Mechanical properties of double-stranded DNA biolayers immobilized on microcantilever under axial compression.
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.
Zhang
Neng-Hui
NH
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.
Chen
Jian-Zhong
JZ
Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China.
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
D004247:DNA