中文摘要：

传统的分子生物学实验方法基本都是系综的方法,测量的信号来自大量的生物分子的平均响应,这不利于得到生物分子的构象转变与功能的动力学细节.另外,很多生物大分子如细胞骨架蛋白、分子马达等在行使功能的时候都会受到或者产生力的作用,传统的实验方法也难于研究生物分子的力学响应.最近20年左右发展起来的单分子操控技术可以实现对单个分子的操控,同时测量单个分子在拉力作用下的力学响应.最为常用的单分子操控技术主要包括光镊、磁镊和原子力显微镜,不同的技术有不同的特点和适用范围.本文对几种常用的单分子操纵技术的特点,包括物理原理、可以施加的力的范围与精度、可以测量的分子长度范围与精度等做一个系统的介绍.另外,单分子操控技术在生物大分子如核糖核酸（DNA）,脱氧核糖核酸（RNA）和蛋白质的构象转变,相互作用,以及分子马达的功能机理等方面已经取得的丰富成果也给出概括性的介绍.本文对生物学家系统的了解单分子操控技术和如何应用该技术解决自己的生物问题提供一个有益的参考.

英文摘要：

Biomolecules such as proteins and nucleic acids play critical roles in biological processes.Traditional molecular biological experimental techniques usually measure the properties of an ensemble of molecules.The detected signal originates from the average response of large number of molecules,which often conceals the detailed dynamic information about conformational transitions.In addition,many biomolecules,such as cytoskeleton proteins and molecular motors,are subjected to stretching forces or are able to generate force while playing their biological roles in vivo.It is difficult for traditional experimental methods to be used to study the mechanical response of biomolecules.Single molecule manipulation techniques developed in recent twenty years are capable of manipulating and measuring the property of single molecule.Especially,the force response of single molecule can be measured in high precision.The most popular single molecular manipulation techniques are atomic force microscope,optical tweezers,and magnetic tweezers.Here we introduce the principle,capability of force and extension measurement,spatial and temporal resolutions of these three techniques.Applications of single molecular manipulation techniques in the conformation transitions of DNA,protein,and their interactions,and mechanism of molecular motors will be briefly reviewed.This review will provide a useful reference to biologists to learn and use single molecular manipulation techniques to solve biological problems.