Real-Time Microwave Characterization of Low Molecular-Weight Antioxidant Biomarkers

This work presents the results of an accurate real time microwave characterization of low-molecular- weight antioxidant biomarkers in low-volume solutions using a high-Q whispering gallery-mode dielectric resonator with a microfluidic channel. Sodium ascorbate and glutathione were characterized as the most significant non-enzymatic biomarkers of oxidative stress with respect to the reactive oxygen species scavenging system of cells. Microwave characterization was performed using a high-Q whispering-gallery-mode dielectric resonator with a microfluidic channel. The experiments demonstrated a fast response with high sensitivity in detecting sodium ascorbate and glutathione of different concentrations in biological solutions of small nanoliter volumes at a resonance frequency of about 35.5 GHz. These results indicate great potential for applying real-time microwave whispering-gallery-mode biosensing techniques in the characterization of low-molecular-weight antioxidant-specific biomarkers, which could be used in the laboratory and clinical biomedical research.