Hyaluronic Acid Transport Properties and Its Medical Applications in Voice Disorders Eduarda F. G. Azevedo, Maria L. G. Azevedo, Ana C. F. Ribeiro, Aleš Mrácek, Lenka Grundelová, and Antonín Minarík

Abstract 310 16.1 Hyaluronic Acid (HA) 310 16.2 Biomedical Application of Hyaluronic Acid 319 16.3 Analysis, Conclusions, and Challenges 323 16.4 Acknowledgment 325 Keywords 325 References 325HYALURONIC ACID TRANSPORT PROPERTIES AND ITS MEDICAL APPLICATIONS IN VOICE DISORDERS EDUARDA F. G. AZEVEDO1,*, MARIA L. G. AZEVEDO2, ANA C. F. RIBEIRO1, ALES MRACEK3,4, LENKA GŘUNDĚLOVA4, AND ANTONIN MINAŘIK3,41Coimbra Chemistry Centre, Department of Chemistry, University of Coimbra, 3004-535, Coimbra, Portugal 2Otorhinolaryngology Service, Centro Hospitalar Baixo Vouga, Aveiro, Portugal, E-mail: luisaazevedo.md@gmail.com 3Department of Physics and Materials Engineering, Faculty of Technology, Tomas Bata University in Zlin, Czech Republic, E-mail: mracek@ft.utb.cz 4Centre of Polymer Systems, Tomas Bata University in Zlin, Czech Republic *Corresponding author. E-mail: edy.gil.azevedo@gmail.comABSTRACTHyaluronic acid (HA) is a natural linear polysaccharide occurring in a wide range of molecular weights. Due to hydrogen bonding, it behaves in solution as an extended, randomly entangled coil, forming a continuous polymer network. The chains entangle each other on this structure if in very low concentration solutions, leading to a mild viscosity (molecular weight dependent), rather than higher than expected viscosity due to greater HA chain entanglement that is shear-dependent if HA solutions are higher concentrations. Ionic effects and electrostatic on HA are considered as a function of counter ion type and valency, as solution properties affect the hydrogen bonding and electrostatic interaction between the solution and HA, resulting in a change in HA chain stiffness. Some of the functions of the polysaccharide are connected to its rheological properties (concentration and molecular weight dependent) and make HA ideal for lubrication in biomedical applications and is known as a “pseudoplastic” material.