Affiliation:
1. Depto. de Madera Universidad de Guadalajara Celulosa y Papel Km. 15.5 Carretera Guadalajara‐Nogales Zapopan Jalisco 45110 México
2. Institut des Sciences Chimiques de Rennes, Université de Rennes 1 équipe CORINT, CNRS, UMR 6226 Campus de Beaulieu, Bat 10A Rennes Cedex 35042 France
3. Departamento de Ingeniería Química Universidad de Guadalajara Blvd. M. García Barragán #1451, C.P Guadalajara Jalisco 44430 México
4. Departamento de Química Universidad de Guadalajara Blvd. M. García Barragán #1451, C.P Guadalajara Jalisco 44430 México
5. CNRS IPR (Institut de Physique de Rennes), Université de Rennes UMR6251 F‐35000 Rennes France
Abstract
AbstractThe study of the dynamics of nucleic acids in solution, their flow properties, and viscoelasticity is of great importance for understanding their biological functions. Many important properties of nucleic acids, such as DNA, depend on polymer concentration, CDNA, molecular weight (MW), rigidity, and external salt content, the latter parameter affecting electrostatic interactions. Furthermore, DNA molecular chains can organize, in vitro, into liquid crystalline phases at high CDNA. In this work, three DNA samples with different MW were studied in solution in a broad concentration range (CDNA from 0.025 to 200 mg mL−1, depending on DNA MW). Firstly, the intrinsic viscosities and MW for all DNA samples were determined through capillary and rheological measurements. Then, the overlap concentrations, C*, were estimated from the relation C* ≈ [η]−1. DNA chain characteristics were then analyzed in terms of the influence of DNA MW on the solution viscosities and on the overlap parameter, CDNA[η]. Flow birefringence appearance was identified by screening a wide CDNA range through visual observations with crossed polarizers. Finally, crossed‐light polarized microscopy was used to identify the appearance of liquid crystals at rest, confirming that higher CDNA are needed to obtain liquid crystals for low MW DNA samples.
Funder
Centre National de la Recherche Scientifique
Consejo Nacional de Ciencia y Tecnología