A Novel Poly(cytosine)-Based Electrochemical Biosensor for Sensitive and Selective Determination of Guanine in Biological Samples
Melaku Metto, Alemu Tesfaye, Minaleshewa Atlabachew, Atakilt Abebe, Tihunie Fentahun, Abaineh Munshea
Abstract
High Resolution Image Download MS PowerPoint Slide The novel poly(cytosine)-modified glassy carbon electrode-based electrochemical sensor was fabricated potentiodynamically for the detection of Guanine (G) in clinical and biological samples. The surface of the electrode was successfully activated by electropolymerization, and about a 7.5-fold current improvement due to modification was achieved. From the analysis of the dependence of peak current and peak potential on a scan rate, a higher R 2 for the peak current on the square root of scan rate ( R 2 = 0.999) than the dependence of peak current on scan rate ( R 2 = 0.982) indicated that the oxidation of G at poly(cytosine)/GCE was predominantly diffusion controlled. The oxidative peak response of the electrode revealed a high linear range of G concentration (0.1–200 μM) under optimized conditions. The detection limit and limit of quantification were 6.10 and 20.13 nM, respectively, associated with the %RSD of under 1%. The validation of the developed electrochemical sensor for the determination of G was investigated by analyzing human urine DNA and serum samples with spike recovery results in the range of 98.20–103.70% with the interferent recovery percentage in the range of 97.86–103.10% containing 50–300% of potential interferents. The newly designed sensor demonstrated the highest level of performance for the G detection in real samples.