Single probe-based sensor array integrated with 3D-printed smartphone platform for the identification of guanine nucleotides, anthrax biomarkers and their derivatives

Sensor array has gained significant attention in the sensing field owing to its unique properties, which allow it to simultaneously detect and distinguish multiple targets. The sensor array mainly relies on a variety of sensing elements to build multiple detection channels so as to function. Among these, the design of multiple sensing elements is relatively complicated. In this paper, a novel strategy was proposed to construct sensor array, which could generate multiple signals through a single probe without the need to build multiple sensing elements, thereby enabling the fast and efficient identification of various analytes. A fluorescence sensor based on ZIF-8@GSH-AuNCs-Tb was constructed by encapsulating glutathione-capped gold nanoclusters (GSH-AuNCs) and terbium ions (Tb³⁺) within zeolitic imidazolate framework-8 (ZIF-8) for the simultaneous discrimination of guanine nucleotides, anthrax biomarkers and their derivatives. Due to its special properties, Tb³⁺ could produce three characteristic emission wavelengths of 492, 547, and 585 nm when excited at 256 nm. Surprisingly, each output signal could be combined with the emission signal of GSH-AuNCs to form ratio fluorescence for the quantification of targets, thus obtaining a three-channel sensor array. A large amount of data was collected to complete the calculation of principal component analysis (PCA), hierarchical cluster analysis (HCA), and other statistical methods, so as to realize the identification of multiple targets. Besides, with the help of 3D printing technology, a portable smartphone platform integrated with the testing paper was developed, showing excellent sensing and recognition ability in serum sample detection.