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1.
Chem Rev ; 123(8): 4510-4601, 2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37022360

RESUMO

Lignin, as a precious resource given to mankind by nature with abundant functional aromatic structures, has drawn much attention in the recent decade from academia to industry worldwide, aiming at harvesting aromatic compounds from this abundant and renewable natural polymer resource. How to efficiently depolymerize lignin to easy-to-handle aromatic monomers is the precondition of lignin utilization. Many strategies/methods have been developed to effectively degrade lignin into monomers, such as the traditional methods of pyrolysis, gasification, liquid-phase reforming, solvolysis, chemical oxidation, hydrogenation, reduction, acidolysis, alkaline hydrolysis, alcoholysis, as well as the newly developed redox-neutral process, biocatalysis, and combinatorial strategies. Therefore, there is a strong demand to systemically summarize these developed strategies and methods and reveal the internal transformation principles of the lignin. Focusing on the topic of lignin depolymerization to aromatic chemicals, this review reorganizes and categorizes the strategies/methods according to their mechanisms, orbiting the center of critical intermediates during the lignin linkage transformation, which includes the critical anionic intermediates, cationic intermediates, organometallic intermediates, organic molecular intermediates, aryl cation radical intermediates, and neutral radical intermediates. The corresponding introduction involves the generation and the transformation chemistry of the critical intermediates via the corresponding C-H/O-H/C-C/C-O chemical bond transformations, leading to the cleavage of the C-C/C-O linkage bonds. Accompanying the brief introduction of lignin chemistry and the final concluding remarks and perspectives on lignin depolymerization, this review aims to provide a current research process of lignin depolymerization, which may provide useful suggestions for this vigorous research field.

2.
Small ; : e2402942, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38975677

RESUMO

Recent advancements in metal-organic frameworks (MOFs) underscore their significant potential in chemical and materials research, owing to their remarkable properties and diverse structures. Despite challenges like intrinsic brittleness, powdered crystalline nature, and limited stability impeding direct applications, MOF-based aerogels have shown superior performance in various areas, particularly in water treatment and contaminant removal. This review highlights the latest progress in MOF-based aerogels, with a focus on hybrid systems incorporating materials like graphene, carbon nanotube, silica, and cellulose in MOF aerogels, which enhance their functional properties. The manifold advantages of MOF-based aerogels in energy storage, adsorption, and catalysis are discussed, with an emphasizing on their improved stability, processability, and ease of handling. This review aims to unlock the potential of MOF-based aerogels and their real-world applications. Aerogels are expected to reshape the technological landscape of MOFs through enhanced stability, adaptability, and efficiency.

3.
Small ; 19(38): e2301472, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37218011

RESUMO

The combination of optical transparency and mechanical strength is a highly desirable attribute of wood-based glazing materials. However, such properties are typically obtained by impregnation of the highly anisotropic wood with index-matching fossil-based polymers. In addition, the presence of hydrophilic cellulose leads to a limited water resistance. Herein, this work reports on an adhesive-free lamination that uses oxidation and densification to produce transparent all-biobased glazes. The latter are produced from multilayered structures, free of adhesives or filling polymers, simultaneously displaying high optical clarity and mechanical strength, in both dry and wet conditions. Specifically, high values of optical transmittance (≈85.4%), clarity (≈20% with low haze) at a thickness of ≈0.3 mm, and highly isotropic mechanical strength and water resistance (wet strength of ≈128.25 MPa) are obtained for insulative glazes exhibiting low thermal conductivity (0.27 W m-1 K-1 , almost four times lower than glass). The proposed strategy results in materials that are systematically tested, with the leading effects of self-adhesion induced by oxidation rationalized by ab initio molecular dynamics simulation. Overall, this work demonstrates wood-derived materials as promising solutions for energy-efficient and sustainable glazing applications.

