RESUMO
Fatty acid cellulose esters (FACE) are common cellulose-based thermoplastics, and their thermoplasticity is determined by both the contents and the lengths of the side chains. Herein, various FACE were synthesized by the ball-milling esterification of cellulose and fatty acyl chlorides containing 10-18 carbons, and their structures and thermoplasticity were thoroughly studied. The results showed that FACE with high degrees of substitution (DS) and low melting flow temperatures (Tf) were achieved as the chain lengths of the fatty acyl chlorides were reduced. In particular, a cellulose decanoate with a DS of 1.85 and a Tf of 186 °C was achieved by feeding 3 mol of decanoyl chloride per mole anhydroglucose units of cellulose. However, cellulose stearate (DS = 1.53) synthesized by the same protocols cannot melt even at 250 °C. More interestingly, the fatty acyl chlorides with 10 and 12 carbons resulted in FACE with superior toughness (elongation at break up to 94.4%). In contrast, due to their potential crystallization of the fatty acyl groups with 14-18 carbons, the corresponding FACE showed higher tensile strength and Young's modulus than the others. This study provides some theoretical basis for the mechanochemical synthesis of thermoplastic FACE with designated properties.
Assuntos
Cloretos , Ésteres , Ésteres/química , Estudos de Viabilidade , Esterificação , Celulose/químicaRESUMO
Hydrogels are crosslinked polymer chains with three-dimensional (3D) network structures, which can absorb relatively large amounts of fluid. Because of the high water content, soft structure, and porosity of hydrogels, they closely resemble living tissues. Research in recent years shows that hydrogels have been applied in various fields, such as agriculture, biomaterials, the food industry, drug delivery, tissue engineering, and regenerative medicine. Along with the underlying technology improvements of hydrogel development, hydrogels can be expected to be applied in more fields. Although not all hydrogels have good biodegradability and biocompatibility, such as synthetic hydrogels (polyvinyl alcohol, polyacrylamide, polyethylene glycol hydrogels, etc.), their biodegradability and biocompatibility can be adjusted by modification of their functional group or incorporation of natural polymers. Hence, scientists are still interested in the biomedical applications of hydrogels due to their creative adjustability for different uses. In this review, we first introduce the basic information of hydrogels, such as structure, classification, and synthesis. Then, we further describe the recent applications of hydrogels in 3D cell cultures, drug delivery, wound dressing, and tissue engineering.
Assuntos
Hidrogéis , Engenharia Tecidual , Materiais Biocompatíveis/química , Sistemas de Liberação de Medicamentos , Hidrogéis/química , Hidrogéis/uso terapêutico , Polímeros/químicaRESUMO
Microbial infections have become a great threat to human health and one of the main risks arises from direct contact with the surfaces contaminated by pathogenic microbes. Herein, a kind of hexagonal column interpenetrated spheres (HCISs) are fabricated by non-covalent assembly of plant gallic acid with quaternary ammonium surfactants. Different from one-time burst release of conventional antimicrobial agents, the HCIS acts like a "antimicrobial molecular bank" and releases the antimicrobial ingredients in a multistage way, leading to long-lasting antimicrobial performance. Taking advantage of strong hydrophobicity and adhesion, HCISs are applicable to various substrates and endowed with anti-water washing property, thus showing high in vitro antimicrobial efficiency (>99 %) even after being used for 10 cycles. Meanwhile, HCISs exhibit broad-spectrum antimicrobial activity against bacteria and fungi, and have good biocompatibility with mammalian cells. Such a low-cost and portable long-lasting antimicrobial agent meets the growing anti-infection demand in public spaces.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Materiais Biocompatíveis/farmacologia , Polifenóis/farmacologia , Tensoativos/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Candida albicans/efeitos dos fármacos , Cátions/química , Cátions/farmacologia , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Tamanho da Partícula , Polifenóis/química , Staphylococcus aureus/efeitos dos fármacos , Tensoativos/químicaRESUMO
