The Chemiluminescence And Fluorescence Switch Based On Functionalized Nanomaterials

Chemiluminescence(CL)and Electrochemiluminescence(ECL)with simple set-up,low background signal,high sensitivity have been developed as powerful analytical tools in the clinical detection.However,the low efficiency of luminescence and difficulty of modifying biomolecule of traditional luminophores,and the instability,volatilization,poor biocompatibility of common coreactants seriously restrict the wide application of CL and ECL in analytical field.Thus designing the highly effective and stable senor interface is highly desirable.Fluorescence switch triggering by electrochemistry is a kind of simple stimuli-responsive device.Among them,the most popular fluorescence switch is based on fluorescence resonance energy transfer and inner filter effect induced by the spectra spectral overlap between fluorescent probe of nanomaterial and electrochromic substance.However,the proposed fluorescence switch based on the traditional three-electrode system is difficult to realize integration.Different from the traditional three-electrode system,bipolar electrode(BPE)as a novel wireless and simple electrode generates the equal electrochemical redox reactions at two poles which is the basis of quantitative analysis.Thus integration and miniaturization of the BPE are easily controlled.Based on the electrochemical reversibility of fluorescence switch and the integration of the BPE,it provides the possibility for the construction of nanomaterial fluorescence switch chip.Based on the above discussion,the nanomaterial with the unique optical,electrical,magnetic,biocompatibility,catalytic property provides new opportunities for improving CL/ECL and constructing fluorescence switch.On the basis of characteristic of signal transmission,we carried out a series of researches on exploring the effect of nanomaterial as luminophor probe,coreactant and catalysis interface.The main progress are described as follows:1.The design of in-situ catalysis interface:in the alkaline condition,the flower-like cobalt hydroxide(f-Co(OH)2)based catalytic interface with porous architecture were in-situ created in the co-existence of BSA and Co2+.The f-Co(OH)2 capped by BSA with the hierarchical and porous morphologies not only provided the efficient reaction interface for enriching the reactants such as luminol and dissolved O2,but also effectively catalyzed the O2 to generate abundant reactive oxygen species(ROS)due to the inherent oxidase activity of the f-Co(OH)2,thus leading to the enhancement of CL.More interestingly,the proposed catalytic amplification mechanism could be extended to the different proteins.A sensitive CL sensor was constructed for the determination of ascorbic acid.2.The exploration of high-efficiency coreactant:boron nitride quantum dots(BNQDs)as coreactant was firstly introduced into the Ru(bpy)32+system and about 400-fold ECL enhancement was obtained compared with the individual Ru(bpy)32+.It was inferred that the electrocatalytic effect of the amino-bearing groups on the BNQDs endowed them as vital roles for the ECL of Ru(bpy)32+by a series of experiments and characteristic.An ECL sensing platform for dopamine in the real sample using the proposed Ru(bpy)32+/BNQDs system was successfully constructed with excellent stability and selectivity.3.The loading interface of luminophor:the Ti3C2-Ru composite was obtained in a few seconds through electrostatic interaction of ingenious 2D material Ti3C2 and Ru(bpy)32+.The composite exhibited the stable and intense ECL performance due to the large surface area,abundant negative functional group and outstanding electrical conductivity of Ti3C2.Besides the sensitive ECL sensing platform based on Ti3C2-Ru composite for lidocaine was successfully constructed with satisfying analytical result in human plasma.More importantly,the proposed approach not only enriched the application of Ti3C2,but also provided the new idea for the preparation of other ECL nanocomposite.4.The integration of fluorescence switch:a highly efficient fluorescence switch system combined with the well-designed closed bipolar electrode system was successfully constructed.Owing to the good stability of Au NCs/chitosan nanocomposite film and the reversibility of the Prussian blue,the BPE chip based fluorescence switch system displayed good reproducibility and reversibility with high on-off ratio.Moreover,the present study may provide a new route for the fabrication of the stimulus-response switch in memory material,logic gate,photoelectron science and electrochemical sensors based on BPE.