Isolation of Exosomes from Human Serum Using Gold-Nanoparticle-Coated Silicon Surface

Abstract

Exosomes, whose mean diameter ranges from 20 nm to 200 nm, are cell-secreted vesicles and are abundant in most biological fluids, such as blood, urine, tears, sweat, breast milk, etc. Exosomal size variations and their composition can be attributed to several factors, such as age, gender and disease conditions of the individual. Existing techniques, such as ultracentrifugation and density gradient ultracentrifugation, for exosome isolation are instrument-dependent, time-consuming and lack specificity. In the present work, a gold-nanoparticle (GNP)-coated silicon (Si) wafer, functionalized with polyethylene glycol (PEG) was used for conjugation with anti-CD63 antibody via EDC NHS chemistry and incubated with serum to immobilize the exosomes on the Si surface. The surface-immobilized exosomes were eluted and quantified by a nanoparticle tracking analyzer (NTA). It was observed that an increase in GNP density on the Si wafer increases the size range and total number of exosomes that are being isolated. Western blotting performed for proteins such as HSP 70 and calnexin confirmed the immobilization and elution of exosomes. The proposed technique can be used as an alternative to existing techniques, as it has several benefits such as reusability of the Si surface for several isolations, minimal instrumental requirement, isolation of exosomes in two hours and compatibility with the microfluidic platform, making the technique suitable for real-time application. The proposed method could be useful in isolating a specific subrange of exosomes by altering the size of the GNP used for coating the Si wafer.

Biogenesis, Isolation, and Detection of Exosomes and Their Potential in Therapeutics and Diagnostics

“…The elaborated schematic representation of the fabrication of Si wafer surface for immobilizing exosomes is depicted in Figure 15 . The advantage of the proposed technique could be the reusability of the Si wafer, and it also allows for the isolation of other sub-ranges of exosomes by altering the size of NPs [ 175 ]. Microfluidic technology is a powerful tool to design and develop lab-on-chip biosensors for the efficient detection and isolation of exosomes.…”

Lens epithelial cell‐derived exosome inhibits angiogenesis in ocular pathological neovascularization through its delivery of miR‐146a‐5p

“…Exosome, a subtype of extracellular vesicles with 20-200 nm diameter, can be secreted by almost all cells and be internalized by target cells. 14 As signal carriers, exosome contains biological information (proteins, lipids, or RNAs) for signal transmission between cells, mediating physiological or pathological processes. [15][16][17] In the recent years, considering its low immunogenicity, high biocompatibility, and targeting ability, exosome has attracted much attention and its application in treating retinal diseases has been investigated.…”

“…Exosome, a subtype of extracellular vesicles with 20–200 nm diameter, can be secreted by almost all cells and be internalized by target cells 14 . As signal carriers, exosome contains biological information (proteins, lipids, or RNAs) for signal transmission between cells, mediating physiological or pathological processes 15–17 .…”