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Fluorescent imaging probes are crucial for exploring nucleus-related cellular events in live cells. Ideal probes should be photostable, small-sized, highly contrasted, and low in background. Here, we discovered that malachite green is a water-soluble near-infrared luminogen with aggregation-induced emission properties. Importantly, it can be used for living cell nucleus staining in a wash-free manner. [ABSTRACT FROM AUTHOR]

Mitochondria play a vital role in maintaining cellular homeostasis. In recent years, studies have found that mitochondria have an important role in the occurrence and development of tumors, and targeting mitochondria has become a new strategy for tumor treatment. Lonidamine (LND), as a hexokinase inhibitor, can block the energy supply and destroy mitochondria. However, poor water solubility and low mitochondrial selectivity limit its clinical application. To overcome these obstacles, we report redox-activated self-assembled carrier-free nanoparticles (Cy-TK-LND NPs) based on a small molecule prodrug, in which photosensitizer IR780 (Cy) which targets mitochondria is conjugated to LND via a sensitive thioketal (TK) linker. Intracellular oxidative stress induced by laser radiation leads to the responsive cleavage of Cy-TK-LND NPs, facilitating the release of free LND into mitochondria. Subsequently, LND damages mitochondria, triggering the apoptosis pathway. The results show the effective killing effect of Cy-TK-LND NPs on cancer cells in vitro and in vivo. The IC50 value of irradiated Cy-TK-LND NPs is 5-fold lower than that of free LND. Moreover, tumor tissue section staining results demonstrate that irradiated Cy-TK-LND NPs induce necrosis and apoptosis of tumor cells, upregulate cytochrome C and pro-apoptotic Bax, and downregulate anti-apoptotic Bcl-2. Generally, Cy-TK-LND NPs exhibit efficient mitochondria-targeted delivery to improve the medicinal availability of LND. Accordingly, such a carrier-free prodrug-based nanomedicine holds promise as an effective cancer chemotherapy strategy. [ABSTRACT FROM AUTHOR]

Butyrylcholinesterase (BChE) is an essential human biomarker which is related to liver and neurodegenerative diseases. It is of great significance to develop a fluorescent probe that can image BChE in vitro and in vivo. Unfortunately, most fluorescent probes that are based on a single change in fluorescence intensity are susceptible to environmental interference. Therefore, we reported an easily available ratiometric fluorescent probe, TB-BChE, with aggregation-induced emission (AIE) characteristics for ratiometric imaging of BChE. TB-BChE demonstrated excellent sensitivity (LOD = 39.24 ng mL−1) and specificity for BChE. Moreover, we have successfully studied the ratiometric imaging of TB-BChE to BChE in a nonalcoholic fatty liver disease model. These results indicated that TB-BChE is expected to become a powerful analysis tool for butyrylcholinesterase research in basic medicine and clinical applications. [ABSTRACT FROM AUTHOR]

Here, we report an easily available endoplasmic reticulum-targeting near-infrared fluorescent probe (ER-CE), which can detect esterase in the endoplasmic reticulum and monitor the changes in the esterase amount in tumors in mice in real time. These results indicate that ER-CE is expected to become a powerful analysis tool for the research of endoplasmic reticulum esterase-related diseases. [ABSTRACT FROM AUTHOR]

A zwitterionic polymer containing a hydrophobic long chain, named MANPS, was independently developed by free radical solution polymerization. The introduction of an hydrophobic long-chain monomer, namely, octadec-9-enioc acid allylamide (NAE) and an amphoteric ionic monomer, i.e., 3-(3-methylacrylamide propyl dimethylamino)-propyl-1-sulfonate (MEPS) in conventional acrylamide (AM) and acrylic acid (AA) enhanced the rheological properties of polymer flooding agents, thereby improving their temperature resistance and salt tolerance. A series of experiments were performed to determine the optimal reaction conditions for the polymer; the structure and molecular weight characteristics of MANPS were confirmed by FT-IR spectroscopy, 1H NMR spectroscopy, intrinsic viscosity, high-performance liquid chromatography (HPLC) and SEM. The rheological test results showed that MANPS had higher apparent viscosity than the partially hydrolyzed polyacrylamide (HPAM). It exhibited good shear recovery at a certain shear rate. The reason was considered to be the long-chain entanglement of molecules and the "anti-polyelectrolyte action" of zwitterions. Thermogravimetric analysis provided good evidence of the thermal properties of the copolymer MANPS. Evaluating the oil displacement performance of the oil-displacing agent was an essential part. The results showed that the copolymer MANPS was comparable to HPAM having a 10.4% higher oil displacement rate under the same concentration and test conditions. [ABSTRACT FROM AUTHOR]

