Targeting Injectable Hydrogels: The Role of Diphenylalanine Peptide Derivative in the Gelation Dynamics of Pluronic® F127

The fluorenyl methyl oxycarbonyl phenylalanyl-phenylalanine methyl ester (Fmoc-Phe-Phe-Ome) was synthetized using the liquid phase synthesis strategy. This derivative was separated by hydrophobic interaction chromatography, its purity was analyzed by RP-HPLC and it was characterized by mass spectrometry. This extremely hydrophobic peptide conjugate was incorporated into aqueous solutions of Pluronic^® F127 at low temperatures (below 10 °C). The temperature induced sol-gel transition was investigated by rheological measurements. A delay of the sol-gel transition, caused by the presence of low concentrations of Fmoc-Phe-Phe-Ome (up to 1%), enables better control of the gelation process. The viscoelastic properties of hybrid networks were investigated at 37 °C in different shear conditions. The Pluronic/peptide systems reported herein provide promising alternatives for developing innovative injectable gels as suitable platforms in cancer treatment.