Polyethylene glycol (PEG) surface film-forming method was used to prepare hydrophilic Indigo Naturalis decoction pieces with stable effect.The preparation process of modified Indigo Naturalis was optimized and its microscopic properties,hydrophilicity,antipyretic efficacy,and safety were systematically evaluated.With equilibrium contact angle as assessment index,the influence of modifier type,modifier dosage,dispersant dosage,and co-grinding time on water solubility of Indigo Naturalis was investigated by single factor test.The results showed that the optimal preparation process was as follows.The 6%PEG6000 is dissolved in 10%anhydrous ethanol solution by sonification and then the mixture is ground with Indigo Naturalis for 2 min.The resultant product is dried on a square tray in an oven at 60âto remove ethanol and thereby the PEG-modified hydrophilic Indigo Naturalis decoction pieces are yielded.The morphological observation under scanning electron microscope (SEM) indicated that the modified Indigo Naturalis had smoother surface than Indigo Naturalis,and energy spectrometer measurement showed that the nitrogen (N),calcium(Ca),oxygen (O),and silicon (Si) on the surface of modified Indigo Naturalis powder were less than those of Indigo Naturalis powder.Modified Indigo Naturalis had the equilibrium contact angle 18.96°smaller,polar component 22.222 m J·m~(-2)more,and nonpolar component 7.277 m J·m~(-2)smaller than the Indigo Naturalis powder.Multiple light scattering technique was employed to evaluate the dispersion in water and the result demonstrated that the transmittance of Indigo Naturalis and modified Indigo Naturalis was about85%and 75%,respectively,suggesting the higher dispersity of modified Indigo Naturalis.The suspension rate of modified Indigo Naturalis in water was determined by reflux treatment.The result showed that 57%of Indigo Naturalis was not wetted after refluxing for1 h,while the modified Indigo Naturalis was all wetted and dispersed into water.The dissolution of indigo and indirubin of modified Indigo Naturalis increased and the process was more stable.Then,rats were randomized into the blank group,model group,acetaminophen group,Indigo Naturalis group,and hydrophilic Indigo Naturalis group.The temperature changes of rats were observed after administration and the concentration of IL-1ßand TNF-αin serum and IL-1ßand PGE_2in hypothalamus was measured.The results indicated that the temperature of Indigo Naturalis group and hydrophilic Indigo Naturalis group dropped and the IL-1ßlevel of the hydrophilic Indigo Naturalis group decreased (P<0.05) as compared with those in the model group.Thus,both Indigo Naturalis and hydrophilic Indigo Naturalis had antipyretic effect,particularly the hydrophilic Indigo Naturalis.The acute toxicity test of hydrophilic Indigo Naturalis verified that it had no toxicity to rats.In this study,the hydrophilic Indigo Naturalis decoction pieces were prepared with the PEG surface film-forming method,and the antipyretic efficacy and safety were evaluated,which expanded the technological means of powder modification for Chinese medicine and provided a method for clinical use of Chinese medicine.
Assuntos
Medicamentos de Ervas Chinesas , Indigofera , Animais , Interações Hidrofóbicas e Hidrofílicas , Índigo Carmim , Polietilenoglicóis , RatosRESUMO
It is a challenging task to suppress the bitterness of liquid preparations, especially for children. Bitter molecules are highly dispersible in liquids, leading to a strong and instant stimulation of the bitter receptors. At present, there is no effective way to correct this issue except for adding sweeteners, resulting in an unsatisfying taste. Based on the three-point contact theory, which is a universally accepted mechanism of bitterness formation, a new idea and application of amphiphilic block copolymers (ABCs) for bitterness suppression was proposed for the first time. We found that ABCs could widely inhibit the bitterness of four typical bitter substances. The mechanism is that ABCs self-assemble to form association colloids, which attract bitter components and reduce their distribution in the molecular form in solution. The bitter components were demonstrated to automatically embed in the spiral hydrophobic cavity of the hydrophobic chain of the ABCs, and their special interaction dispersed the positive electrostatic potential of bitter groups. The combination did not affect the pharmacokinetic parameters and pharmacodynamics of bitter drugs. These findings highlight the novel application of ABCs for the inhibition of bitterness and illuminate the underlying inhibition mechanisms.
