Ratiometric fluorescence detection of the angiotensin-converting enzyme via single-excitation and double-emission biomass-derived carbon quantum dots

Abstract

Efficient and rapid detection of angiotensin-converting enzyme (ACE) activity is important for preventing hypertension and the discovery of new angiotensin-converting enzyme inhibitors (ACEI). In this work, a single-excitation and double-emission biomass-derived carbon quantum dots (CQDs) was prepared and applied for ratiometric fluorescence detection of ACE. Fresh banyan leaves were extracted with ethanol and acetone, and the extracted solution was used as the precursor to produce the carbon quantum dots (BL-CQDs) with single-excitation and double-emission properties. The synthesized BL-CQDs is about 1.7 nm, has a graphene-like structure, contains a variety of hydrophilic functional groups on the surface, and has good fluorescence properties. Its fluorescence intensity ratio (I677/I460) is linear with ACE activity in the range of 0.02-0.8 U/L. The regression equation is △F=2.5371 CACE-0.0311. The method was successfully applied to the determination of ACE activity in pig lung and human serum, and the inhibitory efficiency of the flavonoid extract and captopril tablets on ACE activity was also investigated, which can be applied to the screening of ACEI. The survival rate and fluorescence imaging of Bel-7404 cells under the condition of high concentration BL-CQDs showed BL-CQDs had low cytotoxicity and good biocompatibility. These results indicate that the BL-CQDs can be used as an excellent fluorescent probe, providing a new method for screening ACE activity and plant-derived ACEI.

Advances in Carbon Dot-Based Ratiometric Fluorescent Probes for Environmental Contaminant Detection: A Review

“…Biological and Biomolecular Targets: CD-based ratiometric fluorescence probes have been adapted for detecting specific biological and biomolecular targets, such as bacteria [ 82 , 163 , 164 ], biomarkers [ 75 , 165 ], cholesterol [ 77 ], amino acids [ 64 ], guanine [ 166 , 167 ], DNA [ 168 ] ( Figure 7 d,e), and proteins [ 1 , 91 , 107 , 169 , 170 ]. These probes find applications in genomics, molecular diagnostics, and bioanalytical assays.…”

Portable ratiometric fluorescence detection of Cu2+ and thiram

“…However, these methods are often time-consuming, cumbersome and require tedious sample pretreatment in the applications of water quality and food safety analysis. Comparing with above-mentioned quantitative analysis methods, fluorescent sensing has been applied as a crucial analytical method in food and environmental detection, due to its simple operation procedure, high sensitivity, short response time and low cost [12,13].…”