| dc.description.abstract | Liposomes are hollow spherical nanoparticles mainly composed of single layers of phospholipid bilayer and widely used as drug delivery vehicles, sometimes featuring the capability of targeted delivery. Liposomes are microparticulate vesicles which are under extensive study as carriers for improving the delivery of therapeutic drugs. When liposomal drugs enter human bodies, the phospholipid bilayers of the liposomes may activate the so-called complement system, which triggers a cascade of biochemical reactions leading to adverse immune responses. The immune responses of liposomes focus on complement activation and related physiological variation, which build a uniquely adverse immune phenomenon, the complement activation-related pseudoallergy (CARPA). The activation of the complement system by liposomes is a serious pharmaceutical issue, as it can cause many side effects through the release of toxic proteins, such as heart pain, rash and hypo/hypertension, which complicates the approval or adoption of a new liposomal drug. In many factors of complement activation, surface charge is most amply studied. Despite its pharmaceutical importance, how liposomes interact with the protein components of the complement system and activate it, particularly the influences of the physical properties of liposomes (e.g., the bilayer elasticity, which is critical to the lipid-protein interactions) remains largely unknown. This study will employ a model system which consists of the protein domains responsible for the complement system’s interaction with lipid and liposomes of systematically varied compositions, to explore the factors dictating the activation of the complement system by liposomes. The knowledge learned here will be of great value to the designs of liposomal drugs. The current study is to specify the contribution of lipid elastic property to interaction between liposome and complement system by using Langmuir trough and small angle x-ray scattering (SAXS). We choose the part of the complement protein, liposome mediated complement activation binding site, which is the residues 14-26, A-G-R-P-G-R-R-G-R-P-G-L-K, the highly cationic region of the complement system protein. By exploring affinity between liposome and complement system, we aim to find the importance and the role of the elastic properties of liposome in complement activation events. | en_US |