RESUMO
Auxin is well known to stimulate coleoptile elongation and rapid seedling growth in the air. However, its role in regulating rice germination and seedling establishment under submergence is largely unknown. Previous studies revealed that excessive levels of indole-3-acetic acid(IAA) frequently cause the inhibition of plant growth and development. In this study, the high-level accumulation of endogenous IAA is observed under dark submergence, stimulating rice coleoptile elongation but limiting the root and primary leaf growth during anaerobic germination (AG). We found that oxygen and light can reduce IAA levels, promote the seedling establishment and enhance rice AG tolerance. miRNA microarray profiling and RNA gel blot analysis results show that the expression of miR167 is negatively regulated by submergence; it subsequently modulates the accumulation of free IAA through the miR167-ARF-GH3 pathway. The OsGH3-8 encodes an IAA-amido synthetase that functions to prevent free IAA accumulation. Reduced miR167 levels or overexpressing OsGH3-8 increase auxin metabolism, reduce endogenous levels of free IAA and enhance rice AG tolerance. Our studies reveal that poor seed germination and seedling growth inhibition resulting from excessive IAA accumulation would cause intolerance to submergence in rice, suggesting that a certain threshold level of auxin is essential for rice AG tolerance.
Assuntos
Germinação , Oryza , Plântula/metabolismo , Oryza/genética , Anaerobiose , Proteínas de Plantas/metabolismo , Ácidos Indolacéticos/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
GIBBERELLIN MYB GENE (GAMYB), UNDEVELOPED TAPETUM1 (UDT1), TDR INTERACTING PROTEIN2 (TIP2/bHLH142), TAPETUM DEGENERATION RETARDATION (TDR), and ETERNAL TAPETUM 1/DELAYED TAPETUM DEGENERATION (EAT1/DTD) are important transcription factors that play a crucial role during pollen development in rice. This study demonstrates that bHLH142 acts downstream of UDT1 and GAMYB and works as a 'hub' in these two pollen pathways. We show that GAMYB modulates bHLH142 expression through specific binding to the MYB motif of the bHLH142 promoter during the early stage of pollen development, while TDR acts as a transcriptional repressor of the GAMYB modulation of bHLH142 by binding to the E-box close to the MYB motif on the promoter. Altered expression of these transcription factors highlights that a tight, precise, and coordinated regulation among them is essential for normal pollen development. Most notably, we show that the regulatory pathways of GAMYB and UDT1 rely on bHLH142 in a direct and indirect manner, respectively, and function in different tissues with distinct biological roles during pollen development. This study advances our understanding of the molecular mechanisms of rice pollen development.
Assuntos
Oryza , Flores/genética , Flores/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Pólen/genética , Pólen/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Male sterility plays an important role in F1 hybrid seed production. We identified a male-sterile rice (Oryza sativa) mutant with impaired pollen development and a single T-DNA insertion in the transcription factor gene bHLH142. Knockout mutants of bHLH142 exhibited retarded meiosis and defects in tapetal programmed cell death. RT-PCR and in situ hybridization analyses showed that bHLH142 is specifically expressed in the anther, in the tapetum, and in meiocytes during early meiosis. Three basic helix-loop-helix transcription factors, UDT1 (bHLH164), TDR1 (bHLH5), and EAT1/DTD1 (bHLH141) are known to function in rice pollen development. bHLH142 acts downstream of UDT1 and GAMYB but upstream of TDR1 and EAT1 in pollen development. In vivo and in vitro assays demonstrated that bHLH142 and TDR1 proteins interact. Transient promoter assays demonstrated that regulation of the EAT1 promoter requires bHLH142 and TDR1. Consistent with these results, 3D protein structure modeling predicted that bHLH142 and TDR1 form a heterodimer to bind to the EAT1 promoter. EAT1 positively regulates the expression of AP37 and AP25, which induce tapetal programmed cell death. Thus, in this study, we identified bHLH142 as having a pivotal role in tapetal programmed cell death and pollen development.