Assuntos
Polímeros/farmacologia , Paladar/efeitos dos fármacos , Animais , Berberina/farmacologia , Masculino , Camundongos , Micelas , Simulação de Acoplamento Molecular , Poliésteres/farmacologia , Polietilenoglicóis/farmacologia , SoluçõesRESUMO
In the tissue engineering research field, nanobiomaterials highlight the impact of novel bioactive materials in both current applications and their potentials in future progress for tissue engineering and regenerative medicine. Tissue engineering is a well-investigated and challenging biomedical field, with promising perspectives to improve and support quality of life for the patient. To assess the response of those extracellular matrices (ECMs), induced by biomedical materials, this review will focus on cell response to natural biomaterials for biocompatibility.
Assuntos
Materiais Biocompatíveis , Engenharia Tecidual , Materiais Biocompatíveis/normas , Células/imunologia , Matriz Extracelular/imunologia , Humanos , Qualidade de Vida , Medicina Regenerativa , Engenharia Tecidual/métodosRESUMO
: The new rigid planar ligand 2,5-bis(3-(pyridine-4-yl)phenyl)thiazolo[5,4-d]thiazole (BPPT) has been synthesized, which is an excellent building block for assembling coordination polymer. Under solvothermal reaction conditions, cadmium ion with BPPT in the presence of various carboxylic acids including (1,1'-biphenyl)-4,4'-dicarboxylic acid (BPDC), isophthalic acid (IP), and benzene-1,3,5-tricarboxylic acid (BTC) gave rise to three coordination complexes, viz, [Cd(BPPT)(BPDA)](BPPT)n (1), [Cd(BPPT) (IP)] (CH3OH) (2), and [Cd3(BPPT)3(BTC)2(H2O)2] (3). The structures of 1, 2, and 3 were characterized by single crystal X-ray diffraction. The IR spectra as well as thermogravimetric and luminescence properties were also investigated. Complex 1 is a two-dimensional (2D) network and further stretched to a 3D supramolecular structure through π-π stacking interaction. The complexes 2 and 3 show 3D framework. The complexes 1, 2, and 3 exhibited luminescence property at room temperature.
Assuntos
Cádmio/química , Polímeros/química , Complexos de Coordenação/química , Ácidos Dicarboxílicos/química , Ligação de Hidrogênio , Luminescência , Difração de Raios XRESUMO
Essential oils are easy to cause oxidative damage, chemical transformation or polymerization, and have some intrinsic problems, such as instability, low water solubility and low bioavailability, which restrict their application in the fields of product development. Nanostructured lipid carriers(NLCs) can overcome some of the restrictions of other colloidal carriers, such as emulsions, liposomes, polymer nanoparticles and solid lipid nanoparticles. NLC is an efficient and stable delivery system for bioactive substances. With unique lipid properties(mixture of solid and liquid lipid), it can overcome the disadvantages of essential oils and protect them from adverse environments, thus improving the stability, bioavailability and safety of essential oils, and achieve sustained release and controlled release. In EOs-NLCs system, essential oils, as special liquid lipid with biological activities and medicinal properties, can fully play the role of medicine-adjuvant integration by changing the structural characteristics of mixed lipid. Based on the development of nanocarriers system, this paper introduces the composition and structural characteristics of EOs-NLCs, and clarifies how to improve the stability of essential oils based on the effects of NLCs on physical and chemical properties, physical stability and release of active components of essential oils. In addition, it also introduces the application of the system in the fields of pharmaceutical, food, cosmetics and skin care products. This review aims to provide some references for improving the stability of essential oils and their applications by using NLCs.
