A universal stimuli-responsive biosensor for disease biomarkers through their cysteine residues: A proof of concept on carcinoembryonic antigen (CEA) biomarker.

Carcinoembryonic antigen (CEA) is the gold standard biomarker for the clinical diagnosis of cancers diseases. Accurate, fast, and sensitive screening of CEA plays an important role in cancer disease detection and prognosis. This work reports the development of a new stimuli-responsive biosensor that determines the CEA blood plasma concentration within 10 min. Tert-butyl carbonate Naphthalene-flanked diketopyrroloprrole (mono-TBC-DPPN) fluorescent agent was synthesised, characterised and immobilised gold nanoparticles to develop the stimuli-responsive sensor. The target protein was purified from spiked plasma (from human blood), using an antibody-coated gold substrate. The purified CEA was then chemically modified to provide thiol groups (SH) that interact with the mono-TBC-DPPN on the surface of the stimuli-responsive biosensor to spontaneously displace it, thus leading to its fluorescence emission at 532 nm to a turn on. The new method and sensor was implemented to quantify CEA in spiked blood plasma down to 10 pg.mL−1 within 45 min (35 min for the protein purification and modification and 10 min for its quantification using the sensor) [Display omitted] • New stimuli-responsive probe for the fluorescence detection of CEA. • The probe is utilised in a new paper sensor to screen CEA down to 10 pg.mL−1. • The cysteine residues of CEA stimulate the probe desorption and its FL turn on. • A new method to purify and quantify CEA in blood within 45 min. • The sensor can be extended to screen many cysteine-containing biomarkers. [ABSTRACT FROM AUTHOR]