Surface-engineered prussian blue nanozymes as artificial receptors for universal pattern recognition of metal ions and proteins

Pattern-based array sensing have emerged as an efficient and promising approach for detection of multiple analytes; however, it is still challenging but important to synthesize a range of materials as sensing elements. Surface engineering is a promising strategy for activity modulation or functional design for novel nanomaterials. Herein, we fabricate three Prussian blue (PB)-based nanomaterials by surface modification (pristine PB, PB@MoS2, and PB@Pt), which have exhibited distinct peroxidase-like activities due to varying surfaces. The three PB-based nanozymes have been successfully employed as artificial receptors to construct a cross-reactive colorimetric sensor array. According to the differential interactions between targets and the surface of PB-based nanozymes, the presented sensor array can achieve unique colorimetric response patterns and precisely discriminate 10 metal ions and 13 proteins. This sensor array is sufficiently sensitive to quantitatively analyze individual metal ion and protein with detection limit down to µM and µg/mL, respectively. Moreover, the recognition of metal ions and proteins in complex mixtures has also been achieved. Most importantly, the practical applications have been demonstrated by identifying metal ions in tap water and proteins in human serum samples, differentiating denatured and natural proteins, distinguishing blind samples, and even discriminating clinical samples for cancer identification. This work demonstrates an effective strategy of surface engineering of nanozyme for activity modulation, as well as shows a convenient and universal chemical tongue sensing platform.