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1.
Analyst ; 149(19): 4881-4888, 2024 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-39143943

RESUMEN

Strategies based on nanomaterials for sterilization address the problem of antibiotic resistance faced by conventional antimicrobials, with the contribution of photocatalytic compounds being particularly prominent. Herein, to integrate multiple bactericidal techniques into a system for generating synergistic antibacterial effects, a novel photo-triggered AuAg@g-C3N4 composite nanoplatform was constructed by anchoring AuAg on the surface of a g-C3N4 layer. As the composite nanoplatform had a lower bandgap and superior visible light utilization efficiency, it could facilitate free electron transfer better and exhibit superior photocatalytic activity under light conditions. Moreover, the AuAg@g-C3N4 composite nanoplatform integrated the bactericidal modes of silver ion toxicity, physical disruption of bacterial cell membranes by the multilayer structure, and excellent photocatalytic activity, exhibiting extremely superior bactericidal effects against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis, with a bactericidal efficiency of up to 100%.


Asunto(s)
Antibacterianos , Oro , Plata , Antibacterianos/farmacología , Antibacterianos/química , Plata/química , Plata/farmacología , Oro/química , Oro/farmacología , Luz , Compuestos de Nitrógeno/química , Compuestos de Nitrógeno/efectos de la radiación , Compuestos de Nitrógeno/farmacología , Compuestos de Nitrógeno/toxicidad , Grafito/química , Grafito/efectos de la radiación , Grafito/farmacología , Pruebas de Sensibilidad Microbiana , Catálisis , Nitrilos/química , Nitrilos/farmacología , Nanopartículas del Metal/química , Escherichia coli/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Procesos Fotoquímicos , Bacillus subtilis/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos
2.
Angew Chem Int Ed Engl ; 63(15): e202400281, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38339811

RESUMEN

The development of highly efficient electrocatalysts for complete oxidation of ethylene glycol (EG) in direct EG fuel cells is of decisive importance to hold higher energy efficiency. Despite some achievements, their progress, especially electrocatalytic selectivity to complete oxidated C1 products, is remarkably slower than expected. In this work, we developed a facile aqueous synthesis of Ir-doped CuPd single-crystalline mesoporous nanotetrahedrons (Ir-CuPd SMTs) as high-performance electrocatalyst for promoting oxidation cleavage of C-C bond in alkaline EG oxidation reaction (EGOR) electrocatalysis. The synthesis relied on precise reduction/co-nucleation and epitaxial growth of Ir, Cu and Pd precursors with cetyltrimethylammonium chloride as the mesopore-forming surfactant and extra Br- as the facet-selective agent under ambient conditions. The products featured concave nanotetrahedron morphology enclosed by well-defined (111) facets, single-crystalline and mesoporous structure radiated from the center, and uniform elemental composition without any phase separation. Ir-CuPd SMTs disclosed remarkably enhanced electrocatalytic activity and excellent stability as well as superior selectivity of C1 products for alkaline EGOR electrocatalysis. Detailed mechanism studies demonstrated that performance improvement came from structural and compositional synergies, which kinetically accelerated transports of electrons/reactants within active sites of penetrated mesopores and facilitated oxidation cleavage of high-energy-barrier C-C bond of EG for desired C1 products. More interestingly, Ir-CuPd SMTs performed well in coupled electrocatalysis of anode EGOR and cathode nitrate reduction, highlighting its high potential as bifunctional electrocatalyst in various applications.

3.
Anal Chem ; 94(17): 6607-6614, 2022 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-35446026

RESUMEN

The dysfunctional islet ß-cell triggered by excessive deposition of Zn2+ constituted a striking indicator of the occurrence of diabetic disease. However, it remained a formidable challenge to reflect the real-time function of ß-cell by monitoring the Zn2+ content. Herein, multistage photoactivatable Zn2+-responsive nanodevice (denoted as AD2@USD1) was presented for sensing, regulating, and evaluating Zn2+ levels in dysfunctional islet ß-cells. The photoactivated signatures on the satellite shell layer of the nanodevices and the internally loaded chelating factors effectively identified and intervened in the real-time concentration of Zn2+, the photothermal feedback component decorated on the inner core permitted the assessment of the post-intervention Zn2+ levels, achieving an integrated intervention and prognostic assessment in response to the abnormal islet ß-cell function induced by Zn2+ deposition. In this way, one strategy for sensing and regulating islet ß-cell function-oriented to Zn2+ was established. Our study introduced AD2@USD1 as a tool for effectively sensing, adjusting, and assessing the Zn2+ level in islet ß-cells with abnormalities, gaining a potential breakthrough in the treatment of diabetes.