4.
Biomacromolecules ; 24(2): 841-848, 2023 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-36608216

RESUMO

With the rapid increase of diabetes cases in the world, there is an increasing demand for slowing down and managing diabetes and its effects. It is considered that a viable prophylactic treatment for type 2 diabetes mellitus (T2DM) is to reduce carbohydrate digestibility by controlling the activities of α-amylase and α-glucosidase to control postprandial hyperglycemia and promote the growth of intestinal beneficial bacteria. In this work, the effects of sulfonated lignin with different sulfonation degrees (0.8 mmol/g, SL1; 2.9 mmol/g, SL2) on the inhibition of α-amylase and α-glucosidase and the proliferation of intestinal beneficial bacteria in vitro were investigated. The results showed that both SL1 and SL2 can inhibit the activity of α-amylase and α-glucosidase. The inhibition capacity (IC50, 32.35 µg/mL) of SL2 with a low concentration (0-0.5 mg/mL) to α-amylase was close to that of acarbose to α-amylase (IC50, 27.33 µg/mL). Compared with the control groups, the bacterial cell concentrations of Bifidobacteria adolescentis and Lactobacillus acidophilus cultured with SL1 and SL2 increased in varying degrees (8-36%), and the produced short-chain fatty acids were about 1.2 times higher. This work demonstrates the prospect of sulfonated lignin as a prebiotic for the prevention and treatment of T2DM, which provides new insights for opening up a brand new field of lignin.


Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/prevenção & controle , Lignina , Inibidores de Glicosídeo Hidrolases/farmacologia , Glicemia , alfa-Glucosidases , alfa-Amilases , Extratos Vegetais/farmacologia
5.
Biomacromolecules ; 24(3): 1377-1387, 2023 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-36799412

RESUMO

The abundant and low-cost features of lignin in combination with its natural activities make it a fascinating biopolymer for valorization, especially, in agriculture as an active plant growth regulator. However, the structure-activity relationship of lignin in regulating plant growth and metabolism remains unclear. In this work, rice-straw-based low-molecular-weight (LWM, 1860 Da) and high-molecular-weight (HMW, 6840 Da) alkali-oxygen lignins are structurally and comparatively investigated to understand their effects on the growth and metabolism of maize seedlings. The results indicate that LMW lignin at 150 mg·L-1 displays early growth stimulation in maize. Under the optimal concentration of LMW lignin (25 mg·L-1), the growth of maize shoot is ∼83% higher than that of the control one. Furthermore, LMW lignin also has a positive effect on the upregulation of photosynthetic pigment, carbohydrate, and protein synthesis. In contrast, HMW lignin shows an overall inhibitory effect on the above-mentioned biochemical parameters. Based on the structural characterization, LMW lignin contains a higher syringyl/guaiacyl ratio (0.78) and carboxyl content (1.64 mmol·g-1) than HMW lignin (0.43 and 1.27 mmol·g-1, respectively), which demonstrates that methoxyl and carboxyl content of lignin may play a decisive role in seedling growth.


Assuntos
Lignina , Oryza , Lignina/química , Zea mays , Oryza/química , Plântula , Peso Molecular , Álcalis/química , Oxigênio
6.
Luminescence ; 38(10): 1720-1728, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37462124

RESUMO

Multistimuli-responsive fluorescent materials have garnered great research interest benefited from their practical applications. Two twisted-structure compounds containing tetraphenylethylene (TPE) as the aggregation-induced emission (AIE) group and a pyridine unit as the acid reaction site to obtain new multistimuli-responsive fluorescent compounds (namely, TPECNPy: TPECNPy-2 and TPECNPy-3) were successfully synthesized through a one-step Knoevenagel condensation reaction. The multiple-stimuli response process of TPECNPy was investigated by means of photoluminescence (PL) spectra and emission colour. The results showed that both TPECNPy compounds with excellent AIE abilities displayed reversible emission wavelength and colour changes in response to multiple external stimuli, including grinding-fuming by CH2 Cl2 or annealing and HCl-NH3 vapour fuming. More importantly, fluorescent nanofibre films were prepared by electrospinning a solution of TPECNPy mixed with cellulose acetate (CA), and these exhibited reversible acid-induced discolouration, even with only 1 wt% TPECNPy. The results of this study may inspire strategies for designing multistimuli-responsive materials and preparing fluorescent sensing nanofibre films.


