Tracking Drug‐Induced Epithelial–Mesenchymal Transition in Breast Cancer by a Microfluidic Surface‐Enhanced Raman Spectroscopy Immunoassay

Abstract

Epithelial–mesenchymal transition (EMT) is a primary mechanism for cancer metastasis. Detecting the activation of EMT can potentially convey signs of metastasis to guide treatment management and improve patient survival. One of the classic signatures of EMT is characterized by dynamic changes in cellular expression levels of E‐cadherin and N‐cadherin, whose soluble active fragments have recently been reported to be biomarkers for cancer diagnosis and prognosis. Herein, a microfluidic immunoassay (termed “SERS immunoassay”) based on sensitive and simultaneous detection of soluble E‐cadherin (sE‐cadherin) and soluble N‐cadherin (sN‐cadherin) for EMT monitoring in patients' plasma is presented. The SERS immunoassay integrates in situ nanomixing and surface‐enhanced Raman scattering readout to enable accurate detection of sE‐cadherin and sN‐cadherin from as low as 10 cells mL−1. This assay enables tracking of a concurrent decrease in sE‐cadherin and increase in sN‐cadherin in breast cancer cells undergoing drug‐induced mesenchymal transformation. The clinical potential of the SERS immunoassay is further demonstrated by successful detection of sE‐cadherin and sN‐cadherin in metastatic stage IV breast cancer patient plasma samples. The SERS immunoassay can potentially sense the activation of EMT to provide early indications of cancer invasions or metastasis.

EndoScreen Chip: Serum Complement C9 Immunoassays Improve Risk Prediction and Early Diagnosis of Esophageal Adenocarcinoma

“…The microfluidic device was fabricated using standard photolithography and according to a previous report [23]. Briefly, the EndoScreen Chip with an asymmetric electrode array was fabricated on a borosilicate glass substrate.…”

“…The device was then connected to a signal generator 333510B (Agilent Technologies, Australia). Incubation of the sample was carried out under an applied alternating current electrohydrodynamics (ac-EHD) nanomixing (f=500Hz, Vpp=800 mV, t= 30 min) protocol that we have previously developed to improve detection specificity and sensitivity [23]. Next, the wells were washed with wash buffer (0.1% BSA, 0.01% Tween-20 in PBS) and incubated with 20 µL of SERS nanotags under the same ac-EHD conditions as above, but for 20 min.…”

Amplification-Free SARS-CoV-2 Detection Using Nanoyeast-scFv and Ultrasensitive Plasmonic Nanobox-Integrated Nanomixing Microassay

“…The gold microelectrode array was fabricated on a 4-inch glass substrate by photolithography. 28 For the functionalization, S309 nanoyeast-scFvs were conjugated to the gold microelectrode array via affinity pull down using anti-HA antibody. A solution of 4 mg/mL dithiobis(succinimidyl propionate) (DSP) in dimethyl sulfoxide was incubated on the gold electrodes for 30 min at room temperature.…”

Development of EndoScreen Chip, a Microfluidic Pre-Endoscopy Triage Test for Esophageal Adenocarcinoma

“…The microfluidic device was fabricated using standard photolithography and according to a previous report [28]. Briefly, the EndoScreen Chip with an asymmetric electrode array was fabricated on a borosilicate glass substrate.…”

“…The device was then connected to a signal generator 333510B (Agilent Technologies, Mulgrave, Australia). Incubation of the sample was carried out under an applied alternating current electrohydrodynamics (ac-EHD) nanomixing (f = 500 Hz, Vpp = 800 mV, t = 30 min) protocol that we have previously developed to improve detection specificity and sensitivity [28]. Next, the wells were washed with wash buffer (0.1% BSA, 0.01% Tween-20 in PBS) and incubated with 20 µL of SERS nanotags under the same ac-EHD conditions as above, but for 20 min.…”