The structure-activity relationship of mono-ion complexes (MICs) for plasmid DNA (pDNA) delivery by muscular injection is demonstrated. MICs were formed between pDNA and monocationic poly(ethylene glycol) (PEG) macromolecules. As monocationic PEGs, the ω-amide-pentylimidazolium (APe-Im) end-modified PEGs with a stable amide (Am) and hydrolytic ester (Es) bond, that is, APe-Im-Am-PEG and APe-Im-Es-PEG, respectively, are synthesized. The difference between the APe-Im-Am-PEG and APe-Im-Es-PEG was only a spacer structure between a terminal cation and a PEG chain. The resulting pDNA MICs with APe-Im-Am-PEG at a charge ratio (+/−) of 32 or 64 were more stable than those with APe-Im-Es-PEG in the presence of serum proteins. The highest gene expression by muscular injection was achieved using the APe-Im-Am-PEG/pDNA MIC at a charge ratio (+/−) of 32 with a smaller particle diameter of approximately 50 nm, as compared to that charge ratio of 64. Consequently, the pDNA MIC with the monocationic PEG with a stable amide spacer, as compared to a hydrolytic ester spacer, is considered to be suitable for the highest gene expression by muscular injection.

中文翻译：

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肌肉注射质粒DNA单离子复合物的构效关系

证明了单离子复合物（MIC）通过肌肉注射传递质粒DNA（pDNA）的构效关系。MIC是在pDNA和单阳离子聚乙二醇（PEG）大分子之间形成的。作为单阳离子PEG，具有稳定的酰胺（Am）和水解酯（Es）键的ω-酰胺-戊咪唑鎓（APe-Im）末端修饰的PEG，即APe-Im-Am-PEG和APe-Im-Es分别合成-PEG。APe-Im-Am-PEG和APe-Im-Es-PEG之间的差异只是末端阳离子和PEG链之间的间隔结构。在血清蛋白存在下，具有APe-Im-Am-PEG电荷比（+/-）为32或64的pDNA MIC比具有APe-Im-Es-PEG的pDNA MIC更稳定。