A competitive assay for the detection of a 16-mer peptide from α1 chain of human collagen XI

• Published in: Talanta (Oxford) 2022-04, Vol.240, p.123196-123196, Article 123196
• Main Authors: Lorenzo-Gómez, Ramón, Casero-Álvarez, Alfonso, Miranda-Castro, Rebeca, García-Ocaña, Marcos, de los Toyos, Juan R., de-los-Santos-Alvarez, Noemí, Lobo-Castañón, M. Jesús
• Format: Article
• Language: English
• Subjects: 16-Mer telopeptide; Aptamer; Biomarkers, Tumor; Collagen; Collagen XI alpha 1 chain; ECM component; Electrochemical competitive assay; Extracellular Matrix; Humans; Neoepitope; Neoplasms; Peptides
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2021.123196

Characterization of extracellular matrix (ECM) is becoming more and more important to decipher cancer progression. Constant remodeling results in ECM components degradation or unusual ECM accumulation that releases short fragments to the body fluids. These fragments might be potential cancer biomarkers but to detect them specific receptors are needed. In response to this demand, we present the first electrochemical aptamer-based competitive assay for the minor collagen XI, dysregulated in several carcinomas. It was performed on magnetic beads using enzymatic labeling. First, we selected the most appropriate tag for the aptamer (biotin or 6-carboxyfluorescein). The former yielded higher currents by chronoamperometry and it was used for the competitive assay. The collagen fragment, a 16mer peptide used as the target, was detected from 52 to 1000 nM with an RSD of about 5%. The LOD of the assay was estimated as 24 nM (44 ng/mL). The performance of the assay in serum diluted 1:2 was equivalent to the assay in PBS. The detection of α1 chain of human collagen XI was also possible in cell lysates and confirmed by aptacytofluorescence, which is promising as a new tool to validate this fragment as a cancer biomarker. [Display omitted] •Aptamers against a collagen XI alpha chain peptide characterized.•This collagen is dysregulated in many carcinomas.•Aptamer D1 used in an electrochemical competitive magnetoassay•16-mer peptide detected in buffer, serum and cell lysates.•No significant interferences in biological media.