Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 50
Filtrar
1.
Int J Mol Sci ; 25(7)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38612381

RESUMO

Candida albicans is a prevalent fungal pathogen that displays antibiotic resistance. The polyene antifungal amphotericin B (AmB) has been the gold standard because of its broad antifungal spectra, and its liposomal formulation, AmBisome, has been used widely and clinically in treating fungal infections. Herein, we explored enhancing the antifungal activity of AmBisome by integrating a small chitin-binding domain (LysM) of chitinase A derived from Pteris ryukyuensis. LysM conjugated with a lipid (LysM-lipid) was initially prepared through microbial transglutaminase (MTG)-mediated peptide tag-specific conjugation of LysM with a lipid-peptide substrate. The AmBisome formulation modified with LysM-lipid conjugates had a size distribution that was comparable to the native liposomes but an increased zeta potential, indicating that LysM-lipid conjugates were anchored to AmBisome. LysM-lipid-modified AmBisome exhibited long-term stability at 4 °C while retaining the capacity to bind chitin. Nevertheless, the antifungal efficacy of LysM-lipid-modified AmBisome against C. albicans was modest. We then redesigned a new LysM-lipid conjugate by introducing a peptide linker containing a thrombin digestion (TD) site at the C-terminus of LysM (LysM-TD linker-lipid), thereby facilitating the liberation of the LysM domain from AmBisome upon the addition of thrombin. This new AmBisome formulation anchored with LysM-TD linker-lipid exhibited superior performance in suppressing C. albicans growth in the presence of thrombin compared with the LysM-lipid formulation. These results provide a platform to design stimuli-responsive AmBisome formulations that respond to external environments and thus advance the treatment of pathogenic fungi infections.


Assuntos
Anfotericina B , Antifúngicos , Peptídeo Hidrolases , Antifúngicos/farmacologia , Lipossomos , Trombina , Candida albicans , Quitina , Peptídeos/farmacologia , Lipídeos
2.
Mol Pharm ; 19(11): 3906-3914, 2022 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-36066555

RESUMO

Fungal infections affect more than one billion people worldwide and cause more than one million deaths per year. Amphotericin B (AmB), a polyene antifungal drug, has been used as the gold standard for many years because of its broad antifungal spectrum, high activity, and low tendency of drug resistance. However, the side effects of AmB, such as nephrotoxicity and hepatotoxicity, have hampered its widespread use, leading to the development of a liposome-type AmB formulation, AmBisome. Herein, we report a simple but highly effective strategy to enhance the antifungal activity of AmBisome with a lipid-modified protein. The chitin-binding domain (LysM) of the antifungal chitinase, Pteris ryukyuensis chitinase A (PrChiA), a small 5.3 kDa protein that binds to fungal cell wall chitin, was engineered to have a glutamine-containing peptide tag at the C-terminus for the microbial transglutaminase (MTG)-catalyzed crosslinking reaction (LysM-Q). LysM-Q was site-specifically modified with a lysine-containing lipid peptide substrate of MTG with a palmitoyl moiety (Pal-K). The resulting palmitoylated LysM (LysM-Pal) exhibited negligible cytotoxicity to mammalian cells and can be easily anchored to yield LysM-presenting AmBisome (LysM-AmBisome). LysM-AmBisome exhibited a dramatic enhancement of antifungal activity toward Trichoderma viride and Cryptococcus neoformans, demonstrating the marked impact of displaying a cell-wall binder protein on the targeting ability of antifungal liposomal formulations. Our simple strategy with enzymatic protein lipidation provides a potent approach to upgrade other types of lipid-based drug formulations.


