Manandhar Pradeep, Chen Kan-Sheng, Aledealat Khaled, Mihajlović Goran, Yun C Steven, Field Mark, Sullivan Gerard J, Strouse Geoffrey F, Chase P Bryant, von Molnár Stephan, Xiong Peng
Department of Physics and MARTECH, Florida State University, Tallahassee, FL 32306, USA.
Nanotechnology. 2009 Sep 2;20(35):355501. doi: 10.1088/0957-4484/20/35/355501. Epub 2009 Aug 12.
The detection of reagent-free specific biomolecular interactions through sensing of nanoscopic magnetic labels provides one of the most promising routes to biosensing with solid-state devices. In particular, Hall sensors based on semiconductor heterostructures have shown exceptional magnetic moment sensitivity over a large dynamic field range suitable for magnetic biosensing using superparamagnetic labels. Here we demonstrate the capability of such micro-Hall sensors to detect specific molecular binding using biotin-streptavidin as a model system. We apply dip-pen nanolithography to selectively biotinylate the active areas of InAs micro-Hall devices with nanoscale precision. Specific binding of complementarily functionalized streptavidin-coated superparamagnetic beads to the Hall crosses occurs via molecular recognition, and magnetic detection of the assembled beads is achieved at room temperature using phase sensitive micro-Hall magnetometry. The experiment constitutes the first unambiguous demonstration of magnetic detection of specific biomolecular interactions with semiconductor micro-Hall sensors, and the selective molecular functionalization and resulting localized bead assembly demonstrate the possibility of multiplexed sensing of multiple target molecules using a single device with an array of micro-Hall sensors.
通过对纳米级磁性标记的传感来检测无试剂的特定生物分子相互作用，为利用固态器件进行生物传感提供了最具前景的途径之一。特别是，基于半导体异质结构的霍尔传感器在适合使用超顺磁性标记进行磁生物传感的大动态磁场范围内表现出了卓越的磁矩灵敏度。在此，我们展示了这种微霍尔传感器利用生物素-链霉亲和素作为模型系统来检测特定分子结合的能力。我们应用浸笔纳米光刻技术，以纳米级精度选择性地将生物素化修饰到砷化铟微霍尔器件的有源区域。通过分子识别，功能互补的链霉亲和素包被的超顺磁性珠子与霍尔交叉结构发生特异性结合，并在室温下使用相敏微霍尔磁强计实现对组装珠子的磁性检测。该实验首次明确证明了利用半导体微霍尔传感器对特定生物分子相互作用进行磁性检测，并且选择性分子功能化以及由此产生的局部珠子组装证明了使用具有微霍尔传感器阵列的单个器件对多个目标分子进行多重传感的可能性。