RESUMO
In this study, metalloanthocyanin-inspired, biodegradable packaging films were developed by incorporating purple cauliflower extracted (PCE) anthocyanins into alginate (AL)/carboxymethyl chitosan (CCS) hybrid polymer matrices based on complexation of metal ions with these marine polysaccharides and anthocyanins. PCE anthocyanins-incorporated AL/CCS films were further modified with fucoidan (FD) because this sulfated polysaccharide can form strong interactions with anthocyanins. Metals-involved complexation (Ca2+ and Zn2+-crosslinked films) improved the mechanical strength and water vapor permeability but reduced the swelling degree of the films. Zn2+-cross-linked films exhibited significantly higher antibacterial activity than did pristine (non-crosslinked) and Ca2+-cross-linked films. The metal ion/polysaccharide-involved complexation with anthocyanin reduced the release rate of anthocyanins, increased the storage stability and antioxidant capability, and improved the sensitivity of the colorimetric response of the indicator films for monitoring the freshness of shrimp. The anthocyanin-metal-polysaccharide complex film showed great potential as active and intelligent packaging of food products.
Assuntos
Complexos de Coordenação , Embalagem de Alimentos , Antocianinas , Polissacarídeos , Alginatos , Extratos VegetaisRESUMO
Ophiopogon japonicus polysaccharides (OJPs) have great anti-inflammation and immunomodulatory abilities. However, the low bioavailability of OJPs reduces its applicability in the biomedical and pharmaceutical fields. Chitosan (CS) has excellent mucoadhesive properties and absorption-enhancing ability in oral administration. Casein hydrolysate (CL) has good interfacial diffusivity and emulsifying ability, and can interact with polysaccharides to form complexes combining the individual properties of both. Therefore, chitosan and casein hydrolysate are good candidates for developing nanoformulations for oral delivery. In this study, bioactive polysaccharides (OJPs), CS and CL, were combined to prepare CS/OJPs/CL co-assembled biodegradable nanoparticles. The interactions between polysaccharides (CS and OJPs) and peptide (CL) resulted in the formation of nanoparticles with an average particle size of 198 nm and high OJPs loading efficiency. The colloidal properties of the nanoparticles were pH-dependent, which were changed significantly in simulated digestive fluid at different pH values. OJPs released from the CS/OJPs/CL nanoparticles were greatly affected by pH and enzymatic degradation (trypsin and lysozyme). The nanoparticles were easily internalized by macrophages, thereby enhancing the OJPs' inhibitory ability against Ni2+-induced cytotoxicity and LPS-induced nitric oxide production. This study demonstrates that prepared polysaccharide/protein co-assembled nanoparticles can be potential nanocarriers for the oral delivery of bioactive polysaccharides with anti-inflammatory functions.
RESUMO
Antimicrobial resistance has become a global issue and thus the development of natural products/biomedical materials composites with antibacterial activities is urgently needed. When acute wounds develop into chronic wounds, the wound environments become alkaline. As long as infections occur, the wound pH further increases, making the wounds difficult to heal. Besides, bacterial growth in poultry, meat, fish and seafood products is usually reflected in a marked increase of pH values. Herein, smart, stimuli responsive self-assembled multilayer and complex film were constructed through the formation of hydrogen bonds and hydrophobic interactions between hydroxypropyl methylcellulose (HPMC) and epigallocatechin-3-gallate (EGCG), thereby greatly reducing the hydrophilicity of HPMC and offering enhanced mechanical strength, superior free radical scavenging capability, and improved water vapor and light barrier properties. The EGCG/HPMC complex film was able to control EGCG release by tuning pH or temperature of the release medium. Furthermore, incorporation of CuS nanoparticles into the film allowed it to triggers EGCG release in an on-demand fashion under near-infrared (NIR) exposure. Bacterial growth in glucose-free nutrient broth medium caused pH to rise (near pH 8.0), leading to transformation of EGCG from phenol type to phenolate ion and then quinone, allowing for spontaneous generation of H2O2 to kill bacteria. The complex films changed their color in response to bacterial growth because EGCG transformed from phenol type to quinone type under alkaline condition. The green synthesized EGCG/HPMC complex films can be used as a colorimetric pH indicator and an antibacterial material for wound dressing and food packaging applications.
