科研之友
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摘要
We report a study on chemiluminescence-based chemical analyses using luminol molecules covalently attached to 10 nm diameter gold nanoparticles (GNPs). Chemiluminescence (CL) has been systematically studied under two schemes by varying the concentrations of luminol-labeled GNPs and ]Fe(CN)(6)](3-) catalyst, respectively. The CL signal of luminol-labeled GNPs is enhanced by 5 to 10 times compared to the bulk luminol solutions of the same concentration. The log-log plot of the CL signal versus the number of luminol-labeled GNPs suspended in a standard 96-well plate shows two characteristic linear curves with distinct slopes across eight orders of magnitude variation in the GNP quantity (from 1.82 x 10(2) to 1.82 x 10(10) GNPs per well). The detection limit represented by the cross-point of these two curves can reach down to similar to 6.1 x 10(5) GNPs per well (corresponding to 1.0 x 10(-14) M GNP and 2.4 x 10(-11) M equivalent luminol concentration). The attachment of luminol molecules to GNP nanocarriers allows a large amount of luminol to be placed in a greatly reduced volume (or area) toward developing miniaturized CL sensors. We have demonstrated this by preloading dried luminol-labeled GNPs in homemade microwell arrays (with a volume of similar to 12 mu L per well). A linear log-log curve can be obtained across the full range from 1 x 10(3) to 1 x 10(10) GNPs per microwell. The CL signal was detectable with as few as similar to 1000 GNPs. We have further applied this microwell method to the detection of highly diluted blood samples, in both intact and lysed forms, which releases Fe3+-containing hemoglobin to catalyze luminol CL. The lysed blood sample can be detected even after a 10(8) fold dilution (corresponding to similar to 0.18 cells per well). This ultrasensitive CL detection method may be readily adapted for developing various miniaturized multiplex biosensors for rapid chemical/biochemical analyses.
- 出版日期2013