Assuntos
Anfotericina B , Quitinases , Animais , Humanos , Anfotericina B/farmacologia , Anfotericina B/química , Antifúngicos/química , Quitina , Lipossomos , Lipídeos , Mamíferos/metabolismo
3.
Langmuir ; 38(31): 9640-9648, 2022 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-35882009

RESUMO

Protein palmitoylation, a post-translational modification, is universally observed in eukaryotic cells. The localization of palmitoylated proteins to highly dynamic, sphingolipid- and cholesterol-rich microdomains (called lipid rafts) on the plasma membrane has been shown to play an important role in signal transduction in cells. However, this complex biological system is not yet completely understood. Here, we used a combined approach where an artificial lipidated protein was applied to biomimetic model membranes and plasma membranes in cells to illuminate chemical and physiological properties of the rafts. Using cell-sized giant unilamellar vesicles, we demonstrated the selective partitioning of enhanced green fluorescent protein modified with a C-terminal palmitoyl moiety (EGFP-Pal) into the liquid-ordered phase consisting of saturated phospholipids and cholesterol. Using Jurkat T cells treated with an immunostimulant (concanavalin A), we observed the vesicular transport of EGFP-Pal. Further cellular studies with the treatment of methyl ß-cyclodextrin revealed the cholesterol-dependent internalization of EGFP-Pal, which can be explained by a raft-dependent, caveolae-mediated endocytic pathway. The present synthetic approach using artificial and natural membrane systems can be further extended to explore the potential utility of artificially lipidated proteins at biological and artificial interfaces.


Assuntos
Lipoilação , Microdomínios da Membrana , Membrana Celular/química , Colesterol/química , Microdomínios da Membrana/química , Lipossomas Unilamelares/química
4.
Bioconjug Chem ; 32(8): 1688-1698, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34251809

RESUMO

Enzymatic reaction offers site-specific conjugation of protein units to form protein conjugates or protein polymers with intrinsic functions. Herein, we report horseradish peroxidase (HRP)- and microbial transglutaminase (MTG)-catalyzed orthogonal conjugation reactions to create antifungal protein polymers composed of Pteris ryukyuensis chitinase-A (ChiA) and its two domains, catalytic domain, CatD, and chitin-binding domain, LysM2. We engineered the ChiA and CatD by introducing a peptide tag containing tyrosine (Y-tag) at N-termini and a peptide tag containing lysine and tyrosine (KY-tag) at C-termini to construct Y-ChiA-KY and Y-CatD-KY. Also, LysM2 with Y-tag and KY-tag (Y-LysM2-KY) or with a glutamine-containing peptide tag (Q-tag) (LysM2-Q) were constructed. The proteins with Y-tag and KY-tag were efficiently polymerized by HRP reaction through the formation of dityrosine bonds at the tyrosine residues in the peptide tags. The Y-CatD-KY polymer was further treated by MTG to orthogonally graft LysM2-Q to the KY-tag via isopeptide formation between the side chains of the glutamine and lysine residues in the peptide tags to form LysM2-grafted CatD polymer. The LysM2-grafted CatD polymer exhibited significantly higher antifungal activity than the homopolymer of Y-ChiA-KY and the random copolymer of Y-CatD-KY and Y-LysM2-KY, demonstrating that the structural differences of artificial chitinase polymers have a significant impact on the antifungal activity. This strategy of polymerization and grafting reaction of protein can contribute to the further research and development of functional protein polymers for specific applications in various fields in biotechnology.


Assuntos
Antifúngicos/farmacologia , Quitina/química , Quitinases/química , Quitinases/metabolismo , Enzimas/metabolismo , Antifúngicos/síntese química , Enzimas/química , Polímeros , Ligação Proteica , Domínios Proteicos
5.
Int J Clin Oncol ; 26(11): 2065-2072, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34368921

