Development of a Histidine-Targeted Spectrophotometric Sensor Using Ni(II)NTA-Functionalized Au and Ag Nanoparticles

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• 作者：Joshua D. Swartz ; Christopher P. Gulka ; Frederick R. Haselton ; David W. Wright
• 刊名：Langmuir
• 出版年：2011
• 出版时间：December 20, 2011
• 年：2011
• 卷：27
• 期：24
• 页码：15330-15339
• 全文大小：1176K
• 年卷期：v.27,no.24(December 20, 2011)
• ISSN：1520-5827

文摘

An antibody-free diagnostic reagent has been developed based on the aggregation-induced colorimetric change of Ni(II)NTA-functionalized colloidal gold and silver nanoparticles. This diagnostic strategy utilizes the high binding affinity of histidine-rich proteins with Ni(II)NTA to capture and cross-link the histidine-rich protein mimics with the silver and gold nanoparticles. In model studies, the aggregation behavior of the Ni(II)NTA nanoparticles was tested against synthetic targets including charged poly(amino acid)s (histidine, lysine, arginine, and aspartic acid) and mimics of Plasmodium falciparum histidine-rich protein 2 (pfHRP-II). Aggregation of the nanoparticle sensor was induced by all of the basic poly(amino acid)s including poly(l-histidine) within the pH range (5.5鈥?.0) tested, which is likely caused by the coordination between the multivalent polymer target and Ni(II)NTA groups on multiple particles. The peptide mimics induced aggregation of the nanoparticles only near their pK_a鈥檚 with higher limits of detection. In addition, monomeric amino acids do not show any aggregation behavior, suggesting that multiple target binding sites are necessary for aggregation. Long-term stability studies showed that gold but not silver nanoparticles remained stable and exhibited similar aggregation behavior after 1 month of storage at room temperature and 37 掳C. These results suggest that Ni(II)NTA gold nanoparticles could be further investigated for use as a sensor to detect histidine-rich proteins in biological samples.