Asunto(s)
Diabetes Mellitus , Células Secretoras de Insulina , Islotes Pancreáticos , Quelantes , Humanos , Zinc
4.
Angew Chem Int Ed Engl ; 61(1): e202112511, 2022 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-34709699

RESUMEN

We demonstrate a new material by intercalating Mo3 S13 2- into Mg/Al layered double hydroxide (abbr. Mo3 S13 -LDH), exhibiting excellent capture capability for toxic Hg2+ and noble metal silver (Ag). The as-prepared Mo3 S13 -LDH displays ultra-high selectivity of Ag+ , Hg2+ and Cu2+ in the presence of various competitive ions, with the order of Ag+ >Hg2+ >Cu2+ >Pb2+ ≥Co2+ , Ni2+ , Zn2+ , Cd2+ . For Ag+ and Hg2+ , extremely fast adsorption rates (≈90 % within 10 min, >99 % in 1 h) are observed. Much high selectivity is present for Ag+ and Cu2+ , especially for trace amounts of Ag+ (≈1 ppm), achieving a large separation factor (SFAg/Cu ) of ≈8000 at the large Cu/Ag ratio of 520. The overwhelming adsorption capacities for Ag+ (qm Ag =1073 mg g-1 ) and Hg2+ (qm Hg =594 mg g-1 ) place the Mo3 S13 -LDH at the top of performing sorbent materials. Most importantly, Mo3 S13 -LDH captures Ag+ via two paths: a) formation of Ag2 S due to Ag-S complexation and precipitation, and b) reduction of Ag+ to metallic silver (Ag0 ). The Mo3 S13 -LDH is a promising material to extract low-grade silver from copper-rich minerals and trap highly toxic Hg2+ from polluted water.

5.
J Am Chem Soc ; 142(3): 1574-1583, 2020 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-31855420

RESUMEN

The new material Polypyrrole-Mo3S13 (abbr. Mo3S13-Ppy) is a new material prepared by ion-exchange between Ppy-NO3 and (NH4)2Mo3S13. The Mo3S13-Ppy was designed to exhibit strong selectivity for Ag+ and highly toxic Hg2+ in mixtures with other ions. It displays an apparent selectivity ranking of Hg2+ > Ag+ ≥ Co2+, Ni2+, Cu2+, Zn2+, Cd2+, and Pb2+. The strong affinity of Mo3S13-Ppy for Ag+ and Hg2+ was confirmed with extremely high distribution coefficients (Kd) (∼107 mL/g) and remarkable removal efficiencies (>99.99%), resulting in <1 ppb concentrations of these ions. Furthermore, Mo3S13-Ppy achieved excellent separation selectivity for Ag+ from Cu2+ (even at a high Cu2+/Ag+ ratio, the molar ratio of 867 and mass ratio of 500) because of the special structure of Mo3S132- and its component Mo4+ and (S2)2-. This is promising for the direct extraction of low-grade silver from copper-rich minerals. The maximum Ag uptake capacity of 408 mg/g is redox-based and surprisingly involves the deposition of large, millimeter sized, metallic silver (Ag0) crystals on the surface of Mo3S13-Ppy.

