title: Label-free quantification of Tacrolimus in biological samples by atomic force microscopy.
abstract: In the present paper we describe an atomic force microscopy (AFM)-based method for the quantitative analysis of FK506 (Tacrolimus) in whole blood (WB) samples. Current reference methods used to quantify this immunosuppressive drug are based on mass spectrometry. In addition, an immunoenzymatic assay (ELISA) has been developed and is widely used in clinic, even though it shows a small but consistent overestimation of the actual drug concentration when compared with the mass spectrometry method. The AFM biosensor presented herein utilises the endogen drug receptor, FKBP12, to quantify Tacrolimus levels. The biosensor was first assayed to detect the free drug in solution, and subsequently used for the detection of Tacrolimus in blood samples. The sensor was suitable to generate a dose-response curve in the full range of clinical drug monitoring. A comparison with the clinically tested ELISA assay is also reported.
authors.affiliation: Department of Biomolecular Sciences, University of Urbino "Carlo Bo" via Saffi 2, Urbino, Italy. Electronic address: michele.menotta@uniurb.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Menotta
authors.affiliation: Department of Biomolecular Sciences, University of Urbino "Carlo Bo" via Saffi 2, Urbino, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Biagiotti
authors.affiliation: Physics Laboratory, CNRS-ENS, UMR 5672, Lyon, France; Cell and Molecular Biology Laboratory, CNRS-ENS Lyon, UMR 5239, IFR128, Lyon, France.
authors.forename: Laura
authors.initials: L
authors.lastname: Streppa
authors.affiliation: Department of Biomolecular Sciences, University of Urbino "Carlo Bo" via Saffi 2, Urbino, Italy.
authors.forename: Luigia
authors.initials: L
authors.lastname: Rossi
authors.affiliation: Department of Biomolecular Sciences, University of Urbino "Carlo Bo" via Saffi 2, Urbino, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Magnani
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood; D018625:Microscopy, Atomic Force / Q000379:methods*; D016559:Tacrolimus / Q000097:blood* / Q000276:immunology / Q000378:metabolism; D022061:Tacrolimus Binding Protein 1A / Q000235:genetics / Q000378:metabolism
chemical_list: D007166:Immunosuppressive Agents; D022061:Tacrolimus Binding Protein 1A; D016559:Tacrolimus
keywords: Atomic force microscopy; FK506; Label free; Tacrolimus