A novel sweat glucose biosensor was fabricated using a modified laser-induced graphene (LIG) electrode that was surface-treated with acetic acid. This simple dipping technique increased the conductivity of LIG by reducing the ratio of carbohydrate functional groups and increasing carbon-carbon bonds. The modified LIG also facilitated the uniform and stable deposition of Pt nanoparticles (PtNPs) on the electrode surface, which were used as a catalyst for glucose oxidation.