (DOX) via three different linkages (ester, disulfide, and hydrazone) that are responsive to enzymatic cleavage, reducing conditions, and low pH, respectively. Formation of the QD-[peptide-DOX]-CPP complex is driven by self-assembly that allows control over both the ratio of each peptide species conjugated to the QD and the eventual drug dose delivered to cells. Förster resonance energy transfer assays confirmed successful assembly of the QD-peptide complexes and functionality of the linkages. Confocal microscopy was employed to visualize residence of the QD-[peptide-DOX]-CPP complexes in the endocytic pathway, and distinct differences in DOX localization were noted for the ester linkage, which showed clear signs of nuclear delivery versus the hydrazone, disulfide, and amide control. Finally, delivery of the QD-[peptide-DOX]-CPP conjugate resulted in cytotoxicity for the ester linkage that was comparable to free DOX. Attachment of DOX via the hydrazone linkage facilitated intermediary toxicity, while the disulfide and amide control linkages showed minimal toxicity. Our data demonstrate the utility of hard NP-peptide bioconjugates to function as multifunctional scaffolds for simultaneous control over cellular drug uptake and toxicity and the vital role played by the nature of the chemical linkage that appends the drug to the NP carrier.
纳米粒子 (NP) 介导的药物输送 (NMDD) 已成为克服传统治疗系统输送局限性的新方法，包括 NP 相关药物货物的控制释放。目前，我们对如何控制 NP 相关货物的了解最先进的是在软纳米粒子 (例如，脂质体) 的背景下，但对从硬 NP 表面控制货物释放的了解较少 (例如，金 NP)。在这里，我们采用半导体量子点 (QD) 作为原型硬 NP 平台，并使用细胞内触发致动来实现药物释放的时空控制和药物功效的调制。与 QD 共轭的是两种肽：(1) 一种细胞穿透肽 (CPP)，可促进该缀合物进入内吞途径的摄取，以及 (2) 通过三种不同键 (酯、二硫键和腙) 与阿霉素 (DOX) 共轭的展示肽，分别对酶裂解、还原条件和低 pH 有反应性。QD-[肽-DOX]-CPP 复合物的形成是由自组装驱动的，自组装允许控制每个肽与 QD 共轭的比例以及最终递送到细胞的药物剂量。荧光共振能量转移测定证实了 QD-肽复合物的成功组装和键的功能。共聚焦显微镜用于观察 QD-[肽-DOX]-CPP 复合物在细胞内的定位途径中的驻留，并且酯键的 DOX 定位明显不同，显示出明确的核递呈迹象，而腙、二硫键和酰胺对照则没有。最后，QD-[肽-DOX]-CPP 缀合物的递送导致酯键的细胞毒性与游离 DOX 相当。通过腙键连接的 DOX 递送促进了中间毒性，而二硫键和酰胺对照键显示出最小的毒性。我们的数据表明，硬 NP-肽生物缀合物可作为多功能支架，用于同时控制细胞药物摄取和毒性，并且药物与 NP 载体连接的化学键的性质起着至关重要的作用。