6.
Nanotechnology ; 31(3): 035403, 2020 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-31557753

RESUMEN

The development of low-cost electrocatalysts with high performance is important to provide sustainable hydrogen energy. In this work, via one-step sulfuration of [Formula: see text] intercalated NiFe-layered double hydroxide (abbr. NiFe-MoO4-LDH), hierarchical microspheres are assembled by intersecting nanoplates (15-30 nm in thickness) which are then decorated with MoS2 and (NiFe)S x nanoparticles (∼25 nm in size). The NiFe-MoO4-LDH is synthesized beforehand by a one-pot hydrothermal reaction. Under sulfuration at 300 °C, 400 °C and 600 °C, the NiFe-MoO4-LDH transforms into multi-metal sulfides of NiFeMoS-T (T is applied temperature). During sulfuration, the confinement effect of LDH limits the growth of metal sulfides, causing formation of nanoparticles of MoS2 and (NiFe)S x to expose more catalytic active sites. In an alkaline medium, NiFeMoS-400 depicts superior performance for hydrogen evolution reaction (HER), giving an overpotential of 210 mV at 10 mA cm-2. A Tafel slope of 88 mV dec-1 indicates a mixed Volmer-Heyrovsky rate-determining step. The electrode also maintains long-term electrochemical durability during 15 h electrolysis at 25 mA cm-2. The NiFe-MoO4-LDH precursor owns three metal elements (Ni, Fe and Mo), which ensure the formation of polymetallic sulfides, and maximum utilization of the LDH layer and interlayer metals contributes to the optimal electrocatalytic activity. The NiFeMoS nanoassembly is a potential low-cost and high-efficiency electrocatalyst.

7.
Phys Chem Chem Phys ; 22(39): 22746-22757, 2020 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-33020777

RESUMEN

Herein, a new type of lanthanide coordination polymer film made up of europium (Eu(iii)) and poly(N-methacryloylglycine) (Eu(iii)-PMAG) was prepared on an ITO electrode surface driven by the coordination between N-methacryloylglycine (MAG) and Eu(iii) through a single-step polymerization process. The fluorescence signal of Eu(iii)-PMAG films at 617 nm originating from Eu(iii) could be well retained in the buffer solution but was regulated by the concentration of Cu(ii) and the complexing agent EDTA. The switching of fluorescence by Cu(ii) was attributed to the inhibition of the "antenna effect" between Eu(iii) and the MAG ligand in the films. The coexistence of reduced ß-nicotinamide adenine dinucleotide (NADH) in the solution can apparently quench the fluorescence of Eu(iii)-PMAG films through the internal filtration effect of UV absorbance overlapping the excitation wavelength, but itself exhibiting a fluorescence emission at 468 nm. In addition, the electrocatalytic oxidation of NADH with the help of the ferrocenedicarboxylic acid (FcDA) probe demonstrated a cyclic voltammetry (CV) signal at 0.45 V (vs. SCE). Based on various reversible stimulus-responsive behaviours, a 4-input/10-output logic network was built using Cu(ii), EDTA, NADH and FcDA as inputs and the signals of fluorescence from Eu(iii)-PMAG (617 nm) and NADH (468 nm), the CV response from FcDA and the UV-vis absorbance from the Cu(ii)-EDTA complex as outputs. Meanwhile, 6 different functional logic devices were constructed based on the same versatile platform, including a 2-to-1 encoder, a 1-to-2 decoder, a 1-to-2 demultiplexer, a parity checker, a transfer gate and a reprogrammable 3-input/2-output keypad lock. Combined with the new type of lanthanide coordination polymer film, NADH played central roles in designing sophisticated computing systems with its fluorescence, UV and electrocatalytic properties. This work might provide a novel avenue to develop intelligent multi-analyte sensing and information processing at the molecular level based on one single platform.

8.
J Am Chem Soc ; 141(26): 10417-10430, 2019 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-31244177

RESUMEN

The design of low-cost yet high-efficiency electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) over a wide pH range is highly challenging. We now report a hierarchical co-assembly of interacting MoS2 and Co9S8 nanosheets attached on Ni3S2 nanorod arrays which are supported on nickel foam (NF). This tiered structure endows high performance toward HER and OER over a very broad pH range. By adjusting the molar ratio of the Co:Mo precursors, we have created CoMoNiS-NF- xy composites ( x: y means Co:Mo molar ratios ranging from 5:1 to 1:3) with controllable morphology and composition. The three-dimensional composites have an abundance of active sites capable of universal pH catalytic HER and OER activity. The CoMoNiS-NF-31 demonstrates the best electrocatalytic activity, giving ultralow overpotentials (113, 103, and 117 mV for HER and 166, 228, and 405 mV for OER) to achieve a current density of 10 mA cm-2 in alkaline, acidic, and neutral electrolytes, respectively. It also shows a remarkable balance between electrocatalytic activity and stability. Based on the distinguished catalytic performance of CoMoNiS-NF-31 toward HER and OER, we demonstrate a two-electrode electrolyzer performing water electrolysis over a wide pH range, with low cell voltages of 1.54, 1.45, and 1.80 V at 10 mA cm-2 in alkaline, acidic, and neutral media, respectively. First-principles calculations suggest that the high OER activity arises from electron transfer from Co9S8 to MoS2 at the interface, which alters the binding energies of adsorbed species and decreases overpotentials. Our results demonstrate that hierarchical metal sulfides can serve as highly efficient all-pH (pH = 0-14) electrocatalysts for overall water splitting.