Assuntos
Embalagem de Alimentos , Peróxido de Hidrogênio , Animais , Antibacterianos/farmacologia , Liberação Controlada de Fármacos , CarneRESUMO
Active and intelligent packaging films with multiple functions including antioxidant, antibacterial and colorimetric pH indicator properties were developed by incorporating Clitoria ternatea (CT) extract into gellan gum (G) film. G enhanced the stability of CT anthocyanins and allowed the anthocyanins to release from G film in a pH-responsive behavior. Heat-treated soy protein isolate (HSPI) was able to interact with G and CT anthocyanins through the formation of electrostatic forces and covalent bonds. G film blended with HSPI greatly reduced the swelling capacity of G/HSPI composite film and controlled the anthocyanins release at pH greater than 6.0. The physical and mechanical properties of G films such as hydrophobicity, water vapor permeability, swelling capacity and tensile strength were also significantly modified by addition of HSPI to G films. The smart films changed their color with the increase of total volatile basic nitrogen (TVBN) values during progressive spoilage of shrimp, revealing their potential application for monitoring seafood freshness.
Assuntos
Antocianinas/química , Clitoria/química , Embalagem de Alimentos/métodos , Qualidade dos Alimentos , Extratos Vegetais/química , Polissacarídeos Bacterianos/química , Materiais Inteligentes/química , Cor , Colorimetria/métodos , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Permeabilidade , Alimentos Marinhos , Proteínas de Soja/química , Eletricidade Estática , Vapor , Resistência à TraçãoRESUMO
Rheumatoid arthritis (RA) is of foremost concern among long-term autoimmune disorders, as it leads to inflammation, exudates, chondral degeneration, and painful joints. Because RA severity often fluctuates over time, a local drug delivery method that titrates release of therapeutics to arthritis bioactivity should represent a promising paradigm of RA therapy. Given the local nature of RA chronic illnesses, polysaccharide-drug delivering systems have the promise to augment therapeutic outcomes by offering controlled release of bioactive materials, diminishing the required frequency of administration, and preserving therapeutic levels in affected pathological regions. Herein, an intra-articular photothermal-laden injectable methylcellulose (MC) polymeric hydrogel carrier incorporating strontium ranelate (SrR) and sodium chloride was investigated to resolve these issues. Physicochemical and cellular characteristics of the MC carrier system were thoroughly evaluated. The slow release of SrR, enhancement of the material mechanical strength, and the potential of the non-invasive near-infrared photothermal gel to improve blood circulation and suppress inflammation in a mini-surgical model of RA were examined. Biocompatibility and suppression of intracellular ROS-induced inflammation were observed. This multifunctional photothermal MC hydrogel carrier is anticipated to be an alternative approach for future orthopedic disease treatment.
Assuntos
Hidrogéis , Metilcelulose , Fototerapia , Tiofenos/farmacologiaRESUMO
Influenza, pneumonia, and pathogenic infection of the respiratory system are boosted in cold environments. Low temperatures also result in vasoconstriction, restraint of blood flow, and decreased oxygen to the heart, and the risk of a heart attack would increase accordingly. The present face mask fabric fails to preserve its air-filtering function as its electrostatic function vanishes once exposed to water. Therefore, its filtering efficacy would be decreased meaningfully, making it nearly impracticable to reuse the disposable face masks. The urgent requirement for photothermal fabrics is also rising. Nanobased polyethyleneimine-polypyrrole nanopigments (NPP NPs) have been developed and have strong near-infrared spectrum absorption and exceptional photothermal convertible performance. Herein, the mask fabric used PE-fiber-constructed membrane (PEFM) was coated by the binding affinity of the cationic polyethyleneimine component of NPP NPs forming NPP NPs-PEFM. To the best of our knowledge, no study has investigated NPP NP-coated mask fabric to perform infrared red (solar or body) photothermal conversion efficacy to provide biocompatible warming, remotely photothermally captured antipathogen, and antivasoconstriction in vivo. This pioneering study showed that the developed NPP NPs-PEFM could be washable, reusable, breathable, biocompatible, and photothermal conversable for active eradication of pathogenic bacteria. Further, it possesses warming preservation and antivasoconstriction.
