Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Chem Sci ; 2024 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-39328197

RESUMEN

Photobiocatalytic CO2 reduction represents an attractive approach for conversion of solar light and abundant resources to value-added chemicals. However, the design of suitable systems requires a detailed understanding of the interaction between the artificial photosensitizer and biocatalyst interface. In this work, we investigate the effect of surfactant charge utilized in the preparation of a phenoxazine-based organic molecule nanorod photosensitizer on the interaction with the carbon monoxide dehydrogenase II from Carboxydothermus hydrogenoformans within biohybrid assemblies for sacrificially driven photobiocatalytic CO2 reduction into CO. Electrophoretic mobility shift assay in conjunction with cryogenic electron microscopy (Cryo-EM) and detailed physicochemical characterization are conducted to understand the interaction at the biohybrid interface in order to suggest a strategy for future functionalization of nanoparticles that fulfills the needs of the biocatalyst for green fuel production.

2.
Nat Commun ; 15(1): 6765, 2024 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-39117646

RESUMEN

As a new class of organic photocatalysts, polymer dots show a potential application in photocatalytic hydrogen peroxide production coupled with chemical oxidation such as methanol oxidation. However, the poor methanol oxidation ability by polymer dots still inhibits the overall photocatalytic reaction occurring in the neutral condition. In this work, an organic molecular catalyst 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl radical is covalently linked to a fluorene unit in a polymer skeleton, eventually enabling photocatalytic hydrogen peroxide production coupled with methanol oxidation in the neutral condition. By conducting various spectroscopic measurements, charge transfer between components in this molecular catalyst-immobilized polymer dots system is studied and found to be very efficient for hydrogen peroxide production coupled with alcohol oxidation. This work proves a strategy for designing polymer dots photocatalysts with molecular catalysts, facilitating their future development and potential applications in other fields such as water splitting, CO2 reduction, photoredox catalysis and photodynamic therapy.

3.
Adv Sci (Weinh) ; 11(35): e2403795, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38995228

RESUMEN

The constrained effectiveness of photodynamic therapy (PDT) has impeded its widespread use in clinical practice. Urgent efforts are needed to address the shortcomings faced in photodynamic therapy, such as photosensitizer toxicity, short half-life, and limited action range of reactive oxygen species (ROS). In this study, a biodegradable copolymer nanoamplifier is reported that contains ruthenium complex (Ru-complex) as photosensitizer (PS) and rhenium complex (Re-complex) as carbon monoxide (CO)-release molecule (CORM). The well-designed nanoamplifier brings PS and CORM into close spatial proximity, significantly promotes the utilization of light-stimulated reactive oxygen species (ROS), and cascaded amplifying CO release, thus enabling an enhanced synergistic effect of PDT and gas therapy for cancer treatment. Moreover, owing to its intrinsic photodegradable nature, the nanoamplifier exhibits good tumor accumulation and penetration ability, and excellent biocompatibility in vivo. These findings suggest that the biodegradable cascaded nanoamplifiers pave the way for a synergistic and clinically viable integration of photodynamic and gas therapy.


Asunto(s)
Monóxido de Carbono , Fotoquimioterapia , Fármacos Fotosensibilizantes , Especies Reactivas de Oxígeno , Renio , Rutenio , Especies Reactivas de Oxígeno/metabolismo , Fotoquimioterapia/métodos , Ratones , Animales , Fármacos Fotosensibilizantes/farmacología , Rutenio/química , Renio/química , Humanos , Modelos Animales de Enfermedad , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Línea Celular Tumoral
4.
Foods ; 13(11)2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38890820