Assuntos
Nanofibras , Fluorescência , Corantes Fluorescentes/química
7.
Chem Soc Rev ; 51(15): 6652-6703, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35796314

RESUMO

Prodrugs are developed to increase the therapeutic properties of drugs and reduce their side effects. Polyprodrugs emerged as highly efficient prodrugs produced by the polymerization of one or several drug monomers. Polyprodrugs can be gradually degraded to release therapeutic agents. The complete degradation of polyprodrugs is an important factor to guarantee the successful disposal of the drug delivery system from the body. The degradation of polyprodrugs and release rate of the drugs can be controlled by the type of covalent bonds linking the monomer drug units in the polymer structure. Therefore, various types of polyprodrugs have been developed based on polyesters, polyanhydrides, polycarbonates, polyurethanes, polyamides, polyketals, polymetallodrugs, polyphosphazenes, and polyimines. Furthermore, the presence of stimuli-responsive groups, such as redox-responsive linkages (disulfide, boronate ester, metal-complex, and oxalate), pH-responsive linkages (ester, imine, hydrazone, acetal, orthoester, P-O and P-N), light-responsive (metal-complex, o-nitrophenyl groups) and enzyme-responsive linkages (ester, peptides) allow for a selective degradation of the polymer backbone in targeted tumors. We envision that new strategies providing a more efficient synergistic therapy will be developed by combining polyprodrugs with gene delivery segments and targeting moieties.


Assuntos
Pró-Fármacos , Sistemas de Liberação de Medicamentos , Ésteres , Polimerização , Polímeros/química , Pró-Fármacos/química , Pró-Fármacos/farmacologia
8.
Biomacromolecules ; 22(12): 5204-5213, 2021 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-34787399

RESUMO

The purpose of this research is to develop strong and tough wood-based hydrogels, which are reinforced by an aligned cellulosic wood skeleton. The hypothesis is that improved interfacial interaction between the wood cell wall and a polymer is of great importance for improving the mechanical performance. To this end, a facile and green approach, called ultraviolet (UV) grafting, was performed on the polyacrylamide (PAM)-infiltrated wood skeleton without using initiators. An important finding was that PAM-grafted cellulose nanofiber (CNF) architectures formed in the obtained hydrogels under UV irradiation, where CNFs themselves serve as both initiators and cross-linkers. Moreover, an alkali swelling treatment was utilized to improve the accessibility of the wood cell wall before UV irradiation and thus facilitate grafting efficiency. The resulting alkali-treated Wood-g-PAM hydrogels exhibited significantly higher tensile properties than those of the Wood/PAM hydrogel and were further assembled into conductive devices for sensor applications. We believe that this UV grafting strategy may facilitate the development of strong wood-based composites with interesting features.


Assuntos
Hidrogéis , Nanofibras , Celulose , Condutividade Elétrica , Madeira
9.
Biomacromolecules ; 22(12): 4905-4918, 2021 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-34806363

RESUMO

Bioactive substances, displaying excellent biocompatibility, chemical stability, and processability, could be extensively applied in biomedicine and tissue engineering. In recent years, plant-based bioactive substances such as flavonoids, vitamins, terpenes, and lignin have received considerable attention due to their human health benefits and pharmaceutical/medical applications. Among them is lignin, an amorphous biomacromolecule mainly derived from the combinatorial radical coupling of three phenylpropane units (p-hydroxypenyl, guaiacyl, and syringyl) during lignification. Lignin possesses intrinsic bioactivities (antioxidative, antibacterial, anti-UV activities, etc.) against phytopathogens. Lignin also enhances the plant resistance (adaptability) against environmental stresses. The abundant structural features of lignin offer other significant bioactivities including antitumor and antivirus bioactivities, regulation of plant growth, and enzymatic hydrolysis of cellulose. This Review reports the latest research results on the bioactive potential of lignin and lignin-based substances in biomedicine, agriculture, and biomass conversion. Moreover, the interfacial reactions and bonding mechanisms of lignin with biotissue/cells and other constituents were also discussed, aiming at promoting the conversion or evolution of lignin from industrial wastes to value-added bioactive materials.


