An electrochemical impedance spectroscopy (EIS) assay measuring the calcification inhibition capacity in biological fluids

作者：Ismail A H^*; Schaefer C; Heiss A; Walter M; Jahnen Dechent W; Leonhardt S

来源：Biosensors and Bioelectronics, 2011, 26(12): 4702-4707.

DOI：10.1016/j.bios.2011.05.028

• Electrochemical impedance spectroscopy
• Calcification
• Fetuin-A
• Calciprotein particles
• Dialysis

Pathological calcification of the cardiovascular system is one of the major causes of high mortality and morbidity in dialysis patients. The inhibition of ectopic calcification relies (I) on the formation of calciprotein particles (CPPs), nanospherical complexes of calcium phosphate mineral, fetuin-A and other acidic serum proteins, and (II) on the stabilization of calcium phosphate prenucleation clusters by fetuin-A monomers. In supersaturated serum, mineral ion aggregation leads to a change in the electrical impedance. In this work, we present a method based on electrochemical impedance spectroscopy (EIS) to establish an impedance trace of mineral ion clustering in vitro. In the presence of 20 mu M of serum protein fetuin-A, a prototypic calcification inhibitor, we measured a change in impedance (Delta(R)) of 195.52 +/- 27.78% Omega compared to 430.41 +/- 11.36% Omega in inhibitor-free samples. We also identified a CPP-formation dependency on the actual content of ions and protein in the samples under investigation. Two-step ripening of CPP was also observed. The presented method may form the basis of a simple label-free bedside or online test to be used in routine clinical practice for estimating the calcification risk in serum.

• 出版日期2011-8-15