Assuntos
Materiais Revestidos Biocompatíveis/química , Nanoestruturas/química , Polietileno/química , Polietilenoimina/química , Polímeros/química , Pirróis/química , Têxteis/análise , Animais , Antibacterianos/química , Raios Infravermelhos , Máscaras/microbiologia , Nanoestruturas/ultraestrutura , Processos Fotoquímicos , Coelhos , Ratos , Temperatura , Têxteis/microbiologiaRESUMO
A series of chitosan (CS) derivatives, the 6-O-carboxymethylchitosan (6-O-CC), 2-N sulfated 6-O-carboxymethylchitosan (N-SOCC) and the 2-N and 3,6-O sulfated 6-O-carboxymethyl chitosan (N,O-SOCC) were synthesized in this study. The chemical structures and the degrees of substituted carboxymethyl and sulfate groups of the synthesized compounds were respectively determined by FT-IR spectra and elemental analysis. N,O-SOCC displayed the highest protective efficiency for basic fibroblast growth factor (bFGF) as examined by the L929 fibroblast culture test and docking simulation. N,O-SOCC-4-thio-butylamidine (TBA) conjugates prepared by modification of N,O-SOCC with 2-iminothiolane were in situ cross-linkable. The degrees of thiol substitution of the 2-iminothiolane modified N,O-SOCC polymers were determined to be in the ranges of 45.9 +/- 3.7 and 415.6 +/- 12.5 micromol SH/g SOCC by quantifying the amount of thiol groups on the thiolated polymers with Ellman's reagent. The 2-iminothiolane modified N,O-SOCC and CS complex could be used for preparing nanoparticles by a polyelectrolyte self-assembly method, and the release of bFGF from the nanoparticles was successfully controlled. L929 fibroblast culture tests showed that the thiol modified N,O-SOCC/CS nanoparticles could effectively protect bFGF from inactivation over a 120 h period. The results of this study suggest that the thiol modified N,O-SOCC/CS nanoparticles may be useful as novel materials for specific delivery of bFGF with mitogenic activity.
Assuntos
Quitosana/análogos & derivados , Quitosana/farmacologia , Fator 2 de Crescimento de Fibroblastos/metabolismo , Nanopartículas/química , Compostos de Sulfidrila/química , Animais , Células Cultivadas , Quitosana/síntese química , Quitosana/química , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Simulação de Dinâmica Molecular , Compostos de Sulfidrila/farmacologia , Fatores de TempoRESUMO
The polysaccharides from Ophiopogon japonicus (OJPs) were known to have protective effects against diabetes, and cardiovascular and chronic inflammatory diseases. However, OJPs were poorly absorbed after oral administration, resulting in limited efficacy because of the low bioavailability. In this study, OJPs extracted and fractionated from Ophiopogon japonicus were used to prepare OJPs/chitosan (CS)/whey protein (WP) co-assembled nanoparticles. The OJPs/CS/WP nanoparticles showed high biocompatibility and inhibited the cytotoxicity of RAW264.7 cells induced by nickel. With the assistance of CS and WP, the anti-inflammatory and antioxidant activities of OJPs were enhanced because the nanoparticles improved OJPs uptake by RAW264.7 macrophage cells as evidenced by efficient scavenging of DPPH and ABTS free radicals and effective inhibition of NO production and the gene expressions of iNOS, COX2, TNF-α, CCL2, and CXCL2 inflammatory signals. Determining the transepithelial electrical resistance and paracellular permeability of Caco-2 monolayer/macrophage co-cultured system suggested that the OJPs-loaded nanoparticles effectively protected the intestinal epithelial barrier integrity against the damage caused by LPS-stimulated macrophage inflammation and attenuated the defects of intestinal epithelial TJ barrier and permeability. These findings suggest that the OJPs/CS/WP nanoparticles may be potential carriers for oral delivery of OJPs to treat intestinal barrier defects, such as inflammatory bowel disease (IBD).
Assuntos
Quitosana/química , Células Epiteliais/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Nanopartículas/química , Ophiopogon/química , Polissacarídeos/administração & dosagem , Junções Íntimas/efeitos dos fármacos , Proteínas do Soro do Leite/química , Administração Oral , Animais , Disponibilidade Biológica , Células CACO-2 , Linhagem Celular , Linhagem Celular Tumoral , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Expressão Gênica/efeitos dos fármacos , Humanos , Inflamação/tratamento farmacológico , Mucosa Intestinal/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Camundongos , Permeabilidade/efeitos dos fármacos , Polissacarídeos/química , Células RAW 264.7RESUMO
Nanofiber-based materials have recently gained increasing attention in food packaging, drug delivery, and biomedical applications. In this study, a multi-nanoï¬bers composite film was developed based on bacterial cellulose nanofiber (BCNF)/chitin nanofiber (CNF) hybridization. The nanofibers were responsible for the formation of well-dispersed curcumin (Cur) micro/nanoparticles in the nanocomposite films. The release of Cur from the films were affected by CNF and the sizes of Cur particles formed in situ. The Cur particles reduced tensile strength and increased water vapor permeability of BCNF film. However, CNF improved the mechanical strength and barrier property of the Cur/BCNF/CNF composite film. Moreover, the multi-nanoï¬bers composite film showed excellent dynamic antioxidant capacity and antibacterial activity, as well as was capable to monitor pH change and trace amount of boric acid. Results of this study suggested that the Cur/BCNF/CNF composite film can be used as a smart and active food packaging material.