Assuntos
Portadores de Fármacos , Nanoestruturas , Óleos Voláteis , Emulsões , Lipídeos , Lipossomos , Tamanho da PartículaRESUMO
Tissue engineering technology and stem cell research based on tissue engineering have made great progresses in overcoming the problems of tissue and organ damage, functional loss and surgical complications. Traditional method is to use biological substitute materials to repair tissues, while tissue engineering technology focuses on combining seed cells with biological materials to form biological tissues with the same structure and function as its own to repair tissue defects. The advantage is that such tissue engineering organs and tissues can solve the problem that the donor material is limited, and effectively reduce complications. The purpose of tissue engineering is to find suitable seed cells and biomaterials which can replace the biological function of original tissue and build suitable microenvironment in vivo. This paper mainly describes current technologies of tissue engineering in various fields of urology, and discusses the future trend of tissue engineering technology in the treatment of complex urinary diseases. The results of this study show that although there are relatively few clinical trials, the good results of the existing studies on animal models reveal a bright future of tissue engineering technology for the treatment of various urinary diseases.
Assuntos
Engenharia Tecidual/tendências , Urologia/tendências , Animais , Materiais Biocompatíveis , Humanos , Alicerces TeciduaisRESUMO
Viral respiratory infections trigger severe exacerbations of asthma, worsen disease symptoms, and impair lung function. To investigate the mechanisms underlying viral exacerbation, we established a mouse model of respiratory syncytial virus (RSV)-induced exacerbation after allergen sensitization and challenge. RSV infection of OVA-sensitized/challenged BALB/c mice resulted in significantly increased airway hyperresponsiveness (AHR) and macrophage and neutrophil lung infiltration. Exacerbation was accompanied by increased levels of inflammatory cytokines (including TNF-α, MCP-1, and keratinocyte-derived protein chemokine [KC]) compared with uninfected OVA-treated mice or OVA-treated mice exposed to UV-inactivated RSV. Dexamethasone treatment completely inhibited all features of allergic disease, including AHR and eosinophil infiltration, in uninfected OVA-sensitized/challenged mice. Conversely, dexamethasone treatment following RSV-induced exacerbation only partially suppressed AHR and failed to dampen macrophage and neutrophil infiltration or inflammatory cytokine production (TNF-α, MCP-1, and KC). This mimics clinical observations in patients with exacerbations, which is associated with increased neutrophils and often poorly responds to corticosteroid therapy. Interestingly, we also observed increased TNF-α levels in sputum samples from patients with neutrophilic asthma. Although RSV-induced exacerbation was resistant to steroid treatment, inhibition of TNF-α and MCP-1 function or depletion of macrophages suppressed features of disease, including AHR and macrophage and neutrophil infiltration. Our findings highlight critical roles for macrophages and inflammatory cytokines (including TNF-α and MCP-1) in viral-induced exacerbation of asthma and suggest examination of these pathways as novel therapeutic approaches for disease management.
Assuntos
Pulmão/imunologia , Macrófagos/imunologia , Hipersensibilidade Respiratória/imunologia , Infecções por Vírus Respiratório Sincicial/imunologia , Fator de Necrose Tumoral alfa/imunologia , Alérgenos/imunologia , Animais , Asma/imunologia , Quimiocina CCL2/análise , Quimiocina CCL2/metabolismo , Citocinas/biossíntese , Citocinas/imunologia , Dexametasona/uso terapêutico , Modelos Animais de Doenças , Progressão da Doença , Humanos , Inflamação , Pulmão/fisiopatologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/imunologia , Ovalbumina/administração & dosagem , Ovalbumina/imunologia , Hipersensibilidade Respiratória/fisiopatologia , Infecções por Vírus Respiratório Sincicial/tratamento farmacológico , Infecções por Vírus Respiratório Sincicial/fisiopatologia , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/fisiologia , Vírus Sincicial Respiratório Humano/efeitos da radiação , Saliva/imunologia , Fator de Necrose Tumoral alfa/análise , Raios UltravioletaRESUMO
