Portable point-of-care surface enhanced Raman scattering spectroscopy for the quantification of glutathione in whole blood microsamples.

Glutathione (GSH) is a non-protein tripeptide thiol that plays a prominent role in oxidative stress defense. GSH concentration is particularly critical in the neonatal period, especially for premature newborns that face increased susceptibility to oxidative stress. Monitoring GSH levels provides valuable insights into newborn health, helping to tailor care to their specific needs. The aim of this study was the development of a sensor specifically targeted for its use in neonatology, enabling GSH determination in only 2 μL of whole blood. The newly developed sensing system simplifies sample processing, addressing a critical need in clinical applications. Unlike current methods that demand fast pre-processing of relatively large sample volumes, expensive equipment, and skilled personnel, the developed approach streamlines the analytical process. By using 2 μL of whole blood, a single syringe filter for sample treatment, a deuterated internal standard (IS) for signal normalization, and Surface Enhanced Raman Scattering (SERS) spectroscopy with a silver colloid substrate for GSH detection, the set-up's characteristics are compatible with point-of-care applications. The analytical procedure was validated and applied to diverse populations including healthy adults (N = 63) and newborns (N = 35), yielding GSH concentration values ranging from 0.6 to 1.8 and 0.8-2.1 mM, respectively. This new optical sensor offers a quick and cost-effective solution to support the assessment of GSH levels in newborns that can greatly benefit not only neonatal care, but also the study of adult populations for health monitoring.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Julia Kuligowski reports financial support was provided by Carlos III Health Institute. Abel Albiach-Delgado reports financial support was provided by Carlos III Health Institute. Jose Luis Moreno-Casillas reports financial support was provided by Spain Ministry of Science and Innovation. Julia Kuligowski reports financial support was provided by Government of Valencia. Guillermo Quintas reports financial support was provided by Spain Ministry of Science and Innovation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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