Fullerene-based amino acid nanoparticle interactions with human epidermal keratinocytes

The functionalization of C(60) with such complexes as amino acids has the potential to provide greater interaction between the fullerene and the biological environment yielding potential new medical and pharmacological applications. Although scientific research in the past decade has revealed much about the chemical and physical properties of C(60), the biological activities of this compound and its derivatives are still relatively unclear. In an attempt to understand the biological activity of functionalized C(60), human epidermal keratinocytes (HEK) were exposed to fullerene-based amino acid (Baa) solutions ranging in concentrations of 0.4-0.00004 mg/mL in a humidified 5% CO(2) atmosphere at 37 degrees C. MTT cell viability after 48 h significantly decreased (p<0.05) for concentrations of 0.4 and 0.04 mg/mL. In an additional study, human cytokines IL-6, IL-8, TNF-alpha, IL-1beta, and IL-10 were assessed for concentrations ranging from 0.4-0.004 mg/mL. Media was harvested at 1, 4, 8, 12, 24 and 48 h for cytokine analysis. IL-8 concentrations for the 0.04 mg/mL treatment were significantly greater (p<0.05) than all other concentrations at 8, 12, 24, and 48 h. IL-6 and IL-1beta activities were greater at the 24h and 48 h for 0.4 and 0.04 mg/mL. No significant TNF-alpha or IL-10 activity existed at any time points for any of the concentrations. These results indicate that concentrations lower than 0.04 mg/mL initiate less cytokine activity and maintain cell viability. In HEK, Baa concentrations of 0.4 and 0.04 mg/mL decrease cell viability and initiate a pro-inflammatory response.