Automated Support-Resolution Strategy for a One-Way Chemiluminescent Multiplex Immunoassay

Paper-based chemiluminescence ELISA: lab-on-paper based on chitosan modified paper device and wax-screen-printing

A novel lab-on-paper device combining the simplicity and low-cost of microfluidic paper-based analytical devices (μPADs) and the sensitivity and selectivity of chemiluminescence ELISA (CL-ELISA) for the high-throughput, rapid, stable and reusable point-of-care testing is presented here. Chitosan was used to modify μPADs to covalently immobilize antibodies on μPADs. Thus, sandwich CL-ELISA on μPADs can be easily realized for further development of this technique in sensitive, specific and low-cost application. The paper device was fabricated by a low-cost, simple, and rapid wax-screen-printing method. Using tumor markers and paper microzone plate as model, the application test of this paper-based CL-ELISA was successfully performed with a linear range of 0.1-35.0 ng mL(-1) for α-fetoprotein, 0.5-80.0 U mL(-1) for cancer antigen 125 and 0.1-70.0 ng mL(-1) for carcinoembryonic antigen. Since the cutoff values of the three tumor markers in clinical diagnosis are 25 ng mL(-1), 35 U mL(-1) and 5 ng mL(-1), the sensitivity and linear ranges of the proposed method were enough for clinical application. In addition, this lab-on-paper immunodevice can provide reproducible results upon storage at 4 °C (sealed) for at least 5 weeks. Ultimately, this novel chitosan modification and wax-screen-printing methodology for μPADs can be readily translated to other signal reporting mechanism including electrochemiluminescence and photoelectrochemistry, and other receptors such as enzyme receptors and DNA receptors for determination of DNA, proteins and small molecules in point-of-care testing.

Multianalyte immunoassay chip for detection of tumor markers by chemiluminescent and colorimetric methods

Most cancers developed an elevation of the level of at least two markers associated with their incidence. Simultaneous detection of multi-tumor markers associated with a particular type of cancer plays an important role in cancer diagnostic. Here, a multianalyte immunoassay chip for simple and sensitive detection of tumor markers with chemiluminescent and colorimetric methods was proposed, in which carcinoembryonic antigen (CEA) and carbohydrate antigen (CA19-9) that associated with colorectal cancer were detected as model. The immunoassay chip was fabricated by co-immobilization of CEA/CA19-9 antibody on a glass slide with γ-glycidoxypropyltrimethoxysilane as linkage. Through sandwiched immunoreactions, CEA, CA19-9, and their corresponding enzyme tracers, alkaline phosphatase-labeled anti-CEA and horseradish peroxidase-labeled anti-CA19-9, were introduced on the chip. Then, they were sequentially detected by chemiluminescent method in the range of 0.5-80 μg/L and 0.5-80 kU/L with the detection limits of 0.41 μg/L and 0.36 kU/L at 3σ for CEA and CA19-9, respectively. They could also be detected by colorimetric method in the range of 1-200 μg/L and 5-200 kU/L with the detection limits of 0.25 μg/L and 1.25 kU/L at 3σ for CEA and CA19-9, respectively. All these results demonstrated that the present work provided a promising analytical method for tumor markers' analysis with the advantages of simple analytical procedure, small sample volume and lower cost, which made the proposed method potential for high-throughput detection.