title: Strategies for the development of an electrochemical bioassay for TNF-alpha detection by using a non-immunoglobulin bioreceptor.
abstract: TNF-α is an inflammatory cytokine produced by the immune system. Serum TNF-α level is elevated in some pathological states such as septic shock, graft rejection, HIV infection, neurodegenerative diseases, rheumatoid arthritis and cancer. Detecting trace amount of TNF-α is, also, very important for the understanding of tumor biological processes. Detection of this key biomarker is commonly achieved by use of ELISA or cytofluorimetric based methods. In this study the traditional optical detection was replaced by differential pulse voltammetry (DPV) and an affinity molecule, produced by evolutionary approaches, has been tested as capture bioreceptor. This molecule, namely a combinatorial non-immunoglobulin protein (Affibody®) interacts with TNF-α selectively and was here tested in a sandwich assay format. Moreover magnetic beads were used as support for bioreceptor immobilization and screen printed carbon electrodes were used as transducers. TNF-α calibration curve was performed, obtaining the detection limit of 38pg/mL, the quantification range of 76-5000pg/mL and RSD%=7. Preliminary results of serum samples analysis were also reported.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Firenze, Italy; Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara, Turkey.
authors.forename: Gozde
authors.initials: G
authors.lastname: Baydemir
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Firenze, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bettazzi
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Firenze, Italy. Electronic address: ilaria.palchetti@unifi.it.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Palchetti
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Firenze, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Voccia
mesh_terms: D000906:Antibodies / Q000276:immunology / Q000378:metabolism; D001667:Binding, Competitive; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002352:Carrier Proteins / Q000378:metabolism*; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008280:Magnetics; D008863:Microspheres; D011485:Protein Binding; D015203:Reproducibility of Results; D020349:Surface Plasmon Resonance; D014159:Transducers; D014409:Tumor Necrosis Factor-alpha / Q000097:blood* / Q000276:immunology / Q000378:metabolism
chemical_list: D000906:Antibodies; D002352:Carrier Proteins; D014409:Tumor Necrosis Factor-alpha
keywords: Affibody®; Electrochemical detection; Magnetic beads; TNF-α