Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States.
Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States.
ACS Appl Mater Interfaces. 2020 Sep 2;12(35):39602-39611. doi: 10.1021/acsami.0c05827. Epub 2020 Aug 21.
Porous silicon nanoparticles (PSNPs) offer tunable pore structure and easily modified surface chemistry, enabling high loading capacity for drugs with diverse chemicophysical properties. While PSNPs are also cytocompatible and degradable, PSNP integration into composite structures can be a useful approach to enhance carrier colloidal stability, drug-cargo loading stability, and endosome escape. Here, we explored PSNP polymer composites formed by coating of oxidized PSNPs with a series of poly[ethylene glycol--(dimethylaminoethyl methacrylate--butyl methacrylate)] (PEG-DB) diblock copolymers with varied molar ratios of dimethylaminoethyl methacrylate (D) and butyl methacrylate (B) in the random copolymer block. We screened and developed PSNP composites specifically toward intracellular delivery of microRNA inhibitory peptide nucleic acids (PNA). While a copolymer with 50 mol % B (50B) is optimal for early endosome escape in free polymer form, its pH switch was suppressed when it was formed into 50B polymer-coated PSNP composites (50BCs). We demonstrate that a lower mol % B (30BC) is the ideal PEG-DB composition for PSNP/PEG-DB nanocomposites based on having both the highest endosome disruption potential and miR-122 inhibitory activity. At a 1 mM PNA dose, 30BCs facilitated more potent inhibition of miR-122 in comparison to 40BC ( = 0.0095), 50BC ( < 0.0001), or an anti-miR-122 oligonucleotide delivered with the commercial transfection reagent Fugene 6. Using a live cell galectin 8-based endosome disruption reporter, 30BCs had greater endosomal escape than 40BCs and 50BCs within 2 h after treatment, suggesting that rapid endosome escape correlates with higher intracellular bioactivity. This study provides new insight on the polymer structure-dependent effects on stability, endosome escape, and cargo intracellular bioavailability for endosomolytic polymer-coated PSNPs.
多孔硅纳米粒子 (PSNPs) 具有可调的孔结构和易于修饰的表面化学性质，能够实现对具有不同理化性质的药物的高载药量。虽然 PSNPs 也是细胞相容的和可降解的，但将 PSNP 整合到复合结构中是一种有用的方法，可以提高载体胶体稳定性、药物货物载药量稳定性和内涵体逃逸。在这里，我们探索了由一系列聚[乙二醇-(二甲氨基乙基甲基丙烯酸酯-丁基甲基丙烯酸酯)]（PEG-DB）嵌段共聚物涂覆氧化 PSNPs 形成的 PSNP 聚合物复合材料，其中聚乙二醇-(二甲氨基乙基甲基丙烯酸酯-丁基甲基丙烯酸酯)]（PEG-DB）嵌段共聚物中的二甲氨基乙基甲基丙烯酸酯（D）和丁基甲基丙烯酸酯（B）的摩尔比不同。我们筛选并开发了专门用于细胞内递送 microRNA 抑制肽核酸（PNA）的 PSNP 复合材料。虽然共聚物中 B 的摩尔百分比为 50（50B）时最有利于游离聚合物形式的早期内涵体逃逸，但当它形成 50B 聚合物涂覆 PSNP 复合材料（50BC）时，其 pH 开关被抑制。我们证明，基于具有最高内涵体破坏潜力和 miR-122 抑制活性，较低的 B 摩尔百分比（30BC）是 PSNP/PEG-DB 纳米复合材料的理想 PEG-DB 组成。在 1mM PNA 剂量下，与 40BC（=0.0095）、50BC（<0.0001）或用商业转染试剂 Fugene 6 递送的抗 miR-122 寡核苷酸相比，30BC 更能有效抑制 miR-122。使用活细胞半乳糖凝集素 8 基于内涵体破坏的报告器，在处理后 2 小时内，30BC 比 40BC 和 50BC 具有更大的内涵体逃逸，这表明快速内涵体逃逸与更高的细胞内生物活性相关。这项研究提供了关于聚合物结构依赖性对稳定性、内涵体逃逸和载药细胞内生物利用度的新见解，为具有内涵体溶酶体的 PSNP 聚合物涂层提供了新的见解。
