Thermosensitive gels of pullulan and poloxamer 407 as potential injectable biomaterials

Abstract

The paper presents the preparation and rheological response of thermosensitive gels of poloxamer 407 (P407) in the presence of a versatile polysaccharide, pullulan (PULL). Prior to material formulations, the phase diagram was established for PULL and P407 mixtures in aqueous solutions at 37 °C. Due to the competition between the hydrophobic and hydrophilic interactions, an extended island of immiscibility was observed. Homogeneous solutions of polymer mixtures near the phase boundary conditions were used to prepare gels and their rheological behavior was carefully investigated. Steady shear and oscillatory rheological investigations indicated a temperature induced gelation, shear induced yielding and soft gel characteristics at physiological temperature. Hyperimmune egg white was added to the samples to provide the target gel with appropriate antimicrobial effects coming from the valuable proteins from egg white. The gel samples were characterized and their biocompatibility and antimicrobial properties were compared. PULL/P407 homogeneous mixtures combine the unique characteristics of the two polymers and they are suitable to design polymeric materials with potential bioapplications, such as dressings for wound healing or injectable hydrogels.