The dry root of Scutellaria baicalensis, has traditionally been applied in the treatment of cerebral ischemia in Chinese clinics. Baicalin (BA) is considered the key ingredient in it for the brain protection effects. The bioavailability of BA is very low because of its poor lipid and water solubility, which limits the therapeutic effects and clinical application. The aim of the present study was to develop a novel BA-loaded liposome (BA-LP) formulation to improve the drug lipophilicity and further to enhance the drug-concentration in the brain tissues. This study is also designed to investigate the pharmacokinetics of BA in the pathological conditions of stroke and evaluate the pharmacokinetic differences of BA caused by stroke after intravenous administration with BA and BA-LP. In this study, the novel BA-LP prepared in early stage were characterized by morphology, size, zeta potential, encapsulation rate and the in vitro release. The pharmacokinetics and biodistribution of BA and BA-LP were investigated by intravenous administration in rats with middle cerebral artery occlusion (MCAO) model and normal group respectively. BA-LP had a mean particle size of 160â»190 nm, zeta potential of -5.7 mV, and encapsulation efficiency of 42 ± 1%. The BA-LP showed a sustained-release behavior, the in vitro drug-release kinetic model of BA-LP fit well with the biphasic dynamic model equation: Q = 1 - (60.12e0.56t - 59.08e0.0014t). Pharmacokinetic behavior in MCAO rats is not consistent with that of normal rats. The middle cerebral artery occlusion rats got higher Cmax and AUC0â»t, which were about 1.5â»2 times to normal rats both in BA and liposome groups. In addition, it got especially higher distribution in brain, while BA were not detected in brain tissues on normal rats. The Cmax and AUC0â»t values were significantly greater with liposome than BA on both normal and MCAO rats. The tissue distribution behavior was significantly altered in the case of liposome administrated in comparison with BA, which the concentrations in the heart, liver, spleen, lungs and brain were all increased after administrated liposome, but decreased in kidneys. The TI values showed that the target of liposome was improved especially to heart, spleen and brain, and the brain's target was higher in striatum and cerebellum. In conclusion, BA-LP might be a potential drug delivery system to improve the therapeutic efficacy of BA. In addition, these results also suggest that the pathological damages of ischemia-reperfusion have a significant impact on the pharmacokinetic traits of BA.
Assuntos
Transtornos Cerebrovasculares , Flavonoides , Traumatismo por Reperfusão , Animais , Transtornos Cerebrovasculares/tratamento farmacológico , Transtornos Cerebrovasculares/metabolismo , Flavonoides/química , Flavonoides/farmacocinética , Flavonoides/farmacologia , Lipossomos , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismoRESUMO
To elucidate the compaction behavior of drug nanocrystals based composite particles (NP) during tabletting, the compaction behavior of binary mixtures of microcrystalline cellulose (MCC) and nanocrystal particles was investigated. The force-displacement correlation of mixtures containing different ratios of MCC and micronized NP was studied in order to explain the nature on densification of NP during compaction, and the resultant compaction curves (pressure as function of in-die thickness) were systemically analyzed to elucidate the most important mechanisms of volume reduction for MCC and NP in different stages of compaction. The results showed that the close compaction of individual MCC was relatively quickly achieved, and the drug NP particles could slide into the intrinsic void spaces between MCC microparticles. This was the reason that the particles size of MCC used in this study was significantly larger compared to that of drug NP. This interstitial rearrangement phenomenon of NP occurred on a typical time scale and was strongly dependent on the speed of compaction. This migration behavior occurred on void spaces of MCC inter-particles might be identified as an elastic stress relaxation mechanism and be helpful to dissolution of NP. MCC can effectively shield the NP from significant aggregation during compaction process.
Assuntos
Celulose/química , Nanopartículas/química , Comprimidos/química , Excipientes/química , Tamanho da Partícula , PressãoRESUMO
Choline phosphate (CP), which is a new zwitterionic molecule, and has the reverse order of phosphate choline (PC) and could bind to the cell membrane though the unique CP-PC interaction. Here we modified a glass surface with multilayer CP molecules using surface-initiated atom-transfer radical polymerization (SI-ATRP) and the ring-opening method. Polymeric brushes of (dimethylamino)ethyl methacrylate (DMAEMA) were synthesized by SI-ATRP from the glass surface. Then the grafted PDMAEMA brushes were used to introduce CP groups to fabricate the multilayer CP molecule modified surface. The protein adsorption experiment and cell culture test were used to evaluate the biocompatibility of the modified surfaces by using human umbilical veinendothelial cells (HUVECs). The protein adsorption results demonstrated that the multilayer CP molecule decorated surface could prevent the adsorption of fibrinogen and serum protein. The adhesion and proliferation of cells were improved significantly on the multilayer CP molecule modified surface. Therefore, the biocompatibility of the material surface could be improved by the modified multilayer CP molecule, which exhibits great potential for biomedical applications, e.g., scaffolds in tissue engineering.
