Produzione di microparticelle a base di acido ialuronico per il rilascio di fattori di crescita nella cura di ulcere

The present study describes the production of hyaluronan based porous microparticles by a semi-continuous gas antisolvent (GAS) precipitation process to be used as a growth factor delivery system for in vivo treatment of ulcers. Operative process conditions, such as pressure, nozzle diameter and HYAFF® solution concentrations, were adjusted to optimize particle production in terms of morphology and size. Scanning electron microscopy and light scattering demonstrated that porous nano- structured particles with a size of 300-900 nm had a high specific surface suitable for absorption of growth factors from the aqueous environment within the polymeric matrix. Water acted as a plasticizer, enhancing growth factor absorption. The absorption process was developed using a fluorescent dye and growth factors PDGF and TGF-ß. Immunohistochemical analysis confirmed the high efficiency of absorption of growth factors and a mathematical model was generated to quantify and qualify the in vitro kinetics of growth factor release from the polymeric matrix. In vivo experiments were performed with the aim to optimize timed and focal release of PDGF to promote optimal tissue repair and regeneration of full-thickness wounds.