RESUMEN

A twelve-week feeding experiment was undertaken to explore the impact of substituting dietary fish meal (FM) and fish oil (FO) with complex protein (CP) and canola oil (CO) in the diet of triploid rainbow trout on the quality of their fillets. The control diet (F100) contained FM (60%) and FO (18.6%) as the main protein and lipid sources. Based on this, 50% and 100% of FM and FO were substituted by CP and CO and they were named as F50 and F0, respectively. The results showed that there were no significant differences in the specific growth rates, condition factors, gutted yields, fillet yields and yellowness values as the substitution levels increased (p > 0.05). The F50 treatment obtained the highest values of fillet springiness and chewiness, improved the umami and bitter taste of the fillets by increasing the contents of inosine-5'-monophosphate and histidine, and increased lipid, protein, C18: 1n-9 and C18: 2n-6 contents (p < 0.05). The F0 treatment obtained the highest values of fillet hardness and pH, attenuated the sweet taste of the fillets by decreasing the content of glycine, and decreased the contents of EPA and DHA (p < 0.05). Both F50 and F0 treatments could increase the redness value, decrease the lightness and hue values of fillets, and increase the odor intensity, resulting in the typical fillet odors of green, fatty, orange and fishy (p < 0.05). In general, 50% and 100% of FM and FO substitution did not affect the growth of trout, but it did affect quality. Compared to the F100 treatment, the fillet quality of the F0 treatment was similar to the F50 treatment and could improve the appearance and odor intensity of the fillets. However, the difference was that the F50 treatment increased the springiness, umami, bitterness and lipid nutritional value of the fillets, but the F0 treatment increased the hardness, decreased the sweetness, and decreased the lipid, EPA and DHA contents of the fillets.

5.
Nat Commun ; 15(1): 3202, 2024 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-38615087

RESUMEN

Dye-sensitized photoelectrodes consisting of photosensitizers and molecular catalysts with tunable structures and adjustable energy levels are attractive for low-cost and eco-friendly solar-assisted synthesis of energy rich products. Despite these advantages, dye-sensitized NiO photocathodes suffer from severe electron-hole recombination and facile molecule detachment, limiting photocurrent and stability in photoelectrochemical water-splitting devices. In this work, we develop an efficient and robust biohybrid dye-sensitized NiO photocathode, in which the intermolecular charge transfer is enhanced by a redox polymer. Owing to efficient assisted electron transfer from the dye to the catalyst, the biohybrid NiO photocathode showed a satisfactory photocurrent of 141±17 µA·cm-2 at neutral pH at 0 V versus reversible hydrogen electrode and a stable continuous output within 5 h. This photocathode is capable of driving overall water splitting in combination with a bismuth vanadate photoanode, showing distinguished solar-to-hydrogen efficiency among all reported water-splitting devices based on dye-sensitized photocathodes. These findings demonstrate the opportunity of building green biohybrid systems for artificial synthesis of solar fuels.

6.
ACS Catal ; 14(6): 4186-4201, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38510668

RESUMEN

Systems integrating quantum dots with molecular catalysts are attracting ever more attention, primarily owing to their tunability and notable photocatalytic activity in the context of the hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR). CuInS2 (CIS) quantum dots (QDs) are effective photoreductants, having relatively high-energy conduction bands, but their electronic structure and defect states often lead to poor performance, prompting many researchers to employ them with a core-shell structure. Molecular cobalt HER catalysts, on the other hand, often suffer from poor stability. Here, we have combined CIS QDs, surface-passivated with l-cysteine and iodide from a water-based synthesis, with two tetraazamacrocyclic cobalt complexes to realize systems which demonstrate high turnover numbers for the HER (up to >8000 per catalyst), using ascorbate as the sacrificial electron donor at pH = 4.5. Photoluminescence intensity and lifetime quenching data indicated a large degree of binding of the catalysts to the QDs, even with only ca. 1 µM each of QDs and catalysts, linked to an entirely static quenching mechanism. The data was fitted with a Poissonian distribution of catalyst molecules over the QDs, from which the concentration of QDs could be evaluated. No important difference in either quenching or photocatalysis was observed between catalysts with and without the carboxylate as a potential anchoring group. Femtosecond transient absorption spectroscopy confirmed ultrafast interfacial electron transfer from the QDs and the formation of the singly reduced catalyst (CoII state) for both complexes, with an average electron transfer rate constant of ≈ (10 ps)-1. These favorable results confirm that the core tetraazamacrocyclic cobalt complex is remarkably stable under photocatalytic conditions and that CIS QDs without inorganic shell structures for passivation can act as effective photosensitizers, while their smaller size makes them suitable for application in the sensitization of, inter alia, mesoporous electrodes.

