title: Construction and validation of a Sambucus nigra biosensor for cancer-associated STn antigen.
abstract: A label-free electrochemical impedance spectroscopy biosensor for selective detection and discrimination of the cancer-associated sialyl-Tn (STn) antigen was developed by using Sambucus nigra agglutinin type I (SNA-I) as the recognition element. The SNA-I biosensor was constructed by immobilizing the lectin on screen-printed gold electrodes. The formation of a complex between SNA-I and STn-containing glycoproteins (transferrin and bovine submaxillary mucin) was monitored by measuring the impedance increase of the biosensor. The increase in electron transfer resistance was linearly proportional to the concentration of the glycoproteins up to 70 ng of transferrin and 40 ng of bovine submaxillary mucin, with a limit of detection of 20 ng for transferrin. Albumin, the most abundant serum protein, did not interfere in the detection of the STn-glycoproteins up to a concentration of 0.2 mg ml(-1). The developed lectin-based biosensor was used to evaluate the STn-expression in serum samples and discriminate samples from healthy individuals and patients with different types of malignant tumors, mostly carcinomas, where the increased expression of STn aberrant glycans is well established. This work demonstrates the feasibility of employing SNA-I to selectively recognize the STn epitope in glycoproteins and the use of the constructed biosensor was effective in the analysis of serum samples with the ability to discriminate in a fast way between cancer and healthy status. The proposed biosensor could be used for high-throughput, label-free profiling of the cancer-associated STn glycan expression in serum for diagnosis and therapy monitoring.
authors.affiliation: Centre of Chemical Research, Autonomous University of Hidalgo State, Carr. Pachuca-Tulancingo km 4.5, 42076 Pachuca, Hidalgo, Mexico. Electronic address: mluisasilva@portugalmail.pt.
authors.forename: M Luísa S
authors.initials: ML
authors.lastname: Silva
authors.affiliation: Centre of Chemical Research, Autonomous University of Hidalgo State, Carr. Pachuca-Tulancingo km 4.5, 42076 Pachuca, Hidalgo, Mexico.
authors.forename: Evelin
authors.initials: E
authors.lastname: Gutiérrez
authors.affiliation: Centre of Chemical Research, Autonomous University of Hidalgo State, Carr. Pachuca-Tulancingo km 4.5, 42076 Pachuca, Hidalgo, Mexico.
authors.forename: José A
authors.initials: JA
authors.lastname: Rodríguez
authors.affiliation: Institute of Molecular Pathology and Immunology of the University of Porto - IPATIMUP, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Gomes
authors.affiliation: Institute of Molecular Pathology and Immunology of the University of Porto - IPATIMUP, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal; Medical Faculty of the University of Porto, Alameda Prof. Hernâni Monteiro, 4200-465 Porto, Portugal.
authors.forename: Leonor
authors.initials: L
authors.lastname: David
mesh_terms: D015295:Antigens, Tumor-Associated, Carbohydrate / Q000097:blood* / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000097:blood* / Q000378:metabolism; D015374:Biosensing Techniques / Q000295:instrumentation*; D058266:Dielectric Spectroscopy; D004867:Equipment Design; D006046:Gold / Q000737:chemistry; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism*; D057230:Limit of Detection; D009369:Neoplasms / Q000097:blood* / Q000175:diagnosis; D037121:Plant Lectins / Q000378:metabolism*; D054788:Ribosome Inactivating Proteins / Q000378:metabolism*; D027924:Sambucus nigra / Q000378:metabolism
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D014408:Biomarkers, Tumor; D055767:Immobilized Proteins; D037121:Plant Lectins; C050600:Sambucus nigra lectins; C055491:sialosyl-Tn antigen; D006046:Gold; D054788:Ribosome Inactivating Proteins
keywords: Biosensors; Cancer; STn antigen; Sambucus nigra agglutinin; Screen-printed electrodes