Assuntos
Fosforilcolina/química , Adsorção , Adesão Celular , Células Cultivadas , Humanos , Metacrilatos , Polimerização , Polímeros , Propriedades de SuperfícieRESUMO
This article provides a novel and efficient method of "self-assembly/modification/dispersion" for the preparation of functionalized cellulose nanoparticles (CNPs) based on regenerated cellulose hydrogel (RCH). The process of the preparation of CNPs is simplified greatly, which contributes to broadening the utilization of CNPs. Under the given conditions, cellulose chains self-assemble into nanoparticles, which connect with each other to form strings and walls of nanoparticles inside RCH. Then, RCH acts as the hydrophilic precursor of the preparation of CNPs and is modified by oligo side chains to obtain functionalized RCH with imperfect cellulose II structures. After dispersing the functionalized RCH in dimethyl sulfoxide, individual CNPs are finally isolated from functionalized RCH as a result of the decline of the crystallinity of CNPs. Obtained CNPs possess uniform size and good thermal stability, and also exhibit excellent dispersibility in organic solvents. The particle size of CNPs can be adjusted easily by oligo content and particle size of the self-assembled cellulose nanoparticles in RCH. Prepared CNPs are promising candidates for polymer modification in terms of fillers, and for biomedical fields with respect to drug delivery.
Assuntos
Celulose/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Nanopartículas/química , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Interações Hidrofóbicas e HidrofílicasRESUMO
BACKGROUND: The efficacy and safety of polymer-free stent (PFS) versus permanent polymer drug-eluting stent (PPDES) in patients undergoing percutaneous coronary intervention (PCI) remain controversial. Our meta-analysis was undertaken to evaluate and compare the efficacy and safety of PFS with those of PPDES in patients undergoing PCI. METHODS: We searched PubMed, Cochrane Library, EMBASE, and Clinical Trials.gov databases for randomized controlled trials (RCTs). The primary endpoints were incidence of stent thrombosis (ST) and target-lesion revascularization (TLR). The secondary endpoints included the incidence of major adverse cardiovascular events (MACE), myocardial infarction (MI), cardiac death (CD), late lumen loss (LLL), and diameter stenosis (DS). Subgroup analyses were also conducted based on the follow-up time. RESULTS: Eleven RCTs met the including criteria, and 8616 patients were included in the study. No significant differences were observed between PFS and PPDES treatments in the incidence of ST (RR 0.90; 95% CI: 0.62-1.31; P = 0.58; I 2 = 0), TLR (RR 0.87; 95% CI: 0.76-1.00; P = 0.05; I 2 = 37%), CD (RR 0.89; 95% CI: 0.72-1.10; P = 0.28; I 2 = 0), MI (RR 0.87; 95% CI: 0.71-1.05; P = 0.15; I 2 = 0), LLL (SMD 0.01; 95% CI: -0.29-0.30; P = 0.96; I2 = 90%), and DS (SMD -0.01; 95% CI: - 0.25 to 0.23; P = 0.93; I2 = 83%). Meanwhile, the patients with PFS had a lower incidence of MACE (RR 0.87; 95% CI: 0.78-0.97; P = 0.01; I 2 = 0) than those with PPDES. CONCLUSION: In the overall analysis, patients with PFS presented a lower risk of MACE versus PPDES, but no significant difference were obtained in the risk of ST, TLR, MI, CD, DDD and DS. In the Short term follow up, patients with PSF presented a lower risk of TLR compared with PPDES.