7.
Adv Sci (Weinh) ; 11(21): e2308469, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38460154

RESUMEN

Development of efficient, stable, and recyclable photocatalysts for organic synthesis is vital for transformation of traditional thermal organic chemistry into green sustainable organic chemistry. In this work, the study reports an electrostatic approach to assemble meso-tetra (4-sulfonate phenyl) porphyrin (TPPS)tetra (4-sulfonate phenyl) porphyrin (TPPS) as a donor and benzyl viologen (BV) as an acceptor into stable and recyclable photocatalyst for an efficient organic transformation reaction - aryl sulfide oxidation. By use of the electrostatic TPPS-BV photocatalysts, 0.1 mmol aryl sulfide with electron-donating group can be completely transformed into aryl sulfoxide in 60 min without overoxidation into sulfone, rendering near 100% yield and selectivity. The photocatalyst can be recycled up to 95% when 10 mg amount is used. Mechanistic study reveals that efficient charge separation between TPPS and BV results in sufficient formation of superoxide which further reacts with the oxidized sulfide by the photocatalyst to produce the sulfoxide. This mechanistic pathway differs significantly from the previously proposed singlet oxygen-dominated process in homogeneous TPPS photocatalysis.

8.
JACS Au ; 4(2): 570-577, 2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38425933

RESUMEN

Organic polymers based on the donor-acceptor structure are a promising class of efficient photocatalysts for solar fuel production. Among these polymers, poly(9,9-dioctylfluorene-alt-1,2,3-benzothiadiazole) (PFBT) consisting of fluorene donor and benzothiadiazole acceptor units has shown good photocatalytic activity when it is prepared into polymer dots (Pdots) in water. In this work, we investigate the effect of the chemical environment on the activity of photocatalysis from PFBT Pdots for hydrogen production. This is carried out by comparing the samples with various concentrations of palladium under different pH conditions and with different sacrificial electron donors (SDs). Moreover, a model compound 1,2,3-benzothiadiazole di-9,9-dioctylfluorene (BTDF) is synthesized to investigate the mechanism for protonation of benzothiadiazole and its kinetics in the presence of an organic acid-salicylic acid by cyclic voltammetry. We experimentally show that benzothiadiazole in BTDF can rapidly react with protons with a fitted value of 0.1-5 × 1010 M-1 s-1 which should play a crucial role in the photocatalytic reaction with a polymer photocatalyst containing benzothiadiazole such as PFBT Pdots for hydrogen production in acidic conditions. This work gives insights into why organic polymers with benzothiadiazole work efficiently for photocatalytic hydrogen production.

9.
Angew Chem Int Ed Engl ; 63(7): e202312879, 2024 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-37905977

RESUMEN

In recent years, heterocyclic organic compounds have been explored as molecular electrocatalysts in relevant reactions for energy conversion and storage. Merging mimetics of biological systems that perform hydride transfer with rational synthetic chemical design has opened many opportunities for organic molecules to be tuned at the atomic level conferring them interesting reactivities. These molecular electrocatalysts represent an alternative to traditional metallic materials and metal complexes employed for water oxidation, hydrogen production, and carbon dioxide reduction. This minireview describes recent reports concerning design, catalytic activity and the mechanism of synthetic molecular electrocatalysts towards solar fuels production.

10.
Energy Environ Sci ; 16(10): 4305-4319, 2023 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-38013927

RESUMEN

Biohybrid photosynthesis systems, which combine biological and non-biological materials, have attracted recent interest in solar-to-chemical energy conversion. However, the solar efficiencies of such systems remain low, despite advances in both artificial photosynthesis and synthetic biology. Here we discuss the potential of conjugated organic materials as photosensitisers for biological hybrid systems compared to traditional inorganic semiconductors. Organic materials offer the ability to tune both photophysical properties and the specific physicochemical interactions between the photosensitiser and biological cells, thus improving stability and charge transfer. We highlight the state-of-the-art and opportunities for new approaches in designing new biohybrid systems. This perspective also summarises the current understanding of the underlying electron transport process and highlights the research areas that need to be pursued to underpin the development of hybrid photosynthesis systems.

11.
Angew Chem Int Ed Engl ; 62(45): e202312276, 2023 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-37728510

RESUMEN

Developing low-cost and efficient photocatalysts to convert CO2 into valuable fuels is desirable to realize a carbon-neutral society. In this work, we report that polymer dots (Pdots) of poly[(9,9'-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-thiadiazole)] (PFBT), without adding any extra co-catalyst, can photocatalyze reduction of CO2 into CO in aqueous solution, rendering a CO production rate of 57 µmol g-1 h-1 with a detectable selectivity of up to 100 %. After 5 cycles of CO2 re-purging experiments, no distinct decline in CO amount and reaction rate was observed, indicating the promising photocatalytic stability of PFBT Pdots in the photocatalytic CO2 reduction reaction. A mechanistic study reveals that photoexcited PFBT Pdots are reduced by sacrificial donor first, then the reduced PFBT Pdots can bind CO2 and reduce it into CO via their intrinsic active sites. This work highlights the application of organic Pdots for CO2 reduction in aqueous solution, which therefore provides a strategy to develop highly efficient and environmentally friendly nanoparticulate photocatalysts for CO2 reduction.

