Picomolar selective fluorescent detection of creatinine using porphyrin in aqueous medium

Abstract

Porphyrins are macrocyclic molecules known for their rich electron density and intense fluorescence which enables the ultralow level detection of various analytes with excellent selectivity. Herein, we have made use of 5,10,15,20-tetrakis(4-hydroxy-3,5-trimethoxyphenyl) porphyrin (THMPP), as a fluorescent biosensor for the detection of creatinine (CNN) in picomolar level. The sensing mechanism operated via dynamic collision between the THMPP fluorophore and the CNN and was found to be selective even with the addition of 1000 equivalents excess of biological analytes like urea, uric acid, creatine, glucose and various metal ions. The biosensor could detect as low as concentration of 1.2×10−12 M of CNN with a linear range of 2×10−12 M to 50×10−12 M. This method was extended for the detection of CNN from artificial to human urine sample with excellent reproducibility and hence has the potential for point of healthcare testing.