کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1173466 | 1491402 | 2014 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: On-particle detection of Plasmodium falciparum histidine-rich protein II by a “switch-on” iridium(III) probe On-particle detection of Plasmodium falciparum histidine-rich protein II by a “switch-on” iridium(III) probe](/preview/png/1173466.png)
The need for robust reagents for biomarker detection has become an increasing necessity in designing point-of-care diagnostics. We report a non-emissive, cyclometalated iridium(III) complex, Ir(ppy)2(H2O)2+ (Ir1), which, on coordination to a histidine-containing protein bound to the surface of a magnetic particle, elicits a rapid, long-lived phosphorescent signal. The interactions between Ir1 and numerous other amino acids were examined for activity, but only the addition of histidine resulted in a four orders of magnitude enhancement in signal intensity. Buffer conditions (pH and temperature) and composition (coordinating vs. non-coordinating and ionic strength) were optimized to achieve maximum signal and stability of Ir1. The activity of the probe under optimized conditions was validated with BNT-II, a histidine-containing branched peptide mimic of the malarial biomarker Plasmodium falciparum histidine-rich protein II (PfHRPII). By comparing Ir1 binding to BNT-II versus l-histidine, steric and quenching effects were noted in the peptide. Despite these deviations from ideal conditions, signal response reached saturation with both BNT-II and recombinant HRPII (rcHRPII). When immobilized on the surface of a 50 μM magnetic agarose particles, the limit of detection of rcHRPII was 14.5 nM. The robust signal response of this inorganic probe lends itself to future applications in on-particle enzyme-linked immunosorbent assay (ELISA)-based assays.
Journal: Analytical Biochemistry - Volume 445, 15 January 2014, Pages 60–66