Aminobenzofuran-fused rhodamine dyes with deep-red to near-infrared emission for biological applications.

Aminobenzofuran-fused rhodamine dyes (AFR dyes) containing an amino group were constructed by an efficient condensation based on 3-coumaranone derivatives. AFR dyes exhibited significantly improved properties, including deep-red and near-infrared emissions, a large Stokes shift, good photostability, and wide pH stability. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium assay experiments show that these AFR dyes are biocompatible for their low cytotoxicity to both A549 and HeLa cells. Cell imaging data reveal that AFR1, AFR1E, and AFR2 are mainly located in the mitochondria, while AFR3 is a lysosome tracker. As far as we know, NIR AFR3 is the longest fluorescent rhodamine derivative containing the amino group. These amino group-containing AFR dyes hold great potential in fluorogenic detection, biomolecule labeling, and cell imaging.

Copolythiophene-derived colorimetric and fluorometric sensor for visually supersensitive determination of lipopolysaccharide.

3-Phenylthiophene-based water-soluble copolythiophenes (CPT1) were designed for colorimetric and fluorometric detection of lipopolysaccharide (LPS). The sensor (CPT1-C) shows a high selectivity to LPS in the presence of other negatively charged bioanalytes as well an extreme sensitivity with the detection limit at picomolar level, which is the lowest ever achieved among all synthetic LPS sensors available thus far. Significantly, the sensing interaction can be apparently observed by the naked eyes, which presents a great advantage for its practical applications. The appealing performance of sensor was demonstrated to originate from the multiple electrostatic and hydrophobic cooperative interactions, synergetic with signal amplification via the conformational change of the 3-phenylthiophene-based copolymer main chain. As a straightforward application, CPT1-C is capable of rapidly discriminating the Gram-negative bacteria (with LPS in the membrane) from Gram-positive bacteria (without LPS).

Red Emissive Carbon Dots Prepared from Polymers as an Efficient Nanocarrier for Coptisine Delivery in†vivo and in†vitro.

Negatively charged fluorescent carbon dots (CDs, Em =608 nm) were hydrothermally prepared from thiophene phenylpropionic acid polymers and then successfully loaded with the positively charged anticancer cargo coptisine, which suffers from poor bioavailability. The formed CD-coptisine complexes were thoroughly characterized by particle size, morphology, drug loading efficiency, drug release, cellular uptake and cellular toxicity in vitro and antitumor activities in vivo. In this nano-carrier system, red emissive CDs possess multiple advantages as follows: 1) high drug loading efficiency (>96 %); 2) sustained drug release; 3) enhanced drug efficacy towards cancer cells; 4) EPR effect; 5) drug release tracing with near-infrared imaging. These properties indicated that red emissive CDs prepared from polymers could be used as a novel drug delivery system with integrated therapeutic and imaging functions in cancer therapy, which are expected to have great potential in future clinical applications.

Single-Atom Gadolinium Anchored on Graphene Quantum Dots as a Magnetic Resonance Signal Amplifier.

A single-atom metal doped on carbonaceous nanomaterials has attracted increasing attention due to its potential applications as high-performance catalysts. However, few studies focus on the applications of such nanomaterials as nanotheranostics for simultaneous bioimaging and cancer therapy. Herein, it is pioneeringly demonstrated that the single-atom Gd anchored onto graphene quantum dots (SAGd-GQDs), with dendrite-like morphology, was successfully prepared. More importantly, the as-fabricated SAGd-GQDs exhibits a robustly enhanced longitudinal relaxivity (r1 = 86.08 mM-1 s-1) at a low Gd3+ concentration of 2 µmol kg-1, which is 25 times higher than the commercial Gd-DTPA (r1 = 3.44 mM-1 s-1). In vitro and in vivo studies suggest that the obtained SAGd-GQDs is a highly potent and contrast agent to obtain high-definition MRI, thereby opening up more opportunities for future precise clinical theranostics.

Near-infrared fluorescent carbon dots encapsulated liposomes as multifunctional nano-carrier and tracer of the anticancer agent cinobufagin in vivo and in vitro.

