SERS spectroscopy for the therapeutic drug monitoring of the anticancer drug 6-Mercaptopurine: Molecular and kinetic studies

Gold colloidal solutions were investigated as SERS platforms for the detection and the quantitative analysis of the anticancer drug 6-Mercaptopurine. The study was aimed at verifying the feasibility of a SERS-based assaying method for Therapeutic Drug Monitoring. The interaction mechanism and the adsorbate structure were investigated by a QM vibrational analysis of the title molecule. Furthermore, a kinetic analysis of the adsorption/ aggregation processes made by timeresolved SERS experiments and DLS analysis provided relevant information on the complex behaviour of the system. It was found that the adsorption process is fast and produces significant SERS signalling in the 5-20 mu M range. At 15 and 20 mu M composition, the kinetic analysis evidenced the formation of long-lived metastable aggregates; at 50 mu M the colloidal solution collapsed immediately. A range of high linearity was identified between 5 and 20 mu M, wherein a reliable quantitative analysis could be performed, with an estimated limiting sensitivity (LOD) of 1.0 mu M.

Automated summary

Gold colloidal solutions were used as SERS platforms for the detection and quantitative analysis of the anticancer drug 6-Mercaptopurine. The adsorption process was found to be fast, producing significant SERS signaling in the 5-20 mu M range. Kinetic analysis revealed the formation of long-lived metastable aggregates at 15 and 20 mu M composition, while the colloidal solution collapsed immediately at 50 mu M, indicating a complex behavior of the system.