RESUMO

BACKGROUND: Although FOLFIRINOX is currently one of the standard therapies for chemotherapy-naïve patients with metastatic pancreatic cancer (MPC), the high rate of febrile neutropenia (FN) presents a clinical problem. This study aimed to evaluate the safety and efficacy of primary prophylactic pegfilgrastim with FOLFIRINOX in Japanese MPC patients. METHODS: FOLFIRINOX (intravenous oxaliplatin 85 mg/m2, irinotecan 180 mg/m2, levofolinate 200 mg/m2, 5-fluorouracil (5-FU) bolus 400 mg/m2 and 5-FU 46 h infusion 2400 mg/m2) and pegfilgrastim 3.6 mg on day 4 or 5, every 2 weeks was administered to previously untreated MPC patients. The primary endpoint was the incidence of FN during the first 3 cycles. The planned sample size was 35 patients, but the trial was predefined to discontinue enrollment for safety if 4 patients developed FN. RESULTS: At the enrollment of 22 patients, 4 patients developed FN in the first cycle, resulting in an incidence of FN of 18% {95% confidence interval [CI], 0.5-40.3%}, and enrollment was discontinued early. The incidence of grade 3 or higher neutropenia was 36.4%. Median relative dose intensities during the initial 3 cycles of oxaliplatin, irinotecan, bolus 5-FU, infusional 5-FU, and levofolinate maintained high (100%, 89.0%, 100%, 66.0%, and 100%, respectively). Response rate and median overall survival were 54.5% (95% CI 32.7-74.9) and 15.7 months (95% CI 7.9-18.8), respectively. CONCLUSIONS: This phase II study could not demonstrate any reduction in the incidence of FN, nevertheless some patients experience benefits for efficacy by maintaining dose intensity using prophylactic pegfilgrastim. TRIAL REGISTRATION: http://www.umin.ac.jp/ctr/index-j.htm , UMIN000017538. Date of registration: May/13/2015.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias Pancreáticas , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Filgrastim , Fluoruracila/efeitos adversos , Humanos , Irinotecano/uso terapêutico , Japão , Leucovorina , Oxaliplatina/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Polietilenoglicóis
6.
Biomacromolecules ; 18(2): 422-430, 2017 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-27966931

RESUMO

Protein-polymer conjugates have been developed in many fields. Most hybrids are composed of one protein attached to one or several polymer chains. The other form of hybrid involves the construction of multiple proteins on one polymer chain, thereby facilitating protein assemblies that provide multivalent effects. Unfortunately, synthetic methods for production of these types of hybrids are limited and challenging because precise control of the conjugation sites is needed. Herein, a novel synthetic polymer that can enzymatically assemble multiple proteins was developed. Polyacrylamide grafted with multiple microbial transglutaminase (MTG)-recognizable peptide derivatives was synthesized, and MTG-catalyzed site-specific conjugation of proteins with the polymer was achieved. The application for immunological biosensing was demonstrated using the assembly of a fusion protein composed of antibody-binding and enzyme moieties. This enzymatic method to synthesize a one-dimensional protein assembly on a synthetic polymer is versatile and can be expanded to a wide range of applications.


Assuntos
Bioensaio/métodos , Imunoadsorventes/metabolismo , Polímeros/metabolismo , Proteínas/metabolismo , Transglutaminases/metabolismo , Catálise , Células HEK293 , Humanos , Imunoadsorventes/química , Ovalbumina/química , Ovalbumina/metabolismo , Polímeros/química , Ligação Proteica , Proteínas/química , Transglutaminases/química
7.
Chem Commun (Camb) ; 60(30): 4036-4039, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38466016

RESUMO

Herein, we report ethosome (ET) formulations composed of a safe amount of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC)-based ionic liquid with various concentrations of ethanol as a carrier for the transdermal delivery of a high molecular weight drug, insulin. The Insulin-loaded ET vesicles exhibited long-term stability compared to conventional DMPC ETs, showing significantly higher drug encapsulation efficiency and increased skin permeation ability.