Integrating the optical properties of near-infrared fluorescent carbon dots into liposomes may construct a multifunctional nano-system with the potential as a drug carrier, tracer and efficacy intensifier of the anticancer agent. In this study, the liposomes loaded with hydrophilic near-infrared carbon dots as a nano-carrier and tracer of lipophilic anticancer agent cinobufagin were developed. Prepared liposomes were characterized by particle size, morphology and entrapment efficiency. The drug release behavior, the tracer function, the anticancer effect and the side effect were investigated in vitro and in vivo. It was observed that the photoluminescence emission of carbon dots could be strongly enhanced up to 5 times by nano-liposomes. Due to this property, the bio-imaging of CDs + CB liposomes in vitro and in vivo could be clearly obtained. Our results also showed that the CDs + CB liposomes could be uptaken by cells (the lysosomes targeted) and delivered to the tumor site, and undoubtedly, the CDs + CB liposomes demonstrated sustained drug release, enhanced anticancer efficacy and low side effects in vivo. With the assistance of imaging function of CDs, the CDs + CB liposomes can easily display the distribution of drugs, which is very helpful for drug development and may open a novel avenue for drug delivery.

Biodegradable hypocrellin derivative nanovesicle as a near-infrared light-driven theranostic for dually photoactive cancer imaging and therapy.

Photoactive agents based on natural products have attracted substantial attention in clinical applications because of their distinct biological activity, molecular structure multiformity, and low biotoxicity. Herein, we initially modify hypocrellin B (HB) with 1,2-diamino-2-methyl propane to form near-infrared (NIR) light (>700 nm)-responsive amino-substituted HB derivative (DPAHB). The DPAHB exhibit broad absorption (400-800 nm), NIR emission (maximum emission peak at 710 nm), and high singlet oxygen (1O2) quantum yield (∼0.33) under NIR light (721 nm) irradiation. After self-assembly by using DPAHB with PEG-PLGA, the as-prepared nanovesicles (DPAHB NVs) retain efficient 1O2 generation, more interestingly, show high photothermal conversion efficiency (∼0.24) under NIR light (721 nm) irradiation for synergistic photodynamic therapy (PDT) and photothermal therapy toward hypoxic tumor. The DPAHB NVs can not only be as a fluorescence/photoacoustic imaging agent but also exhibit an even stronger PDT efficiency than that of chlorin e6 (a widely used classic photosensitizer). In vitro and in vivo studies demonstrate that DPAHB NVs possess high photothermal stability, enhanced tumor accumulation, and suitable biodegradation rate, thus, show a highly promising clinical potential as a new photoactive agent for cancer therapy.

Biocompatible Iron Phthalocyanine-Albumin Assemblies as Photoacoustic and Thermal Theranostics in Living Mice.

Exploring novel and versatile nanomaterials for the construction of personalized multifunctional phototheranostics with significant potentials in bioimaging-guided tumor phototherapies has attracted considerable attention. Herein, the phototheranostic agent human serum albumin-iron (II) phthalocyanine FePc nanoparticles (HSA-FePc NPs) were fabricated for photoacoustic (PA) imaging-guided photothermal therapy (PTT) of cancer in vivo. The prepared HSA-FePc NPs exhibited high stability, efficient NIR absorption, good capability and stability of photothermal behavior with a high photothermal conversion efficiency of ∼44.4%, high contrast and spatial resolution of PA imaging, efficient cancer therapy, and low long-term toxicity. This potent multifunctional phototheranostic is, therefore, very promising and favorable for effective, precise, and safe antitumor treatment in clinical application.

Versatile Polymer Nanoparticles as Two-Photon-Triggered Photosensitizers for Simultaneous Cellular, Deep-Tissue Imaging, and Photodynamic Therapy.

Clinical applications of current photodynamic therapy (PDT) photosensitizers (PSs) are often limited by their absorption in the UV-vis range that possesses limited tissue penetration ability, leading to ineffective therapeutic response for deep-seated tumors. Alternatively, two-photon excited PS (TPE-PS) using NIR light triggered is one the most promising candidates for PDT improvement. Herein, multimodal polymer nanoparticles (PNPs) from polythiophene derivative as two-photon fluorescence imaging as well as two-photon-excited PDT agent are developed. The prepared PNPs exhibit excellent water dispersibility, high photostability and pH stability, strong fluorescence brightness, and low dark toxicity. More importantly, the PNPs also possess other outstanding features including: (1) the high 1 O2 quantum yield; (2) the strong two-photon-induced fluorescence and efficient 1 O2 generation; (3) the specific accumulation in lysosomes of HeLa cells; and (4) the imaging detection depth up to 2100 µm in the mock tissue under two-photon. The multifunctional PNPs are promising candidates as TPE-PDT agent for simultaneous cellular, deep-tissue imaging, and highly efficient in vivo PDT of cancer.