Assuntos
Celulose/química , Quitina/química , Nanofibras/química , Animais , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Curcumina/farmacologia , Decapodiformes/metabolismo , Portadores de Fármacos , Liberação Controlada de Fármacos , Escherichia coli/efeitos dos fármacos , Embalagem de Alimentos , Microesferas , Nanocompostos/química , Nanopartículas/química , Staphylococcus aureus/efeitos dos fármacos , Resistência à TraçãoRESUMO
Epigallocatechin gallate (EGCG) has many biological functions; however, the use of EGCG in biomedical and food industries was limited due to its poor oral absorption and high susceptibility to degradation. In this study, a mucoadhesive quaternary chitosan was synthesized and combined with fucoidan (FD) (or depolymerized lower molecular weight fucoidan, LMWF) to prepare EGCG-loaded nanoparticles, which extended EGCG release over 300â¯min and enhanced the transepithelial permeation of EGCG using Caco-2 cells as a model for intestinal absorption. The nanoparticls protected EGCG against degradation in phosphate buffer (pH 6.8) and the remaining EGCG was 1.7-folds higher than the control (EGCG alone). The additive effects of EGCG combined with FD or LMWF in the nanoparticles increased the DPPH radical scavenging activity and the enzyme inhibitory activity against α-amylase (2.82-4.92 fold increase) and α-glucosidase (1.35-1.67 fold increase), while quaternary chitosan helped to enhance the antibacterial effect of EGCG.
Assuntos
Catequina/análogos & derivados , Quitosana/química , Inibidores Enzimáticos/química , Nanopartículas/química , Polissacarídeos/química , Compostos de Amônio Quaternário/química , Catequina/química , Catequina/farmacologia , Quitosana/síntese química , Quitosana/farmacologia , Inibidores Enzimáticos/farmacologia , Fucus/química , Tamanho da Partícula , Polissacarídeos/farmacologia , Compostos de Amônio Quaternário/farmacologia , Propriedades de Superfície , alfa-Amilases/antagonistas & inibidores , alfa-Amilases/metabolismo , alfa-Glucosidases/metabolismoRESUMO
Oral administration is a highly attractive approach for the delivery of protein drugs. However, oral protein therapeutics typically exhibit extremely poor bioavailability due to the harsh gastrointestinal (GI) environments and low permeability of protein across the intestinal barrier. Trimethyl chitosan (TMC) shows excellent mucoadhesive and absorption-enhancing properties while fucoidan (FD) has hypoglycemic effects and can prevent diabetes-related complications. Here we report, for the first time, that TMC combined with FD can be developed to a mutlifunctional nanoplatform for enhancing the transepithelial permeation of insulin through the intestinal epithelial cell barrier and inhibiting the α-glucosidase activity. TMC and FD self-assembled into spherical nanoparticles (NPs) for insulin encapsulation. TMC/FD NPs protected insulin against degradation by releasing insulin in a pH-dependent manner in the gastrointestinal tract fluids. The NPs were able to modulate the barrier function of the Caco-2 intestinal epithelial cell monolayer, and enhance paracellular transport of insulin across the intestinal barrier. TMC/FD NPs also showed α-glucosidase inhibitory activity, with an inhibition ratio of 33.2% at 2â¯mg/mL. The superior transepithelial absorption enhancing property of the TMC/FD NPs is expected to combine in the future with the functions of fucoidan against diabetes-related complications for development of advanced mutlifunctional therapeutic platforms for diabetes.
