Filter-assisted smartphone colorimetry / ICP-MS dual-mode biosensor of butyrylcholinesterase in clinical samples

Clinically, butyrylcholinesterase (BChE) is an indispensable biochemical marker for evaluating liver function and organophosphorus poisoning. In this work, we proposed a novel smartphone readable colorimetry and inductively coupled plasma mass spectrometer (ICP-MS) dual-mode analytical strategy for BChE detection in clinical patients based on the phenomenon that the filter membrane can selectively separate MnO2 nanosheets (MnO2 NSs) and Mn2+. In the presence of BChE and acetylthiocholine (ATCh), the enzymatic hydrolysate (thiocholine) can efficiently trigger the decomposition of MnO2 NSs to Mn2+. After selective separation of MnO2 NSs and Mn2+ via the filter, colorimetric detection was achieved with a smartphone by identifying the RGB value of the MnO2 NSs coated membrane, while the Mn2+ in the filtrate was detected by ICP-MS. Under optimal conditions, the limits of detection (LODs) were as low as 1.3 U/L and 0.001 U/L for the smartphone-based RGB analysis and ICP-MS assay, respectively. This method was applied to quantify BChE in 40 clinical whole blood samples of patients with clinical liver disease. The levels of BChE detected in clinical samples by this method were consistent with clinical Ellman’s colorimetric findings. Therefore, this method can provide more options for clinical cholinesterase detection and is expected to be developed into a kit.