Functionalized gold nanoparticles with zinc finger-fused proteins as a colorimetric immunoassay platform.

Dasom Kim, Hyo-Deok Seo, Yiseul Ryu, Hak-Sung Kim

Analytica chimica acta 2020 Aug 22

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The quest for highly sensitive and specific detection of disease biomarkers is high, despite many advances in analysis system. Here, we present a sensitive immunoassay platform using DNA-tethered gold nanoparticles and DNA-binding zinc fingers (ZFs). Monomeric alkaline phosphatase (mAP) and human TNF-α were employed as a signal generator and a disease biomarker, respectively. Gold nanoparticles (AuNPs) were first grafted with double-stranded DNAs having specific sequences for two different types of ZFs (QNK and zif268). The alkaline phosphatase and TNF-α-specific protein binder were genetically fused to each of two different types of ZFs, respectively, followed by conjugation with the DNA-tethered AuNPs in a sequence-specific manner. The use of the functionalized AuNPs as a signal generator in a colorimetric immunoassay of TNF-α led to LOD of 120 pg/ml, showing about 161-fold higher sensitivity than a protein binder-fused mAP. The present immunoassay platform could be applied to other analytes by simply replacing a targeting moiety, allowing a versatile and reproducible colorimetric immunoassay. Copyright © 2020 Elsevier B.V. All rights reserved.

Citation

Dasom Kim, Hyo-Deok Seo, Yiseul Ryu, Hak-Sung Kim. Functionalized gold nanoparticles with zinc finger-fused proteins as a colorimetric immunoassay platform. Analytica chimica acta. 2020 Aug 22;1126:154-162