Electrokinetic elucidation of the interactions between persistent luminescent nanoprobes and the binary apolipoprotein-E/albumin protein system

• Published in: Analyst (London) Vol. 146; no. 17; pp. 5245 - 5254
• Main Authors: Ramírez García, Gonzalo, d'Orlyé, Fanny, Richard, Cyrille, Mignet, Nathalie, Varenne, Anne
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 07.09.2021
• Subjects: Affinity; Apolipoproteins; Biomedical materials; Blood-brain barrier; Business competition; Chemical Sciences; Electrokinetics; Material chemistry; Nanoparticles; Nanosensors; Proteins; Serum albumin; Serum proteins
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/d1an00781e

The affinity between functional nanoparticles (NPs) and proteins could determine the efficacy of nanoprobes, nanosensors, nanocarriers, and many other devices for biomedical applications. Therefore, it is necessary to develop analytical strategies to accurately evaluate the magnitude of these protein corona interactions in physiological media. In this work, different electrokinetic strategies were implemented to accurately determine the interactions between PEGylated ZnGa 1.995 Cr 0.005 O 4 persistent luminescent NPs (ZGO-PEG) and two important serum proteins: human serum albumin (HSA), the most abundant serum protein, and apolipoprotein-E (ApoE), associated with the active transport of NPs through the blood-brain barrier. Firstly, the injection of ZGO-PEG in a background electrolyte (BGE) containing individual proteins allowed an affinity study to separately characterize each NP-protein system. Then, the same procedure was applied in a buffer containing a mixture of the two proteins at different molar ratios. Finally, the NPs were pre-incubated with one protein and thereafter electrokinetically separated in a BGE containing the second protein. These analytical strategies revealed the mechanisms (comparative, cooperative or competitive systems) and the magnitude of their interactions, resulting in all cases in notably higher affinity and stability between ZGO-PEG and ApoE ( K a = 1.96 ± 0.25 × 10 10 M −M ) compared to HSA ( K a = 4.60 ± 0.41 × 10 6 M −M ). For the first time, the inter-protein ApoE/HSA interactions with ZGO-PEG were also demonstrated, highlighting the formation of a ternary ZGO-PEG/ApoE/HSA nanocomplex. These results open the way for a deeper understanding of the protein corona formation, and the development of versatile optical imaging applications for ZGO-PEG and other systemically delivered nanoprobes ideally vectorized to the brain. The interactions between NPs and a binary system of proteins were studied through a systematic set of capillary electrophoresis models. The results revealed precise details of the soft and hard protein corona formation and dynamics.