Assuntos
Líquidos Iônicos , Insulina , Dimiristoilfosfatidilcolina , Administração Cutânea , Pele , Preparações Farmacêuticas , Lipossomos
8.
Anal Biochem ; 434(2): 269-74, 2013 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-23274363

RESUMO

We synthesized several surfactant-like ligands and prepared affinity membranes by introducing them into porous polymeric membranes using the thermally induced phase separation method. The ligands (nitrilotriacetate, iminodiacetate, and glutathione) were successfully displayed on the surfaces of cellulose diacetate membranes. Membranes functionalized with nitrilotriacetate and glutathione captured and released hexahistidine-tagged enhanced green fluorescent protein (His-tag GFP) and glutathione S-transferase (GST) selectively under appropriate conditions. The affinity membranes also enabled highly selective purification of target proteins (GFP and GST) from cell lysates. The protein-binding capacity was 15 µg/cm(2) for His-tag GFP and 13 µg/cm(2) for GST. The application-specific membranes described in this work will aid high-throughput screening and high-throughput analysis of recombinant proteins.


Assuntos
Cromatografia de Afinidade , Membranas Artificiais , Proteínas Recombinantes/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Glutationa/química , Ligantes , Microscopia Eletrônica de Varredura , Ligação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Tensoativos/química , Temperatura , Fatores de Tempo
9.
Biomacromolecules ; 13(9): 2716-22, 2012 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-22871106

RESUMO

Direct and efficient enzymatic synthesis of long-chain cellulose from cellobiose in its original form was successfully achieved via the combination of a surfactant-enveloped enzyme (SEE) and a protic acid in an aprotic organic solvent, lithium chloride/N,N-dimethylacetamide system. The SEE biocatalyst was prepared by protecting the surface of cellulase with the nonionic surfactant dioleyl-N-D-glucona-L-glutamate for keeping its enzymatic activity in nonaqueous media. Fourier transform infrared and nuclear magnetic resonance analyses elucidated the successful synthesis of cellulose, ß-1,4-linked D-glucopyranose polymer, through the reverse hydrolysis of cellobiose. By using protic acid cocatalysts, a degree of polymerization of as-synthesized cellulose reached more than 120, in a ca. 26% conversion, which was 5 times higher than that obtained in an acid-free SEE system. A novel-concept biocatalysis, i.e., a protic acid-assisted SEE-mediated reaction, enables a facile, one-step chain elongation of carbohydrates without any activation via multistep organic chemistry, and can provide potential applications in the functional design of glycomaterials.


Assuntos
Celobiose/química , Celulase/química , Celulose/síntese química , Cloreto de Lítio/química , Ácidos Sulfúricos/química , Tensoativos/química , Biocatálise , Hidrólise , Espectroscopia de Ressonância Magnética , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água
10.
Org Biomol Chem ; 10(38): 7707-13, 2012 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-22903458

RESUMO

The aim of this study was to develop ionic liquid (IL) polymer materials incorporating enzymes that can be used as active, stable and reusable biocatalysts. To this goal, Candida rugosa lipase has been microencapsulated in surfactant aggregates formed in an IL monomer or the solution of an IL monomer/IL and then incorporated into polymer frameworks through the free radical polymerization of an IL (1-vinyl-3-ethylimidazolium bis(trifluoromethyl-sulfonyl) amide) ([veim][Tf(2)N]). The activity, stability and reusability of such IL polymer materials containing lipase were evaluated using lipase-catalyzed hydrolysis of p-nitrophenyl butyrate (p-PNB) as a model reaction. Lipase encapsulated within ionic liquid polymer materials remained active and exhibited excellent stability in aqueous solutions. More importantly, these biopolymer materials retained most of their activity after five reaction cycles, in which biopolymers were recovered from the reaction mixture simply by centrifugation. This study promulgates a direction toward the design of IL - an interesting class of tunable and designable solvents - based polymer materials containing biomolecules via a combination of polymer and supramolecular chemistry for diverse applications.