Assuntos
Síndrome Coronariana Aguda/terapia , Stents Farmacológicos , Intervenção Coronária Percutânea/instrumentação , Polímeros/química , Síndrome Coronariana Aguda/diagnóstico , Síndrome Coronariana Aguda/mortalidade , Distribuição de Qui-Quadrado , Intervalo Livre de Doença , Humanos , Razão de Chances , Intervenção Coronária Percutânea/efeitos adversos , Polímeros/efeitos adversos , Desenho de Prótese , Ensaios Clínicos Controlados Aleatórios como Assunto , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do TratamentoRESUMO
Interconnectivity of components in three-dimensional networks (3DNs) is essential for stress transfer in hydrogels, aerogels, and composites. Entanglement of nanoscale components in the network relies on weak short-range intermolecular interactions. The intrinsic stiffness and rod-like geometry of nanoscale components limit the cohesive energy of the physical crosslinks in 3DN materials. Nature realizes networked gels differently using components with extensive branching. Branched aramid nanofibers (BANFs) mimicking polymeric components of biological gels were synthesized to produce 3DNs with high efficiency stress transfer. Individual BANFs are flexible, with the number of branches controlled by base strength in the hydrolysis process. The extensive connectivity of the BANFs allows them to form hydro- and aerogel monoliths with an order of magnitude less solid content than rod-like nanocomponents. Branching of nanofibers also leads to improved mechanics of gels and nanocomposites.
Assuntos
Nanofibras/química , Polímeros/química , Celulose/química , Géis/química , Ligação de Hidrogênio , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanocompostos/química , Resistência ao Cisalhamento , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
BACKGROUND: Foot-and-mouth disease (FMD) is an economically devastating disease that severely limits international trade of animals. Of the seven FMD virus (FMDV) serotypes, serotype A is one of the most widespread cross the world. Currently antibodies to FMDV are detected in animals using the virus neutralization test (VNT) and the enzyme-linked immunosorbent assay (ELISA). The VNT is laborious, time-consuming and reliant on live virus and cell cultures, while ELISA has the advantage of using inactivated antigens and often provides more reproducible results. The aim of this study was to develop a reliable and rapid competitive ELISA (cELISA) for the detection of antibodies to FMDV serotype A (FMDV/A). RESULTS: A panel of FMDV/A specific monoclonal antibodies (mAbs) was generated and their ability to compete with a polyclonal serum from FMDV/A-infected cattle was examined. Two mAbs inhibited the binding of a polyclonal serum to FMDV/A viruses. The binding epitopes of each were determined as conformational and located on the VP2 viral capsid protein. The FMDV/A cELISA was developed using these two mAbs and FMDV/A inactivated virus as antigen. The diagnostic specificity and sensitivity were 99.7 and 99.3% (98.5-100%) respectively, based on a predetermined cut-off of 50% inhibition. When analysing sera from animals experimentally infected with FMDV/A, the cELISA detected antibodies from 5-days post infection (dpi) and remained positive for at least 21-28 days post infection. Comparison based on the Kappa coefficient showed strong agreement (90-94%) between cELISA and VNT. CONCLUSION: The cELISA results are comparable to the VNT for antibody detection making it a simple and reliable test to detect antibodies against FMDV/A.
Assuntos
Anticorpos Monoclonais/isolamento & purificação , Anticorpos Antivirais/sangue , Anticorpos Antivirais/isolamento & purificação , Ensaio de Imunoadsorção Enzimática/métodos , Vírus da Febre Aftosa/imunologia , Febre Aftosa/virologia , Testes Sorológicos/métodos , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Aesthetic and functional mandibular reconstruction can be achieved in 1-stage. It involves simultaneous dental implant placement in a free vascularized fibula transfer with a low-profile reconstruction plate. The aim of this study was to assess the postoperative aesthetic profile and oral functional result. MATERIAL AND METHODS: Ten patients with a mean age of 31.6 years and an average follow-up time of 83.7 months underwent 1-staged mandibular reconstructions after segmental mandibulectomies. Simultaneous dental implantation was placed at the fibular segment according to the maxillary dentition. The fibula-implant construct was stabilized superiorly with miniplates and an additional low-profile reconstruction plate recreated the inferior mandibular contour. Any remaining vascularized soft tissue was used for augmentation. Palatal mucosa grafts were placed around the dental implant healing abutment at the uncovering stage surface. Aesthetic profile and oral function were evaluated postoperatively for 5 years. RESULTS: All microsurgical transplantations were successful. None of the patients required subsequent revisions. All patients completed prosthodontic rehabilitation. All patients had palatal mucosal grafts placed around the dental implants. The mean probing pocket depths were shallower around the implants, 3.09 ± 0.82 mm at mesial, 3.33 ± 1.05 mm at distal, 3.02 ± 1.13 mm at buccal, and 3.23 ± 1.17 mm at lingual surfaces. Radiographs revealed no statistical differences in mean of the mesial [0.27 ± 0.26 mm] and distal [0.33 ± 0.25 mm] of peri-implant bone loss. The prosthetic load mean follow-up time was 71.7 months with a satisfactory implant-supported prosthesis. Two slender female patients palpated the reconstruction plate beneath the soft tissue envelope. CONCLUSIONS: This approach is selectively fashioned for patients with benign disease when the overlying soft tissue drape is adequate. The technique described results in improved appearance and function through definition of the lower third of the face and simultaneous dental implant replacement.
