Fei-Fei An

Ultrabright and ultrastable near-infrared dye nanoparticles for in vitro and in vivo bioimaging

We report a new strategy of using carrier-free pure near-infrared (NIR) dye nanoparticles (NPs) to achieve highly luminescent NIR fluorescent probes for in vitro and in vivo imaging. Bis(4-(N-(2-naphthyl)phenylamino) phenyl)-fumaronitrile (NPAPF) NPs are shown to exhibit favorable biocompatibility, wide-range pH stability (pH 4-10) and much more superior photostability than conventional dyes. Importantly, the combined merits of high dye loading content and aggregation-induced emission enhancement properties, endow the NIR probes with high brightness and a high quantum yield up to 14.9%. The NPAPF NPs can be readily conjugated with folic acid for targeted in vitro cell imaging. Applications of the NPs probes in high efficiency in vivo and ex vivo imaging were successfully demonstrated. Intense fluorescent signals of NPAPF NPs can be distinctly, selectively and spatially resolved in tumor sites with ultrahigh sensitivity, even with 5 ms exposure time, due to the preferentially accumulation of NPs in tumor sites through passive enhanced permeability and retention effect. The totality of results clearly demonstrate the exciting potential of the functionalized NPAPF NPs as a NIR fluorescent probe for in vitro and in vivo imaging and diagnostics.

Preparation and size control of sub-100 nm pure nanodrugs.

Pure nanodrugs (PNDs), nanoparticles consisting entirely of drug molecules, have been considered as promising candidates for next-generation nanodrugs. However, the traditional preparation method via reprecipitation faces critical challenges including low production rates, relatively large particle sizes, and batch-to-batch variations. Here, for the first time, we successfully developed a novel, versatile, and controllable strategy for preparing PNDs via an anodized aluminum oxide (AAO) template-assisted method. With this approach, we prepared PNDs of an anticancer drug (VM-26) with precisely controlled sizes reaching the sub-20 nm range. This template-assisted approach has much higher feasibility for mass production comparing to the conventional reprecipitation method and is beneficial for future clinical translation. The present method is further demonstrated to be easily applicable for a wide range of hydrophobic biomolecules without the need of custom molecular modifications and can be extended for preparing all-in-one nanostructures with different functional agents.

Aggregation-Induced Near-Infrared Absorption of Squaraine Dye in an Albumin Nanocomplex for Photoacoustic Tomography in Vivo

Photoacoustic tomography (PAT) is a newly emerging noninvasive imaging modality that could be further enhanced using near-infrared (NIR)-absorbing materials as contrast agents. To date, the most extensively studied photoacoustic imaging agents are inorganic nanomaterials because organic materials with NIR-absorption capabilities are limited. In this study, a NIR-absorbing nanocomplex composed of a squaraine dye (SQ) and albumin was prepared based on the aggregation-induced NIR absorption of SQ. Through aggregation, the absorption spectrum of SQ was widened from the visible-light region to the NIR region, which facilitated photoacoustic signal generation in the tissue-transparent NIR optical window (700-900 nm). Blood analysis and histology measurements revealed that the nanocomplex can be used for PAT applications in vivo without obvious toxicity to living mice.

Achieving Highly Efficient Simple-Emission Layer Fluorescence/Phosphorescence Hybrid White Organic Light-Emitting Devices via Effective Confinement of Triplets

Achieving high efficiencies in simple device configurations is a long-standing and meaningful target for organic light-emitting devices (OLEDs). Herein, by utilizing an efficient blue-violet fluorophor (CzS1) that has a high triplet energy of 2.62 eV, the significance of effective confinement of the green triplets in fluorescence/phosphorescence hybrid white devices (F/P-WOLEDs) that have highly simplified emission layers (EMLs) containing only RGB emitters was demonstrated. The non-p-i-n warm-white device exhibited excellent performance with a maximum forward power efficiency high up to 42.1 lm W(-1), and maintaining at 26.3 lm W(1-) at a practical luminance of 1000 cd m(-2).

A reticuloendothelial system-stealthy dye–albumin nanocomplex as a highly biocompatible and highly luminescent nanoprobe for targeted in vivo tumor imaging

A reticuloendothelial system (RES)-stealthy nanoprobe for enhanced tumor imaging is a longstanding pursuit. In this study, a nanocomplex comprising albumin and dye is assembled without crosslinker use. The nanocomplex shows intense luminescence with a photoluminescence quantum yield of up to 0.39 and a large Stokes shift of >130 nm. The nanocomplex also exhibits higher stability against hydrolysis than indocyanine green during the 14 days test. The nanocomplex shows favourable high biocompatibility and can be used for cell labelling. Remarkably, the nanocomplex exhibits six times higher tumor accumulation than that in the liver and spleen. At 96 h post-injection, the nanoprobe is still observable and gives a clear imaging of tumors, which can help in convenient diagnosis post-injection.

Carrier-free, functionalized pure drug nanorods as a novel cancer-targeted drug delivery platform.

A one-dimensional drug delivery system (1D DDS) is highly attractive since it has distinct advantages such as enhanced drug efficiency and better pharmacokinetics. However, drugs in 1D DDSs are all encapsulated in inert carriers, and problems such as low drug loading content and possible undesirable side effects caused by the carriers remain a serious challenge. In this paper, a novel, carrier-free, pure drug nanorod-based, tumor-targeted 1D DDS has been developed. Drugs are first prepared as nanorods and then surface functionalized to achieve excellent water dispersity and stability. The resulting drug nanorods show enhanced internalization rates mainly through energy-dependent endocytosis, with the shape-mediated nanorod (NR) diffusion process as a secondary pathway. The multiple endocytotic mechanisms lead to significantly improved drug efficiency of functionalized NRs with nearly ten times higher cytotoxicity than those of free molecules and unfunctionalized NRs. A targeted drug delivery system can be readily achieved through surface functionalization with targeting group linked amphipathic surfactant, which exhibits significantly enhanced drug efficacy and discriminates between cell lines with high selectivity. These results clearly show that this tumor-targeting DDS demonstrates high potential toward specific cancer cell lines.