Carbonized Tetracycline: a new class of nanomaterial with tuneable antioxidant, reduced cytotoxicity, immunomodulatory, and osteogenic properties

Tetracycline (TET), a broad-spectrum antibiotic, also possesses different non-antibiotic activities such as inhibition of metalloproteinase (MMP), anti-inflammatory, antioxidant, high bone affinity, etc. However, the comparatively low efficacy of these non-antibiotic properties along with adverse effects such as hyperpigmentation, phototoxicity, long-term skeletal retention, etc. have not helped their broad utilization similar to their use as an antibiotic. In a unique attempt to improve the non-antibiotic properties while reducing the adverse effects, we converted the TET to nano-carbons through partial carbonization. After sorting out two water-dispersible C-TETs (C-TETHT - hydrothermal and C-TETHP - hot plate) based on their improved antioxidant activity, they have been characterized through a host of analytical techniques that showed distinct differences in morphology, size, shape, and surface functionality. Excitingly, the C-TETHT and C-TETHP have shown differential biological activity in a dosage and time-dependent manner in terms of cytotoxicity, immunomodulation, and osteogenic activity that was found to be associated with their carbonized parameters. Overall, the carbonized nano-drugs, C-TETHT and C-TETHP have presented substantial early promises on their non-antibiotic properties that could be further explored to develop into some effective therapeutics.