title: Imaging soft matters in water with torsional mode atomic force microscopy.
abstract: We have developed a high-sensitivity atomic force microscopy (AFM) mode operated in aqueous environment based on the torsional resonance of the cantilever. It is found that the torsional mode can achieve a good spatial resolution even with a relatively large tip. We have used this mode to image different soft materials in water, including DNA molecules and purple membrane. High-resolution images of purple membrane can be obtained at a relatively low ion concentration under a long-range electrostatic force. Thus the torsional mode allows investigators to probe surface structures and their properties under a wide range of solution conditions.
authors.affiliation: Institute of Physics, Academia Sinica, 128 Sec. 2 Academia Rd., Nankang, Taipei, Taiwan, ROC. Electronic address: ishwang@phys.sinica.edu.tw.
authors.forename: Ing-Shouh
authors.initials: IS
authors.lastname: Hwang
authors.forename: Chih-Wen
authors.initials: CW
authors.lastname: Yang
authors.forename: Ping-Hsiang
authors.initials: PH
authors.lastname: Su
authors.forename: En-Te
authors.initials: ET
authors.lastname: Hwu
authors.forename: Hsien-Shun
authors.initials: HS
authors.lastname: Liao
mesh_terms: D004247:DNA / Q000737:chemistry; D018625:Microscopy, Atomic Force / Q000379:methods*; D018717:Purple Membrane / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D004247:DNA