The enhanced photothermal effect of graphene/conjugated polymer composites: Photoinduced energy transfer and applications in photocontrolled switches

Composites prepared by grafting poly(3-hexylthiophene) (P3HT) onto the surfaces of reduced graphene oxide (RGO) (RGO-g-P3HT) exhibit an enhanced photothermal effect due to photoinduced energy transfer from P3HT to RGO. A remote photo-controlled electrical switch was prepared using RGO-g-P3HT as a photothermal layer.close2

Biodegradable Metal Complex-Gated Organosilica for Dually Enhanced Chemodynamic Therapy through GSH Depletions and NIR Light-Triggered Photothermal Effects

Hollow silica spheres have been widely studied for drug delivery because of their excellent biosecurity and high porosity. However, difficulties with degradation in the tumor microenvironment (TME) and premature leaking during drug delivery limit their clinical applications. To alleviate these problems, herein, hollow organosilica spheres (HOS) were initially prepared using a “selective etching strategy” and loaded with a photothermal drug: new indocyanine green (IR820). Then, the Cu2+–tannic acid complex (Cu-TA) was deposited on the surface of the HOS, and a new nanoplatform named HOS@IR820@Cu-TA (HICT) was finally obtained. The deposition of Cu-TA can gate the pores of HOS completely to prevent the leakage of IR820 and significantly enhance the loading capacity of HOS. Once in the mildly acidic TME, the HOS and outer Cu-TA decompose quickly in response, resulting in the release of Cu2+ and IR820. The released Cu2+ can react with the endogenous glutathione (GSH) to consume it and produce Cu+, leading to the enhanced production of highly toxic ·OH through a Fenton-like reaction due to the overexpressed H2O2 in the TME. Meanwhile, the ·OH generation was remarkably enhanced by the NIR light-responsive photothermal effect of IR820. These collective properties of HICT enable it to be a smart nanomedicine for dually enhanced chemodynamic therapy through GSH depletions and NIR light-triggered photothermal effects

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

Deep-Red Emissive Crescent-Shaped Fluorescent Dyes: Substituent Effect on Live Cell Imaging

A series of crescent-shaped fluorescent dyes (<b>CP1</b>–<b>CP6</b>) were synthesized by hybridizing coumarin and pyronin moieties with different amino substituents at both ends. The molecular structures and photophysical properties of these fluorescent dyes were investigated through X-ray diffraction, absorption spectroscopy, and fluorescence spectroscopy. Results show that the fluorescent dyes exhibited crescent-shaped structures, deep-red emissions (approximately 650 nm), and significant Stokes shifts. In live-cell-imaging experiments, <b>CP1</b> stains mitochondria, whereas <b>CP3</b> and <b>CP6</b> stain the lysosomes in a cytoplasm and the RNA in nucleoli. The relationships between different amino substituent groups and the imaging properties of <b>CP</b> dyes were discussed as well. Additionally, findings from the cytotoxicity and photostability experiments on living cells indicated the favorable biocompatibility and high photostability of the <b>CP</b> dyes

Deep-Red and Near-Infrared Xanthene Dyes for Rapid Live Cell Imaging

In this work, two xanthene dyes (<b>H-hNR</b> and <b>TF-hNR</b>) have been synthesized by a convenient and efficient method. These two dyes exhibited deep-red and near-infrared emissions, high fluorescence quantum yields, and good photostability. Their structure–optical properties were investigated by X-ray crystal structure analysis and density functional theory calculations. Live cell imaging data revealed that <b>H-hNR</b> and <b>TF-hNR</b> could rapidly stain both A549 and HeLa cells with low concentrations. The excellent photophysical and imaging properties render them as promising candidates for use in live cell imaging

Copolythiophene-Derived Colorimetric and Fluorometric Sensor for Lysophosphatidic Acid Based on Multipoint Interactions

3-Phenylthiophene-based water-soluble copolythiophenes (<b>CPT9</b>) 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 <b>CPT9</b> 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

Copolythiophene-Derived Colorimetric and Fluorometric Sensor for Visually Supersensitive Determination of Lipopolysaccharide

3-Phenylthiophene-based water-soluble copolythiophenes (CPT<b>1</b>) were designed for colorimetric and fluorometric detection of lipopolysaccharide (LPS). The sensor (CPT<b>1</b>-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, CPT<b>1</b>-C is capable of rapidly discriminating the Gram-negative bacteria (with LPS in the membrane) from Gram-positive bacteria (without LPS)