Assuntos
Líquidos Iônicos/metabolismo , Lipase/metabolismo , Polímeros/metabolismo , Biocatálise , Candida/enzimologia , Ativação Enzimática , Estabilidade Enzimática , Hidrólise , Líquidos Iônicos/química , Lipase/química , Estrutura Molecular , Tamanho da Partícula , Polímeros/química , Propriedades de Superfície
11.
J Biosci Bioeng ; 134(3): 259-263, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35781189

RESUMO

Amphotericin B (AMB) is a gold standard antifungal drug because of its broad-spectrum activity toward pathogenic yeasts and molds. Because of its low solubility in water and toxicity toward humans, several lipid-based formulations that either increase the aqueous solubility or decrease the side effects have been employed in practical use. In our previous research, we found that the combination of AMB with an artificial palmitoylated chitin-binding domain from Pteris ryukyuensis chitinase (LysM-Pal) resulted in synergistic antifungal action against Trichoderma viride. Herein, we prepared hybrid liposomal formulations by combining a commercially available AMB formulation and liposomes with different surface charges to explore key factors in the antifungal activity. The characterization of AMB-loaded liposomal formulations (AMB-LFs), including particle size distribution and zeta potential, showed that anionic and neutral AMB-LFs could stably encapsulate AMB. The combination of either anionic or neutral AMB-LFs with unmodified LysM decreased the minimum inhibitory concentration of AMB. The combination of neutral AMB-LF with LysM-Pal resulted in a further decrease in the MIC, up to 15-fold compared with that of the neutral AMB-LF alone. Our results demonstrate the potential utility of lipid-based liposomal formulations of AMB combined with lipid-modified proteinaceous binders to tackle fungal infections.


Assuntos
Anfotericina B , Antifúngicos , Anfotericina B/efeitos adversos , Antifúngicos/química , Antifúngicos/farmacologia , Proteínas de Transporte , Quitina , Humanos , Lipídeos/química , Lipossomos
12.
Anal Sci ; 37(3): 425-429, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33455962

RESUMO

Enzymes play a central role in the detection of target molecules in biotechnological fields. Most probes used in detection are bifunctional proteins comprising enzymes and binding proteins conjugated by chemical reactions. To create a highly sensitive detection probe, it is essential to increase the enzyme-to-binding protein ratio in the probe. However, if the chemical reactions required to prepare the probe are insufficiently site-specific, the detection probe may lose functionality. Genetic modifications and enzyme-mediated post-translational modifications (PTMs) can ensure the site-specific conjugation of proteins. They are therefore promising strategies for the production of detection probes with high enzyme contents, i.e., polymeric bifunctional proteins. Herein, we review recent advances in the preparation of bifunctional protein conjugates and polymeric bifunctional protein conjugates for detection. We have summarized research on genetically fused proteins and enzymatically prepared polymeric bifunctional proteins, and will discuss the potential use of protein polymers in various detection applications.


Assuntos
Polímeros/química , Proteínas/química , Animais , Polímeros/metabolismo , Proteínas/metabolismo
13.
ACS Appl Mater Interfaces ; 13(17): 19745-19755, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33891816

