Immuno-modified superparamagnetic nanoparticles via host–guest interactions for high-purity capture and mild release of exosomes

Abstract

The study of exosomes has great significance for cancer diagnosis and prognosis, in which damage-free isolation of exosomes is a critically important step due to their extremely low concentration in body fluids. Herein, immunoaffinitive superparamagnetic nanoparticles (IS-NPs) were successfully constructed by combining antibodies with superparamagnetic nanoparticles through host-guest interactions between β-cyclodextrin (β-CD) and 4-aminoazobenzene (AAB). Exosomes in cell-culture supernatants or body fluids can be efficiently captured by IS-NPs and then mildly eluted by competitive host molecules, α-CD. Approximately 80% of the exosomes were captured by the IS-NPs from the model samples containing varied concentrations of exosomes (10-10 exosomes per mL). After elution, the release efficiency of the captured exosomes was as high as 86.5%, as calculated from the extracted RNA content. A comparison between the exosomes isolated by our IS-NPs, conventional ultracentrifugation (UC), polyethylene glycol (PEG)-based precipitation, and a commercial kit was conducted to examine the performance of the IS-NP exosome isolation. The particle-to-protein ratio of IS-NP captured exosomes (8.8 ± 1.3 × 10) was eight-fold higher than that of the UC (1.1 ± 0.4 × 10) and more than two-fold that of the PEG-based precipitation (3.7 ± 0.8 × 10) and commercial kit (3.2 ± 0.8 × 10) isolated ones, revealing that IS-NPs yielded more exosomes with higher purity than all the other three approaches. Cellular uptake experiments demonstrated that the exosomes captured by IS-NPs have retained their structural and functional integrities, and their broad applications in biomedical areas could therefore be expected. Promisingly, this host-guest interaction involving immunoaffinity magnetic particle system could offer a new way for fast, high-efficiency and high-purity exosome isolation and elution, further benefitting exosomes' applications in desired areas.

The significance of exosomes in the development and treatment of hepatocellular carcinoma

“…The isolation of exosomes mainly involves5 methods, which include differential ultracentrifugation [44,45], polyethylene glycol (PEG) precipitation [46,47], sucrose and iodixanol density ultracentrifugation [38], immunoaffinity (IAC) capture [48], and size exclusion chromatography [49,50]. In this review, we mainly introduced differential ultracentrifugation, as it is considered as gold standard for isolating exosomes [51].…”

Leukocyte‐Repelling Biomimetic Immunomagnetic Nanoplatform for High‐Performance Circulating Tumor Cells Isolation

“…Negatively charged MNs with excellent superparamagnetic property (magnetic saturation value 57.2 emu g −1 , Figure J) were prepared through hydrothermal method . Modified with positively charged polyethyleneimine (PEI) and negatively charged carboxylated graphene nanosheet (G), the surface potential of the nanoparticles changed from −20.7 to +36.3 and −10.8 mV successively.…”

“…Construction and Characterization of BMNs : The citrate‐coated MNs were synthesized through hydrothermal method . Fabrication of the BMNs was carried out with the LbL assembly method.…”

Proteomic Analysis of Exosomes for Discovery of Protein Biomarkers for Prostate and Bladder Cancer

“…Affinity isolation ( Figure 1 E) is based on the strong binding affinity of immobilized molecules to specific ligands on the exosome surface. Most immunocapture assays use monoclonal antibodies immobilized on a solid-phase (e.g., magnetic beads) to capture EVs that expose a specific ligand [ 57 , 58 , 59 , 60 ]. Other affinity isolation methods use chemical affinity [ 61 , 62 ] or annexin A5 which binds to phosphatidylserine moieties on the surface of most EVs [ 63 ].…”