Assuntos
Celulose , Lignina , Biomassa , Humanos , Hidrólise , Lignina/química , Plantas/química
10.
Biomacromolecules ; 22(4): 1654-1663, 2021 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-33655745

RESUMO

Hydrogels as a wound dressing, integrated with ultrastretchability, rapid self-healing, and excellent antimicrobial activity, are in high demand, particularly for joint skin wound healing. Herein, a multifunctional and ductile composite hydrogel was developed using poly(vinyl alcohol) (PVA)-borax gel as a matrix that was synergized or dual-reinforced with dopamine-grafted oxidized carboxymethyl cellulose (OCMC-DA) and cellulose nanofibers (CNF). Moreover, neomycin (NEO), an aminoglycoside antibiotic with multifunctional groups, was incorporated into the hydrogel network as both an antibacterial agent and a cross-linker. The dynamic reversible borate ester linkages and hydrogen bonds between OCMC-DA, PVA, and CNF, along with dynamic cross-linking imine linkages between NEO and OCMC-DA, endowed the hydrogel with excellent self-healing ability and stretchability (3300%). The as-reinforced networks enhanced the mechanical properties of hydrogels significantly. More remarkably, the composite hydrogel with improved biodegradability and biocompatibility is pH-responsive and effective against a broad spectrum of bacteria, which is attributed to the controllable release of NEO for steady availability of the antibiotic on the wound location. Overall, the antimicrobial hydrogel with rapid self-healing and reliable mechanical properties holds significant promise as dressing material for wound healing.


Assuntos
Anti-Infecciosos , Hidrogéis , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Bandagens , Celulose
11.
Bioconjug Chem ; 31(1): 113-122, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31841319

RESUMO

Antimicrobial peptides (AMPs) are typical cell penetrating peptides (CPPs) that intercalate into biomembranes and exhibit broad activities. We designed a triple fusion protein consisting of an AMP, Ib-AMP4 at the N-terminus, a fluorescent GFP probe in the center, and the tumor-targeting peptide P1c at the other terminus. After purification from E. coli, the interaction between the Ib-AMP4-GFP-P1c fusion protein (IGP) and the lipid membrane was characterized. Experiments using isothermal titration calorimetry (ITC) and quartz crystal microbalance with dissipation (QCM-D) demonstrated that IGP proteins spontaneously bound the lipid bilayer with a maximal molar ratio of 1:52 (protein:lipid). Furthermore, transmission electron microscopy (TEM) confirmed that the IGP protein was present in the liposome membrane. After decoration with IGP proteins, the DOPC:DOPG liposomes were applied to cancer cells. Microscopy and flow cytometry reveal that the decorated liposomes selectively bound integrin αvß3-positive A549 cells. In addition, compared with the common chemical conjugation method, the reported method seemed to be superior in certain aspects, such as simple sample preparation and cost-effectiveness. Next, the IGP protein was applied to decorate red blood cell (RBC) liposomes for targeted delivery in both in vitro and in vivo applications. The IGP-decorated RBC liposomes preferentially targeted integrin αvß3 expressing A549 cancer cells. The in vivo imaging showed that IGP-decorated RBC liposomes were concentrated in tumor tissue and were primarily metabolized by the liver and kidney.


