Multi-optical signal channel gold nanoclusters and their application in heavy metal ions sensing arrays

To improve the performance of an array-based sensing system, a novel one-pot method was designed to prepare multi-optical signal channel gold nanoclusters (MS-AuNCs), including chemiluminescence (CL) and fluorescence (FL). And multi parameters were extracted from the CL and FL spectra of MS-AuNCs to realize the excellent performance of sensing arrays for heavy metal ion differentiation. In this synthetic strategy, 11-mercaptoundecanoic acid (MUA) was used as the capping agent to form Au(i)-thiol complexes first. Then luminol was introduced as a reductant to reduce the Au(i)-thiol complexes and as a chemiluminescent reagent to form MS-AuNCs. Compared with previous methods for preparing luminescent functionalized nanoparticles, the proposed method could obtain functionalized nanoparticles with multi-optical signal channels in one step and is much simple. The obtained MS-AuNCs exhibited excellent CL performance when reacting with hydrogen dioxide. The peak position of the MS-AuNCs FL emission spectra does not shift as increasing excitation wavelengths. The bright orange FL of MS-AuNCs was strong enough to be seen with naked eye. Based on five parameters extracted from the CL and FL spectra of MS-AuNCs, one sensing array was developed for distinguishing heavy metal ions. The sensing strategy could differentiate seven heavy metal ions with different concentrations, including Al3+, Co2+, Cr3+, Cu2+, Hg2+, Pb2+ and Zn2+. Moreover, novel multi-optical signal channel gold nanoclusters were obtained for the first time in this work, which may find more promising applications in fields such as bioassays and bioimaging.

Automated summary

A novel one-pot method was developed to prepare multi-optical signal channel gold nanoclusters (MS-AuNCs) for heavy metal ion differentiation, extracting multiple parameters from the CL and FL spectra of MS-AuNCs for excellent sensing array performance. The obtained functionalized nanoparticles exhibited strong chemiluminescence performance and stable fluorescence emission spectra, allowing for the differentiation of seven heavy metal ions. This work also yielded novel multi-optical signal channel gold nanoclusters with potential applications in bioassays and bioimaging.