Stimuli responsive self-assembled hydrogel of a low molecular weight free dipeptide with potential for tunable drug delivery

Bottom-up fabrication by molecular self-assembly is now widely recognized as a potent method for generating interesting and functional nano- and mesoscale structures. Hydrogels from biocompatible molecules are an interesting class of mesoscale assemblies with potential biomedical applications. The self-assembly of a proteolysis resistant aromatic dipeptide containing a conformational constraining residue (ΔPhe) into a stable hydrogel has been studied in this work. The reported dipeptide has free -N and -C termini. The hydrogel was self-supportive, was fractaline in nature, and possessed high mechanical strength. It was responsive to environmental conditions like pH, temperature, and ionic strength. The gel matrix could encapsulate and release bioactive molecules in a sustained manner. The described hydrogel showed no observable cytotoxicity to the HeLa and L929 cell lines in culture

Designed peptides as model self-assembling nanosystems: characterization and potential biomedical applications

Synthesis of nanomaterials via 'molecular self-assembly' allows one to define the properties of the nanomaterial by rational design of the individual constituents. Use of peptides for self-assembly offers the ease of design and synthesis, and provides higher biofunctionality and biocompatibility to nanomaterials. Our work focused on the synthesis, characterization and potential biomedical applications of small self-assembled peptide-based nanosystems. We demonstrated that dipeptides containing the conformational restricting residue α,β-dehydrophenylalanine, self-assembled into nanovesicular and nanotubular structures. The nanosystems could encapsulate and release anticancer drugs, showed enhanced stability to proteinase K degradation, a property crucial for them to have a high in vivo half-life, and exhibited no cytotoxicity towards cultured mammalian cells. The dipeptide nanostructures were easily taken up by cells and could evade uptake by reticuloendothelial systems when injected into healthy laboratory animals. Thus, small self-assembling peptides may offer novel scaffolds for the future design of nanostructures with potential applications in the field of drug delivery