Sulfur-Doped Graphene-Based Immunological Biosensing Platform for Multianalysis of Cancer Biomarkers

The accurate tumor marker detection at an early stage can prevent people from getting cancer to a great extent. Herein, a novel tri-antibody dual-channel biosensing strategy is applied in multianalysis of carcino-embryonic antigen (CEA) and nuclear matrix protein 22 (NMP22). In this immunosensor fabrication process, graphene oxide/polyaniline nanostructures are used as matrix and mesoporous NKF-5-3 is used as labels. Two kinds of antigens can be obtained from the signals of neutral red and toluidine blue, respectively, which are modified on the labels. In this tri-antibody dual-channel biosensing platform, sulfur-doped graphene sheet is synthesized by click chemistry as the framework structure. Majority of the incubations are conducted in individual steps, which ensure the surface incubation more tightly. The detection limit of NMP22 and CEA are 25 and 30 fg/mL, respectively. The low detection limit and excellent stability can ascribe to the tri-antibody dual-channel strategy, which makes the sensor platform from surface to the space. The clinical urine sample analysis achieves a good performance. The urine-based test can avoid the secondary injury on hemophilia or ischemic patients, displaying a potential application in clinical diagnosis.