Red emitting human serum albumin templated copper nanoclusters as effective candidates for highly specific biosensing of bilirubin

Abstract In this paper, we report a new type of human serum albumin (HSA) stabilized red emissive copper nanoclusters (HSA–CuNCs) were prepared at room temperature and HSA–CuNCs were applied to identify the bilirubin in human urine and blood serum samples. The emission characteristics of synthesized HSA–CuNCs were pH responsive to that the intensity of emission enhanced quickly with varying the pH range from 12 to 6. Emission spectral signal of HSA–CuNCs was found as reduced well with the raise in the amounts of bilirubin attributed to strong binding attraction leads to the non-fluorescent complex formation of HSA–CuNCs with bilirubin. Due to the strong affinity between the nanoprobe and analyte, the red emissive HSA–CuNCs illustrates more specific for the detection bilirubin over the different potential interfering molecules. Two good linear relationships were distinguished the relative emission intensity of HSA–CuNCs versus bilirubin concentrations range from 1.25 × 10 −6 to 7.50 × 10 −6  M and 5.00 × 10 −6 to 2.875 × 10 −5  M with lowest limit of detection was determined as 35.00 × 10 −9  M and 145.00 × 10 −9  M (S/N = 3), respectively. Furthermore, this methodology was effectively used in the quantification of bilirubin in clinical (real) samples. In addition, this fluorometric method offers cost-effective, easy, highly specific and ultrasensitive optical platform for the determination of bilirubin.