12.
J Am Chem Soc ; 145(34): 18687-18692, 2023 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-37582183

RESUMEN

Developing light-harvesting systems with efficient photoinduced charge separation and long-lived charge-separated (CS) state is desirable but still challenging. In this study, we designed a zinc porphyrin photosensitizer covalently linked with viologen (ZnP-V) that can be prepared into nanoparticles in aqueous solution. In DMF solution, the monomeric ZnP-V dyads show no electron transfer between the ZnP and viologen units. In contrast, the ZnP-V nanoparticles in aqueous solution show fast charge separation with a CS state lifetime of up to 4.3 ms. This can be attributed to charge hopping induced by aggregation or distance modification between the donor and acceptor induced by electronic interaction. Nevertheless, the lifetime of the CS state is orders of magnitude longer than for molecular aggregates reported previously. The ZnP-V nanoparticles show enhanced photocatalytic hydrogen production as compared to the ZnP nanoparticles and still hold promise for other applications such as photovoltaic devices and photoredox catalysis.

13.
J Agric Food Chem ; 71(28): 10841-10849, 2023 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-37406351

RESUMEN

To avoid false-positive results in immunoassays due to cross-reactivity of antibodies with structural analogues, especially metabolites of target compounds, the preparation of highly specific antibodies is crucial. Preserving the characteristic structure of a target compound when designing a hapten is important when preparing highly specific antibodies. Here, we designed a novel hapten, 4-(((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4yl)amino)methyl)benzoic acid, named AA-BA, to improve the specificity of antibodies for detection of 4-methylaminoantipyrine (MAA), a residual marker of dipyrone, an important antipyretic-analgesic and anti-inflammatory drug. The structural features of the hapten remained almost the same as those of MAA. After experimental validation, monoclonal antibody 6A4 (mAb 6A4) was prepared with the half maximal inhibitory concentration (IC50) value of 4.03 ng/mL and negligible cross-reactivity with dipyrone metabolites and other antibiotics. In addition, a specific lateral flow immunoassay (LFA) strip based on colloidal gold was developed for screening MAA with a cutoff value of 25 ng/mL in milk. The developed LFA is a useful tool for rapid and accurate detection of MAA.


Asunto(s)
Anticuerpos Monoclonales , Dipirona , Dipirona/farmacología , Inmunoensayo/métodos , Haptenos , Oro Coloide/química , Límite de Detección
14.
Aquac Nutr ; 2023: 4733343, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37288329

RESUMEN

The research is aimed at investigating the effects of dietary protein and lipid levels on adult triploid rainbow trout growth performance, feed utilization, digestive and metabolic enzyme activities, antioxidative capacity, and fillet quality. Nine diets containing three dietary protein levels (DP) (300, 350, and 400 g kg-1) and three dietary lipid levels (DL) (200, 250, and 300 g kg-1) were prepared using a 3 × 3 factorial design. In freshwater cages, 13,500 adult female triploid rainbow trout (3.2 ± 0.1 kg) were cultured for 77 days. Triplicate cages (500 fish per cage) were used as repetitions of each experimental diet. The findings revealed that as DP increased to 400 g kg-1 and DL raised to 300 g kg-1, the weight gain ratio (WGR) elevated significantly (P < 0.05). However, when DP ≥ 350 g kg-1, WGR was similar in the DL250 and DL300 groups. As DP raised to 350 g kg-1, the feed conversion ratio (FCR) notably decreased (P < 0.05). In the DP350DL300 group, lipids had a protein-sparing impact. High DP diet (400 g kg-1) generally improved fish health status by increasing antioxidant capacity in the liver and intestine. A high DL diet (300 g kg-1) showed no harmful effect on hepatic health based on plasma levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and antioxidant capacity in the liver. For fillet quality, a high DP diet could increase fillet yield, improve fillet hardness, springiness, and water-holding capacity values, and inhibit the production of off-flavors caused by n-6 fatty acids. A high DL diet could increase odor intensity, and EPA, DHA, and n-3 fatty acid concentrations decrease the thrombogenicity index value. The maximum fillet redness value was discovered in the DP400DL300 group. Overall, for adult triploid rainbow trout (≥3 kg), the minimum recommended DP and DL according to growth performance were 400 and 250 g kg-1, respectively; DP and DL based on feed utilization were 350 and 200 g kg-1, respectively; DP and DL based on fillet quality were 400 and 300 g kg-1, respectively.

