Encapsulation of anticancer drug curcumin and co-loading with photosensitizer hypericin into lipoproteins investigated by fluorescence resonance energy transfer.

Low-density lipoproteins (LDL) and high-density lipoproteins (HDL) are natural occurring vehicles attractive for drug delivery and targeting tumor cells. Here we have investigated the encapsulation and interaction of a well-known anticancer agent curcumin with LDL and HDL. LDL particles have been found to accumulate more curcumin molecules inside their structure than HDL. The chemical stability of curcumin is enhanced and its photo-physical properties are altered due to encapsulation inside both lipoproteins. Combining photodynamic therapy with chemotherapy can improve anticancer treatment by overcoming drug resistance in cancer therapy. Therefore, we have also investigated a co-loading of curcumin with a natural potent photosensitizer hypericin into molecules of LDL using fluorescence resonance energy transfer. The loading patterns of curcumin and hypericin into LDL particles were found to be different as revealed by the fluorescence resonance energy transfer experiments. Present study illustrates the potential of LDL nanoparticles in combination therapy because of simultaneous loading of more than one type of drugs into these nanoparticles with high level of efficiency.