Conventional in vitro study often involves the destruction of the cells followed by purification and dilution steps before applying enzymatic assay or metabolomic analysis. It is a costly and laborious process, and it cannot monitor changes as a function of time. Recently, we have developed a new label-free live-cell FTIR approach that can directly measure biochemical compositional changes within living cells in situ and the spectral changes are shown to be highly specific to the drug applied. In this work, we have demonstrated for the first time the effect of two anti-diabetic drugs, metformin and Resveratrol, on insulin-resistant liver cells (HepG2). Using live-cell FTIR with principal component analysis, we have shown the differences in the biochemical profiles between normal and insulin-resistant cells (p < 0.05), the lack of response/difference from the insulin-resistant cell to insulin (p > 0.05) and the restoration of the biochemical profile and sensitivity to insulin from the insulin-resistant cells after the drug treatment (p < 0.05). Particularly, a rise in the glycogen level, marked by three distinctive peaks at 1150, 1080 and 1020 cm-1, within the living cells after the anti-diabetic drug treatments is observed. The live-cell FTIR results are confirmed by a parallel gold-standard biochemical assay, demonstrating the restoration of insulin sensitivity of the insulin-resistance cells. Live-cell FTIR can be a complementary tool for drug efficacy screening, especially for insulin sensitizers.
Keywords: Anti-diabetic drugs; Chemometric analysis; Diabetes; Drug screening; High throughput; Infrared spectroscopy.
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