title: Label-free quantification of cystatin C as an improved marker for renal failure.
abstract: A label-free biosensor has been developed, allowing quantification of cystatin C in human serum. This was achieved by using reflectometric interference spectroscopy as detection method. Cystatin C is a small serum protein that allows detection of renal failure more reliably than established parameters as creatinine. The protein was immobilized on the surface of a glass transducer, forming the sensitive layer of the sensor chip. Based on a binding-inhibition assay, two different types of monoclonal cystatin C antibodies were compared, by their behavior and their obtained working range in buffer and serum as matrix. Both antibodies allowed quantification of the protein in serum as matrix within the required clinical ranges of 0.53-1.02 mg/L. Detected recovery rates are in a range between 84.8% and 116.1%. The developed sensor shows high inner chip reproducibility and low cross-sensitivity.
authors.affiliation: Institute of Physical and Theoretical Chemistry (IPTC), Eberhard Karls University Tuebingen, Tuebingen, Germany. oliver.bleher@uni-tuebingen.de
authors.forename: Oliver
authors.initials: O
authors.lastname: Bleher
authors.forename: Markus
authors.initials: M
authors.lastname: Ehni
authors.forename: Günter
authors.initials: G
authors.lastname: Gauglitz
mesh_terms: D015415:Biomarkers / Q000097:blood; D015374:Biosensing Techniques; D055316:Cystatin C; D006801:Humans; D051437:Renal Insufficiency / Q000097:blood* / Q000175:diagnosis; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D015415:Biomarkers; D055316:Cystatin C