Radiation Manipulation Investigations And Biosensing Applications Of Electrochemiluminescence With Nanoparticles As Emitters

Electrochemiluminescence(ECL)refers to a light emission process whereby reactive species generated at electrodes undergo high-energy electron-transfer reactions.ECL has been extensively utilized in various inspections due to its superior properties,such as free external light sources,high signal-to-noise ratio,sensitivity,and controllable electrochemical process.Only the molecular tris(bipyridyl)ruthenium/tripropylamine system has been applied in commercially available ECL immunoassay.Herein,nanoparticles are successfully exploited as electrochemiluminophore to achieve ECL with turnable intensity,wavebands,monochromaticity,triggering-potential,and triggering-potential-window,as well as single/multi-targets biosensing for the promising ECL bioassays and commercial application.1.By focusing on the enhancing of the intrinsic bandgap-engineered ECL,CdSe nanocrystal(NCs)aerogels is developed as novel ECL luminophores via a versatile waterinduced gelation strategy.The strong electronic coupling between adjacent NCs enables efficient charge transport within the aerogel network,leading to the CdSe aerogels/triethanolamin with 126-fold higher ECL based on the selectively improved interparticle charge-transfer route,By skillfully designing a CdSe-CdTe mixed NCs aerogel and applying a coreactant that is solely suitable for CdTe,confirming the charge-transport-promoted ECL mechanism in spectral-determining and total-intensity-measuring combined modes.The interparticle charge-transfer route is anticipated to advance the intrinsic bandgap-engineered ECL of nanoparticles.2.Aiming at the manipulation of the surface defect-involved ECL,an effective way to enhance the radiative recombination within the atomically-precise Ag nanoclusters is proposed with unpassivated Ag29(BDT)12(BDT=1,3-benzenedithiol)and Ag29(BDT)12(TPP)4(TPP=triphenylphosphine)as models.Surface-engineering Ag29(BDT)12 with TPP can circumvent the geometric packing limitation induced by the wide footprint of BDT,which enable Ag29(BDT)12(TPP)4 with 10-fold higher annihilation(-1.35 V→+1.30 V)and 20-fold enhanced oxidative-reduction ECL beneficial from the enhanced charge injection,as well as the improved annihilation(-1.35 V→0.76 V)and reduction-oxidative ECL.The surfaceengineering strategy is promising for the boasted surface defect-involved ECL of nanoparticles.3.To modulate ECL radiation band and monochromaticity of nanoparticles,the Zn2+aggregation-induced Au NCs is developed as luminophore using 6-mercaptocarboxylic acid as a protective ligand and reductant.By effectively exploring and precisely controlling of ECL test conditions,the ECL waveband modulation of Au NCs is achieved via bandgap transition and energy transfer pathways.Au NCs/tripropylamine system can only exhibit bandgaptransition induced ECL at 485 nm(FWHM=36 nm)with Au NCs as the emitter in carbonatefree buffers;the energy-transfer mediated ECL of Au NCs/tripropylamine system in carbonate buffer is located at 703 nm(FWHM=176 nm)with 1O2 as emitter;no emissive 1O2 is detected via electrochemically oxidizing the Au NCs in the case without either carbonate buffer or tripropylamine.4.Focusing on the expanding of ECL waveband,by extensively exploiting the bandgapengineered ECL nature of dual-stabilizers-capped’ CdTe NCs,an efficient electrochemiluminophore with monochromatic near-infrared ECL around 815 nm is developed via doping CdTe NCs with Co2+ species in a growth-doping way.A spectrum-based ECL immunosensor is fabricated with Co2+-CdTe NCs as tag,which can selectively determine human carcinoembryonic antigen with a wide linearity range from 1 fg/mL to 10 pg/mL and a low limit of detection(LOD)at 0.2 fg/mL.This surface doping strategy would open a way to modulate the ECL waveband of nanoparticles as well as to implement spectrum-resolved ECL assay.5.Developing low-triggering-potential ECL system is highly demanded for ECL evolution towards less electrochemical interference as well as high electrode compatibility.By effectively modifing precursor pH and purification process of CdTe NCs,the low-triggering-potential(～0.21 V)ECL is achieved via merely oxidizing optimized CdTe NCs.By extensively exploiting the electrosteric-involved ECL nature of bioconjugates and sandwich-type immunocomplexes with CdTe NCs as lable,a coreactant-free ECL immunoassay is achieved at 0.24 V upon employing recombinant pro-gastrin releasing peptide as analyte(linearity range:0.1～2000 pg/mL;LOD:0.05 pg/mL).The electrosteric involved way might provide an alternative to simplify the ECL assay procedure and commercialized instruments.6.By exploiting the electrostatic interaction between the carbonyl groups of trisodium citrates and the Ag atoms within triangular silver nanoparticles,not only the redox reversibility with a narrow electrochemical-potential-window of 0.16 V is discussed,but also the efficient ECL with narrow triggering-potential-window of 0.32 V is achieved.The trisodium citrates of Ag nanoparticles can be selectively replaced by thiols and enables quenched electrochemical redox(～0.08 V)and ECL(～1.35 V)responses,which can be utilized to detect a series of thiols with similar linear response range(30 pM～3 nM),response slope,and LOD(10 pM).This manipulation approach is anticipated for potential-resolved multi-targets ECL assay with less overlapped triggering-potential-range,and enables a high academic value.7.To overcome the limitation of ECL multiplex immunoassay and DNA probe assay together,by extensively multiplexing the intrinsic bandgap-engineered ECL(485 nm)of Au NCs/N2H4 system and the surface-defect-involved ECL(775 nm)of CuInS2@ZnS NCs/N2H4 system,a dual-targets ECL assay strategy is developed in a spectrum-resolved mode upon employing Au NCs and CuInS2@ZnS NCs as tags.The multiplexing ECL with maximum emission wavelength at 485 nm and 775 nm can be utilized to simultaneous detect carcinoembryonic antigen(linearity range:1 pg/mL～50 ng/mL;LOD:0.3 pg/mL)and wildtype p53 gene(linearity range:1 pM～50 nM;LOD:0.5 pM),respectively.The gene detection is free from the interference of synchronously conducted ECL immunoassay,and vice versa,which would open an avenue for accurate clinical diagnosis in high throughput way.8.Focusing on the improvement of detecting throughput,a labeling-bond engineered way is proposed upon posting surface-engineering the CdTe NCs with RNA of different terminal groups,enables narrow triggering-potential-window ECL at 0.32 V and 0.82 V via Cd-S bond and amide linkage,respectively.Upon employing coreactant-free CdTe NCs as lables,a dualtargets ECL assay strategy is developed in a potential-resolved mode by exploiting the multiplexing ECL with maximum triggering potential at 0.32 V and 0.82 V,which can be utilized to simultaneously detect the open reading frame 1ab(linearity range:200 aM～10 fM;LOD:100 aM)and the nucleoprotein(linearity range:5 fM～1 pM;LOD:2 fM)genes without crosstalk.This ECL multiplexed gene assay is anticipated for rapid coronavirus 2 diagnostics.