Carbon quantum dots originated from chicken blood as peroxidase mimics for colorimetric detection of biothiols

Abstract Carbon quantum dots (CQDs) were prepared from chicken blood by hydrothermal method, which could catalyze the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine (TMB) in the presence of H2O2 to generate the blue oxidized TMB (ox-TMB) with a strong absorption peak at 652 nm. However, the introduction of biothiols could induce the reduction of ox-TMB, leading to shallower blueness and lower absorbance. Based on this fact, a convenient and sensitive colorimetric method for detection of biothiols using CQDs as peroxidase mimics was established. Several factors, such as acidity, temperature, incubating time, CQDs dosage, H2O2 and TMB concentrations, which might influence the response of the analysis signal, were optimized by taking cysteine (CySH) as an example. Under the selected conditions, sensitive detection of biothiols was achieved, and the limits of detection (LOD) for CySH, glutathione (GSH), and homocysteine (HcySH) were 0.4, 0.6, and 0.9 μM respectively. This method was successfully applied for the determination of CySH in human serum samples with the recovery of 91.5 %–109.3 %, indicating the potential application of this method for biothiols sensing in real samples.