Non-natural oligomers with well-defined three dimensional structures (foldamers) raise great interest owing to their ability to mimic and expand the world of biopolymers. Closest analogues are foldamers constructed using β-amino acids since their physical properties resemble those of natural peptides and they offer additional advantages of proteolytic stability and unprecedented architectures. Key challenge is to use these important β-peptides for construction of ordered structures at nanoscale. It is also well understood that process of molecular recognition and self-assembly direct the way in which simple foldamers recognize each other, associate and form ordered nanostructures. Hence we are working on design and synthesis of functional nanostructures using short β-peptides based on β-Alanine considering the conformational flexibility it provides as compared to other members of the clan. We have a main objective to design self-assembled nanostructures from these β-peptides for use as delivery vehicles.
In present paper we discuss the self-assembly of short β-Alanine containing tetrapeptides to formation of nanovesicular structures that can possibly be used as delivery vehicles of drug L-DOPA. Taking examples of two tetramers namely H2N-β-Ala-β-Ala-β-Ala-β-Ala-CONH2 and H2N-β-Ala-β-Ala-Lys-β-Ala-CONH2 we have explored the self-assembly process using circular dichroism, IR, absorption and emission spectroscopy. The secondary structure estimations as well as structural changes occurring during self-assembly are discussed. Supportive theoretical studies conducted to determine minimum energy conformations and simulation of self-aggregated structures using computational methods are described. Morphological studies reveal the formation of uniformly shaped nanodimensional spherical vesicles with average particle size of 150 nm. Encapsulation and slow release of L-DOPA an antiparkinson’s drug by described nanonvesicles is probed by absorption and emission spectroscopy assessing their potential use as drug delivery vehicles.