A Novel Fluorescence Immunosensing Method Based On Regulation Of The Interaction Between Graphene And Graphene Quantum Dots

Recently, it has received much attention on the rapid, sensitive and specific detection of targets in biological and environmental analysis. Generally, the traditional methods, such as instrumental analysis (GC/MS, LC/MS, ICP/MS), are complicated, expensive, time-consuming and in need of large equipment, which limit their application. Compare to the traditional methods, the sensing analysis methods have the advantage of easy pretreatments, rapid response and being not necessary for technical skills, so it is available to realize the real-time detecting. Due to their unique structures and properities, nanomaterials have been widely used to develop the novel sensors. However, these sensing methods still suffer from the design defects in the sensing mechanism, many pollutants can’t be determinated through the sensing methods. Thus, it’s necessary to explore new universal signal transduction strategies to meet these challenges.In the present work, we utilize the unique sp2hybrid structure of graphene (Gr) and graphene quantum dots (GQDs) to present a universal signaling transduction strategy in the fluoroimmunoassay based on regulation of the interaction between Gr with excellent quenching ability and GQDs with excellent luminescence property, and explore its application in detecting antigens (human immunoglobulin G(IgG)).The fluorospectro photometer was used to detect human IgG in phosphate buffer solution and in real sample. The results demonstrated the feasibility of this sensor, and further demonstrated its sensitivity, specificity, versatility. Under the optimal conditions, it was observed that the detection range of this strategy was0.2μg/mL-12μg/mL. The detection limit of10ng/mL was estimated based on3δ/slope criterion, which is comparable and even better than those of many reported immunoassay methods for human IgG, suggesting its sensitivity. Furthermore, a relative standard deviation of4.6%(n=5, human IgG) was obtained for this method, indicating the good reproducibility of this immunoassay. In contrast to human IgG, the low response of this strategy to human Immunoglobulin M and bovine serum albumin under the same conditions, which could ensure its good specificity. What is more, it can be used for determination of other antigens by simple replacement of antibodies on the surface of GQDs.This work combines the π-π interaction between the two carbon materials with their unique optical and electrical properties to propose a new immunosensing method. This novel method provides a new idea for detecting biomacromolecule. Furthermore, it is expected to be applied for detection of targets in the environment.