Abstract
In this work, we present a simple and rapid method to synthesize red luminescent gold nanoclusters (AuNCs) with high quantum yield (QY, ~16%), excellent photostability and biocompatibility. Next, we fabricated a solid membrane by loading the as-prepared AuNCs in an agar matrix. Different from nanomaterials dispersed in solution, the AuNCs-based solid membrane has distinct advantages including convenience of transportation, while still maintaining strong red luminescence, and relatively long duration storage without aggregation. Taking hydrogen peroxide (H2O2) as a typical example, we then employed the AuNCs as a luminescent probe and investigated their sensing performance, either in solution phase or on a solid substrate. The detection of H2O2 could be achieved in wide concentration ranges over 805 nM–1.61 mM and 161 μM–19.32 mM in solution and on a solid membrane, respectively, with limits of detection (LOD) of 80 nM and 20 μM. Moreover, the AuNCs-based membrane could also be used for visual detection of H2O2 in the range of 0–3.22 mM. In view of the convenient synthesis route and attractive luminescent properties, the AuNCs-based membrane presented in this work is quite promising for applications such as optical sensing, fluorescent imaging, and photovoltaics.
Highlights
Fluorescent probes usually play an important role in the assays and imaging applications where fluorescence is employed as a signal
An aqueous solution of HAuCl4 and bovine serum albumin (BSA) was mixed under vigorous stirring at room temperature, in which HAuCl4 was used as a precursor of Au, and BSA acted as both a reductant and a stabilizer
An analytical method for H2 O2 determination was further established based on the relationship between the luminescence quenching and the concentration of H2 O2
Summary
Fluorescent probes usually play an important role in the assays and imaging applications where fluorescence is employed as a signal. The systematic design and synthesis of effective fluorescent probes have attracted a lot of attention in the past many years. With the development of nanoscience and nanotechnology, a variety of different luminescent nanomaterials such as semi-conductor quantum dots [1,2], carbon quantum dots [3,4], silicon quantum dots [5], and metal nanoclusters [6,7,8,9] have been synthesized and developed as luminescent probes for a wide range of applications in environmental, food and pharmaceutical analysis, and bioimaging. AuNCs are new rising stars in the field of nanotechnology, which have recently attracted increasing attention due to their excellent features including subnanometer sizes, high luminescence quantum yield (QY), good biocompatibility and photostability, as well as easy preparation [10]. AuNCs with tunable luminescence from the visible to the near-infrared regions can be achieved by manipulating the reaction parameters during the Sensors 2016, 16, 1124; doi:10.3390/s16071124 www.mdpi.com/journal/sensors
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