Assuntos
Antineoplásicos/administração & dosagem , Peptídeos Penetradores de Células/química , Sistemas de Liberação de Medicamentos , Lipossomos/química , Células A549 , Animais , Antineoplásicos/uso terapêutico , Eritrócitos/química , Células HEK293 , Humanos , Ligantes , Neoplasias Pulmonares/tratamento farmacológico , Camundongos , Camundongos Nus , Proteínas Recombinantes de Fusão/química
12.
Chem Rec ; 20(8): 857-881, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32286725

RESUMO

Manipulation and engineering of the surfaces has a key role in improving the materials properties. Anchoring of thin hydrogels on the materials surface is one of the recently developed methods to achieve surfaces with high potential applications. Layer-by-layer (LBL) has been used widely as a strong strategy for immobilization of thin hydrogel films on the surface of various organic/inorganic substrates. Electrostatic LBL and covalent LBL are two main strategies used in this regard. In electrostatic LBL, negatively and positively hydrophilic polymers are sequentially assembled to create a multilayer hydrogel which subsequent covalent crosslinking of multilayers improved the stability of the inserted layers. On the other hand, covalent LBL requires hydrophilic polymers bearing reactive telechelic groups. These reactive polymers are prepared by various polymerization techniques or by post-functionalization of biopolymers. The principles of hydrogel anchoring have described along with representative examples. Besides, the potential applications of the modified surfaces in specific cases have been addressed and overviewed.

13.
Biomacromolecules ; 21(8): 2983-3006, 2020 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-32672446

RESUMO

Wound healing is usually accompanied by bacterial infection. The excessive use of synthetic antibiotics leads to drug resistance, posing a significant threat to human health. Hydrogel-based wound dressings aimed at mitigating bacterial infections have emerged as an effective wound treatment. The review presented herein particularly focuses on the hydrogels originating from natural polymers. To further enhance the performance of wound dressings, various strategies and approaches have been developed to endow the hydrogels with excellent broad-spectrum antibacterial activity. Those that are summarized in the current review are the hydrogels with intrinsic or stimuli-triggered bactericidal properties and others that serve as vehicles for loading antibacterial agents without synthetic antibiotics. Specific attention is paid to antimicrobial mechanisms and the antibacterial performance of hydrogels. Practical antibacterial applications to accelerate the wound healing employing these antibiotic-free hydrogels are also introduced along with the discussion on the current challenges and perspectives leading to new technologies.


Assuntos
Anti-Infecciosos , Hidrogéis , Antibacterianos/farmacologia , Bandagens , Humanos , Polímeros
14.
Mikrochim Acta ; 187(1): 23, 2019 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-31807912

RESUMO

An electrochemical sensor for Pb(II) is described that exploits (a) the outstanding adsorption ability of chitosan modified with quaternary ammonium groups (CQAS; cationic) and of lignosulfonate (LSN; anionic), and (b) the good electrical conductivity of polypyrrole nanoparticles (PPy NPs). A glassy carbon electrode (GCE) was modified with PPy NPs and polydopamine, and CQAS and LSN are used as dispersants in PPy. The modified GCE exhibits high selectivity and sensitivity for Pb(II) in the 0.1 to 50 µM concentration range, with a 55 nM detection limit (3σ method). The redox potentials for Pb(II) is around -0.55 V, and the sensor is not interfered by the presence of Hg(II) and Cu(II). The time dependent stability test showed that this sensor can maintain good reproducibility for one month. This sensor was applied to the determination of Pb(II) in wastewater samples. An electrochemical sensor for lead(II) is described that exploits the outstanding adsorption ability of chitosan that carries quaternary ammonium groups (CQAS), of lignosulfonate (LSN), and the good electrical conductivity of polypyrrole nanoparticles. CQAS and LSN are used as dispersants in PPy. The sensor exhibits high selectivity and sensitivity for Pb(II) in the range of 0.1 to 50 µM with a 55 nM detection limit.

