Investigating the Interactions of Hyaluronan Derivatives with Biomolecules. The Use of Diffusional NMR Techniques

Abstract

[Chemical structure: see text] The interactions between a biomaterial and biomolecules present in body fluids often determine the fate of the biomaterial. This paper presents a study on hyaluronan (HA)-containing materials (in soluble or colloidal form) that focuses on their interactions with lipids and proteins and for the first time uses PFG NMR as an analytical technique for probing these events. The interactions of HA-based polymers with phospholipids (DPPC and DPPG liposomes) are shown to depend both on charge and hydrophobicity factors. Despite the difference in behavior between albumin (substantially non-adhesive) and fibrinogen (adhesive), the interactions of the polymers with proteins do not seem to be based on hydrophobic effects but on surface polar interactions.

Probing interactions by means of pulsed field gradient nuclear magnetic resonance spectroscopy

“…[68,69] Hydrophobically modified HAderivatives [70] obtained through the partial esterification of the HA carboxyl groups with methylprednisolone (45% in HYCp45 and 60% in HYCp60) [71] have been deeply studied. [14] A key point prior to any in vivo study of the biomaterial is the assessment of the so-called 'stealth character' of the species itself. Such characteristic corresponds to be invisible to the immune system, so that the colloids are not recognised as foreign objects by body fluid components, i.e.…”

“…One might face different situations; the easiest occurs when the two interacting species are very different in size; in fact, the D value of the low-molecular-weight component is largely reduced when aggregated. [14] A semi-quantitative D measurement is therefore informative, as illustrated later for the protein-colloid systems. [15] When species are similar in size and shape, having therefore comparable D values, and the interaction is weak, involves only a portion of the molecules and the equilibrium is faster than the NMR time scale, it is still possible to study the aggregation.…”

Rheological investigation on hyaluronan–fibrinogen interaction

“…Other papers claim that albumin interaction cannot exist at pH ∼ 7, the two polymers being negatively charged; or that interaction should occur at pH > 5 [13].…”

Fluorescence Spectroscopy Study of Hyaluronan–Phospholipid Interactions

“…Taglienti et al [20] utilized diffusional NMR techniques for investigation of the interactions between hyaluronan and phospholipids (DPPC and 1,2-Dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt). They showed that they are dependent both on charge and hydrophobicity factors.…”