Fluorescent biosensor based cerium-doped carbon quantum dots for albumin detection

Accurate detection of albumin proteins is crucial for diagnosing different diseases. A fluorescent sensor has been developed using cerium (Ce) doped carbon quantum dots (CQDs) to detect bovine serum albumin (BSA) in blood and urine samples. Pristine CQDs and Ce-CQDs were synthesized through citric acid pyrolysis. CQDs and Ce-CQDs exhibited emission peaks at 415 nm and 426 nm, respectively. Based on the photoluminescence (PL) enhancement of Ce-CQDs resulting from adding BSA, BSA was quantified within two minutes. This biosensor was selective and sensitive towards BSA in the concentrations ranging from 1 to 1000 µM with a high correlation coefficient and a low detection limit of 0.98 µM (6.5 × 10^-2 g L^-1), which meets the requirement well for clinical analysis. The practical usefulness of Ce-CQDs as a fluorescent biosensor was confirmed by accurately quantifying BSA in human serum and urine samples with satisfactory recovery percentages.