Albertknight5473

Developing a universal and simple structure with an excellent fluorescence enhancement is a highly desirable goal for practical applications in optical detection and imaging. Herein, a hybrid structure composed of melamine-formaldehyde (MF) microspheres covering an Au nanorod (AuNR) film (MS/AuNR for short) is reported to enhance fluorescence, which is based on the cooperative effects of a photonic nanojet and plasmon resonance. Moreover, to obtain an excellent plasmonic property, an additional poly(methyl methacrylate) (PMMA) spacing layer with an optimal thickness of 8 nm is added to prevent the fluorescence from directly coming in contact with the AuNR film. Using the proposed hybrid structure and taking the quantum dots (QDs) as fluorescent materials, a maximum enhancement of fluorescence of up to 260 fold is measured. Besides, the hybrid structure is also applied in fluorescence imaging. Utilizing the fluorescence enhancement and pattern magnification effects of the hybrid structure, clear imaging of the 100 nm fluorescent particles is achieved. The above results have important academic value and application prospects in many fields such as weak fluorescence detection and nano-fluorescence imaging.We report that MoS2 nanosheets (MoS2 NSs) as a cocatalyst in situ coupled with MAPbI3 lead to a highly efficient composite photocatalyst for visible-light-driven photocatalytic H2 evolution. The most efficient MAPbI3/MoS2 NSs composite exhibits a high H2 evolution rate (206.1 μmol h-1) in MAPbI3-saturated HI solution, which is 121 times higher than that of pristine MAPbI3 (1.7 μmol h-1) and greatly superior to that of MAPbI3/Pt/C (68.5 μmol h-1), and the composite is very stable for H2 evolution in a 156 h reaction.Reactions of 1,3-ketoesters, -diesters, -diketones, and -ketoamides with [Me4N][SeCF3] in the presence of an appropriate oxidant provided a series of 2-trifluoromethylselenolated 1,3-dicarbonyls in moderate to good yields. The trifluoromethylselenolation featured simplicity, mildness, high efficiency, transition-metal-free conditions, and compatibility of various oxidants, and represented the first oxidative trifluoromethylselenolation of 1,3-dicarbonyl compounds with [Me4N][SeCF3]. This protocol was also applicable to the oxidative trifluoromethylthiolation of 1,3-dicarbonyls with [Me4N][SCF3]/NCS, and oxidative trifluoromethylchalcogenation with nucleophilic XCF3 (X = O, S, and Se) reagents were compared. The results demonstrated that these nucleophilic XCF3 salts showed different reaction profiles towards 1,3-dicarbonyls under oxidation conditions.The combination of immunotherapy and chemotherapy has shown great potential for treating solid tumors. Although various combination therapy regimens have been demonstrated to be effective, their implementation in practice always needs separate drugs or modalities, which in turn requires specific and complicated operation procedures. Here, we describe the use of enzyme-instructed self-assembly (EISA) of a phosphotyrosine-cholesterol (PTC) conjugate to combine immune microenvironment modulation and chemotherapy. The enzymatic dephosphorylation of PTC results in the assembly of its derivatives inside and outside the cells, which leads to repolarization of the macrophage phenotype and direct death of cancer cells. The generation of reactive oxygen species and actin disturbance induced by the assemblies has been verified relative to the macrophage repolarization. We also demonstrate its dual repolarization and inhibition effects in vivo using an ovarian cancer bearing immunocompetent murine model. The EISA of cholesterol conjugates is an effective yet simple approach for the combination of tumor microenvironment immunomodulation and chemotherapy.Plasmonic nanohole arrays for biosensing applications have attracted tremendous attention because of their flexibility in optical signature design, high multiplexing capabilities, simple optical alignment setup, and high sensitivity. The quality of the metal film, including metal crystallinity and surface roughness, plays an important role in determining the sensing performance because the interaction between free electrons in the metal and incident light is strongly influenced by the metal surface morphology. We systematically investigated the influence of metal crystallinity-related morphologies on the sensing performance of plasmonic nanohole arrays after different metal deposition processes. We utilised several non-destructive nanoscale surface characterisation techniques to perform a quantitative and comparative analysis of the Au quality of the fabricated sensor. We found empirically how the surface roughness and grain sizes influence the permittivity of the Au film and thus the sensitivity of the fabricated sensor. Finally we confirmed that the deposition conditions that provide both low surface roughness and large metal grain sizes improve the sensitivity of the plasmonic sensor.Synthesis of tetra-armed cyclens (2a-2e), with substituted styrylmethyl groups as side-arms, and their Ag+ complexes is reported. The Ag+ complex with a tetra styrylmethyl-armed cyclen (2a) incorporates alkyl nitriles in a pseudo-cavity formed by the four styrylmethyl side-arms. This prompted us to apply this system to the determination of the absolute configurations of chiral nitriles with low [α]D and low circular dichroism (CD) intensity. In the CD spectra of the 2a/Ag+ complex, (S)- and (R)-G1 did not show a specific Cotton effect, while when chiral nitriles were added to the 2a/Ag+ complex, drastic spectral changes were observed. The (S)-G1@2a/Ag+ system exhibited first a negative and then a positive Cotton