β-Cyclodextrin has attracted considerable attention due to its unique structure with a hydrophobic cavity and a hydrophilic rim, allowing hydrophobic guest molecules to enter the hydrophobic cavity from aqueous solution to form stable host–guest inclusions. Based on this, two kinds of copolymers with host–guest interaction based on modified β-cyclodextrin and hydrophobic twin-tail structures, which are expected to be alternatives to currently used copolymers in the oil field, were successfully synthesized via free-radical copolymerization in this study. Subsequently, the copolymers were characterized by FT-IR, 1H NMR, SEM and TG-DTG to confirm that they were prepared successfully and exhibited favorable thermal stability. Furthermore, the copolymers could enormously increase the viscosity of the aqueous solution compared with partially hydrolyzed polyacrylamide. And static experiments have convincingly proved that the β-cyclodextrin and twin-tail structure endowed the copolymers with excellent shear resistance, temperature resistance, salt tolerance, and viscoelasticity. Core flooding experiments further indicated that this unique type of host–guest interaction can make the copolymers have great potential for enhanced oil recovery. [ABSTRACT FROM AUTHOR]

The “trash to treasure” process has been extensively demonstrated for various energy and environmental issues in the past few decades. Abundant biomass is well accepted as a carbon-rich, sustainable, and renewable precursor, offering us a plethora of possibilities for advanced materials for energy conversion and storage as well as environmental treatments; spatial modification of biomass facilitates the formation of a unique three-dimensional (3D) structure with micro- to macropores, yielding higher surface area and enhanced physicochemical properties. This novel concept provides sufficient reaction sites, excellent adsorption capability, more activated sites for catalyst doping, and fascinating electrochemical performance. Basically, the 3D cadre of biomass-derived carbon strengthens the economic competitiveness of these materials and broadens their applications in fields such as in supercapacitors, chemical batteries, bioenergy harvest, adsorbents for organic pollutants and greenhouse gases, and efficient (photo)catalysts. The scope of this review mainly focuses on the most popular synthesis methodology of three-dimensional carbon materials derived from biomass and their critical applications in the fields of energy and environment. [ABSTRACT FROM AUTHOR]

We developed highly bright and stable far-red emissive AIEdots by using a new kind of click-functional PEG grafted amphiphilic polymer to coat hydrophobic AIE-active polymers (PDFDP). Furthermore, an anti-HER2 recombinant fully human antibody was produced and conjugated on the AIEdots via metal-free click chemistry to fabricate in vivo tumor-targeting nanoprobes. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) organic dyes have received increasing attention in recent years as diagnostic and therapeutic agents in the field of tumor research. In this study, IR-822, a near-infrared fluorescence (NIRF) heptamethine cyanine dye, was chosen as a fluorophore due to its high extinction coefficients, and native preferential tumor accumulation property. To enhance its specificity in tumor imaging, N1-(pyridin-4-ylmethyl)ethane-1,2-diamine (PY) was conjugated to IR-822 as a pH-sensing receptor, forming a fluorophore–spacer–receptor molecular probe (IR-PY) that can modulate the fluorescence emission intensity through a fast photoinduced electron-transfer process, which allowed the probe to “switch on” significantly in an acidic tumor microenvironment and which realized enhanced NIRF imaging in vivo. Having a strong NIR absorption at 600–850 nm, this small-molecule IR-PY showed not only high spatial resolution photoacoustic (PA) imaging in mice, but also effective tumor photothermal ablation in vivo. After photothermal therapy (PTT) with IR-PY under NIR 808 nm laser irradiation, the mice exhibited remarkable ablation with no tumor recurrence after treatment. Therefore, a single smart small-molecule probe IR-PY has been designed, synthesized and verified as an “all in one” multifunctional agent, including pH sensitivity, tumor targeting, “switch-on” near-infrared fluorescence imaging, high-spatial-resolution PA imaging and efficient near-infrared photothermal therapy, which is promising for clinical application in NIRF/PA dual-modal imaging-guided cancer diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Heteroatom-doped hollow carbon nanospheres (HCNs) have drawn significant attention as alternative catalysts towards the oxygen reduction reaction (ORR). However, the simple and environmentally friendly synthesis of heteroatom-doped HCNs is a great challenge. Herein, an Fe/N-doped porous HCN (Fe/N-HCN) has been fabricated via a simple pyrolysis method using one-step synthesized poly(aniline-co-pyrrole) copolymer hollow nanospheres as precursors. The prepared Fe/N-HCN exhibited excellent ORR activity (onset potential of 0.02 V and half-wave potential of −0.12 V vs. Ag/AgCl), comparable to that of the Pt/C catalyst (onset potential of 0.01 V and half-wave potential of −0.14 V vs. Ag/AgCl) and superior to those of most of the reported noble metal-free carbon catalysts with hollow structures. The catalytic proficiency of the as-prepared catalyst was attributed to the abundant N and Fe atoms within the carbon lattice and a high surface area due to its hollow morphology. The as-prepared Fe/N-HCN also exhibited remarkable ORR activity in neutral solution, displaying potential application as a cathode catalyst in a microbial fuel cell (MFC). A maximum power density of 1300 ± 64 mW m−2 was achieved from an MFC equipped with the resultant Fe/N-HCN cathode, which outperformed that of the MFC with a Pt/C cathode. In this study, we reported a new approach for the production of Fe/N-doped carbon materials with a hollow morphology that exhibited high performance towards ORR. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) electrodes have been intensively investigated as high-performance electrodes to harvest microbial energy in bioelectrochemical systems (BESs). However, the fabrication of low-cost high-performance 3D electrodes is still a great challenge. Herein, we reported a new highly conductive and biocompatible 3D electrode by simply coating natural loofah sponge (LS) with low-cost Chinese ink (CI) that has been used for writing and drawing for thousands of years. A high current density of 16.3 ± 0.5 mA cm−3 was achieved by the as-prepared Chinese ink-coated loofah sponge (CI-LS), which is close to that of the 3D electrode produced from the carbonized LS and equals those of most of the available materials in the current state of research. This high current density is attributed to the open macroporous structure of the LS as well as high conductivity and good biocompatibility of the carbon nanoparticle coating layers. The performance of the CI-LS depended strongly on the type of CI used as the conductive coating material. Besides, the resulting bioelectrode displayed promising stability, which outperformed other 3D electrodes based on synthetic sponges. Considering the low-cost and facile fabrication, this CI-LS 3D electrode has promising potential for high-performance and cost-effective BESs on a large scale. [ABSTRACT FROM AUTHOR]

