Isolation of Circulating Biomarkers for Liquid Biopsy using Immunoaffinity‐Based Stimuli‐Responsive Hybrid Hydrogel Beads

Abstract

This work presents chemically stable and biodegradable hydrogel beads for the isolation of circulating tumor cells (CTCs) and circulating exosomes in liquid biopsy. The liquid biopsy hydrogel beads ( LB beads) consisting of alginate and poly(vinyl alcohol) hydrogels show both chemical stability and stimuli-degradable characteristics. Unlike single-component hydrogels, this hybrid form is not easily degraded by buffers or cell culture media while its degradable characteristic remains; thus, it is useful in bio-applications requiring multi-step processes with various reagents and lengthy incubation periods. We applied our platform to clinical samples for isolating two promising circulating biomarkers for a liquid biopsy, CTCs and exosomes, by conjugating the hydrogel surface with anti-EpCAM and anti-CD63 antibodies, respectively, thus achieving 37.4 CTCs and comparable amount of exosome recovery per 1 milliliter of blood. The results show easy device-free isolation and retrieval of CTCs and exosomes, with recovered circulating biomarkers successfully analyzed by western blot analysis and fluorescence microscopy. We believe that this simple and versatile platform enables us to isolate prominent circulating biomarkers for clinical use in cancer diagnosis.

Porous PDMS‐Based Microsystem (ExoSponge) for Rapid Cost‐Effective Tumor Extracellular Vesicle Isolation and Mass Spectrometry‐Based Metabolic Biomarker Screening

“…While the bath allows for sufficient oxidation of the surface, it also roughened the surface of the device which increased the surface area without affecting its ability to be further functionalized. [33,34] The surface was then conjugated following previous standard avidin-biotin chemistry [13,24] with optimization. Briefly, PDMS cubes were immersed in silane solution and incubated for an hour.…”

Hydrogel-Based Biosensors

“…Many researchers have been developing different techniques for the isolation and detection of circulating biomarkers. In their 2021 study, Kang et al isolated circulating tumor cells (CTCs) and exosomes from a liquid biopsy [ 31 ]. They generated chemically stable and biodegradable hydrogel beads made of alginate and poly(vinylalcohol), which are advantageous over single component hydrogels, as they can endure multi-step processing and prolonged incubation periods.…”

“… Performance of liquid biopsy hydrogel beads (LBBeads) for circulating tumor cell (CTC) recovery. ( A ) CTC capture performance comparison based on fluorescence intensities using fluorescent cancer cells with three different hydrogel beads; ( B ) CTC recovery performance after capture and release of cancer cells from the beads ( C , D ) Isolated fluorescent MCF-7 cancer cells under fluorescence microscope ( C ) and scanning electron microscope (SEM) ( D ) (Reprinted with permission from [ 31 ]. Copyright 2021 Wiley).…”

Emerging micro-nanotechnologies for extracellular vesicles in immuno-oncology: from target specific isolations to immunomodulation

“…In light of this, the Nagrath group has made considerable progress in addressing the scalability issue through the development of both the ExoSponge and ExoBead, two devices which boast simple, quick, and affordable manufacturing. 93,94 Specificity and preprocessing continue to be hurdles as developing devices make efforts towards immunoaffinity and size-based isolations. 95 Yeo et al contributed to solving these issues by introducing a label-free centrifugal microfluidic device, μCENSE.…”