Affinity-Enhanced CTC-Capturing Hydrogel Microparticles Fabricated by Degassed Mold Lithography

Abstract

Technologies for the detection and isolation of circulating tumor cells (CTCs) are essential in liquid biopsy, a minimally invasive technique for early diagnosis and medical intervention in cancer patients. A promising method for CTC capture, using an affinity-based approach, is the use of functionalized hydrogel microparticles (MP), which have the advantages of water-like reactivity, biologically compatible materials, and synergy with various analysis platforms. In this paper, we demonstrate the feasibility of CTC capture by hydrogel particles synthesized using a novel method called degassed mold lithography (DML). This technique increases the porosity and functionality of the MPs for effective conjugation with antibodies. Qualitative fluorescence analysis demonstrates that DML produces superior uniformity, integrity, and functionality of the MPs, as compared to conventional stop flow lithography (SFL). Analysis of the fluorescence intensity from porosity-controlled MPs by each reaction step of antibody conjugation elucidates that more antibodies are loaded when the particles are more porous. The feasibility of selective cell capture is demonstrated using breast cancer cell lines. In conclusion, using DML for the synthesis of porous MPs offers a powerful method for improving the cell affinity of the antibody-conjugated MPs.

CRISPR‐Enhanced Hydrogel Microparticles for Multiplexed Detection of Nucleic Acids

“…The optimal concentration of crosslinking monomers (PEGDA) was found to be 5% (volume fraction), which produced structurally robust, highly permeable HMPs. [ 24 ] To further validate that HMPs had large enough pores, we incubated particles with fluorescent‐dextran whose molecular weight (150 kDa) was similar to that of Cas12a (145 kDa). The partition coefficient ( K ) was then estimated by taking the fluorescent intensity ratio between HMPs and the bulk solution (Figure S1 , Supporting Information).…”

Advanced Bioresponsive Multitasking Hydrogels in the New Era of Biomedicine

“…A promising method for CTC capture was described using an affinity‐based approach with functionalized hydrogel microparticles (MPs) prepared by the degassed mold lithography (DML) technique, which increases the porosity and functionality of the MPs for effective conjugation with antibodies, e.g., antiepithelial cell adhesion molecule (EpCAM). [ 46 ] Likewise, a micropatterned, immunofunctionalized (anti‐EpCAM), photodegradable PEGdiPDA hydrogel was described as a cytocompatible platform for the capture and selective release of pure, viable CTC‐derived A549 lung cancer cells in blood samples. [ 47 ] The effect of shape on the efficient recovery of CTCs was investigated using an octopus‐inspired hydrogel prepared by micromolding and copolymerization of polyethylene glycol diacrylate (PEGDA) with AAc, to form particles with a photomask defined pattern.…”

Discontinuous Dewetting in a Degassed Mold for Fabrication of Homogeneous Polymeric Microparticles

“…In the case of using a PDMS mold, independent microparticles can be produced despite the presence of a residual layer between the mold and the cover when the precursors are polymerized using free-radical polymerization . Because the effluent oxygen diffusion from the PDMS mold inhibits the polymerization of the residual layer, only the precursor inside the microwell is polymerized. , However, commonly used biomaterials such as agarose, alginate, and hyaluronic acid , are incompatible with this technique since the residual layer between the mold and the cover causes the production of embossed films.…”

“…18 Because the effluent oxygen diffusion from the PDMS mold inhibits the polymerization of the residual layer, only the precursor inside the microwell is polymerized. 19,20 However, commonly used biomaterials such as agarose, 21 alginate, 22 and hyaluronic acid 23,24 are incompatible with this technique since the residual layer between the mold and the cover causes the production of embossed films.…”