Haiyan Wang,Chunling Qi,Wenhuan He,Minghui Wang,Wenjing Jiang,Huanshun Yin,Shiyun Ai
A novel, simple and sensitive photoelectrochemical (PEC) immunosensing platform was constructed for detecting N 6 -methyladenosine (m 6 A) based on the carboxylated CN and avidin functionalized [email protected] 2 (ARS) nanocomposite . Herein, the N 6 -methyladenosine-5′-triphosphate (m 6 ATP) was selected as the detection target molecule, m 6 A antibody was used as recognition unit for m 6 A, the carboxylated g-C 3 N 4 (CN) was not only used as the photoactive substance, but the substrate for the m 6 A antibody immobilization , ARS was synthesized and used as signal amplification unit to improve the photocurrent of CN, Phos-tag-biotin was employed as bridge of m 6 ATP and [email protected] 2 through the specific interaction between phosphate group of m 6 ATP and Phos-tag, biotin and avidin, respectively. Under the optimal condition, the fabricated PEC biosensor showed a linear range of 0.01–10 nM and high detection sensitivity with low detection limit of 3.23 pM for m 6 ATP. Besides, the developed strategy was also successfully applied to evaluate the content of m 6 A in human serum samples.
Yeru Liu,Sisi Si,Shengyi Dong,Bozhi Ji,Huimin Li,Song Liu
In this work, an ultrasensitive and low-cost electrochemical immunosensor has been constructed for ProGRP detection. The prepared three-dimensional reduced graphene oxide-gold nanoparticles (3D-rGO@Au) composite as substrate materials were applied for electrode modification, which can enhance electrical conductivity and enlarge the effective surface area for immobilizing capture antibody. Detection antibody-coated non-conductive SiO 2 nanospheres were used for specifically recognize ProGRP and form a sandwich structure. The electrochemical response signal of the sandwich-type immunosensor was based on the electron transferability between the electrode and [Fe(CN) 6 ] 3−/4− . 3D-rGO@Au can significantly increase the initial current, while SiO 2 can greatly reduce the response current. The combined effects of these nanomaterials can thus effectively enhance the sensitivity. Under optimal conditions, the constructed immunosensor exhibited a wide linear range (1 fg/mL to 10 ng/mL) with a low limit of detection (0.14 fg/mL). Moreover, the immunosensor exhibited superior stability, good reproducibility, favorable selectivity, and high sensitivity. Meanwhile, the concentration of ProGRP in human serum samples was measured with satisfactory results. This device is promising in the early screening of lung cancer, which can be applied as an over-the-counter test at home or in the community.
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