Key Laboratory of Mesoscopic Chemistry (Ministry of Education), School of Chemistry and Chemical Engineering, Nanjing University, China.
Chemistry. 2011 Jan 17;17(3):810-5. doi: 10.1002/chem.201002899. Epub 2011 Jan 5.
The controlled release of drugs by biostimuli is highly desirable under physiological conditions for their potential use in advanced applications. The enzyme-inspired controlled release of cucurbituril nanovalves by using magnetic mesoporous silica nanoparticles (MSNs) in near-neutral aqueous solutions is reported for the first time. The encirclement of cucurbit[7]uril (CB[7]) onto the protonated 1,4-butanediamine stalks tethered to the external surfaces of superparamagnetic Fe(3) O(4) -embedded mesoporous silica particles leads to tight blocking of the nanopores. The supramolecular nanovalves are activated by the enzymatic decarboxylation products of lysine, cadaverine (in the protonated form), which has a high affinity for CB[7], so that the encapsulated guest molecules, calcein, in the nanopores are released into the bulk solution. The release of calcein can be controlled in small portions on command by alternating changes in enzymatic decarboxylation products and CB[7]. The amino acid derived polyamines have long been associated with cell growth and cancers. The guest molecules released from the delivery system of magnetic MSNs can act not only on sensing probes for levels of decarboxylases and polyamines, but also on efficacious drugs to specific tissues and cells for regulation of polyamine synthesis.
在生理条件下，生物刺激物控制药物释放是非常理想的，因为它们有可能在先进的应用中使用。首次报道了在近中性水溶液中使用磁性介孔硅纳米粒子（MSNs）通过酶启发控制葫芦[7]脲（CB[7]）纳米阀的控制释放。葫芦[7]脲（CB[7]）围绕质子化的 1,4-丁二胺支链包围在超顺磁 Fe(3)O(4)嵌入介孔硅颗粒的外表面上，导致纳米孔的紧密阻塞。超分子纳米阀通过赖氨酸的酶解产物（以质子化形式存在的尸胺）激活，赖氨酸、尸胺对 CB[7]具有高亲和力，因此纳米孔中的包封客体分子钙黄绿素被释放到体相溶液中。通过交替改变酶解产物和 CB[7]，可以按指令分小部分控制钙黄绿素的释放。衍生自氨基酸的多胺长期以来一直与细胞生长和癌症有关。从磁 MSNs 递药系统释放的客体分子不仅可以作用于脱羧酶和多胺水平的传感探针，还可以作用于有效的药物，以调节多胺合成，将其靶向特定的组织和细胞。