Assuntos
Quitosana/química , Sistemas de Liberação de Medicamentos , Insulina/administração & dosagem , Nanopartículas/química , Polissacarídeos/química , Administração Oral , Células CACO-2 , Morte Celular/efeitos dos fármacos , Liberação Controlada de Fármacos , Impedância Elétrica , Inibidores de Glicosídeo Hidrolases/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Intestinos/citologia , Modelos Biológicos , Nanopartículas/ultraestrutura , Permeabilidade , Espectroscopia de Infravermelho com Transformada de Fourier , alfa-Amilases/antagonistas & inibidores , alfa-Amilases/metabolismo , alfa-Glucosidases/metabolismoRESUMO
An in situ forming gel based on simply blending carboxymethyl hexanoyl chitosan (CHC) with low molecular weight hyaluronic acid (LMW HA) was developed, without needing cross-linking, photopolymerization or thermal treatments. The CHC/LMW HA blends formed nanoparticles and then rapidly transformed into supermolecular hydrogels under stirring. The gel formation mechanism was examined by Förster resonance energy transfer (FRET). The gels were injectable, cytocompatible and biodegradable, and showed shape-persistent behavior and adhesive property. Berberine, an anti-apoptotic and anti-arthritis naturally occurring compound, was encapsulated within the CHC/LMW HA gels. The gels demonstrated a pH-responsive characteristic which were able to release berberine in a sustained manner at pH 6.0 (simulating inflamed arthritic articular cartilage) and the degradation rates were accelerated at pH 7.4 (simulating healed normal tissue). The berberine-loaded gels effectively protected chondrocytes against sodium nitroprusside-induced apoptosis. The gels may be potentially useful as an injectable system for intra-articular drug delivery and cartilage tissue engineering.
Assuntos
Berberina/farmacologia , Quitosana/análogos & derivados , Preparações de Ação Retardada/química , Géis/química , Ácido Hialurônico/química , Apoptose/efeitos dos fármacos , Células Cultivadas , Quitosana/síntese química , Quitosana/química , Quitosana/toxicidade , Condrócitos/efeitos dos fármacos , Coloides/síntese química , Coloides/química , Coloides/toxicidade , Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/toxicidade , Géis/síntese química , Géis/toxicidade , Humanos , Ácido Hialurônico/síntese química , Ácido Hialurônico/toxicidade , Concentração de Íons de Hidrogênio , Nanopartículas/química , Nanopartículas/toxicidade , Nitroprussiato , Tamanho da PartículaRESUMO
In the study, chitosan (CS) was conjugated with trimethyl groups for the synthesis of N-trimethyl chitosan (TMC) polymers with different degrees of quaternization. Nanoparticles (NPs) self-assembled by the synthesized TMC and poly(gamma-glutamic acid) (gamma-PGA, TMC/gamma-PGA NPs) were prepared for oral delivery of insulin. The loading efficiency and loading content of insulin in TMC/gamma-PGA NPs were 73.8 +/- 2.9% and 23.5 +/- 2.1%, respectively. TMC/gamma-PGA NPs had superior stability in a broader pH range to CS/gamma-PGA NPs; the in vitro release profiles of insulin from both test NPs were significantly affected by their stability at distinct pH environments. At pH 7.0, CS/gamma-PGA NPs became disintegrated, resulting in a rapid release of insulin, which failed to provide an adequate retention of loaded insulin, while the cumulative amount of insulin released from TMC/gamma-PGA NPs was significantly reduced. At pH 7.4, TMC/gamma-PGA NPs were significantly swelled and a sustained release profile of insulin was observed. Confocal microscopy confirmed that TMC40/gamma-PGA NPs opened the tight junctions of Caco-2 cells to allow the transport of insulin along the paracellular pathway. Transepithelial-electrical-resistance measurements and transport studies implied that CS/gamma-PGA NPs can be effective as an insulin carrier only in a limited area of the intestinal lumen where the pH values are close to the p K a of CS. In contrast, TMC40/gamma-PGA NPs may be a suitable carrier for transmucosal delivery of insulin within the entire intestinal tract.