RESUMO

Chemotherapeutic cytotoxic agents such as paclitaxel (PTX) are considered essential for the treatment of various cancers. However, PTX injection is associated with severe systemic side effects and high rates of patient noncompliance. Micelle formulations (MFs) are nano-drug delivery systems that offer a solution to these problems. Herein, we report an advantageous carrier for the transdermal delivery of PTX comprising a new MF that consists of two biocompatible surfactants: cholinium oleate ([Cho][Ole]), which is a surface-active ionic liquid (SAIL), and sorbitan monolaurate (Span-20). A solubility assessment confirmed that PTX was readily solubilized in the SAIL-based micelles via multipoint hydrogen bonding and cation-π and π-π interactions between PTX and SAIL[Cho][Ole]. Dynamic light scattering (DLS) and transmission electron microscopy revealed that in the presence of PTX, the MF formed spherical PTX-loaded micelles that were well-distributed in the range 8.7-25.3 nm. According to DLS, the sizes and size distributions of the micelle droplets did not change significantly over the entire storage period, attesting to their physical stability. In vitro transdermal assessments using a Franz diffusion cell revealed that the MF absorbed PTX 4 times more effectively than a Tween 80-based formulation and 6 times more effectively than an ethanol-based formulation. In vitro and in vivo skin irritation tests revealed that the new carrier had a negligible toxicity profile compared with a conventional ionic liquid-based carrier. Based on these findings, we believe that the SAIL[Cho][Ole]-based MF has potential as a biocompatible nanocarrier for the effective transdermal delivery of poorly soluble chemotherapeutics such as PTX.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Materiais Biocompatíveis , Sistemas de Liberação de Medicamentos , Líquidos Iônicos/química , Micelas , Paclitaxel/administração & dosagem , Administração Cutânea , Animais , Antineoplásicos Fitogênicos/farmacocinética , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Paclitaxel/farmacocinética , Espectroscopia de Prótons por Ressonância Magnética , Absorção Cutânea , Espectroscopia de Infravermelho com Transformada de Fourier , Tensoativos/química
14.
Chem Commun (Camb) ; 56(89): 13756-13759, 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33073787

RESUMO

We report a new series of lipid-based biocompatible ionic liquids (LBILs) consisting of the long-chain phosphonium compound 1,2-dimyristoyl-sn-glycero-3-ethyl-phosphatidylcholine as the cation and the long-chain fatty acids stearic acid, oleic acid, or linoleic acid as anions. These materials were found to be completely miscible with many polar and nonpolar organic solvents as well as dispersible in water. These LBILs also exhibited excellent biocompatibility with an artificial three-dimensional human epidermis model.


Assuntos
Materiais Biocompatíveis/química , Líquidos Iônicos/química , Lipídeos/química , Materiais Biocompatíveis/síntese química , Epiderme/química , Humanos , Líquidos Iônicos/síntese química , Estrutura Molecular , Solventes/síntese química , Solventes/química
15.
J Biosci Bioeng ; 130(4): 416-423, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32636145

RESUMO

Liquid marbles (LMs) have recently shown a great promise as microbioreactors to construct self-supported aqueous compartments for chemical and biological reactions. However, the evaporation of the inner aqueous liquid core has limited their application, especially in studying cellular functions. Hydrogels are promising scaffolds that provide a spatial environment suitable for three-dimensional cell culture. Here, we describe the fabrication of redox-responsive hydrogel marbles (HMs) as a three-dimensional cell culture platform. The HMs are prepared by introducing an aqueous mixture of a tetra-thiolated polyethylene glycol (PEG) derivative, thiolated gelatin (Gela-SH), horseradish peroxidase, a small phenolic compound, and human hepatocellular carcinoma cells (HepG2) to the inner aqueous phase of LMs. Eventually, HepG2 cells are encapsulated in the HMs then immersed in culture media, where they proliferate and form cellular spheroids. Experimental results show that the Gela-SH concentration strongly influences the physicochemical and microstructure properties of the HMs. After 6 days in culture, the spheroids were recovered from the HMs by degrading the scaffold, and examination showed that they had reached up to about 180 µm in diameter depending on the Gela-SH concentration, compared with 60 µm in conventional HMs without Gela-SH. After long-term culture (over 12 days), the liver-specific functions (secretion of albumin and urea) and DNA contents of the spheroids cultured in the HMs were elevated compared with those cultured in LMs. These results suggest that the developed HMs can be useful in designing a variety of microbioreactors for tissue engineering applications.


