Current-Volt Biosensing “Cystatin C” on Carbon Nanowired Interdigitated Electrode Surface: A Clinical Marker Analysis for Bulged Aorta

Figure 5

(a) Differences in current response (from blank) for different concentrations of Cystatin C were plotted in an excel sheet, and the limit of Cystatin C detection was calculated in the range between 100 and 200 pg/mL with the R² value of 0.9878. (b) Reproducibility analysis of Cystatin C identification. There are no significant changes in the current response of the bare electrode, APTES, CNW, papain, PEG-NH₂, and Cystatin C with five different electrodes, which confirms the reproducibility of the papain-modified electrode. The figure inset displays the specificity analysis of Cystatin C control experiments with creatinine and gliadin (instead of Cystatin C) conducted to identify the specific detection of Cystatin C on the papain-modified electrode surface. Without Cystatin C and with control protein, no significant changes of current response were noted. Cystatin C was specifically recognised by the immobilized papain.

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