A smartphone-assisted dual-response imprinted fluorescence sensor based on UiO-66 and quantum dots for detecting bovine hemoglobin

Establishment of precise, visual and on-site fluorescence detection system for proteins is of great importance in the field of biology and medicine. Herein, a novel dual-emission molecularly imprinted fluorescence sensor was designed for detecting bovine hemoglobin (BHb) based on silicon quantum dots (Si QDs), red CdTe QDs (r-CdTe QDs) and zirconium-based metal–organic framework (UiO-66). In this system, the porous UiO-66, served as supporter, endowed imprinted polymer (Si QDs/r-CdTe@UiO-66@MIP) with more specific binding sites and boosted mass transfer rate. Si QDs and r-CdTe QDs were used as optosensing centers and provided two-emission signals at 438 nm and 658 nm. Under the optimal detection conditions, Si QDs/r-CdTe@UiO-66@MIP exhibited good linear relationship to BHb in the range of 0.1–10 µM with a low detection limit (32 nM). Meanwhile, given by outstanding performances of Si QDs/r-CdTe@UiO-66@MIP, a home-made sensing device based on smartphone incorporating nanosensor was designed for the analysis of BHb. The portable optical device exhibited obvious color changes from blue to yellow, and provided visual detection. Significantly, the smartphone sensing system was successfully applied to analysis of BHb in simulated actual samples (urine and human serum), indicating that the smartphone-assisted fluorescence platform had great application potential for on-site monitoring BHb.