15.
Carbohydr Polym ; 330: 121832, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38368087

RESUMO

In this work, new N, O-codoped chitosan-derived carbon adsorbents (CKC-x, x refer to the calcination temperature) were synthesized over a simple process of chitosan-KOH aerogel production and simultaneous carbonization/activation of the aerogel. CKC-700 was characterized by sheet-like morphology (even containing a portion of carbon nano-sheet of 3 nm thickness), high porosity and specific surface area (1702.1 m2/g), and pyridinic/pyrrolic/graphitic N groups. The simultaneous carbonization/activation of chitosan-KOH aerogel prepared by top-down coagulation of chitosan aqueous solution by KOH aqueous solution rendered these beneficial characteristics. CKC-700 exhibited a superior adsorption capacity for Rhodamine B (RhB) to other chitosan-derived carbon adsorbents, and the maximum adsorption capacity for RhB of 594 mg/g was achieved at 55 °C. CKC-700 also possessed reasonable reusability for the removal of RhB, and the removal efficiency was still above 95 % in the fifth cycle. The effects of adsorption temperature and time, adsorbent dose, organic dye concentration, and solution pH on the adsorption capacity of CKC-700 were studied. Moreover, the adsorption isotherm, kinetics, thermodynamics, and the adsorption mechanism of RhB on CKC-700 were discussed. In addition, CKC-700 also showed favorable adsorption performance for methylene blue (441 mg/g), methyl orange (457 mg/g), and congo red (500 mg/g) at around 25 °C.

16.
Int J Biol Macromol ; 255: 128188, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37977473

RESUMO

Petroleum-based plastics are useful but they pose a great threat to the environment and human health. It is highly desirable yet challenging to develop sustainable structural materials with excellent mechanical and optical properties for plastic replacement. Here, we report a simple and efficient method to manufacture high-performance all-biobased structural materials from cellulosic wood skeleton (WS) and gelatin via oxidation and densification. Specifically, gelatin was grafted to the oxidized cellulose wood skeletons (DAWS) and then physically crosslinked via Tannic acid (TA), resulting in a significant enhancement of the material properties. Notably, only a mild pressure was applied during the drying process to form a densified TA/Gelatin/transparent wood film(TWF). The developed TA/Gelatin/TWF (thickness:100 ± 12 µm) exhibited a desirable combination of high strength (∼154.59 MPa), light transmittance (86.2 % at 600 nm), low haze (16.7 %), high water stability (wet strength: ∼130.13 MPa) and ultraviolet blocking efficacy which surpass most of the petroleum-based plastics. In addition, due to the all bio-based origins (wood and gelatin), TA/Gelatin/TWF are easily biodegradable under natural conditions, leading to less impact on the environment. These findings would hold promises for exploring high-quality all bio-based wood composites as eco-friendly alternatives to substitute plastics with wide applications, e.g. anti-counterfeiting, UV protection, and flexible electricals.


Assuntos
Celulose Oxidada , Petróleo , Humanos , Gelatina , Madeira
17.
Int J Biol Macromol ; 267(Pt 2): 131505, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38631574

RESUMO

Cellulose, hemicellulose, and lignin are the major bio-components in lignocellulosic biomass (BC-LB), which possess excellent biomechanical properties and biocompatibility to satisfy the demands of orthopedic applications. To understand the basis and trends in the development of major bio-components in BC-LB in orthopedics, the bibliometric technology was applied to get unique insights based on the published papers (741) in the Web of Science (WOS) database from January 1st, 2001, to February 14th, 2023. The analysis includes the annual distributions of publications, keywords co-linearity, research hotspots exploration, author collaboration networks, published journals, and clustering of co-cited literature. The results reveal a steady growth in publications focusing on the application of BC-LB in orthopedics, with China and the United States leading in research output. The "International Journal of Biological Macromolecules" was identified as the most cited journal for BC-LB research in orthopedics. The research hotspots encompassed bone tissue engineering, cartilage tissue engineering, and drug delivery systems, indicating the fundamental research and potential development in these areas. This study also highlights the challenges associated with the clinical application of BC-LB in orthopedics and provides valuable insights for future advancements in the field.