Assuntos
Quitosana/química , Portadores de Fármacos/química , Insulina/química , Insulina/farmacologia , Nanopartículas/química , Ácido Poliglutâmico/análogos & derivados , Polímeros/química , Administração Oral , Animais , Células CACO-2 , Portadores de Fármacos/síntese química , Impedância Elétrica , Ensaio de Imunoadsorção Enzimática , Células Epiteliais/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Insulina/administração & dosagem , Metilação , Modelos Moleculares , Conformação Molecular , Ácido Poliglutâmico/química , Polímeros/síntese química , SolubilidadeRESUMO
This study attempted to develop chitosan-based nanoparticles with increased stability and antibacterial activity. The chitosan/protamine hybrid nanoparticles were formed based on an ionic gelation method by mixing chitosan with protamine and subsequently cross-linking the mixtures with sodium tripolyphosphate (TPP). The effects of protamine on the chemical structures, physical properties, and antibacterial activities of the hybrid nanoparticles were investigated. The antibacterial experiments demonstrated that the addition of protamine (125 µg/mL) in the hybrid nanoparticles (500 µg/mL chitosan and 166.67 µg/mL TPP) improved the antimicrobial specificity with the minimum inhibitory concentration (MIC) value of 31.25 µg/mL towards Escherichia coli (E. coli), while the MIC value was higher than 250 µg/mL towards Bacillus cereus. The chitosan/protamine hybrid nanoparticles induced the formation of biofilm-like structure in B. cereus and non-motile-like structure in E. coli. The detection of bacterial cell ruptures showed that the inclusion of protamine in the hybrid nanoparticles caused different membrane permeability compared to chitosan nanoparticles and chitosan alone. The chitosan/protamine nanoparticles also exhibited lower binding affinity towards B. cereus than E. coli. The results suggested that the hybridization of chitosan with protamine improved the antibacterial activity of chitosan nanoparticles towards pathogenic E. coli, but the inhibitory effect against probiotic B. cereus was significantly reduced.
RESUMO
Bacterial cellulose (BC) is a biopolymer composed of nanofibers which has excellent film-forming ability. However, BC do not have antibacterial or antioxidant activity, thus limiting the applicability of BC for food and biomedical applications. In this study, flavonoid silymarin (SMN) and zein were assembled into spherical SMN-Zein nanoparticles that could be effectively adsorbed onto BC nanofibers. SMN-Zein nanoparticles greatly changed the wettability and swelling property of BC films due to the formation of nanoparticles/nanofibers nanocomposites. SMN-Zein nanoparticles enhanced the release of sparingly soluble silymarin from the nanocomposite films. The active films showed more effective antioxidant and antibacterial activities as compared with pure BC films and thus were able to protect salmon muscle from deterioration and lipid oxidation. These findings suggest that the nanoparticle/nanofiber composites may offer a suitable platform for modification of BC films with improved drug release properties and biological activities.
Assuntos
Antibacterianos/química , Antioxidantes/química , Celulose/análogos & derivados , Conservação de Alimentos/métodos , Nanocompostos/química , Silimarina/química , Zeína/química , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Liberação Controlada de Fármacos , Produtos Pesqueiros , Gluconacetobacter xylinus/química , Nanofibras/química , Nanopartículas/química , Polissacarídeos Bacterianos/química , Pseudomonas/efeitos dos fármacos , Silimarina/farmacologia , Staphylococcus/efeitos dos fármacos , Molhabilidade , Zeína/farmacologiaRESUMO
Solid tumors characteristically display higher levels of lactate production due to anaerobic metabolism of glucose. Meanwhile, the U.S. Food and Drug Administration (FDA) has approved virotherapy for use in cancer treatment; however systemic administration remains as a particular challenge. Here we report exploitation of tumor lactate production in designing a hypoxia-responsive carrier, self-assembled from hyaluronic acid (HA) conjugated with 6-(2-nitroimidazole)hexylamine, for localized release of recombinant adeno-associated virus serotype 2 (AAV2). The carrier is loaded with lactate oxidase (LOX) and is permeable to small molecules such as the lactate that accumulates in the tumor. Subsequently, LOX oxidizes the lactate to pyruvate inside the carrier, accompanied by internal lowering of oxygen partial pressure. Bioreduction of the 2-nitroimidazole of the HA conjugated with 6-(2-nitroimidazole)hexylamine converts it into a hydrophilic moiety and electrostatically dissociates the carrier and virus. Efficacious and specific delivery was proven by transduction of a photosensitive protein (KillerRed), enabling significant limitation in tumor growth in vivo with photodynamic therapy. An approximate 2.44-fold reduction in tumor weight was achieved after a 2-week course, compared with control groups. Furthermore, conjugation of the AAV2 with iron oxide nanoparticles ("magnetized" AAV2) facilitated magnetic resonance imaging tracking of the virus in vivo. Taken together, the solid tumor microenvironment promotes bioreduction of the lactate-responsive carrier, providing rapid and specific delivery of AAV2 for light-triggered virotherapy via systemic administration.