Evidence of Protein Adsorption in Pegylated Liposomes: Influence of Liposomal Decoration

Abstract

In order to contribute to a better knowledge of the events involved in the formation of the protein corona when nanoparticles (NPs) come in contact with proteins, we report a study about the changes on the physicochemical properties of pristine, PEGylated and Cyclic Arginine-Glycine-Aspartate peptide (RGD)-functionalized large unilamelar liposomes (LUVs) or magnetoliposomes (MLs) upon incubation with Bovine Serum Albumin (BSA). The main phospholipid component of both LUVs and MLs was l-α-phosphatydylcholine (PC) or 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) with 20% of cholesterol. The most obvious indication of the interaction of BSA-nanosystems is given by changes in the hydrodynamic diameter of the particles but other evidence is needed to corroborate the process. Our findings indicate that size modification is a process that is accomplished in few hours and that is strongly dependent not only on the surface decoration but also of the lipid composition of both LUVs and MLs. Fluorescence quenching experiments as well as cryogenic transmission electron microscopy (Cryo-TEM) images assessed these changes and confirmed that although each system has to be studied in a particular way, we can establish three distinctive features that turn into more reactive systems: (a) compositions containing PC compared with their DMPC counterparts; (b) the presence of PEG and/or RGD compared to the pristine counterparts; and (c) the presence of SPIONs: MLs show higher interaction than LUVs of the same lipid composition. Consequently, PEGylation (that is supposed to make stealth NPs) actually fails in preventing complete protein binding.

Synthesis of cationic carbon dots and their effects on human serum proteins and in vitro blood coagulation

“…As shown in Figure 6, the HSA, hFIB, and hTRF CD spectra exhibited two negative bands at $209 and 220 nm, while the hIgG spectrum showed positive and negative bands at 206 and 216 nm, respectively. The results were consistent with previous reports that HSA, hFIB, and hTRF exhibit typical α-helical structures, [24,25] whereas hIgG exhibits a typical β-folded structure. [26] At low SG-CCD concentrations (<20 μM), the addition of SG-CCDs produced no significant changes in the characteristic peptide CD bands of HSA and hIgG, indicating that the SG-CCDs did not induce any changes to protein folding.…”

Physicochemical characterization of dual action liposomal formulations: anticancer and antimicrobial

“…Surface charge of the liposome was made positive by incubating the stealth liposome formulations with histone. On incubation protein gets adsorbed on the surface of the liposome [42]. It is reported earlier that neutral and anionic liposomes clear extravasations from the tumor vasculature [43].…”

Design of a novel vaccine nanotechnology-based delivery system comprising CpGODN-protein conjugate anchored to liposomes

“…Geometry of liposomes was observed by cryo-TEM as described previously by others [39][40][41] with minor modifications. For TEM observations, a Jeol Jem F-200 microscope (Jeol, Tokyo, Japan) operating at 200,000 V was used.…”