Disposable Microfluidic Immunoarray Device for Sensitive Breast Cancer Biomarker Detection.

Breast cancer is the most common cancer in women worldwide. The detection of biomarkers has played a significant role in the early diagnosis and prognosis of breast cancer. Herein, we describe the construction of a disposable microfluidic immunoarray device (DµID) for rapid and low-cost detection of CA15-3 a protein biomarker for breast cancer. The DµID was constructed using a simple and rapid prototyping technique and was applied to detect CA15-3 in cancer patients. The DµID construction was based on a use of double-sided adhesive card with the microfluidic channel and a screen-printed array with 8 electrodes. Both the immunoarray and microfluidic channel were designed using an inexpensive home cutter printer and using low-cost materials. The immunoarray was modified using the layer-by-layer technique aiming at immobilizing the primary antibody. For the biomarker detection, magnetic particles (MPs) modified with polyclonal antibodies and peroxidase enzymes were used as a strategy for capture, separation, and pre-concentration of the biomarker, in addition to amplifying the electroanalytical signal. The pre-concentration and amplification strategies integrated with the nanostructured immunosensors of the DµID contributed meaningfully towards the detection of CA15-3 with a limit of detection (LoD) 6 µU mL-1, requiring as low as 2 µL of serum samples for 8 simultaneous detections. The LoD obtained was 1200 times lower compared to other immunosensors previously reported in the literature. The DµID was applied for the detection of CA15-3 in real samples of breast cancer patients and was found to present excellent correlation with the well-established commercial electrochemiluminescence immunoassay. The association of DµID with nanostructured surfaces and analyte capturing with bioconjugated paramagnetic particles are essentially a promising breakthrough for low-cost and accurate detection of cancer biomarkers.