Antioxidant potential of tea assessed by optical absorption spectroscopy in DNA-encased carbon nanotubes

It is essential to develop a simple method to assess food quality quantitatively. Available methods primarily rely on nanotechnology and offer high selectivity and sensitivity. In this study, we aimed to develop a sensitive nanoprobe, and, to this end, a double-stranded DNA-encased HiPco carbon nanotube (dsDNA-HiPco) hybrid was prepared and used to evaluate the antioxidant potential of a Chinese tea against hydrogen peroxide (H2O2) with a range of irradiation wavelengths. The morphology and dispersion of the hybrids were analysed using atomic force microscopy, which showed that dsDNA wrapped on the SWCNT surface well and homogeneous dispersion of the rod-shaped tubes while the concentration of dsDNA was 1 mg mL-1. The antioxidant effect of Chinese tea was evaluated by using near-infrared absorption and photoluminescence of the hybrid. Experimental results revealed that the tea exerted excellent antioxidant effects when the hybrid was pre-treated with 0.03% wt H2O2. Catechin present in the Chinese tea played a pivotal role in exerting the antioxidant effects. Therefore, a simple detection method proposed herein can be successfully applied in various fields, including biology, medicine, and the food industry.