Study On The Electrochemiluminescence Resonance Energy Transfer Technique To The Application In Biological Analysis

Electrochemiluminescence (ECL), which is produced directly or indirectly as a result of electrochemical reactions, has attracted growing attention in analytical field owing to its advantages such as higher sensitivity, the potential controllability over the ECL reaction, no need of expensive instruments. Resonance energy transfer is the theoretical basis for establishing a new molecular spectroscopy method, referring to the transfer of electronic excitation energy from the appropriate energy donors to receptors. Electrochemiluminescence resonance energy transfer (ECL-RET), which combines the advantages of both, such as the absence of background from unselective photoexcitation and no impact from the scattered light, is a new area with great development potential and has been used in the construction of biosensors in recent years. Based on ECL-RET, we try to develop reversible ECL biosensor and to find new ECL-RET donor-receptor paris to achieve the rapid and sensitive detection of biologically relevant molecules. The major contents are described as follows:1. Reusable Potassium Ion Biosensor based on Electrochemiluminescence Resonance Energy TransferA simple and resuable ECL biosensor has been constructed for the detection of K+ion based on DNA structural changes and the interaction between surface plasmons of AuNPs and ECL emission of CdS NCs. Under the negative ECL potential, negatively-charged ssDNA stood upright on the electrode. The reversibly conformational change of DNA with K+introduction and removal resulted in AuNPs away from the CdS NCs to near the CdS NCs, leading to the SPR-induced ECL enhancement changing to Forster energy transfer-induced ECL quenching. According to all of this, we can realize the sensitive detection of K+. This smart NCs-based ECL detection strategy may open up a new way for developing reusable biosensors.2. RuSi@Ru(bpy)32+/Au@Ag2S nanoparticles Electrochemiluminescence Resonance Energy Transfer System for Sensitive DNA detectionHerein, we have designed an ECL-RET system that combines the properties of a molecular beacon to sensitively and selectively detect DNA using GO-Au/RuSi@Ru(bpy)32+/CS composites as an ECL donor and Au@Ag2S NPs as an ECL acceptor. We synthesized a water-soluble graphene oxide-gold nanoparticles (GO-Au) composite materials, and successfully immobilized RuSi@Ru(bpy)32+on the electrode surface with excellent ECL intensity and stability. In addition, we synthesized Au@Ag2S core-shell NPs with UV-vis absorption peak at about620nm, which is good spectral overlap with the ECL spectral of GO-Au/RuSi@Ru(bpy)32+/CS composites. Then we researched the resonance energy transfer efficiency between GO-Au/RuSi@Ru(bpy)32+/CS composites and Au@Ag2S NPs, and the results showed that Au@Ag2S NPs has a good ECL quenching effect and the quenching effect is distance-related. The presence of target DNA made the hairpin DNA open the ring and form a rigid double-stranded DNA, then Au@Ag2S NPs was able to attach to the other end of the DNA and caused ECL quenching, which allowed us to achieve the sensitive detection of target DNA.