Fluorescence Study of the Curcumin−Casein Micelle Complexation and Its Application as a Drug Nanocarrier to Cancer Cells

Abstract

In milk caseins exists a natural nanostructure, which can be exploited as a carrier of hydrophobic drugs. Here we investigated the complex formation of curcumin with bovine casein micelles (CMs) and its use as a vehicle for drug delivery to cancer cells. DLS studies of the CM suspension that was stable in buffer solution (pH 7.4) showed an average size distribution of 4 M⁻¹, as determined by the curcumin fluorescence. Fluorescence quenching showed that curcumin molecules quench the intrinsic fluorescence of caseins upon binding. We evaluated the utility of CMs as carriers of curcumin by using in vitro cultured HeLa cells. Cytotoxicity studies of HeLa cells revealed that the IC₅₀ of free curcumin and the CM−curcumin complex was 14.85 and 12.69 μM, respectively.