Kirigami paper-based colorimetric immunosensor integrating smartphone readout for determination of humoral autoantibody immune response

Abstract

Ultrasensitive, rapid, and low-cost paper-based immunodevice integrating a smartphone platform to detect ultra-low concentrations of tumour-specific anti-p53 autoantibodies (anti-p53aAbs) in human serum samples was developed. The immunodevice was fabricated based on the principles of kirigami (paper cutting and pasting art). It consisted of hydrophilic paper discs sandwiched between a superhydrophobic paper basement and polyethylene terephthalate-ethylene vinyl acetate (PET-EVA) laminate to delineate the sensing discs. The human p53 antigen (p53Ag) was covalently immobilized onto the pre-functionalized paper disc and used as the biorecognition element to capture anti-p53aAbs in human serum samples. The Fe3O4@SiO2-prNH2-Au@Pd0.30NPs-anti-IgG immunonanoprobes were used as the catalytic label for substrate (TMB/H2O2) oxidation, which generates blue colourimetric spots on the paper sensor. A smartphone installed on a custom-made imaging photo box equipped with colour analysis software was used as a reader to capture and quantitatively analyze the images. The immunodevice exhibited a linear increase in the colour pixel intensity with increasing concentrations of anti-p53aAbs from 10 pg.mL−1 to 25.0 ng.mL−1, with a sensitivity of 1.05 pixel.mL.pg−1 and a detection limit of 3.1 pg.mL−1. The fabricated proof-of-concept immunodevice could provide a simple, affordable, and minimally invasive method for cancer diagnosis at point-of-care.