Assuntos
Bibliometria , Biomassa , Celulose , Lignina , Ortopedia , Polissacarídeos , Lignina/química , Polissacarídeos/química , Celulose/química , Humanos , Engenharia Tecidual/métodos
18.
Int J Biol Macromol ; 273(Pt 1): 133017, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38876242

RESUMO

Supercapacitors are the preferred option for supporting renewable energy sources owing to many benefits, including fast charging, long life, high energy and power density, and saving energy. While electrode materials with environmentally friendly preparation, high performance, and low cost are important research directions of supercapacitors. At present, the growing global population and the increasingly pressing issue of environmental pollution have drawn the focus of numerous researchers worldwide to the development and utilization of renewable biomass resources. Lignin, a renewable aromatic polymer, has reserves second only to cellulose in nature. Ten million tonnes of industrial lignin are produced in pulp and paper mills annually, most of which are disposed of as waste or burned for fuel, seriously depleting natural resources and polluting the environment. One practical strategy to accomplish sustainable development is to employ lignin resources to create high-value materials. Based on the high carbon content and rich functional groups of lignin, the lignin-based carbon materials generated after carbonization treatment display specific electrochemical properties as electrode materials. Nevertheless, low electrochemical activity of untreated lignin precludes it from achieving its full potential for application in energy storage. Heteroatom doping is a common modification method that aims to improve the electrochemical performance of the electrode materials by optimizing the structure of the lignin, improving its pore structure and increasing the number of active sites on its surface. This paper aims to establish theoretical foundations for design, preparation, and optimizing the performance of heteroatom-doped lignin-based carbon materials, as well as for developing high-value-added lignin materials. The most reported the mechanism of supercapacitors, the doping process involving various types of heteroatoms, and the analysis of how heteroatoms affect the performance of lignin-based carbon materials are also detailed in this review.


Assuntos
Carbono , Capacitância Elétrica , Eletrodos , Lignina , Lignina/química , Carbono/química
19.
ACS Nano ; 18(5): 4329-4342, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38261787

RESUMO

Lignin, as an abundant aromatic biopolymer in plants, has great potential for medical applications due to its active sites, antioxidant activity, low biotoxicity, and good biocompatibility. In this work, a simple and ecofriendly approach for lignin fractionation and modification was developed to improve the antitumor activity of lignin. The lignin fraction KL-3 obtained by the lignin gradient acid precipitation at pH = 9-13 showed good cytotoxicity. Furthermore, the cell-feeding lignin after additional structural modifications such as demethylation (DKL-3), sulfonation (SL-3), and demethylsulfonation (DSKL-3) could exhibit higher glutathione responsiveness in the tumor microenvironment, resulting in reactive oxygen species accumulation and mitochondrial damage and eventually leading to apoptosis in HepG2 cells with minimal damage to normal cells. The IC50 values for KL-3, SL-3, and DSKL-3 were 0.71, 0.57, and 0.41 mg/mL, respectively, which were superior to those of other biomass extractives or unmodified lignin. Importantly, in vivo experiments conducted in nude mouse models demonstrated good biosafety and effective tumor destruction. This work provides a promising example of constructing carrier-free functionalized lignin antitumor materials with different structures for inhibiting the growth of human hepatocellular carcinoma (HepG2) cells, which is expected to improve cancer therapy outcomes.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Poliuretanos , Animais , Camundongos , Humanos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Células Hep G2 , Lignina/farmacologia , Microambiente Tumoral
20.
Carbohydr Polym ; 330: 121822, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38368103

RESUMO

Hydroxypropyl cellulose (HPC) is a sustainable cellulose derivative valued for its excellent biocompatibility and solubility and is widely used in various fields. Recent scientific research on high-substituted HPC mainly focused on its efficient preparation and phase transition behavior. Herein, a novel strategy of high-substituted HPC synthesis was demonstrated by employing DMSO/TBAF·3H2O as a cellulose solvent, exhibiting more efficiency than traditional approaches. High-substituted HPC prepared has remarkable thermal stability, exceptional hydrophilicity, and satisfactory solubility. Phase transition behavior of HPC with varying molar degrees of substitution (MS) was delved and a notable negative correlation between MS and cloud point temperature (TCP), was revealed, particularly evident at an MS of 12.3, where the TCP drops to 33 °C. Moreover, a unique self-assembly behavior featuring structural color and responsiveness to force in a solvent-free environment emerged when the MS exceeded 10.4. These insights comprehensively strengthen the understanding and knowledge of high-substituted HPC, simultaneously paving the way for further HPC investigation and exploitation.

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