Assuntos
Reatores Biológicos , Hidrogéis/química , Esferoides Celulares/metabolismo , Gelatina/química , Células Hep G2 , Peroxidase do Rábano Silvestre/metabolismo , Humanos , Oxirredução , Polietilenoglicóis/química , Engenharia Tecidual
16.
Biomacromolecules ; 10(5): 1265-9, 2009 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-19317400

RESUMO

Enzymatic glyco-modification of transparent cellulose films with lactose was achieved by nonaqueous biocatalysis, and rat hepatocyte attachment behavior to the lactose-modified cellulose films was investigated. Regenerated cellulose films were incubated with lactose using a surfactant-enveloped cellulase in lithium chloride/dimethylacetamide solvent at 37 degrees C for 24 h, and lactose molecules were successfully introduced to the cellulose films. The initial cell adhesion on the lactose-modified cellulose films was superior to the original cellulose film. In the absence of serum, hepatocytes were significantly attached only on the lactose-modified cellulose films. This process was markedly suppressed by the addition of free lactose as an inhibitor. These results suggest that such cell adhesion proceeded through a direct interaction between galactose residues on the cellulose films and asialoglycoprotein receptors on the rat liver cell surface. This novel approach for surface glyco-modification of a cellulose matrix and its biofunctional properties are expected to provide potential application as a bioactive scaffold for cell culture engineering.


Assuntos
Técnicas de Cultura de Células/métodos , Celulose/química , Celulose/metabolismo , Lactose/metabolismo , Membranas Artificiais , Alicerces Teciduais/química , Acetamidas/química , Animais , Biocatálise , Adesão Celular/fisiologia , Hepatócitos/química , Cloreto de Lítio/química , Substâncias Macromoleculares/química , Teste de Materiais , Ratos , Propriedades de Superfície , Fatores de Tempo
17.
Org Biomol Chem ; 7(11): 2353-8, 2009 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-19462045

RESUMO

Horseradish peroxidase (HRP) is encapsulated in polymerized ionic liquid microparticles (pIL-MP), which are prepared by polymerization of 1-vinyl-3-ethylimidazolium bromide in the presence of the crosslinker N,N'-methylenebis(acrylamide) in a concentrated water-in-oil (W/O) emulsion. pIL-MP encapsulating HRP chemically-modified with comb-shaped polyethylene glycol (PM(13)-HRP) exhibit excellent activity for guaiacol oxidation in an aqueous solution. The PM(13)-HRP in pIL-MP shows more than 2-fold higher activity than that of the enzyme encapsulated in a polyacrylamide microparticle. The catalytic activity declines with an increase in the crosslinker concentration of the pIL-MP, probably due to suppression of substrate diffusion. The activity of PM(13)-HRP in pIL-MP depends on the external environment of the gel (i.e. pH and temperature). The pIL-MP are easily recovered from the reaction mixture by centrifugation, which makes it possible to recycle the biocatalyst for repeated oxidation reactions.


Assuntos
Emulsões/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Líquidos Iônicos/química , Acrilamidas , Reagentes de Ligações Cruzadas , Oxirredução , Polivinil/química
18.
Adv Biochem Eng Biotechnol ; 168: 61-77, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29744542

RESUMO

Ionic liquids (ILs), a potentially attractive "green," recyclable alternative to environmentally harmful volatile organic compounds, have been increasingly exploited as solvents and/or cosolvents and/or reagents in a wide range of applications, including pretreatment of lignocellulosic biomass for further processing. The enzymatic delignification of biomass to degrade lignin, a complex aromatic polymer, has received much attention as an environmentally friendly process for clean separation of biopolymers including cellulose and lignin. For this purpose, enzymes are generally isolated from naturally occurring fungi or genetically engineered fungi and used in an aqueous medium. However, enzymatic delignification has been found to be very slow in these conditions, sometimes taking several months for completion. In this chapter, we highlight an environmentally friendly and efficient approach for enzymatic delignification of lignocellulosic biomass using room temperature ionic liquids (ILs) as (co)solvents or/and pretreatment agents. The method comprises pretreatment of lignocellulosic biomass in IL-aqueous systems before enzymatic delignification, with the aim of overcoming the low delignification efficiency associated with low enzyme accessibility to the solid substrate and low substrate and product solubilities in aqueous systems. We believe the processes described here can play an important role in the conversion of lignocellulosic biomass-the most abundant renewable biomaterial in the world-to biomaterials, biopolymers, biofuels, bioplastics, and hydrocarbons. Graphical Abstract.


