Biodegradable double nanocapsule as a novel multifunctional carrier for drug delivery and cell imaging

Highly-efficient delivery of macromolecules into cells for both imaging and therapy (theranostics) remains a challenge for the design of a delivery system. Here, we suggested a novel hybrid protein–lipid polymer nanocapsule as an effective and nontoxic drug delivery and imaging carrier. The biodegradable nanocapsules showed the typical double emulsion features, including fluorescently labeled bovine serum albumin shell, oil phase containing poly(lactic-co-glycolic acid) and linoleic acid, and inner aqueous phase. The nanocapsules were spherical in shape, with an average size of about 180 nm. Proteins packed into the inner aqueous phase of the nanocapsules could be delivered into cells with high efficiency, and the fluorescence of the fluorescently labeled bovine serum albumin could be used for tracing the protein migration and cellular location. Further studies suggested that the co-delivery of transcription factor p53 and lipophilic drug paclitaxel with the nanocapsules acted synergistically to induce Hela cell apoptosis, and the fluorescence of apoptotic cells was clearly observed under a fluorescence microscope. Such multifunctional delivery system would have great potential applications in drug delivery and theranostic fields.