Colorimetric determination of sarcosine in urine samples of prostatic carcinoma by mimic enzyme palladium nanoparticles.

The proposed palladium nanoparticles (Pd NPs), which with the catalytic activity similar to the horseradish peroxidase (HRP) mimic enzyme, can effectively catalyze the H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine sulfate (TMB) accompanied with a color change from colorless to blue in solution. And as a result, the sensitive detection of sarcosine can be realized by the naked eye observation and ultraviolet spectrophotometry, using Pd NPs as catalyst and TMB as the substrate of the simulation enzyme catalytic reaction. Under the optimal condition, the catalytic system of Pd NPs mimic enzyme can be used for the detection of sarcosine. It has been found that the color change could be clearly observed with the naked eyes, and the absorbance intensity at 653 nm showed a fine linear fitting with the concentration of sarcosine in the range from 0.01 μM to 50 μM, and the detection limit (3σ/S) for sarcosine was calculated to be 5.0 nM. In order to evaluate the feasibility and reliability, the method was also used for analyzing concentrations of sarcosine in human urine samples from diagnosed prostate cancer patients and healthy donors. It is expected to provide a convenient and efficient method for indirect evaluation for the diagnosis of prostatic carcinoma (PCa).