Gold nanoparticle-protein agglomerates as versatile nanocarriers for drug delivery.

The fabrication of a versatile nanocarrier based on agglomerated structures of gold nanoparticle (Au NP)-lysozyme (Lyz) in aqueous medium is reported. The carriers exhibit efficient loading capacities for both hydrophilic (doxorubicin) and hydrophobic (pyrene) molecules. The nanocarriers are finally coated with an albumin layer to render them stable and also facilitate their uptake by cancer cells. The interaction between agglomerated structures and the payloads is non-covalent. Cell viability assay in vitro showed that the nanocarriers by themselves are non-cytotoxic, whereas the doxorubicin-loaded ones are cytotoxic, with efficiencies higher than that of the free drug. Transmission electron microscopy and fluorescence microscopy along with flow cytometry analysis confirm the uptake of the drug-loaded nanocarriers by a human cervical cancer HeLa cell line. Field-emission scanning electron microscopy reveals the formation of apoptotic bodies leading to cell death, confirming the release of the payloads from the nanocarriers into the cell. Overall, the findings suggest the fabrication of novel Au NP-protein agglomerate-based nanocarriers with efficient drug-loading and -releasing capabilities, enabling them to act as multimodal drug-delivery vehicles.