Applications Of Graphene Quantum Dots Based Fluorescent Probes In Aqueous Media And In Vitro

Realizing the selective detection of phosphate(PO43-)and thiosulfate(S2O32-)plays an important role in environmental assessment,drug diagnosis,food safety,etc.Therefore,it is of great significance to develop a simple,efficient and sensitive detection method.Compared with other traditional analytical detection methods,graphene quantum dots have many advantages such as superior optical performance,good stability and biocompatibility,and mature and convenient synthesis methods,and have become a substitute for traditional organic fluorescent emitters.Based on the literature investigation,this paper carried out the construction of fluorescent probes based on graphene quantum dots and achieved the selective detection of PO43-and S2O32-details as follows:The first part is based on a nitrogen-doped graphene quantum dot fluorescent material(N-GQDs),which achieves(PO43-)selective detection of inorganic phosphate by means of fluorescence off-on mode.Preparation,in this work,N-GQDs emitting yellow fluorescence are prepared by using more common organic raw materials such as Giulidine,acetic acid,ethanol,etc.,and Mo7O246-/N-GQDs is formed through the mediation of molybdate(Mo7O246-)GQDs complex,quenching the fluorescence of N-GQDs;then added PO43-and Mo7O246-to form a stronger bonding compound to remove Mo7O246-in the Mo7O246-/N-GQDs complex from the N-GQDs surface-The yellow fluorescence of GQDs is restored,thereby enabling selective detection of Po43-.Under optimized conditions,MO7O246-mediated N-GQDs can be detected in the phosphate concentration range of 1-35 ?M,the detection limit is as low as 0.05 ?M,and the fluorescent probe shows good selectivity.This probe not only realizes the detection of phosphate content in the actual water environment,but also shows a good detection effect on phosphate in Hela cells.Based on the foundation of the first part,the second part deeply explores the application of N-GQDs,combined with the traditional classic iodometric reaction to realize the detection of inorganic thiosulfate(S2O32-)in water environment and in vitro.Due to the large surface area of N-GQDs,the addition of elemental iodine can cause iodine to adsorb on its surface.Due to the internal filtration effect between the two,the yellow fluorescence of N-GQDs is quenched The subsequent addition of S2O32-quantitative oxidation reduction with elemental iodine The reaction gradually consumes the elemental iodine on the surface of the quantum dot,thereby gradually weakening the above-mentioned internal filtering effect,and finally causing the yellow fluorescence of the quantum dot to recover.Therefore this can be developed as a fluorescent "off-on" fluorescent probe based on N-GQDs.Under optimized conditions,the probe can achieve sensitive and quantitative detection of thiosulfate in the range of 2-10 nM,with a detection limit as low as 0.07 nM.The probe not only detects the S2O32-content in actual water samples,but also shows a strong S2O32-detection ability in RAW cells.