Ultrasensitive Electrochemical Biosensor For Des-gamma-carboxy Prothrombin Analysis Based On Core-shell Pd@PtCu-alloy Loaded On WS₂ Nanosheet

Des-gamma-carboxy pro-thrombin（DCP）is an abnormal form of prothrombin induced by vitamin K absence or antagonist-II.DCP,a powerful biomarker,has great potential in the early diagnosis and prognosis for liver cancer.Therefore,the exploration of highly specific and sensitive detecting DCP method for clinical diagnosis of liver cancer is highly desirable.However,the existing DCP detection methods generally have disadvantages,such as costly instrument,high detection cost,and cumbersome operation,which greatly limit the extensive application of DCP in clinical diagnosis.Herein,a sandwich-type electrochemical biosensor was developed for determination of des-gamma-carboxy prothrombin（DCP）.Core-shell Pd@PtCu loaded on WS₂ nanosheet（Pd@PtCu-WS₂）nanocomposite was lightly synthesized,which possessed large surface area and remarkable peroxidase-like activity,and thus acted as nanocarrier and signal nanoprobe.Secondary DCP antibodies（Ab₂）were then tethered on the surface of the nanocomposite,forming the superior label to product and amplify electrochemical signal.Additionally,gold nanoparticles-functionalized multi-wall carbon nanotubes（Au NPs@MWCNTs）was employed as the electrode matrix,which could accelerate electron transfer and improve the immobilization of primary DCP antibodies（Ab₁）.After the typical sandwich-type recognition,an obvious current response was generated through the reduction of hydrogen peroxide（H₂O₂）.With this strategy,the biosensor revealed ultra-sensitivity ranging from 100 fg m L^-1 to 100 ng m L^-1 with a low limit of detection of 71.6 fg m L^-1.What’s more,it was demonstrated to successfully analyze DCP in clinical serum sample.Therefore,the biosensor provided an alternative tool for clinical biomarker analyses.