Taratula Olena, Galoppini Elena, Mendelsohn Richard, Reyes Pavel Ivanoff, Zhang Zheng, Duan Ziqing, Zhong Jian, Lu Yicheng
Department of Chemistry, Rutgers, The State University of New Jersey, 73 Warren Street, Newark, New Jersey 07102, USA.
Langmuir. 2009 Feb 17;25(4):2107-13. doi: 10.1021/la8026946.
A surface functionalization methodology for the development of ZnO nanotips biosensors that can be integrated with microelectronics was developed. Two types of long chain carboxylic acids linkers were employed for the functionalization of 0.5 mum thick MOCVD-grown ZnO nanotip films with single-stranded DNA (ssDNA), followed by hybridization with complementary ssDNA tagged with fluorescein. The ZnO functionalization strategy was developed for the fabrication of ZnO nanotips-linker-biomolecule films integrated with bulk acoustic wave (BAW) biosensors, and it involved three main steps. First, 16-(2-pyridyldithiol)hexadecanoic acid or N-(15-carboxypentadecanoyloxy)succinimide, both bifunctional C16 carboxylic acids, were bound to ZnO nanotip films through the COOH group, leaving at the opposite end of the alkyl chain a thiol group protected as a 2-pyridyl disulfide, or a carboxylic group protected as a N-succinimide, respectively. In the second step, ssDNA was covalently linked to each type of ZnO-linker film: the 2-pyridyl disulfide end group was substituted with 16 bases 5'-thiol-modified DNA (SH-ssDNA), and the N-succinimide ester end group was substituted with 16 bases 5'-amino-modified DNA (NH(2)-ssDNA). In the third step, the DNA-functionalized ZnO nanotip films were hybridized with complementary 5'-fluorescein ssDNA. The surface-modified ZnO nanotip films were characterized after each step by FT-IR-ATR, fluorescence emission spectroscopy, and fluorescence microscopy. This functionalization approach allows sequential reactions on the surface and, in principle, can be extended to numerous other molecules and biomolecules.
开发了一种用于制备可与微电子集成的ZnO纳米尖生物传感器的表面功能化方法。采用两种长链羧酸连接剂对通过金属有机化学气相沉积（MOCVD）生长的0.5μm厚的ZnO纳米尖薄膜进行功能化，使其与单链DNA（ssDNA）结合，随后与标记有荧光素的互补ssDNA杂交。开发ZnO功能化策略是为了制造与体声波（BAW）生物传感器集成的ZnO纳米尖-连接剂-生物分子薄膜，该策略包括三个主要步骤。首先，16-(2-吡啶二硫基)十六烷酸或N-(15-羧基十五烷酰氧基)琥珀酰亚胺这两种双功能C16羧酸，通过COOH基团与ZnO纳米尖薄膜结合，在烷基链的另一端分别留下一个被保护为2-吡啶二硫化物的硫醇基团或被保护为N-琥珀酰亚胺的羧基。第二步，将ssDNA共价连接到每种类型的ZnO-连接剂薄膜上：2-吡啶二硫端基被16个碱基的5'-硫醇修饰DNA（SH-ssDNA）取代，N-琥珀酰亚胺酯端基被16个碱基的5'-氨基修饰DNA（NH₂-ssDNA）取代。第三步，将DNA功能化的ZnO纳米尖薄膜与互补的5'-荧光素ssDNA杂交。在每一步之后，通过傅里叶变换红外衰减全反射光谱（FT-IR-ATR）、荧光发射光谱和荧光显微镜对表面改性的ZnO纳米尖薄膜进行表征。这种功能化方法允许在表面进行顺序反应，并且原则上可以扩展到许多其他分子和生物分子。
