Supramolecular structures prevailing in aqueous hyaluronic acid and phospholipid vesicles mixtures: an electron microscopy and rheometric study

The interactions of high molecular weight hyaluronan (HA) with di-palmitoyl phosphatidylcholine (DPPC) liposomes in aqueous buffer have been investigated. The superstructures resulting from co-incubation in vitro were observed by means of negative staining and rotary shadowing electron microscopy and were also characterized by rheometric techniques. The existence of a supramolecular complex between the two partners is clearly demonstrated; this complex would exist in vivo in the synovial fluid (whose major components are, in fact, HA and DPPC) and should be responsible for the unique physiological properties of the latter.