標題: Using protein-encapsulated gold nanoclusters as photoluminescent sensing probes for biomolecules
作者: Selvaprakash, Karuppuchamy
Chen, Yu-Chie
應用化學系
Department of Applied Chemistry
關鍵字: Gold nanoclusters;Egg white;Ovalbumin;Adenosine-5'-triphosphate;Pyrophosphate;Photoluminescence
公開日期: 15-Nov-2014
摘要: In this study, we generated gold nanoclusters (AuNCs) using inexpensive chicken egg white proteins (AuNCs@ew) as reagents. AuNCs@ew were generated by reacting aqueous tetrachloroauric acid with diluted chicken egg white under microwave heating (90 W) through subsequent heating cycles (5 min/cycle). Within 10 cycles, red photoluminescent AuNCs@ew with maximum emission wavelength at similar to 640 nm (lambda(ex)=370 nm) were obtained. The quantum yield of the as-generated AuNCs was similar to 6.6%. The intact and the tryptic digest of AuNCs@ew were characterized by mass spectrometry. The results showed that the AuNCs@ew were mainly derived from ovalbumin, i.e., the major protein in egg white, encapsulated AuNCs. The AuNCs@ew also has the common features found in AuNCs@protein, which is sensitive to the presence of heavy metal ions such as Cu2+. The photoluminescence of the AuNCs@ew was quenched with the addition of Cu2+. Furthermore, the photoluminescence of the quenched AuNCs@ew can be restored in the presence of the molecules containing phosphate functional groups because of the strong binding affinity between Cu2+ and phosphates. We used the AuNCs@ew-Cu2+ conjugates as switch-on sensing probes for the detection of phosphate containing metabolites such as adenosine-5\'-triphosphate (ATP) and pyrophosphate (PPi). The results showed that the photoluminescence of the sensing probes increased as the concentration of the phosphate-containing molecules in the sample solution increased. The limits of detection achieved using the AuNCs@ew-Cu2+ for ATP and PPi were 19 and 5 mu M, respectively. Additionally, we also demonstrated the feasibility of using the AuNCs@ew as the sensing probes for lectins such as concanavalin A (Con A) based on the molecular recognitions between the glycan ligands on the AuNCs@ew and glycan binding sites on Con A. (C) 2014 Elsevier B.V. All rights reserved.
URI: http://dx.doi.org/10.1016/j.bios.2014.04.055
http://hdl.handle.net/11536/24797
ISSN: 0956-5663
DOI: 10.1016/j.bios.2014.04.055
期刊: BIOSENSORS & BIOELECTRONICS
Volume: 61
Issue: 
起始頁: 88
結束頁: 94
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