运用功能化修饰的碳纳米管针尖测量配体-受体的作用力

电弧法自制碳纳米管原子力显微镜针尖,对其末端进行功能化修饰,然后测量配体-受体之间的作用力。运用没有功能化修饰的碳纳米管针尖与修饰有亲和素分子的基底进行接触测量时,没有粘滞力出现;而运用末端修饰生物素分子的碳纳米管针尖测量时,有粘滞力产生。功能化的碳纳米管针尖直接测得的粘滞力均大约200pN,此值符合一对配体生物素和受体亲和素之间的作用力。这一结果很难用传统的针尖获得,功能化修饰的碳纳米管针尖能够克服传统针尖在力测量中的局限,在生物学和化学领域有着广泛的应用前景。

Measuring the Adhesion Forces of Ligand-Receptor Bonds Using Functionalized Carbon Nanotube Atomic Force Microscopic Tips

The atomic force microscope (AFM) mounted with functionalized carbon nanotube (CNT) tips was used to study the interaction forces of a receptor streptavidin with its ligand biotin under physiological condition. While surface functionalized with streptavidin responses to forced contact with a non-functionalized CNT tip rarely showed evidence of tip-surface interaction, those obtained with a modified CNT tip with the biotin gave clear indication of the adhesion force. The functionalized nanotube tips show binding force quanta of about 200 pN that agree with per biotin-steptavidin pair binding force. This result cannot be reproduced using conventional AFM silicon probes. This indicates that the covalent modified CNT tips can overcome AFM conventional tips limitations of force sensitivity measurements and opens up significant opportunities in chemistry and biology.