Array-based sensing of amyloidogenic proteins and discrimination of cancer by using different oxidants doped carbon nanodots as fluorescent probes

Disease-related proteins are biomarkers for disease diagnosis and treatment, e.g. amyloidogenic proteins are highly related to neurodegenerative diseases. Detection and monitoring of disease-related proteins is significant for the biomedical research and early disease diagnosis. Thus, the rapid, sensitive and low-cost approach is highly desired. For this purpose, herein, a novel dual-element sensor array was constructed based on two carbon nanodots (CDs). The CDs were prepared using citric acid and Congo red as carbon source by deliberately doping with two different oxidants, i.e. ammonium persulfate and hydrogen peroxide. The fluorescence of CDs could be efficiently and selectively quenched by proteins to different degrees, in which electrostatic and hydrophobic interactions might co-contribute to the sensing process. In the differentiability test, the established sensor array could accurately discriminate four amyloidogenic proteins and two serum proteins with a classification accuracy of 100%. The applicability could be extended to proteins quantification and mixture proteins discrimination. Typically, fibrillation stages of amyloidogenic protein (α-synuclein as example) in artificial cerebrospinal fluid were differentiated by the array, which was meaningful to illustrate the process of neurodegenerative diseases. Moreover, the sensor array successfully distinguished cancer patients (liver and breast cancers) and healthy people based on μL-level of serum sample, demonstrating its potential for fast screen of cancer at large scale. The constructed sensor array based on the oxidants doped CDs was promising for disease-related proteins discrimination, quantification and progressive fibrillation monitoring, and afforded a powerful discriminative and adaptive tool for biomedical research and disease diagnosis.