Identification of Low Concentrations of Flucytosine Drug Using a Surface-Enhanced Raman Scattering (SERS)-Active Filter Paper Substrate

Treatment of cryptococcal meningitis relies primarily on flucytosine (5FC), which is also used to treat candidiasis and infections caused by Cryptococcus neoformans. High dosages of this drug, despite its therapeutic properties, may cause hazardous side effects such as bone marrow suppression, hepatotoxicity, and gastrointestinal toxicity. The detection of trace amounts of 5FC medication may aid in tracking the treatment's efficacy and mitigating unwanted effects. Surface-enhanced Raman spectroscopy (SERS) is a rapid, reliable, and precise approach for detecting extremely low amounts of biological and chemical compounds. A filter paper-based SERS biosensor coated with silver nanoparticles (AgNPs) were employed to detect the 5FC drug. The AgNPs fabricated via the chemical reduction method were characterized by FE-SEM, TEM, XRD, AFM, and UV-Vis spectroscopy. Plasmonic active sites were made by coating the filter paper substrate with AgNPs to detect the 5FC drug's molecular vibrations. As the 5FC drug was coated onto the filter paper substrate, the AgNPs interacted with it, allowing for the detection of very low concentrations of the drug. The SERS filter paper substrate could detect concentrations of 5FC as low as 10(-10) M. The Raman spectra and peak signals obtained experimentally were also simulated and validated using the density functional theory (DFT) approach. Six sets of measurements were taken, and the average RSD was obtained to be 4.62%. The experimentally measured enhancement factor for recognizing molecular vibrations of the 5FC was 9.065 x 10(7), and it was numerically estimated as 10.044 x 10(7). Therefore, the fabricated SERS-based filter paper substrate is useful for drug monitoring since they can detect even trace amounts of the targeted drug.

Automated summary

The treatment of cryptococcal meningitis relies on 5FC, but high dosages may have harmful side effects. By using a SERS biosensor with AgNPs on a filter paper substrate, low concentrations of 5FC drug can be detected.