University of Linz, Institute for Biophysics, Altenbergerstr. 69, Linz, Austria.
Ultramicroscopy. 2010 May;110(6):605-11. doi: 10.1016/j.ultramic.2010.02.019. Epub 2010 Mar 2.
We demonstrate simultaneous transverse dynamic force microscopy and molecular recognition imaging using tuning forks as piezoelectric sensors. Tapered aluminum-coated glass fibers were chemically functionalized with biotin and anti-lysozyme molecules and attached to one of the prongs of a 32kHz tuning fork. The lateral oscillation amplitude of the tuning fork was used as feedback signal for topographical imaging of avidin aggregates and lysozyme molecules on mica substrate. The phase difference between the excitation and detection signals of the tuning fork provided molecular recognition between avidin/biotin or lysozyme/anti-lysozyme. Aggregates of avidin and lysozyme molecules appeared as features with heights of 1-4nm in the topographic images, consistent with single molecule atomic force microscopy imaging. Recognition events between avidin/biotin or lysozyme/anti-lysozyme were detected in the phase image at high signal-to-noise ratio with phase shifts of 1-2 degrees. Because tapered glass fibers and shear-force microscopy based on tuning forks are commonly used for near-field scanning optical microscopy (NSOM), these results open the door to the exciting possibility of combining optical, topographic and biochemical recognition at the nanometer scale in a single measurement and in liquid conditions.
我们使用音叉作为压电传感器，展示了同时的横向动态力显微镜和分子识别成像。经过化学功能化处理的锥形铝涂层玻璃纤维分别与生物素和抗溶菌酶分子结合，并附着在 32kHz 音叉的一个叉齿上。音叉的横向振荡幅度被用作反馈信号，用于在云母衬底上对亲和素聚集体和溶菌酶分子进行形貌成像。音叉的激励和检测信号之间的相位差提供了亲和素/生物素或溶菌酶/抗溶菌酶之间的分子识别。亲和素和溶菌酶分子的聚集体在形貌图像中表现为高度为 1-4nm 的特征，与单分子原子力显微镜成像一致。在高信噪比的相位图像中，可以检测到亲和素/生物素或溶菌酶/抗溶菌酶之间的识别事件，相位偏移为 1-2 度。由于锥形玻璃纤维和基于音叉的剪切力显微镜通常用于近场扫描光学显微镜 (NSOM)，因此这些结果为在单个测量和液体条件下在纳米尺度上结合光学、形貌和生化识别提供了令人兴奋的可能性。