Catalysts for the oxygen reduction reaction (ORR) are crucial in fuel cells and metal–air batteries. The development of metal-free catalysts with high activity at low cost remains a great challenge. In this paper, a novel type of fluorescent carbon nanodots (CDs) supported by graphene have been developed through a microbial reduction process followed by a simple hydrothermal treatment. In the synthesis, microorganisms have the multi-function of simultaneously reducing and doping graphene oxide as reductants during the incubation process and producing CDs as self-sacrifice precursors during the hydrothermal treatment. Meanwhile, the CDs derived from bacterial cells were simultaneously self-packed on the microbially reduced graphene oxide (M-rGO) during the hydrothermal treatment to produce CD-coated M-rGO (CDs/M-rGO). Chemical analyses revealed that both CDs and M-rGO were doped with heteroatoms such as N, S, and P. Electrochemical characterization showed that the CDs/M-rGO hybrid had good catalytic properties with excellent long-term stability and resistance to methanol crossover for the ORR via a four-electron pathway in alkaline solution. The excellent electrocatalytic properties of CDs/M-rGO originate from the combined effect of heteroatom doping and numerous surface/edge defects that induce the high-density distribution of highly active and stable catalytic sites, and the strong coupling effects between CDs and graphene that can facilitate the charge transport and ionic motion during the ORR. This study presents a new approach to the production of inexpensive, graphene-based materials that exhibit high performance in the ORR. [ABSTRACT FROM AUTHOR]

We report here a novel anti-biodegradable hydrophobic acrylamide copolymer that was prepared from acrylamide, acrylic acid, sodium 3-(allyloxy)-2-hydroxypropane-1-sulfonate and N-allyl-2-(2,4-dichlorophenoxy) acetamide using the 2,2′-azobis(2-methylpropionamide) dihydrochloride initiation system. Subsequently, the copolymer was characterized by FT-IR, 1H NMR, TG-DTG and water-solubility. And the biodegradability test indicated that the copolymer was not deemed to be readily biodegradable via a closed bottle test established by the Organization for Economic Co-operation and Development (OECD 301 D). Meanwhile the copolymer could significantly enhance the viscosity of the aqueous solution in comparison with partially hydrolyzed polyacrylamide. A viscosity retention of 51.9% indicated the result of a dramatic improvement of temperature tolerance. And then the excellent salt resistance, shear resistance, viscoelasticity, long-term stability of the copolymer could be obtained, which provides a good theoretical foundation for the application in enhanced oil recovery. In addition, this copolymer exerted stronger mobility control ability with a resistance factor of 22.1 and a residual resistance factor of 5.0, and superior ability for enhanced oil recovery of 12.9%. Hence, the copolymer has potential application for enhanced oil recovery in high-temperature and high-salinity reservoirs. [ABSTRACT FROM AUTHOR]