15.
J Am Chem Soc ; 145(20): 11067-11073, 2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37191461

RESUMEN

Control of charge separation and recombination is critical for dye-sensitized solar cells and photoelectrochemical cells, and for p-type cells, the latter process limits their photovoltaic performance. We speculated that the lateral electron hopping between dyes on a p-type semiconductor surface can effectively separate electrons and holes in space and retard recombination. Thus, device designs where lateral electron hopping is promoted can lead to enhanced cell performance. Herein, we present an indirect proof by involving a second dye to monitor the effect of electron hopping after hole injection into the semiconductor. In mesoporous NiO films sensitized with peryleneimide (PMI) or naphthalene diimide (NDI) dyes, dye excitation led to ultrafast hole injection into NiO from either excited PMI* (τ < 200 fs) or NDI* (τ = 1.2 ps). In cosensitized films, surface electron transfer from PMI- to NDI was rapid (τ = 24 ps). Interestingly, the subsequent charge recombination (ps-µs) with NiO holes was much slower when NDI- was generated by electron transfer from PMI- than when NDI was excited directly. We therefore indicate that the charge recombination is slowed down after the charge hopping from the original PMI sites to the NDI sites. The experimental results supported our hypothesis and revealed important information on the charge carrier kinetics for the dye-sensitized NiO photoelectrode system.

16.
J Am Chem Soc ; 145(21): 11472-11476, 2023 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-37127024

RESUMEN

Lateral intermolecular charge transfer between photosensitizers on metal oxide substrates is important for the understanding on the overall working principles of dye-sensitized systems. Such studies usually concentrate on either hole or electron transfer separately and are conducted in solvents with a high dielectric constant (εs) that are known, however, to show a drastic decrease of the local dielectric constant close to the metal oxide surface. In the present study, both hole and electron hopping between organic donor-acceptor photosensitizers was experimentally investigated on PB6 dye-sensitized mesoporous ZrO2 films. The donor (close to the surface) and acceptor (away from surface) subunit of the PB6 dye were observed to be involved in hole and electron hopping, respectively. Hole and electron transfer kinetics were found to differ remarkably in high-εs solvents, but similar in solvents with εs < 12. This finding indicates that low-εs solvents maintain similar local dielectric constant values close to, and further away from, the semiconductor surface, which is different from the previously observed behavior of high dielectric constant solvents at a metal oxide interface.

17.
Chem Commun (Camb) ; 59(37): 5611-5614, 2023 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-37078914

RESUMEN

A phenoxazine-based small organic molecular donor POZ-M is designed and synthesized to prepare organic heterojunction nanoparticles (NPs) with a small molecular acceptor ITIC for photocatalytic hydrogen production, giving a reaction rate of up to 63 mmol g-1 h-1. A beneficial molecular design strategy highlights the role of miscibility between POZ-M and ITIC, which is necessary to achieve satisfactory charge separation at the donor/acceptor interface.

