Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.
ACS Nano. 2013 Oct 22;7(10):8455-68. doi: 10.1021/nn403772j. Epub 2013 Sep 25.
DNA-gated mesoporous SiO2 nanoparticles, MP-SiO2 NPs, loaded with rhodamine B, RhB, act as "smart" materials that reveal complementary "sense" and "release" functionalities. The unlocking of the DNA pore-capping units is achieved by the biocatalytic cleavage of the DNA, and the unlocking process is amplified by the regeneration of the analyte-trigger. The RhB-loaded MP-SiO2 NPs are capped with nucleic acid hairpin structures that lock the RhB in the pores. Opening of the hairpin structures by a nucleic acid analyte trigger or by the formation of an aptamer-substrate (ATP) complex leads to the formation of duplex structures being cleaved by exonuclease III, Exo III, or the nicking enzyme, Nb. BbvCI. This results in the regeneration of the target analytes, the autonomous unlocking of the pores, and the release of RhB. The systems reveal selectivity, and one-, two-, three-base mutations in the target DNA, or substitution of ATP with other triphosphate nucleotides, prohibit the unlocking of the pores. In analogy to the biocatalytic release of the model fluorophore substrates, the anticancer drug camptothecin, CPT, was entrapped in the pores and locked by the 1 or 11 hairpin structures. The drug was released from the pores in the presence of the nucleic acid 2 or ATP and the Exo III, as biocatalyst. Similarly, CPT locked in the pores by the 6 or 12 hairpins were released from the pores in the presence of ATP and Nb. BbvCI, as nicking enzyme, respectively. The effects of the CPT-loaded MP-SiO2 NPs, capped with the ATP-dependent lock 6, on the viability of MDA-231 breast cancer cells and MCF-10a normal breast cells were examined. We find that after 48 h, 65% cell death was observed for the MDA-231 cancer cells, where only 25% cell death was observed for the normal cells. The higher cell death of the cancer cells correlates well with the enhanced metabolic synthesis of ATP in the cancerous cells.
DNA 门控介孔二氧化硅纳米粒子（MP-SiO2 NPs）负载罗丹明 B（RhB），充当“智能”材料，揭示互补的“感应”和“释放”功能。DNA 孔封闭单元的解锁是通过 DNA 的生物催化切割实现的，并且通过分析物触发物的再生放大了解锁过程。负载 RhB 的 MP-SiO2 NPs 被核酸发夹结构封闭，将 RhB 锁定在孔内。核酸分析物触发物或适体-底物（ATP）复合物的形成打开发夹结构，导致被外切核酸酶 III（Exo III）或切口酶 Nb.BbvCI 切割形成双链结构。这导致目标分析物的再生、孔的自主解锁和 RhB 的释放。该系统显示出选择性，并且目标 DNA 中的一个、两个或三个碱基突变，或用其他三磷酸核苷酸替代 ATP，会阻止孔的解锁。类似于模型荧光团底物的生物催化释放，阿霉素（CPT）被包埋在孔内并被 1 或 11 个发夹结构封闭。在存在核酸 2 或 ATP 和 Exo III 的情况下，药物作为生物催化剂从孔中释放出来。类似地，在存在 ATP 和 Nb.BbvCI 的情况下，分别用 6 或 12 个发夹封闭在孔内的 CPT 从孔中释放出来。用依赖 ATP 的锁 6 封闭的 CPT 负载的 MP-SiO2 NPs 对 MDA-231 乳腺癌细胞和 MCF-10a 正常乳腺细胞活力的影响进行了研究。我们发现，48 小时后，MDA-231 癌细胞的细胞死亡率为 65%，而正常细胞的细胞死亡率为 25%。癌细胞的高细胞死亡率与癌细胞中 ATP 的代谢合成增强密切相关。
