title: Mechanical properties of double-stranded DNA biolayers immobilized on microcantilever under axial compression.
abstract: In label-free biodetections based on microcantilever technology, double-stranded DNA (dsDNA) structures form through the linkage between probe single-stranded DNA (ssDNA) molecules immobilized on solid substrates and target ssDNA molecules in solutions. Mechanical/electrical properties of these biolayers are important factors for nanomechanical deflections of microcantilevers. In this paper, the biolayer immobilized on microcantilever is treated as a bar with a macroscopic elastic modulus on the basis of continuum mechanics viewpoints. In consideration of hydration force, screened electrostatic repulsion and conformational fluctuation in biolayers, load-deformation curves of dsDNA biolayers under axial compression are depicted with the help of the energy conservation law and a mesoscopic free energy presented by Strey et al. (1997, 1999) [Strey, H.H., Parsegian, V.A., Podgornik, R., 1997. Equation of state for DNA liquid crystals: fluctuation enhanced electrostatic double layer repulsion. Physical Review Letters 78, 895-898; Strey, H.H., Parsegian, V.A., Podgornik, R., 1999. Equation of state for polymer liquid crystals: theory and experiment. Physical Review E 59, 999-1008] from a liquid crystal theory. And the analytical relation between macroscopic Young's modulus of biolayers and nanoscopic geometrical properties of dsDNA, packing density, buffer salt solution concentration, etc. is also formulated.
authors.affiliation: Department of Mechanics, College of Sciences, Shanghai University, Shanghai 200444, China; Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China. Electronic address: nhzhang@shu.edu.cn.
authors.forename: Neng-Hui
authors.initials: NH
authors.lastname: Zhang
authors.affiliation: Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China.
authors.forename: Jian-Zhong
authors.initials: JZ
authors.lastname: Chen
mesh_terms: D001696:Biomechanical Phenomena; D055592:Biophysical Phenomena; D015374:Biosensing Techniques; D019245:Compressive Strength; D004247:DNA / Q000737:chemistry*; D004548:Elasticity; D008954:Models, Biological; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D004247:DNA