One-dimensional hierarchical layered KxMnO2 (x < 0.3) nanoarchitectures: synthesis, characterization, and their magnetic properties.

One-dimensional (1D) hierarchical nanostructures of ultralong layered K(x)MnO(2) (x < 0.3) bundles with diameters 50-100 nm and lengths up to 50-100 microm have been successfully prepared by a PEG-assisted hydrothermal method based on the reaction of KMnO(4) with 2-ethylhexanol. The obtained samples ascribe to the monoclinic phase and exhibit ferromagnetic behaviors below 32 K and paramagnetic behaviors above 32 K, which may make this system a promising base material for magnetic devices. A series of contrastive experiments have illustrated that 2-ethylhexanol, PEG 400, KOH, and reaction time play an important role in the synthesis of the nanobundles. A possible growth mechanism has been proposed.

Tunable multicolor carbon dots prepared from well-defined polythiophene derivatives and their emission mechanism.

Various functional precursors based on polythiophene derivatives are designed to prepare carbon dots (C-dots) with tunable emissions ranging from blue to near-infrared (NIR) at a single excitation wavelength (400 nm). The as-prepared C-dots demonstrate homogeneous size, superior optical properties, excellent water solubility, and low cytotoxicity. Thus, the C-dots are candidates for bio-imaging. A tunable photoluminescence mechanism is proposed to result from variations in the surface state and N content.

A selective fluorescent and colorimetric dual-responses chemosensor for streptomycin based on polythiophene derivative.

A colorimetric and fluorescent dual-responses chemosensor (PT3, a water-soluble polythiophene) for streptomycin was designed and synthesized. The structure of PT3 was characterized by using infrared spectroscopy, (1)H NMR and gel-permeation chromatography analyses. The conformational change of PT3 induced by streptomycin resulted in the red shift of absorption spectra and fluorescent quenching. Moreover, PT3 showed excellent selectivity for streptomycin over other antibiotics and biomolecules. PT3 could quantificationally detect streptomycin in the range of 2-70 µM with a detection limit of 0.2 µM (116 ppb), which is lower than the maximum residue limit defined by World Health Organization (200 ppb).

A graphene quantum dot photodynamic therapy agent with high singlet oxygen generation.

Clinical applications of current photodynamic therapy (PDT) agents are often limited by their low singlet oxygen ((1)O2) quantum yields, as well as by photobleaching and poor biocompatibility. Here we present a new PDT agent based on graphene quantum dots (GQDs) that can produce (1)O2 via a multistate sensitization process, resulting in a quantum yield of ~1.3, the highest reported for PDT agents. The GQDs also exhibit a broad absorption band spanning the UV region and the entire visible region and a strong deep-red emission. Through in vitro and in vivo studies, we demonstrate that GQDs can be used as PDT agents, simultaneously allowing imaging and providing a highly efficient cancer therapy. The present work may lead to a new generation of carbon-based nanomaterial PDT agents with overall performance superior to conventional agents in terms of (1)O2 quantum yield, water dispersibility, photo- and pH-stability, and biocompatibility.

Copolythiophene-derived colorimetric and fluorometric sensor for lysophosphatidic acid based on multipoint interactions.

3-Phenylthiophene-based water-soluble copolythiophenes (CPT9) were designed for colorimetric and fluorometric detection of lysophosphatidic acid (LPA) based on electrostatic interaction, hydrophobic interaction, and hydrogen bonding. Other negatively charged species gave nearly no interference, and the detection limit reached to 0.6 µM, which is below the requisite detection limits for LPA in human plasma samples. The appealing performance of CPT9 was demonstrated to originate from the multipoint interaction-induced conformational change of conjugated backbone and weakened electron transfer effect. To our best knowledge, this is the first polythiophene based optical sensor which displays emission peak red-shift followed with fluorescence enhancement.

A polythiophene-derived ratiometric fluorescent sensor for highly sensitive determination of carbenicillin in aqueous solution.

A new ratiometric fluorescent sensor based on a quaternized quinine substituted 3-phenylpolythiophene derivative (PTQ1) was designed and developed for facile and reliable detection of carbenicillin with high sensitivity and selectivity.