Self-Assembling Peptide-Based Hydrogel: Regulation of Mechanical Stiffness and Thermal Stability and 3D Cell Culture of Fibroblasts

A histidine-containing peptide-based amphiphile (P1) forms a transparent hydrogel within a pH range of 5.5 to 8.5 in phosphate buffer solution. Interestingly, thermal stability and mechanical stiffness are modulated by incorporating different types of dicarboxylic acids into the hydrogels. Inclusion of succinic acid with the molar ratio 2:1 (peptide:dicarboxylic acid) yields improved properties compared to the other tested dicarboxylic acids such as oxalic, glutaric and octanedioic acids. Transmission electron microscopic (TEM) images show the assembly of nanospheres is responsible for the hydrogel obtained from the assembly of native peptide. However, a morphological transformation takes place from nanosphere to nanofibers, when the peptide gels with succinic acid. XRD and FT-IR studies reveal interactions between peptide amphiphiles and the acids are responsible for the formation of a two-component hydrogel. Gel stiffness is enhanced considerably upon the addition of succinic acid to P1 with a 1:2 molar...