9.
Inorg Chem ; 58(8): 4979-4988, 2019 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-30933488

RESUMEN

Tunable luminescence (quenching or blue shift) of HNA/OS-LRH composites (HNA is 3-hydroxy-2-naphthoic acid; OS is the anionic surfactant of 1-octanesulfonic acid sodium; LRHs are layered rare-earth hydroxides, R = Tb3+, Y3+) in the solid state and delaminated state is reported, which is utilized as an effective fluorescent probe for detecting metal ions. HNA/OS species are intercalated into LRH layers to generate composites of HNA xOS1- x-LTbH ( x = 0.10, 0.15, 0.20 , 0.25) and HNA yOS1- y-LYH ( y = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30). In the solid state, LYH composites exhibit green emissions (from 493 to 504 nm) with a large blue shift in comparison to the 542 nm emission of free HNA- anions, while in the delaminated state in formamide (FM), the composites display blue emission (480 nm) relative to the green emission (512 nm) of an HNA soltuion in FM. However, LTbH composites display coquenched luminescence in both the solid state and delaminated state. Also, HNA0.25OS0.75-1:1-LYH, HNA0.25OS0.75-1:2-LYH, and HNA0.05OS0.95-1:1-LYH (1:1 and 1:2 are HNA:NaOH molar ratios) show significantly elongated fluorescence lifetimes of 15.35, 14.37, and 12.72 ns, respectively, in comparison with free HNA-Na (6.44 ns), and their quantum yields of 23.40%, 21.97%, and 22.31%, respectively, are much larger than that of free HNA-Na (4.86%). The LTbH composite (HNA0.25OS0.75-1:1-LTbH) has also a relatively higher quantum yield of 12.46%. The HNA0.25OS0.75-1:1-LYH colloid exhibits excellent recognition selectivity for Al3+ over other metal ions (Mg2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, and Hg2+) with distinct fluorescence sensitization. It shows an intense change in its fluorescence emission when it is bound to Al3+ ions, giving a lower detection limit of 6.32 × 10-6 M. This is novel research on the fluorescence chemosensing of LRH composites.

10.
Phys Chem Chem Phys ; 21(44): 24572-24583, 2019 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-31663551

RESUMEN

In this work, poly(N,N'-dimethylaminoethylmethacrylate-co-N-isopropylacrylamide) copolymer films were polymerized on the surface of Au electrodes with a facile one-step method, and Au nanoclusters (AuNCs) and tetraphenylethene (TPE) were synchronously embedded in the films, designated as P(DMA-co-NIPA)/AuNCs/TPE. Ferrocene dicarboxylic acid (FDA), an electroactive probe in solution displayed inverse pH- and SO42--sensitive on-off cyclic voltammetric (CV) behaviors at the film electrodes. The electrocatalytic oxidation of nicotinamide adenine dinucleotide (NADH) mediated by FDA in solution could substantially amplify the CV response difference between the on and off states. Moreover, the two fluorescence emission (FL) signals from the TPE constituent at 450 nm and AuNCs component at 660 nm in the films also demonstrated SO42-- and pH-sensitive behaviors. Based on the aforementioned results, a 4-input/9-output biomolecular logic circuit was constructed with pH, Na2SO4, FDA and NADH as the inputs, and the CV signals and the FL responses at 450 and 660 nm at different levels as the outputs. Additionally, some functional non-Boolean devices were elaborately designed on an identical platform, including a 1-to-2 decoder, a 2-to-1 encoder, a 1-to-2 demultiplexer and different types of keypad locks. This work combines copolymer films, bioelectrocatalysis, and fluorescence together so that more complicated biocomputing systems could be established. This work may pave a new way to develop advanced and sophisticated biocomputing logic circuits and functional devices in the future.


Asunto(s)
Técnicas Electroquímicas/métodos , Nanopartículas del Metal/química , NAD/química , Polímeros/química , Estilbenos/química , Benzoatos/química , Electrodos , Compuestos Ferrosos/química , Oro/química , Concentración de Iones de Hidrógeno , Metalocenos , Oxidación-Reducción , Espectrometría de Fluorescencia , Sulfatos/química
11.
Sensors (Basel) ; 18(10)2018 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-30297654

RESUMEN

In this work, binary hydrogel films based on carboxylated multi-walled carbon nanotubes/poly(N,N-diethylacrylamide) (c-MWCNTs/PDEA) were successfully polymerized and assembled on a glassy carbon (GC) electrode surface. The electroactive drug probes matrine and sophoridine in solution showed reversible thermal-, salt-, methanol- and pH-responsive switchable cyclic voltammetric (CV) behaviors at the film electrodes. The control experiments showed that the pH-responsive property of the system could be ascribed to the drug components of the solutions, whereas the thermal-, salt- and methanol-sensitive behaviors were attributed to the PDEA constituent of the films. The CV signals particularly, of matrine and sophoridine were significantly amplified by the electrocatalysis of c-MWCNTs in the films at 1.02 V and 0.91 V, respectively. Moreover, the addition of esterase, urease, ethyl butyrate, and urea to the solution also changed the pH of the system, and produced similar CV peaks as with dilution by HCl or NaOH. Based on these experiments, a 6-input/5-output logic gate system and 2-to-1 encoder were successfully constructed. The present system may lead to the development of novel types of molecular computing systems.

12.
Molecules ; 22(2)2017 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-28125037

RESUMEN

Cistanoside A (Cis A), an active phenylethanoid glycoside isolated from Cistanche deserticola Y. C. Ma, has received our attention because of its possible role in the treatment of osteoporosis. In the present study, we evaluated the effects of Cis A on an ovariectomized (OVX) mice model and investigated its underlying molecular mechanisms of action. After 12 weeks of orally-administrated intervention, Cis A (20, 40 and 80 mg/kg body weight/day) exhibited significant antiosteoporotic effects on OVX mice, evidenced by enhanced bone strength, bone mineral density and improved trabecular bone microarchitecture. Meanwhile, the activities of bone resorption markers, including tartrate-resistant acid phosphatase (TRAP), deoxypyridinoline (DPD) and cathepsin K, were decreased, and the bioactivity of bone formation marker alkaline phosphatase (ALP) was increased. Mechanistically, Cis A inhibited the expression of TNF-receptor associated factor 6 (TRAF6), an upstream molecule that is shared by both nuclear factor kappa-light chain enhancer of activated B cells (NF-κB) and phosphatidylinositol 3-kinase (PI3K)/Akt pathways and subsequently suppressed the levels of receptor activators of nuclear factor kappaB ligand (RANKL), downregulated the expression of NF-κB and upregulated osteoprotegerin (OPG), PI3K and Akt, which means Cis A possessed antiosteoporotic activity in ovariectomized mice via TRAF6-mediated NF-kappaB inactivation and PI3K/Akt activation. Put together, we present novel findings that Cis A, by downregulating TRAF6, coordinates the inhibition of NF-κB and stimulation of PI3K/Akt pathways to promote bone formation and prevent bone resorption. These data demonstrated the potential of Cis A as a promising agent for the treatment of osteoporosis disease.


Asunto(s)
Huesos/efectos de los fármacos , Huesos/metabolismo , Catecoles/farmacología , Glicósidos/farmacología , Animales , Biomarcadores , Densidad Ósea/efectos de los fármacos , Resorción Ósea/metabolismo , Huesos/diagnóstico por imagen , Huesos/patología , Hueso Esponjoso/diagnóstico por imagen , Hueso Esponjoso/efectos de los fármacos , Hueso Esponjoso/metabolismo , Hueso Esponjoso/patología , Femenino , Fenómenos Mecánicos/efectos de los fármacos , Ratones , Osteogénesis/efectos de los fármacos , Osteoporosis/tratamiento farmacológico , Osteoporosis/etiología , Osteoporosis/metabolismo , Osteoporosis/patología , Ovariectomía , Microtomografía por Rayos X
13.
J Am Chem Soc ; 138(14): 4718-21, 2016 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-27014928

RESUMEN

We report a robust, universal "soft" nitriding method to grow in situ ligand-free ultrasmall noble metal nanocatalysts (UNMN; e.g., Au, Pd, and Pt) onto carbon. Using low-temperature urea pretreatment at 300 °C, soft nitriding enriches nitrogen-containing species on the surface of carbon supports and enhances the affinity of noble metal precursors onto these supports. We demonstrated sub-2-nm, ligand-free UNMNs grown in situ on seven different types of nitrided carbons with no organic ligands via chemical reduction or thermolysis. Ligand-free UNMNs supported on carbon showed superior electrocatalytic activity for methanol oxidation compared to counterparts with surface capping agents or larger nanocrystals on the same carbon supports. Our method is expected to provide guidelines for the preparation of ligand-free UNMNs on a variety of supports and, additionally, to broaden their applications in energy conversion and electrochemical catalysis.


Asunto(s)
Carbono/química , Nanopartículas del Metal/química , Metales Pesados/química , Catálisis , Electroquímica , Oro/química , Paladio/química , Platino (Metal)/química
14.
Anal Biochem ; 492: 63-8, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26416691

RESUMEN

A novel magnetic colorimetric immunoassay strategy was designed for sensitive detection of human interleukin-6 (IL-6) using ceria spheres as labels. Ceria spheres showed excellent oxidase activity, which can directly catalyze the oxidation of substrate o-phenylenediamine (OPD) to a stable yellow product, 2,3-diaminophenazine (oxOPD). The absorbance of oxOPD was recorded to reflect the level of IL-6. The relatively mild conditions made the immunoassay strategy more robust, reliable, and easy. A linear relationship between absorbance intensity and the logarithm of IL-6 concentrations was obtained in the range of 0.0001-10 ng mL(-1) with a detection limit of 0.04 pg mL(-1) (S/N = 3). The colorimetric immunoassay exhibited high sensitivity and specificity for the detection of IL-6. This immunoassay has been successfully applied in the detection of IL-6 in serum samples and can be readily extended toward the on-site monitoring of cancer biomarkers in serum samples.


Asunto(s)
Cerio/química , Inmunoensayo , Interleucina-6/sangre , Magnetismo , Anticuerpos/química , Anticuerpos/inmunología , Cerio/metabolismo , Colorimetría , Óxido Ferrosoférrico/química , Humanos , Interleucina-6/química , Interleucina-6/inmunología , Límite de Detección , Nanopartículas de Magnetita/química , Oxidación-Reducción , Oxidorreductasas/metabolismo , Fenilendiaminas/química , Espectroscopía Infrarroja por Transformada de Fourier
15.
Sensors (Basel) ; 16(4)2016 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-27104542

RESUMEN

The research on intelligent bioelectrocatalysis based on stimuli-responsive materials or interfaces is of great significance for biosensors and other bioelectronic devices. In the present work, lectin protein concanavalin A (Con A) and glycoenzyme glucose oxidase (GOD) were assembled into {Con A/GOD}n layer-by-layer (LbL) films by taking advantage of the biospecific lectin-glycoenzyme affinity between them. These film electrodes possess stimuli-responsive properties toward electroactive probes such as ferrocenedicarboxylic acid (Fc(COOH)2) by modulating the surrounding pH. The CV peak currents of Fc(COOH)2 were quite large at pH 4.0 but significantly suppressed at pH 8.0, demonstrating reversible stimuli-responsive on-off behavior. The mechanism of stimuli-responsive property of the films was explored by comparative experiments and attributed to the different electrostatic interaction between the films and the probes at different pH. This stimuli-responsive films could be used to realize active/inactive electrocatalytic oxidation of glucose by GOD in the films and mediated by Fc(COOH)2 in solution, which may establish a foundation for fabricating novel stimuli-responsive electrochemical biosensors based on bioelectrocatalysis with immobilized enzymes.


Asunto(s)
Técnicas Biosensibles/métodos , Enzimas Inmovilizadas/química , Glucosa Oxidasa/química , Glucosa/aislamiento & purificación , Biocatálisis , Concanavalina A/química , Compuestos Ferrosos/química , Glucosa/química , Peroxidasa de Rábano Silvestre/química , Concentración de Iones de Hidrógeno , Metalocenos , Oxidación-Reducción , Polímeros/química
16.
AIDS Behav ; 18 Suppl 2: S172-80, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23912337

RESUMEN

Prior research on female sex workers (FSW) in China, and their risk for HIV and STI, neglects the nuanced experiences of ethnic minority FSW. We conducted participant observations and in-depth interviews with 33 FSW and six venue bosses to describe the experiences of FSW and management structures in low and high-priced sex work venues in Liuzhou, China. In low-priced venues, FSW had more autonomy and stronger relationships with their ethnic minority peers. Mid- and high-priced venues had more formal management structures. Ethnic minority FSW working in higher priced venues experienced less support and kinship with their peers. HIV/STI prevention outreach activities occurred in all of the venues, but they were not tailored for different venue types or for ethnic minority FSW. Our findings provide guidance for tailoring public health programs that meet the needs of ethnic minority women working in different types of sex work venues.


Asunto(s)
Infecciones por VIH/prevención & control , Trabajo Sexual/etnología , Trabajadores Sexuales/psicología , Lugar de Trabajo/organización & administración , Adulto , China , Etnicidad/psicología , Femenino , Humanos , Entrevistas como Asunto , Grupo Paritario , Clase Social
17.
Adv Mater ; 36(35): e2407940, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38962849

RESUMEN

The development of active and selective metal electrocatalysts for complete ethanol oxidation reaction (EOR) into desired C1 products is extremely promising for practical application of direct ethanol fuel cells. Despite some encouraging achievements, their activity and selectivity remain unsatisfactory. In this work, it is reported that 2D PtRhPb mesoporous nanosheets (MNSs) with anisotropic structure and surface-clean metal site perform perfectly for complete EOR electrocatalysis in both three-electrode and two-electrode systems. Different to the traditional routes, a selective etching strategy is developed to produce surface-clean mesopores while retaining parent anisotropy quasi-single-crystalline structure without the mesopore-forming surfactants. This method also allows the general synthesis of surface-clean mesoporous metals with other compositions and structures. When being performed for alkaline EOR electrocatalysis, the best PtRhPb MNSs deliver remarkably high activity (7.8 A mg-1) and superior C1 product selectivity (70% of Faradaic efficiency), both of which are much better than reported electrocatalysts. High performance is assigned to multiple structural and compositional synergies that not only stabilized key OHads intermediate by surface-clean mesopores but also separated the chemisorption of two carbons in ethanol by adjacent Pt and Rh sites, which facilitate the oxidation cleavage of stable C─C bond for complete EOR electrocatalysis.

18.
J Colloid Interface Sci ; 659: 550-559, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38198932

RESUMEN

From the swollen LDH, bulky [Mo3S13]2- anions are facilely introduced into the LDH interlayers to assemble the Mo3S13-LDH composite, which exhibits excellent iodine capture performance and good irradiation resistance. The positive-charged LDH layers may disperse the [Mo3S13]2- uniformly within the interlayers, providing abundant adsorption sites for effectively trapping iodine. The Mo-S bond serving as a soft Lewis base has strong affinity to I2 with soft Lewis acidic characteristic, which is conducive to improvement of iodine capture via physical sorption. Besides, chemisorption has a significant contribution to the iodine adsorption. The S22-/S2- in [Mo3S13]2- can reduce the I2 to [I3]- ions, which are facilely fixed within the LDH gallery in virtue of electrostatic attraction. Meanwhile, the S22-/S2- themselves are oxidized to S8 and SO42-, while Mo4+ is oxidized (by O2 in air) to Mo6+, which combines with SO42- forming amorphous Mo(SO4)3. With the collective interactions of chemical and physical adsorption, the Mo3S13-LDH demonstrates an extremely large iodine adsorption capacity of 1580 mg/g. Under γ radiation, the structure of Mo3S13-LDH well maintains and iodine adsorption capability does not deteriorate, indicating the good irradiation resistance. This work provides an important reference to tailor cost-effective sorbents for trapping iodine from radioactive nuclear wastes.

19.
Nanoscale ; 16(5): 2361-2372, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38198207

RESUMEN

An integral approach towards augmenting the performance of photocatalytic hydrogen production lies in the induction of charge transfer mediators within the material matrix itself, thereby facilitating swift and efficient charge transfer processes. Here, CoTiO3 is induced to grow its electronic attraction center, CoP3, through a high-temperature phosphatization strategy. CoP3 acts as the active reduction site for the hydrogen evolution reaction and enhances the photocatalytic performance of the pristine catalyst. Compared with pure CoTiO3, the PCTO7 hybrid catalyst with the electronic attraction center CoP3 exhibits a superior photocatalytic performance and good stability. Experimental results show that the hydrogen evolution performance of the PCTO7 hybrid catalyst reaches 56.52 µmol, which is 78 times higher than that of the single catalyst CoTiO3 (0.72 µmol). These results demonstrate that the hybrid catalyst with the self-induced electronic attraction center has a higher light absorption capacity, faster charge carrier dynamics and improved photogenerated charge carrier separation and transfer than pure CoTiO3, resulting in excellent redox capability. DFT calculations provide evidence supporting the topological metal properties of CoP3 as the electron sink center. This study provides a feasible approach for enhancing the photocatalytic performance of a pristine catalyst employing a high-temperature phosphatization-induced electron sink center.

20.
Biomater Sci ; 12(14): 3686-3699, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38873991

RESUMEN

PROteolysis TArgeting Chimeras have received increasing attention due to their capability to induce potent degradation of various disease-related proteins. However, the effective and controlled cytosolic delivery of current small-molecule PROTACs remains a challenge, primarily due to their intrinsic shortcomings, including unfavorable solubility, poor cell permeability, and limited spatiotemporal precision. Here, we develop a near-infrared light-controlled PROTAC delivery device (abbreviated as USDPR) that allows the efficient photoactivation of PROTAC function to achieve enhanced protein degradation. The nanodevice is constructed by encapsulating the commercial BRD4-targeting PROTACs (dBET6) in the hollow cavity of mesoporous silica-coated upconversion nanoparticles, followed by coating a Rose Bengal (RB) photosensitizer conjugated poly-L-lysine (PLL-RB). This composition enables NIR light-activatable generation of cytotoxic reactive oxygen species due to the energy transfer from the UCNPs to PLL-RB, which boosts the endo/lysosomal escape and subsequent cytosolic release of dBET6. We demonstrate that USDPR is capable of effectively degrading BRD4 in a NIR light-controlled manner. This in combination with NIR light-triggered photodynamic therapy enables an enhanced antitumor effect both in vitro and in vivo. This work thus presents a versatile strategy for controlled release of PROTACs and codelivery with photosensitizers using an NIR-responsive nanodevice, providing important insight into the design of effective PROTAC-based combination therapy.


Asunto(s)
Lisosomas , Nanopartículas , Fotoquimioterapia , Fármacos Fotosensibilizantes , Proteolisis , Humanos , Lisosomas/metabolismo , Nanopartículas/química , Nanopartículas/administración & dosificación , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/administración & dosificación , Animales , Proteolisis/efectos de los fármacos , Factores de Transcripción/metabolismo , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/química , Ratones , Proteínas de Ciclo Celular/antagonistas & inhibidores , Proteínas de Ciclo Celular/metabolismo , Rayos Infrarrojos , Rosa Bengala/química , Rosa Bengala/farmacología , Rosa Bengala/administración & dosificación , Dióxido de Silicio/química , Polilisina/química , Especies Reactivas de Oxígeno/metabolismo , Línea Celular Tumoral , Antineoplásicos/química , Antineoplásicos/farmacología , Antineoplásicos/administración & dosificación , Proteínas que Contienen Bromodominio
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