Abstract:

Objective To construct a highly sensitive electrochemical biosensor for the detection of cytokeratin 19-fragment（CYFRA21-1）. Methods Three-dimensional graphene @gold nanoparticles（3D-G@Au）nanocomposite was modified on glassy carbon electrode surface to enhance the conductivity of electrochemical biosensor. Anti-CYFRA21-1 was captured and fixed on the modified 3D-G@Au glassy carbon electrode through the cross-linking of chitosan and glutaraldehyde. The 3D-G@Au electrochemical biosensor had been completed as to determine CYFRA21-1. The electrochemical and determination performance of successfully constructed 3D-G@Au electrochemical biosensor was evaluated preliminarily. Results The cyclic voltammetry showed that the redox peaks of bare glassy carbon electrode,3D-G modified glassy carbon electrode and 3D-G@Au modified glassy carbon electrode increased gradually,indicating that the 3D-G@Au electrochemical biosensor was successfully constructed. The optimal incubation time of antigen-antibody interaction was 60 min,and the optimal incubation temperature was 35 ℃. CYFRA21-1 was detected by 3D-G@Au electrochemical biosensor,the linear range was 0.1-300.0 ng/mL,and the determination limit was 0.1 ng/mL（signal-to-noise ratio=3）. 10 mmol/L Vit C,10 mmol/L DA and 10 mmol/L UA had no interference to the determination,and the reproducibility was good [relative standard deviations（RSD） were 1.08% and 3.11%], compared with that of chemiluminescence method (RSD was 19.6%-4.78%). The 3D-G@Au electrochemical biosensor can be stable for 30 d at 4 ℃. Conclusions It is potential for the determination of serum CYFRA21-1 with 3D-G@Au electrochemical biosensor.

Key words: Cytokeratin 19-fragment, Three-dimensional graphene, Gold nanoparticle, Electrochemical biosensor