18.
Metabolites ; 13(3)2023 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-36984836

RESUMEN

Triploid rainbow trout can adapt to various dietary lipid levels; however, the mechanisms of systematic adaptation are not well understood. To investigate how adult triploid rainbow trout maintains lipid hemostasis under different exogenous lipid intake, a 77-day feeding trial was conducted. Diets with lipid contents of 20%, 25%, and 30% were formulated and fed to triploid rainbow trout with an initial weight of 3 ± 0.02 kg, and they were named L20, L25, and L30 group, respectively. Results showed that the condition factor, hepatosomatic index, liver color, and plasma triglyceride were comparable among three groups (p > 0.05), whereas the value of specific growth rate, viscerosomatic index, and liver glycogen content gradually increased with increasing dietary lipid level (p < 0.05). A significantly highest value of plasma glucose and nonesterified fatty acids were found in the L30 group (p < 0.05), whereas the significantly higher content of plasma total cholesterol, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol was found in the L25 group compared with those in L20 group (p < 0.05). As for lipid deposition, abdominal adipose tissue, and muscle were the main lipid storage place for triploid rainbow trout when tissues' weight is taken into consideration. Overall quantitative PCR showed that the lipid transport and glycolysis were upregulated, and fatty acids oxidative was downregulated in liver when fish were fed low lipid diets. It meant that the liver was the primary lipid metabolizing organ to low lipid diet feeding, which could switch energy supply between glycolysis and fatty acids oxidation. Fish fed with a moderate dietary lipid level diet could increase lipid uptake and promote lipogenesis in muscle. Abdominal adipose tissue could efficiently uptake excess exogenous free fatty acid through upregulating fatty acid uptake and synthesis de novo and then storing it in the form of triglyceride. Excess lipid uptake is preferentially stored in abdominal adipose tissue through coordinated fatty acid uptake and fatty acid synthesis de novo as dietary lipid levels increased. In summary, triploid rainbow trout can adapt to various dietary lipid levels by coordinating metabolism in different tissues.

19.
Phys Chem Chem Phys ; 25(4): 2935-2945, 2023 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-36606387

RESUMEN

Aqueous dispersed conjugated polymer dots (Pdots) have shown promising application in photocatalytic hydrogen evolution. To efficiently extract photogenerated charges from type-II heterojunction Pdots for hydrogen evolution, the mechanistic study of photophysical processes is essential for Pdot optimization. Within this work, we use a PFODTBT donor (D) polymer and an ITIC small molecule acceptor (A) as a donor/acceptor (D/A) model system to study their excited states and charge/energy transfer dynamics via steady-state and time-resolved photoluminescence spectroscopy, respectively. Charge-carrier generation and the recombination dynamics of binary Pdots with different D/A ratios were followed using femtosecond transient absorption spectroscopy. A significant spectral relaxation of photoluminescence was observed for individual D Pdots, implying an energetic disorder by nature. However, this was not seen for charge carriers in binary Pdots, probably due to the ultrafast charge generation process at an early time (<200 fs). The results showed slower charge recombination upon increasing the ratio of ITIC in binary Pdots, which further resulted in an enhanced photocatalytic hydrogen evolution, twice that as compared to individual D Pdots. Although binary Pdots prepared via the nanoprecipitation method exhibit a large interfacial area that allows high charge generation efficiencies, it also provides a high possibility for charge recombination and limits the further utilization of free charges. Therefore, for the future design of type-II heterojunction Pdots, suppressing the charge carrier recombination via increasing the crystallinity and proper phase segregation is necessary for enhanced photocatalytic hydrogen evolution.

20.
ACS Appl Mater Interfaces ; 15(1): 2183-2191, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36563111

RESUMEN

Organic semiconductor-microbial photosynthetic biohybrid systems show great potential in light-driven biosynthesis. In such a system, an organic semiconductor is used to harvest solar energy and generate electrons, which can be further transported to microorganisms with a wide range of metabolic pathways for final biosynthesis. However, the lack of direct electron transport proteins in existing microorganisms hinders the hybrid system of photosynthesis. In this work, we have designed a photosynthetic biohybrid system based on transmembrane electron transport that can effectively deliver the electrons from organic semiconductor across the cell wall to the microbe. Biocompatible organic semiconductor polymer dots (Pdots) are used as photosensitizers to construct a ternary synergistic biochemical factory in collaboration with Ralstonia eutropha H16 (RH16) and electron shuttle neutral red (NR). Photogenerated electrons from Pdots promote the proportion of nicotinamide adenine dinucleotide phosphate (NADPH) through NR, driving the Calvin cycle of RH16 to convert CO2 into poly-3-hydroxybutyrate (PHB), with a yield of 21.3 ± 3.78 mg/L, almost 3 times higher than that of original RH16. This work provides a concept of an integrated photoactive biological factory based on organic semiconductor polymer dots/bacteria for valuable chemical production only using solar energy as the energy input.


Asunto(s)
Dióxido de Carbono , Electrones , Transporte de Electrón , Dióxido de Carbono/química , Polímeros/metabolismo , Fotosíntesis , Poliésteres/metabolismo , Bacterias/metabolismo , Bacterias Gramnegativas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA