State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, People’s Republic of China.
Int J Nanomedicine. 2012;7:1069-78. doi: 10.2147/IJN.S28947. Epub 2012 Feb 22.
There is a general necessity to improve the specificity and efficiency of the polymerase chain reaction (PCR), and exploring the PCR-enhancing mechanism still remains a great challenge. In this paper we report the use of branched polyethyleneimine (PEI)-based derivatives and hybrid nanocomposites as a novel class of enhancers to improve the specificity and efficiency of a nonspecific PCR system. We show that the surface-charge polarity of PEI and PEI derivatives plays a major role in their effectiveness to enhance the PCR. Positively charged amine-terminated pristine PEI, partially (50%) acetylated PEI (PEI-Ac(50)), and completely acetylated PEI (PEI-Ac) are able to improve PCR efficiency and specificity with an optimum concentration order of PEI < PEI-Ac(50) < PEI-Ac, whereas negatively charged carboxyl-terminated PEI (PEI-SAH; SAH denotes succinamic acid groups) and neutralized PEI modified with both polyethylene glycol (PEG) and acetyl (Ac) groups (PEI-PEG-Ac) are unable to improve PCR specificity and efficiency even at concentrations three orders of magnitude higher than that of PEI. Our data clearly suggests that the PCR-enhancing effect is primarily based on the interaction between the PCR components and the PEI derivatives, where electrostatic interaction plays a major role in concentrating the PCR components locally on the backbones of the branched PEI. In addition, multiwalled carbon nanotubes modified with PEI and PEI-stabilized gold nanoparticles are also able to improve the PCR specificity and efficiency with an optimum PEI concentration less than that of the PEI alone, indicating that the inorganic component of the nanocomposites may help improve the interaction between PEI and the PCR components. The developed PEI-based derivatives or nanocomposites may be used as efficient additives to enhance other PCR systems for different biomedical applications.
提高聚合酶链反应（PCR）的特异性和效率是普遍需要的，探索 PCR 增强机制仍然是一个巨大的挑战。本文报道了使用支化聚乙烯亚胺（PEI）基衍生物和混合纳米复合材料作为一类新型增强剂，以提高非特异性 PCR 系统的特异性和效率。我们表明，PEI 和 PEI 衍生物的表面电荷极性在其增强 PCR 的有效性中起着主要作用。带正电荷的伯胺封端的原始 PEI、部分（50%）乙酰化 PEI（PEI-Ac（50））和完全乙酰化 PEI（PEI-Ac）能够以 PEI < PEI-Ac（50）< PEI-Ac 的最佳浓度顺序提高 PCR 效率和特异性，而带负电荷的羧基封端的 PEI（PEI-SAH；SAH 表示琥珀酰亚胺酸基团）和用聚乙二醇（PEG）和乙酰（Ac）基团修饰的中性化 PEI（PEI-PEG-Ac）即使在浓度比 PEI 高三个数量级的情况下也不能提高 PCR 的特异性和效率。我们的数据清楚地表明，PCR 增强效应主要基于 PCR 成分与 PEI 衍生物之间的相互作用，其中静电相互作用在将 PCR 成分局部集中在支化 PEI 的骨架上起着主要作用。此外，用 PEI 和 PEI 稳定的金纳米粒子修饰的多壁碳纳米管也能够以低于单独使用 PEI 的最佳 PEI 浓度提高 PCR 的特异性和效率，表明纳米复合材料的无机成分可能有助于改善 PEI 与 PCR 成分之间的相互作用。开发的基于 PEI 的衍生物或纳米复合材料可用作有效的添加剂，以增强其他用于不同生物医学应用的 PCR 系统。
