Ultrasensitive detection of anti-p53 autoantibodies based on nanomagnetic capture and separation with fluorescent sensing nanobioprobe for signal amplification

• Published in: Biosensors & bioelectronics Vol. 170; p. 112640
• Main Authors: Adeniyi, Omotayo K., Ngqinambi, Akhona, Mashazi, Philani N.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.12.2020
• Subjects: alkaline hydrolysis; anti-p53 autoantibody; Autoantibodies; Bioconjugated nanomagnetic particles; biomarkers; Biosensing Techniques; blood serum; Cancer biomarker; carcinogenesis; detection limit; FITC-fluorescence nanobioprobe; fluorescence; Gold; Humans; immune response; Immunoassay; immunosensors; Limit of Detection; Metal Nanoparticles; Nanomagnetic capture beads; neoplasms; silica; Silicon Dioxide; Tumor Suppressor Protein p53; Cancer biomarker; Nanomagnetic capture beads; Bioconjugated nanomagnetic particles; FITC-fluorescence nanobioprobe; anti-p53 autoantibody
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2020.112640

The detection of biomarkers expressed at early onset of carcinogenesis, hold promise for the identification of subjects with a preclinical malignant tumor. However, these biomarkers exist in bodily fluids at an ultra-low concentration. Therefore, ultrasensitive techniques are required for their detection. This work investigated the detection of anti-p53 autoantibodies (anti-p53aAbs) using nanomagnetic beads capture probe and anti-IgG functionalized-fluorescence nanoparticles as the detection probe. Specificity was achieved by the use of human p53 protein (p53Ag) immobilized onto nanomagnetic beads, blocked with BSA (MB-p53Ag/BSA) for capture and separation. Anti-IgG antibody conjugated FITC-doped silica nanoparticles (FITC@SiO2–NH2-anti-IgGNPs) used as the sensing nanobioprobe. The target anti-p53aAbs from human serum samples is selectively isolated and purified using the MB-p53Ag/BSA. A sandwich-type immunoreaction was achieved via the Fc-specific FITC@SiO2–NH2-anti-IgG binding to the captured anti-p53aAbs. The alkali hydrolysis of the FITC@SiO2–NH2-anti-IgG released FITC molecules, leading to an amplified fluorescence detection signal. The analytical performance evaluated using the FITC@SiO2–NH2-anti-IgGNPs as sensing nanobioprobe, MB-p53Ag/BSA as a nanomagnetic bead, and microwell ELISA plate, MTP-p53Ag/BSA were compared. The proposed immunosensor exhibited linear correlation in two concentration ranges from 1.50 to 500 pg mL−1 and from 0.50 to 100 ng mL−1. The limit of detection (LoD) and limit of quantification were calculated from the lower linear concentration range close to zero (1.50–500 pg mL−1) following a method reported in literature. The LoD was found to be 1.49 pg mL−1 and the limit of quantification was 3.81 pg mL−1. For the microwell ELISA plate assay, the LoD was 42.0 pg mL−1 and the linear range was 1.60–100 ng mL−1. The nanomagnetic capture-based assay time was 50 min, which is quicker than 3 h needed for the microwell ELISA plate assay. •Ultrasensitive detection of anti-p53 autoantibodies (anti-p53aAbs) is accomplished with limit of detection in pg.mL−1 range.•Nanomagnetic beads as antibody capture and anti-IgG functionalized fluorescence nanoparticles as the detection nanobioprobe.•Signal enhancement was achieved by the dissolution of the fluorescent silica nanobioprobes releasing the encapsulated FITC molecules.•The nanomagnetic capture-based assay time was 50 min and less than 3 h for the microwell ELISA plate assay.