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Disposable electrochemical immunosensor for analysis of cystatin C, a CKD biomarker

Lopes, Paula, Costa-Rama, Estefanía, Beirão, Idalina, Nouws, Henri P.A., Santos-Silva, Alice, Delerue-Matos, Cristina
Talanta 2019 v.201 pp. 211-216
biomarkers, blood serum, cost effectiveness, detection limit, diagnostic techniques, electrochemistry, electrodes, immunoassays, immunosensors, kidney diseases, monitoring, patients, risk
Specific monitoring of cystatin C (CysC) levels in biological fluids is critical for diagnosis, treatment and mechanistic understanding of a spectrum of diseases, particularly chronic kidney disease (CKD). Despite evidences that CysC correlates with the high risk and/or progression of CKD, its use in clinical practice is still scarce. In this context, we report the development of a simple and sensitive immunosensor for the detection of CysC. The biosensor combines the technology of cost-effective screen-printed electrodes with the high specificity of a sandwich immunoassay. Optimized conditions showed that the sensor operates in a linear range between 10 and 100 ng mL−1, with a detection limit and a sensitivity of 6.0 ng mL−1 and 6.4 ± 0.3 μA ng mL−1 cm−2, respectively. Moreover, the sensor provided precise results (RSD ≤ 6.2%) and the quantification of CysC in CKD serum samples revealed to be in agreement with the values obtained by a particle-enhanced nephelometric immunoassay. In this light, the proposed immunosensor qualifies for clinical application, constituting a step forward in the development of fast, sensitive and cost-effective diagnostic tools that can improve the current medical care settings of CKD patients.