基于脂质体-DNA复合体的“条形码分子开关”及其生物识别功能

GUV-DNA-Based Complex for “Bar-Coded” Molecular Switching and Bio-Recognition

构建了一种由DNA链和大单室囊泡(GUV)组装成的具有智能靶向功能的复合体(GUV-DNA)。该复合体的粒径分布及形态学大小可以通过动态光散射(DLS)技术、表面Zeta电位及暗场显微镜进行测定及观察。组装后的GUV-DNA复合体可以藏匿靶向基团于高分子结构中;而该结构中的"立足点"(Toehold)序列使外源性的另一条寡核苷酸链能够通过DNA链置换反应竞争性地将靶向基团暴露于环境中,从而实现该结构的核酸敏感型变化。荧光共振能力转移(FRET)技术及生物素-亲和素(Biotin-Avidin)捕获法阐明了该结构中的碱基配对"条形码"序列可以确保只有特异性的寡核苷酸序列才能"打开"复合体,从而暴露靶向基团。所构建的GUV-DNA复合体可以实现程序化的"开启"功能,从而释放藏匿于其中的生物靶向功能基团。

A hybrid complex consisted of DNA molecule and giant unilamellar vesicles（GUV）which had smart targeting profile was constructed.The size distribution and the morphology of the complex were characterized by Dynamic Light Scattering（DLS）,surface Zeta potential and dark-field microscope.Such designed structure could not only hide a recognition signal inside the polymer molecules,but also contain toehold sequences which allow selective unveiling of the ligand on addition of a competing conjugate strand,thereby realizing its nucleic acid responsive property.Frster Resonance Energy Transfer（FRET）signalling and the biotin-avidin capture assay were used to demonstrate the efficacy of assembly,disassembly and biomolecular recognition established upon switching ＂on＂of the ligand by the opening of the complex by the complementary strand.In conclusion,the GUV-DNA complex can be unpacked in a preprogrammable manner,thereby revealing the previously shielded ligands which are then available to act as targeting moieties.