effect, whereas the (R)-G1@2a/Ag+ system showed the mirror image of the Cotton effect of (S)-G1@2a/Ag+. We have, therefore, demonstrated a new technique for determining the absolute configurations of weak optical rotation molecules using the Ag+ complex with 2a.Novel orange-emitting N-doped carbon dots (N-CDs) were prepared as fluorescent and colorimetric dual-mode probes for sensing nitrite (NO2-). The obtained N-CDs possessed fantastic optical properties and specific responses to NO2-. NO2- could induce the fluorescence static quenching of N-CDs, and a linear relationship was obtained in the range from 2 to 60 μM with the detection limit of 0.35 μM. More interestingly, the N-CDs exhibited ratiometric absorption signals with visible color conversion (red-purple), which allowed the development of a simple colorimetric method for NO2- monitoring in the linear range of 2-80 μM with a detection limit down to 0.13 μM. Additionally, the N-CDs were capable of monitoring NO2- in the A549 cells, which indicated their great potential in biosensing.In this academic research, we report the polyvinylpyrrolidone (PVP) assisted synthesis of a Ni3S2 electrode material containing a plentiful number of active sites on Ni foam by a novel hydrothermal approach. Interestingly, the Ni3S2 electrode is a highly efficient electroactive material, as evidenced by the physical and electrochemical characterization. Based on the physical characterization, the constructed Ni3S2 nano architecture exhibited plentiful electroactive sites, quick charge/discharge transportation and better maximum conductivity, which gave rise to enhanced electrochemical activity for large-scale supercapacitors (SCs). Besides, the electrochemical characterization of the as-developed Ni3S2 electrode obviously displayed a faradaic battery-based redox profile, which is distinct from the profiles of carbon-type materials. The battery-based PVP-assisted Ni3S2 electrode achieved impressive electrochemical activity, namely exceptional SC activity with a superior specific capacity of ∼316.8 mA h g-1 at 2 A g-1 current density, high rate capability with ∼91.4% of capacity retained at 20 A g-1, and superb cycling performance with ∼96.7% of capacity retained at 6 A g-1 after 4000 cycles. Thus, considering the best findings above, the as-developed PVP-assisted Ni3S2 is a highly efficient candidate for SCs and could effectively serve in various advanced energy storage applications.As nonspecific adsorption or biofouling has obvious side effects on the selectivity, it is a great challenge for cytosensors to detect target cells in practical biological samples. In this study, we first propose the design and synthesis of an antifouling photoelectrode. The antifouling photoelectrode not only has the desired photocurrent response, but also possesses an unexpected antifouling capability of resisting nonspecific adsorption of biomolecules. selleck chemicals llc Herein, the PEDOT-HPG/SnS/ZnO-NT antifouling photoelectrode was formed and a robust photoelectrochemical cytosensor with enhanced sensitivity and selectivity has been demonstrated.Melatonin (MT) is an important electroactive hormone that regulates different physiological actions in the brain, ranging from circadian clock to neurodegeneration. An impressive number of publications have highlighted the effectiveness of MT treatments in different types of sleep and neurological disorders, including Alzheimer's and Parkinson's disease. The ability to detect MT in different regions of the brain would provide further insights into the physiological roles and therapeutic effects of MT. While multiple electrochemical methods have been used to detect MT in biological samples, monitoring MT in the brain of live animals has not been demonstrated. Here, we optimized a square wave voltammetry (SWV) electroanalytical method to evaluate the MT detection performance at CFEs in vitro and in vivo. SWV was able to sensitively detect the MT oxidation peak at 0.7 V, and discriminate MT from most common interferents in vitro. More importantly, using the optimized SWV, CFEs successfully detected and reliably quantified MT concentrations in the visual cortex of anesthetized mice after intraperitoneal injections of different MT doses, offering stable MT signals for up to 40 minutes. To the best of our knowledge, this is the first electrochemical measurement of exogenously administered MT in vivo. This electrochemical MT sensing technique will provide a powerful tool for further understanding MT's action in the brain.Finding out how to overcome multistage biological barriers for nanocarriers in cancer therapy to obtain highly precise drug delivery is still a challenge. Herein, we prepared a multistage and cascaded switchable polymeric nanovehicle, self-assembled from polyethylene glycol grafted amphiphilic copolymer containing hydrophobic poly(ortho ester) and hydrophilic ethylenediamine-modified poly(glycidyl methacrylate) (PEG-g-p(GEDA-co-DMDEA)) for imaging-guided chemo-photothermal combination anticancer therapy. Notably, a novel ATRP initiator containing cyanine dye was designed and attached to the polymer, providing the nanovehicle with NIR-light induced photothermal and fluorescent properties. The PEG shell displayed tumor-microenvironment-induced detachment, resulting in the surface charge change of the nanovehicle from neutral to positive and thus enhancing cellular uptake. Subsequently, the hydrophobic pDMDEA hydrolyzed into a hydrophilic segment in the acidic lysosome, leading to sufficient drug release. Finally, with the aid of the photothermal property, the therapeutic drug DOX successfully escaped from the lysosome to exert chemotherapy.