The effects of ionic strength and pH on self-assembly of peptide

• Main Author: Zhu, Yinqi
• Other Authors: Yu Jing
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials::Biomaterials
• Online Access: https://hdl.handle.net/10356/166705
• Institution: Nanyang Technological University

Self-coacervation of peptides is a spontaneous liquid-liquid phase separation triggered by the non-covalent interactions between peptide molecules. The coacervation behaviours can be regulated by both internal and external stimuli. The project aims to investigate the parameters, which are the ionic strength, pH, and composition of peptide GG23, that affect the coacervation of the peptide. The effect of ionic strength on self-coacervation was evaluated by altering the concentration of sodium chloride in the peptide-salt solution. And the pH effect on the coacervation was revealed by dissolving peptide powder in two buffer solutions with different pH values. To investigate the effect of the peptide composition on self-coacervation, the peptide GG23K was prepared by substituting lysine (Lys) residues for aspartic acid (Asp) residues in GG23. The coacervates formed under different conditions were investigated by the optical microscope. GG23 tends to form coacervates under low pH and high ionic strength conditions. And Lys residues in GG23K help to improve the capability of peptide self-coacervation. The results may be beneficial for controlling self-coacervation behaviours and designing self-coacervating peptides for biomedical applications. Further research can be carried out to investigate the precise pH range where coacervates can be formed and the effects of temperature on the peptide coacervation.