One-pot green hydrothermal synthesis of fluorescent nitrogen-doped carbon nanodots for in vivo bioimaging.

One-pot green synthesis of fluorescent nitrogen-doped carbon nanodots (CNDs) was developed by hydrothermal treatments of biocompatible polyvinylpyrrolidone (PVP) and glycine. The fluorescent nitrogen-doped CNDs exhibited excellent water solubility, low cytotoxicity, and good salt stability for biological imaging. UV-vis spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) spectroscopy, and Raman spectroscopy were applied to confirm the optical and structural characteristics of the CNDs. Fluorescence of the CNDs was tunable from 417 to 450 nm adjusted by different excitation energy. Fluorescent quantum yield of the CNDs (21.43%) was significantly increased ~47.59% in comparison to that of the CNDs (14.52%) without nitrogen doping by glycine. In the in vivo imaging system (IVIS), fluorescence signal of the nitrogen-doped CNDs was obviously observed in the lungs at 12- and 24-h post-injection. Our work has shown the potential applications of the nitrogen-doped CNDs in fluorescence imaging in vivo.

The Penetrated Delivery of Drug and Energy to Tumors by Lipo-Graphene Nanosponges for Photolytic Therapy.

Delivery of drug and energy within responsive carriers that effectively target and accumulate in cancer cells promises to mitigate side effects and to enhance the uniquely therapeutic efficacy demanded for personalized medicine. To achieve this goal, however, these carriers, which are usually piled up at the periphery of tumors near the blood vessel, must simultaneously overcome the challenges associated with low tumor penetration and the transport of sufficient cargos to deep tumors to eradicate whole cancer cells. Here, we report a sponge-like carbon material on graphene nanosheet (graphene nanosponge)-supported lipid bilayers (lipo-GNS) that doubles as a photothermal agent and a high cargo payload platform and releases a burst of drug/energy (docetaxel (DTX) and gasified perfluorohexane (PFH)) and intense heat upon near-infrared irradiation. Ultrasmall lipo-GNS (40 nm) modified with a tumor-targeting protein that penetrates tumor spheroids through transcytosis exhibited a 200-fold increase in accumulation relative to a 270 nm variant of the lipo-GNS. Furthermore, a combination of therapeutic agents (DTX and PFH) delivered by lipo-GNS into tumors was gasified and released into tumor spheroids and successfully ruptured and suppressed xenograft tumors in 16 days without distal harm when subjected to a single 10 min near-infrared laser treatment. Moreover, no tumor recurrence was observed over 60 days post-treatment. This sophisticated lipo-GNS is an excellent delivery platform for penetrated, photoresponsive, and combined gasification/chemo-thermotherapy to facilitate tumor treatment and for use in other biological applications.

An NAD(P)H:quinone oxidoreductase 1 (NQO1) enzyme responsive nanocarrier based on mesoporous silica nanoparticles for tumor targeted drug delivery in vitro and in vivo.

The synthesis and characterization of an NAD(P)H: quinone oxidoreductase 1 (NQO1) enzyme responsive nanocarrier based on mesoporous silica nanoparticles (MSNPs) for on-command delivery applications has been described in this paper. Gatekeeping of MSNPs is achieved by the integration of mechanically interlocked rotaxane nanovalves on the surface of MSNPs. The rotaxane nanovalve system is composed of a linear stalk anchoring on the surface of MSNPs, an α-cyclodextrin ring that encircles it and locks the payload "cargo" molecules in the mesopores, and a benzoquinone stopper incorporated at the end of the stalk. The gate opening and controlled release of the cargo are triggered by cleavage of the benzoquinone stopper using an endogenous NQO1 enzyme. In addition to having efficient drug loading and controlled release mechanisms, this smart biocompatible carrier system showed obvious uptake and consequent release of the drug in tumor cells, could selectively induce the tumor cell death and enhance the capability of inhibition of tumor growth in vivo. The controlled drug delivery system demonstrated its use as a potential theranostic material.