Murugan Eagambaram, J Nimita Jebaranjitham, Ariraman Mathivathanan, Rajendran Saravanan, Kathirvel Janankiraman, Akshata C R, Kumar Kalpana
Department of Physical Chemistry, School of Chemical Sciences, University of Madras, Maraimalai Campus, Chennai 600025, Tamil Nadu, India.
PG Department of Chemistry, Women's Christian College (An Autonomous Institution Affiliated to University of Madras), College Road, Chennai 600 006, India.
ACS Omega. 2018 Oct 31;3(10):13685-13693. doi: 10.1021/acsomega.8b01326. Epub 2018 Oct 19.
Four different novel magnetic core-shell nanocomposites stabilized with Au/Pd nanoparticles (NPs) were prepared by a simple procedure and demonstrated their catalytic activity for effective cleavage of pBR322 DNA. Initially, the FeO-poly(styrene-divinylbenzene-vinylbenzyl chloride) (ST-DVB-VBC) matrix functionalized with 3-aminobenzoic acid was prepared and grafted with PPI-G(2) and PPI-G(3) dendrimers. Each core-shell matrix was immobilized with AuNPs and PdNPs separately. The resulting composites were characterized by FT-IR, UV-vis, SEM, TEM, XRD, VSM, XPS, Raman, and TGA. The magnetic core-shell nanocomposites at concentrations from 30 to 50 μM were employed separately to study DNA cleavage by agarose gel electrophoresis. Among the four magnetic core-shell nanocomposites, FeO-poly(ST-DVB-VBC)-PPI-G(3)-AuNPs showed higher activity than others for DNA cleavage, and formed Form-II and -III DNA. When the concentration of FeO-poly(ST-DVB-VBC)-PPI-G(3)-AuNPs was increased from 40 to 45 and 45 to 50 μM, Form-III (linear) DNA was observed with 10 and 22%, respectively, in addition to Form-II. This observation suggests formation of linear DNA from the supercoiled DNA via nicked DNA-intermediated consecutive cleaving process. The magnetic core-shell nanocomposites were stable and monodispersed, and exhibited rapid magnetic response. These properties are crucial for their application in biomolecular separations and targeted drug-delivery in the future.
通过一种简单的方法制备了四种用金/钯纳米颗粒（NPs）稳定的新型磁性核壳纳米复合材料，并展示了它们对pBR322 DNA有效切割的催化活性。首先，制备了用3-氨基苯甲酸功能化的FeO-聚（苯乙烯-二乙烯基苯-乙烯基苄基氯）（ST-DVB-VBC）基质，并用PPI-G(2)和PPI-G(3)树枝状聚合物进行接枝。每个核壳基质分别固定有金纳米颗粒和钯纳米颗粒。通过傅里叶变换红外光谱（FT-IR）、紫外可见光谱（UV-vis）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线衍射（XRD）、振动样品磁强计（VSM）、X射线光电子能谱（XPS）、拉曼光谱和热重分析（TGA）对所得复合材料进行了表征。分别使用浓度为30至50μM的磁性核壳纳米复合材料通过琼脂糖凝胶电泳研究DNA切割。在这四种磁性核壳纳米复合材料中，FeO-聚（ST-DVB-VBC）-PPI-G(3)-AuNPs在DNA切割方面表现出比其他材料更高的活性，并形成了II型和III型DNA。当FeO-聚（ST-DVB-VBC）-PPI-G(3)-AuNPs的浓度从40μM增加到45μM以及从45μM增加到50μM时，除了II型DNA外，还分别观察到10%和22%的III型（线性）DNA。这一观察结果表明，超螺旋DNA通过带切口的DNA介导的连续切割过程形成线性DNA。磁性核壳纳米复合材料稳定且单分散，并表现出快速的磁响应。这些特性对于它们未来在生物分子分离和靶向药物递送中的应用至关重要。
