Intermolecular interactions play a role in the distribution and transport of charged contrast agents in a cartilage model

• Published in: bioRxiv
• Main Authors: Söderman, Olle, Algotsson, Jenny, Jönsson, Peter, sman, Jan, Topgaard, Daniel
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 27.03.2019; Cold Spring Harbor Laboratory
• Edition: 1.1
• Subjects: Biophysics; Cartilage (articular); Contrast agents; Electrostatic properties; Magnetic resonance imaging; NMR; Nuclear magnetic resonance; Polyelectrolytes; Solutes; Synovial fluid
• ISSN: 2692-8205; 2692-8205
• DOI: 10.1101/591255

The transport of charged solutes into articular cartilage through diffusion mechanism is important both for the maintaining of the metabolic function of the tissue, as well as for medical examinations of the cartilage status with help of contrast agents. The scientific issues include the rate of transport, as well as equilibrium concentrations in cartilage and the synovial fluid. To address these questions, we present results from magnetic resonance micro-imaging experiments on a model system of articular cartilage. The experiments yield temporally and spatially resolved data on the transport of a negatively charged contrast agent (charge = -2), used in medical examinations of cartilage, into a polyelectrolyte solution, which is designed to capture the electrostatic interactions in cartilage. Also presented is a theoretical analysis of the transport where the relevant differential equations are solved using finite element techniques as well as treated with approximate analytical expressions. In the analysis, non-ideal effects are included in the treatment of the mobile species in the system. This is made possible by comparison with previous Monte Carlo simulations. The results demonstrate the importance of taking non-idealities into account when the data of transport of charged solutes in a system with fixed charges from biological polyelectrolytes are analyzed.