Herceptin functionalized microfluidic polydimethylsiloxane devices for the capture of human epidermal growth factor receptor 2 positive circulating breast cancer cells

Abstract

Building on recent breakthroughs in the field of microfluidic-based capture of rare cancer cells circulating in the blood, the present article reports on the use of Herceptin functionalized PDMS devices designed to efficiently capture from blood cancer cells, overexpressing the tyrosine kinase human epidermal growth factor receptor (HER2). The identification of patients overexpressing HER2 is critical as it typically associates with an aggressive disease course in breast cancer and poor prognosis. Importantly, HER2 positive patients have been found to significantly benefit from Herceptin (Trastuzumab), a humanized monoclonal antibody (MAb) against HER2. Disposable PDMS devices prepared using standard soft lithography were functionalized by the plasma polymerization of an epoxy-containing monomer. The epoxy-rich thin film (AGEpp) thus created could be conjugated with Herceptin either directly or through a polyethylene glycol interlayer. The properties and reactivity toward the monoclonal antibody conjugation of these coatings were determined using x-ray photoelectron spectroscopy; direct conjugation provided a good compromise in reactivity and resistance to biologically nonspecific fouling and was selected. Using the breast cancer cell line SK-BR-3 as a model for cells overexpressing HER2, the immunocapture efficacy of the Herceptin functionalized PDMS was demonstrated in model studies. Validation studies confirmed the ability of the device to efficiently capture (∼80% capture yield) HER2 positive cells from full blood.

PEGylation of magnetic poly(glycidyl methacrylate) microparticles for microfluidic bioassays

“…Covalent binding through PEG can result in enhanced steric accessibility of bioligand 55,67 , but, on the other hand, it can also reduce grafting density compared to immobilization on neat surface 68 . In this study, the model enzyme (HRP) was immobilized on the microspheres modified by heterobifunctional HO-PEG 3,400 -NH 2 .…”

Selective cell capture and analysis using shallow antibody-coated microchannels

“…This rate is relatively lower than the capture rate of a micropillar array, which is near 90%. 18 One of the possible reasons for the discrepancy is that SK-BR-3 cell size is not homogeneous; therefore, relatively small cells passed through the shallow channel. To prevent this, a combination of cell separation methods before capture may be a powerful way to enhance target cell capture in the shallow channel structure.…”

“…Fluorescence-activated cell sorting (FACS) is a widely used method that has recently been integrated on microchips. 13,14 There have also been several reports on cell-selective structures based on antibody-coated micropillars, [15][16][17][18] herringbone structures, 19 or aptamer-coated flat microchannels 20 or micropilars. 21 Although these methods achieve high selective capture rates, it is difficult to securely capture the desired cells in the target area because capture depends on the likelihood of collisions between cells and capturing molecules.…”

Protein immobilization techniques for microfluidic assays

“…106 A common epoxide functional group used in protein immobilization is glycidyl. 96,172,180,181 Thierry et al reported epoxide-based capture of tyrosine-kinase human epidermal growth factor receptor (HER2) on PDMS microfluidic devices. 181 They coated a PDMS microchannel and the surface of a glass substrate using a pulsed plasma polymerization of allyl glycidyl ether (AEG) monomer (Figure 9).…”

“…96,172,180,181 Thierry et al reported epoxide-based capture of tyrosine-kinase human epidermal growth factor receptor (HER2) on PDMS microfluidic devices. 181 They coated a PDMS microchannel and the surface of a glass substrate using a pulsed plasma polymerization of allyl glycidyl ether (AEG) monomer (Figure 9). 172 The authors reasoned that a common epoxidation reagent GOPTS (3-glycidoxypropyltrimethoxysilane) was unstable owing to hydrolysis, but pulsed plasma yielded a conformal, adherent, defect-free glycidyl coatings on the surface.…”