title: Influence of concentration on distribution properties of stretched-DNA in the MEC studied with fluorescence imaging and drop shape analyzing.
abstract: Stretching and manipulating DNA efficiently is significant for exploring the properties and applications of single DNA molecules. Here, the influence of concentrations of buffer and DNA on properties of stretched DNA molecules in the molecular evaporation combing (MEC) is investigated systematically with the single molecule fluorescence imaging microscopy and the high-precision drop shape analyzing technology. The stretched degree and uniformity of combed DNA molecules decrease as the buffer concentration are increased from 7 to 20mM. When the buffer concentration changes from 12 to 15mM, the stretched DNA molecules are apt to form a ringlike pattern. During the MEC process, there exist two kinds of evaporation modes, i.e., the constant contact angle mode and the constant contact radius mode. The former only takes effect in the lower concentration of buffer and DNA, enabling the uniform stretching. While the latter plays the leading role in the higher concentration, promoting the formation of the ringlike pattern of DNA molecules.
authors.affiliation: State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials, Laboratory of Optoelectronic Technology of Shaanxi Province, National Center for International Research of Photoelectric Technology & Nanofunctional Materials and Application, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, Shaanxi, China; School of Physics, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Mengjiao
authors.initials: M
authors.lastname: Wan
authors.affiliation: State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials, Laboratory of Optoelectronic Technology of Shaanxi Province, National Center for International Research of Photoelectric Technology & Nanofunctional Materials and Application, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials, Laboratory of Optoelectronic Technology of Shaanxi Province, National Center for International Research of Photoelectric Technology & Nanofunctional Materials and Application, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials, Laboratory of Optoelectronic Technology of Shaanxi Province, National Center for International Research of Photoelectric Technology & Nanofunctional Materials and Application, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials, Laboratory of Optoelectronic Technology of Shaanxi Province, National Center for International Research of Photoelectric Technology & Nanofunctional Materials and Application, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials, Laboratory of Optoelectronic Technology of Shaanxi Province, National Center for International Research of Photoelectric Technology & Nanofunctional Materials and Application, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, Shaanxi, China. Electronic address: wangkg@nwu.edu.cn.
authors.forename: Kaige
authors.initials: K
authors.lastname: Wang
authors.affiliation: School of Physics, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Qingli
authors.initials: Q
authors.lastname: He
authors.affiliation: State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials, Laboratory of Optoelectronic Technology of Shaanxi Province, National Center for International Research of Photoelectric Technology & Nanofunctional Materials and Application, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, Shaanxi, China; Mechanical Engineering Department & Biomedical Engineering Program, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Guiren
authors.initials: G
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials, Laboratory of Optoelectronic Technology of Shaanxi Province, National Center for International Research of Photoelectric Technology & Nanofunctional Materials and Application, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, Shaanxi, China; School of Physics, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Jintao
authors.initials: J
authors.lastname: Bai
mesh_terms: D002021:Buffers; D004247:DNA / Q000737:chemistry*; D015342:DNA Probes / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008856:Microscopy, Fluorescence / Q000379:methods*; D009690:Nucleic Acid Conformation; D019904:Polymethyl Methacrylate / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D002021:Buffers; D015342:DNA Probes; D005456:Fluorescent Dyes; D004247:DNA; D019904:Polymethyl Methacrylate
keywords: Coffee-ring effect; DNA concentration; Dynamic behaviors; Molecular evaporation combing method; Ringlike pattern