Assuntos
Ameloblastoma/cirurgia , Transplante Ósseo/métodos , Implantação Dentária/métodos , Fíbula/transplante , Retalhos de Tecido Biológico/transplante , Neoplasias Mandibulares/cirurgia , Reconstrução Mandibular/métodos , Adolescente , Adulto , Implantação Dentária/instrumentação , Implantes Dentários , Feminino , Seguimentos , Humanos , Masculino , Osteotomia Mandibular , Reconstrução Mandibular/instrumentação , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto JovemRESUMO
Silk fibroin (SF) is a protein with bulky hydrophobic domains and can be easily purified as sericin-free silk-based biomaterial. Silk fibroin modified chitosan nanoparticle (SF-CSNP), a biocompatible material, has been widely used as a potential drug delivery system. Our current investigation studied the bio-effects of the SF-CSNP uptake by liver cells. In this experiment, the characterizations of SF-CSNPs were measured by particle size analysis and protein assay. The average size of the SF-CSNP was 311.9 ± 10.7 nm, and the average zeta potential was +13.33 ± 0.3 mV. The SF coating on the SF-CSNP was 6.27 ± 0.17 µg/mL. Moreover, using proteomic approaches, several proteins involved in the ubiquitin proteasome pathway were identified by analysis of differential protein expressions of HepG2 cell uptake the SF-CSNP. Our experimental results have demonstrated that the SF-CSNP may be involved in liver cancer cell survival and proliferation.
Assuntos
Quitosana/metabolismo , Portadores de Fármacos/metabolismo , Fibroínas/metabolismo , Nanopartículas/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina/metabolismo , Materiais Biocompatíveis/metabolismo , Linhagem Celular , Células Hep G2 , Humanos , Proteômica , Transdução de SinaisRESUMO
Alcohol consumption is an established risk factor for head and neck cancer (HNC). The major carcinogen from alcohol is acetaldehyde, which may be produced by humans or by oral microorganisms through the metabolism of ethanol. To account for the different sources of acetaldehyde production, the current study examined the interplay between alcohol consumption, oral hygiene (as a proxy measure for the growth of oral microorganisms), and alcohol-metabolizing genes (ADH1B and ALDH2) in the risk of HNC. We found that both the fast (*2/*2) and the slow (*1/*1+ *1/*2) ADH1B genotypes increased the risk of HNC due to alcohol consumption, and this association differed according to the slow/non-functional ALDH2 genotypes (*1/*2+ *2/*2) or poor oral hygiene. In persons with the fast ADH1B genotype, the HNC risk associated with alcohol drinking was increased for those with the slow/non-functional ALDH2 genotypes. For those with the slow ADH1B genotypes, oral hygiene appeared to play an important role; the highest magnitude of an increased HNC risk in alcohol drinkers occurred among those with the worst oral hygiene. This is the first study to show that the association between alcohol drinking and HNC risk may be modified by the interplay between genetic polymorphisms of ADH1B and ALDH2 and oral hygiene. Although it is important to promote abstinence from or reduction of alcohol drinking to decrease the occurrence of HNC, improving oral hygiene practices may provide additional benefit.