Two/three-dimensional interfacial properties of the novel peptide as a selective destroyer of biomembrane

Glycolipids improve the stability of liposomes: The perspective of bilayer membrane structure

The storage and thermal stability of liposomes, which are amphiphilic carriers, cause very large challenges. However, glycolipid modification may be a potential method to improve the stability of liposomes. In this study, the mechanism by which tilapia head glycolipids improve the stability of liposomes was studied. The head groups of glycolipids and liposomes have a strong interaction (K_a = 633.650 M^-1), mainly due to hydrogen bonds, which promote the formation of microstructure domains between glycolipids and liposomes. In addition, glycolipids caused the bilayer structure of liposomes to rearrange, resulting in an increase in the phase transition temperature, tight arrangement of membrane molecules, and increase in membrane thickness (from 2.4 nm to 3.5 nm). Novelty, the formation of microstructure domains helped prevent the liposomes membrane structure from being disrupted during storage and heat. Therefore, glycolipid modification improved the stability of liposomes. This study can provide new insights into the development of high-stability liposomes.

Novel Peptide-Polymer Conjugate with pH-Responsive Targeting/Disrupting Effects on Biomembranes

Conjugating polymers to peptides has become a new strategy of designing functional antitumor agents for their improved stability and enhanced activity. In this paper, a novel peptide-polymer conjugate PEPc-PMAA with pH responsiveness was designed and synthesized. The isoelectric point of PEPc was studied by dynamic light scattering for the targeting effect. Also, the transmittances of PMAA at different pHs were measured using an ultraviolet-visible spectrophotometer for determining the triggering pH of the disrupting effect. The results showed that PEPc-PMAA was hydrophilic under neutral conditions and changed to be amphiphilic composed of positively charged PEPc and hydrophobic PMAA under acidic conditions. The interactions between PEPc-PMAA and mimic cells were investigated by the measurements of membrane fluidity and cargo leakage from 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine and 1,2-dipalmitoyl-sn-glycerol-3-phospho-(1-rac-glycerol) (DPPG) liposomes. It proved that PEPc-PMAA caused a distinct membrane disturbance of the DPPG liposome at pH 5.5, resulting in more serious cargo leakage. Because of its targeting and disrupting effects on negatively charged biomembranes under acidic conditions, PEPc-PMAA showed its good potential as an antitumor agent.