Highly sensitive and selective tryptophan colorimetric sensor based on 4,4-bipyridine-functionalized silver nanoparticles
2009; Elsevier BV; Volume: 145; Issue: 1 Linguagem: Inglês
10.1016/j.snb.2009.11.062
ISSN1873-3077
AutoresHaibing Li, Fengying Li, Cuiping Han, Zhimin Cui, Guangyong Xie, Aiqing Zhang,
Tópico(s)Electrochemical sensors and biosensors
ResumoThis paper reports a novel colorimetric sensor for tryptophan based on 4,4-bipyridine-functionalized silver nanoparticles (4-DPD-Ag NPs) which were characterized by IR spectroscopy, ultraviolet–visible spectroscopy (UV–vis), and transmission electron microscopy (TEM). The newly synthesized 4-DPD-Ag NPs are yellow in color due to the intense surface plasmon absorption band centered at 390 nm. In the presence of tryptophan, the yellow 4-DPD-Ag NPs solution turns to red accompanying a dramatic surface plasmon absorption band centered at 556 nm. However, the sensitivity of 4-DPD-Ag NPs towards other neutral amino acids, including leucine, threonine, valine, phenylalanine, tyrosine, proline, serine, pyroglutamic acid and cysteine can be negligible. This highly selective sensor allows a direct and rapid quantitative assay of tryptophan with a colorimetric limited detection concentration of 2 × 10−5 M. The possible underlying mechanism is discussed.
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