| Electrochemiluminescence(ECL)is light emission generated by the electrochemical induced electron-transfer at the electrode surface.ECL,which has been widely applied in bioanalytical applications,combines the analytical advantages of electrochemical assay with chemiluminescent analysis such as low background,high sensitivity,wide dynamic concentration response range,andsimple instrumentation.Thedevelopment of multiplexing immunoassay(MIA)for simultaneously identifying several tumor markers in single assay procedure was promising in bio-related assay and clinical diagnosis due to the advantages of improved detection throughput,shortened assay time,enhanced analysis accuracy.This paper develops a dual-wavebands-resolved ECL MIA for simultaneously detecting two components.1.A dual-wavebands-resolved ECL MIA was developed for simultaneously detecting alphafetoprotein antigen(AFP)in greenish waveband with CdSe550(λmax =550 nm)nanocrystals(NCs)and cancer antigen 125(CA125)in near-infrared waveband with CdTe790(λmax= 790 nm)NCs via one-pot ECL reaction,in which dichroic mirror works as a key part to reflect ECL from CdSe550 to one photomultiplier-tube(PMT)and transmit ECL from CdTe790 to the other PMT for dual-wavebands-resolved assay.The proposed ECL-MIA strategy was capable of simultaneously determining AFP with linearly response from 5.0 pg/mL to 5.0 ng/mL and limit of detection at 1,0 pg/mL,and CA125 with linearly response from 5.0 mU/mL to 1.0 U/mL and limit of detection at 1.0 mU/mL,with desired specificity and without obvious energy-transfer between ECL tags.2.To screen novel toxic-element-free and biocompatible electrochemiluminophores,ECL from multinary NCs was investigated for the first time with Zn-Ag-In-S(ZAIS)NCs as model.Aqueous soluble ZAIS NCs could bring out efficient reductive-oxidation ECL with tri-n-propylamine as co-reactant,while coating the ZAIS NCs with a ZnS shell could enable 6.7 folds enhanced ECL from ZAIS/ZnS NCs than ZAIS NCs by reducing surface defects for enhanced radiative charge transfer.ECL of ZAIS/ZnS NCs was about 4.2 folds to that of ternary CuInS2/ZnS NCs,spectrally similar to that of Ru(bpy)32-with maximum emission around 605 nm.and favorable for less electrochemical interference with a lowered triggering potential(～0.95 V)than that of Ru(bpy)32+.An ultrasensitive ECL microRNA sensor was fabricated with ZAIS/ZnS NCs as tags,which could specifically and selectively determine microRNA-141 with a wide linearity range from 0.1 fmol/L to 20 pmol/L and a low limit of detection at 50 amol/L(S/N = 3).Multinary NCs might provide a promising alternative to traditional binary NCs for ECL assay. |
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