Tumor-tropic endothelial colony forming cells (ECFCs) loaded with near-infrared sensitive Au nanoparticles: A "cellular stove" approach to the photoablation of melanoma

In the photothermal treatments (PTs) of tumor, the localization of a high number of near-infrared (NIR) absorbing gold nanoparticles in the tumor mass is still a challenging issue. Here, we propose a promising strategy to deliver therapeutic chitosan-coated gold nanoparticles to tumor cells as hidden cargo of Endothelial Colony Forming Cells (ECFCs) endowed with an innate tumor-tropism. Remarkably, ECFC gold enrichement doesn't affect cell viability and preserves the endothelial lineage characteristics such as capillary morphogenesis and cell migration. We demonstrate that heavily Au-doped ECFCs are able to efficiently warm up the tumor environment, and kill the cancer cells via hyperthermic heating both in vitro as well as in vivo. Thus, we show an excellent thermotransductive property of gold enriched ECFCs and their capability to kill melanoma cells at moderate NIR light intensities.

Surface plasmon enhanced energy transfer between gold nanorods and fluorophores: application to endocytosis study and RNA detection

Previously we have demonstrated surface plasmon enhanced energy transfer between fluorophores and gold nanorods under two-photon excitation using fluorescence lifetime imaging microscopy (FLIM) in both solution and intracellular phases. These studies demonstrated that gold nanoparticle-dye energy transfer combinations are appealing, not only in Förster resonance energy transfer (FRET) imaging, but also energy transfer-based fluorescence lifetime sensing of bio-analytes. Here, we apply this approach to study the internalization of gold nanorods (GNRs) in HeLa cells using the early endosome labeling marker GFP. The observed energy transfer between GFP and the GNRs indicates the involvement of endocytosis in GNR uptake. Moreover, a novel nanoprobe based on oligonucleotide functionalized gold nanorods for nucleic acid sensing via dye-GNRs energy transfer is demonstrated, potentially opening up new possibilities in cancer diagnosis and prognosis. The influence of oligonucleotide design on such nanoprobe performance was studied for the first time using time-resolved fluorescence spectroscopy, bringing new insights to the optimization of the nanoprobe.

Targeting polymeric fluorescent nanodiamond-gold/silver multi-functional nanoparticles as a light-transforming hyperthermia reagent for cancer cells

This work demonstrates a simple route for synthesizing multi-functional fluorescent nanodiamond-gold/silver nanoparticles. The fluorescent nanodiamond is formed by the surface passivation of poly(ethylene glycol) bis(3-aminopropyl) terminated. Urchin-like gold/silver nanoparticles can be obtained via one-pot synthesis, and combined with each other via further thiolation of nanodiamond. The morphology of the nanodiamond-gold/silver nanoparticles thus formed was identified herein by high-resolution transmission electron microscopy, and clarified using diffraction patterns. Fourier transform infrared spectroscopy clearly revealed the surface functionalization of the nanoparticles. The fluorescence of the materials with high photo stability was examined by high power laser irradiation and long-term storage at room temperature. To develop the bio-recognition of fluorescent nanodiamond-gold/silver nanoparticles, pre-modified transferrin was conjugated with the gold/silver nanoparticles, and the specificity and activity were confirmed in vitro using human hepatoma cell line (J5). The cellular uptake analysis that was conducted using flow cytometry and inductively coupled plasma mass spectrometry exhibited that twice as many transferrin-modified nanoparticles as bare nanoparticles were engulfed, revealing the targeting and ease of internalization of the human hepatoma cell. Additionally, the in situ monitoring of photothermal therapeutic behavior reveals that the nanodiamond-gold/silver nanoparticles conjugated with transferrin was more therapeutic than the bare nanodiamond-gold/silver materials, even when exposed to a less energetic laser source. Ultimately, this multi-functional material has great potential for application in simple synthesis. It is non-cytotoxic, supports long-term tracing and can be used in highly efficient photothermal therapy against cancer cells.