Discoid Nanoparticles: pH-dependent Size Response

Introduction: Tumor targeting is a major issue point in development of new drugs. The targeting can be making by conjugating specific targeting molecole or modifying their size or shape. Discoidal Nanopartcles (DNs) have discoidal shape and are very small. DNs is obtained from liposomes by adding Styrene-Maleic Acid copolimer (SMAnh) (Fig. 1). Molecular ratio between styrene and maleic anhydride and pH of microenvironment reaction can however affect the synthesis of DNs [1]. In this work we studied the use of SMAnh as copolymers capable to synthesis DNs starting from spherical liposomes at different molar ratio of copolymer and pH. Materials and Methods: Different liposomes formulations were synthesized using thin layer evaporation method, freeze and thaw and extrusion. The DNs are synthesized by incubating the best resulting liposomes (DMPC) with SMAnh with molecular ratio 2:1 in Hepes 10 mM at pH=7.4; pH=6.5 and pH=5.5. The liposomes and resulting DNs are further physiochemically characterized by DLS and UV-Vis spectrophotometer (Fig. 2). Results and Discussion: The SMAnh copolymer is able to form DNs, but its behavior depends on pH enviroment. Infact, at several pH is possible find different particle sizes. Currently the best enviroment condition is at pH=6.5. Conclusion: DNs could be a innovative drug delivery systems for anticancer therapy. SMAnh molar ratio affects the synthesis of DNs as well as drug delivery.