Assuntos
Técnicas de Química Analítica/métodos , Líquidos Iônicos , Lignina , Biocombustíveis , Biomassa , Líquidos Iônicos/química , Lignina/química , Lignina/metabolismo , Solventes/química
19.
Int J Pharm ; 569: 118582, 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31381987

RESUMO

The objective of this study was to prepare a supersaturated formulation based on formation of a co-amorphous system of a drug and a coformer in order to enhance skin permeation. Atenolol (ATE) and urea (URE) were used as the model drug and the coformer, respectively. Thermal analysis of physical mixtures of ATE and URE showed decreases in the melting points and the formation of a co-amorphous system which was in a supercooled liquid state because of a low glass transition temperature. Supersaturated solutions of ATE and URE at different molar ratios in polyethylene glycol 400 (PEG400) were prepared. The precipitations were observed under storage at 25 °C for all formulations except for ATE-URE at 1:8 molar ratio which remained in the supersaturated state for 2 months. 1H NMR analysis confirmed the interactions between ATE and URE in PEG400. The ATE-URE supersaturated formulation showed higher permeability for mice skin than that of ATE saturated formulation, which was superior to the expected permeability from the degree of supersaturation. We concluded that co-amorphous based supersaturated formulation offers much promise for transdermal drug delivery.


Assuntos
Atenolol/administração & dosagem , Polietilenoglicóis/administração & dosagem , Pele/metabolismo , Ureia/administração & dosagem , Administração Cutânea , Animais , Atenolol/química , Sistemas de Liberação de Medicamentos , Técnicas In Vitro , Masculino , Camundongos Pelados , Permeabilidade , Polietilenoglicóis/química , Ureia/química
20.
J Colloid Interface Sci ; 551: 72-80, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31075635

RESUMO

Ionic liquid (IL) surfactants have attracted great interest as promising substitutes for conventional surfactants owing to their exceptional and favorable physico-chemical properties. However, most IL surfactants are not eco-friendly and form unstable micelles, even when using a high concentration of the surfactant. In this study, we prepared a series of halogen-free and biocompatible choline-fatty-acid-based ILs with different chain lengths and degrees of saturation, and we then investigated their micellar properties in aqueous solutions. Characterization of the synthesized surface-active ILs (SAILs) was performed by 1H and 13C nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and elemental analysis. The surface-active properties of the SAILs were investigated by tensiometry, conductometry, and dynamic light scattering measurements. The critical micelle concentration of the SAILs was found to be 2-4 times lower than those of conventional surfactants. The thermodynamic properties of micellization (ΔG0m, ΔH0m, and ΔS0m) indicate that the micellization process of the SAILs is spontaneous, stable, and entropy-driven at room temperature. The cytotoxicity of the SAILs was evaluated using mammalian cell line NIH 3T3. Importantly, [Cho][Ole] shows lower toxicity than the analogous ILs with conventional surfactants. These results clearly suggest that these environmentally friendly SAILs can be used as a potential alternative to conventional ILs for various purposes, including biological applications.


Assuntos
Materiais Biocompatíveis/química , Colina/química , Ácidos Graxos/química , Líquidos Iônicos/química , Tensoativos/química , Células 3T3 , Animais , Sobrevivência Celular/efeitos dos fármacos , Líquidos Iônicos/toxicidade , Camundongos , Micelas , Propriedades de Superfície , Tensoativos/toxicidade , Temperatura , Termodinâmica , Água
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA