College of Nanoscale Science and Engineering, University at Albany, SUNY, 257 Fuller Road, Albany, New York 12203, USA.
ACS Appl Mater Interfaces. 2012 Oct 24;4(10):5360-8. doi: 10.1021/am3013032. Epub 2012 Sep 21.
Immobilization of biomolecular probes to the sensing substrate is a critical step for biosensor fabrication. In this work we investigated the phosphate-dependent, oriented immobilization of DNA to hafnium dioxide surfaces for biosensing applications. Phosphate-dependent immobilization was confirmed on a wide range of hafnium oxide surfaces; however, a second interaction mode was observed on monoclinic hafnium dioxide. On the basis of previous materials studies on these films, DNA immobilization studies, and density functional theory (DFT) modeling, we propose that this secondary interaction is between the exposed nucleobases of single stranded DNA and the surface. The lattice spacing of monoclinic hafnium dioxide matches the base-to-base pitch of DNA. Monoclinic hafnium dioxide is advantageous for nanoelectronic applications, yet because of this secondary DNA immobilization mechanism, it could impede DNA hybridization or cause nonspecific surface intereactions. Nonetheless, DNA immobilization on polycrystalline and amorphous hafnium dioxide is predominately mediated by the terminal phosphate in an oriented manner which is desirable for biosensing applications.
生物分子探针固定到传感基底是生物传感器制造的关键步骤。在这项工作中，我们研究了用于生物传感应用的磷依赖性、定向 DNA 固定到二氧化铪表面。在各种氧化铪表面上都证实了磷依赖性固定；然而，在单斜二氧化铪上观察到第二种相互作用模式。基于对这些薄膜的先前材料研究、DNA 固定研究和密度泛函理论 (DFT) 建模，我们提出这种二次相互作用是在单链 DNA 的暴露碱基和表面之间发生的。单斜二氧化铪的晶格间距与 DNA 的碱基对间距匹配。单斜二氧化铪有利于纳米电子应用，但由于这种二次 DNA 固定机制，它可能会阻碍 DNA 杂交或导致非特异性表面相互作用。尽管如此，DNA 主要以定向方式固定在多晶和非晶二氧化铪上，这对于生物传感应用是理想的。
