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1.
Bone Joint J ; 101-B(10): 1192-1198, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31564144

RESUMO

AIMS: Radiostereometric analysis (RSA) studies of vitamin E-doped, highly crosslinked polyethylene (VEPE) liners show low head penetration rates in cementless acetabular components. There is, however, currently no data on cemented VEPE acetabular components in total hip arthroplasty (THA). The aim of this study was to evaluate the safety of a new cemented VEPE component, compared with a conventional polyethylene (PE) component regarding migration, head penetration, and clinical results. PATIENTS AND METHODS: We enrolled 42 patients (21 male, 21 female) with osteoarthritis and a mean age of 67 years (sd 5), in a double-blinded, noninferiority, randomized controlled trial. The subjects were randomized in a 1:1 ratio to receive a reverse hybrid THA with a cemented component of either argon-gas gamma-sterilized PE component (controls) or VEPE, with identical geometry. The primary endpoint was proximal implant migration of the component at two years postoperatively measured with RSA. Secondary endpoints included total migration of the component, penetration of the femoral head into the component, and patient-reported outcome measurements. RESULTS: In total, 19 control implants and 18 implants in the VEPE group were analyzed for the primary endpoint. We found a continuous proximal migration of the component in the VEPE group that was significantly higher with a difference at two years of a mean 0.21 mm (95% confidence interval (CI) 0.05 to 0.37; p = 0.013). The total migration was also significantly higher in the VEPE group, but femoral head penetration was lower. We found no difference in clinical outcomes between the groups. CONCLUSION: At two years, this cemented VEPE component, although having a low head penetration and excellent clinical results, failed to meet noninferiority compared with the conventional implant by a proximal migration above the proposed safety threshold of RSA. The early proximal migration pattern of the VEPE component is a reason for continued monitoring, although a specific threshold for proximal migration and risk for later failure cannot be defined and needs further study. Cite this article: Bone Joint J 2019;101-B:1192-1198.


Assuntos
Artroplastia de Quadril/efeitos adversos , Migração de Corpo Estranho/diagnóstico por imagem , Osteoartrite do Quadril/cirurgia , Polietilenos/química , Desenho de Prótese , Falha de Prótese/tendências , Fatores Etários , Idoso , Artroplastia de Quadril/métodos , Método Duplo-Cego , Feminino , Migração de Corpo Estranho/epidemiologia , Prótese de Quadril , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Osteoartrite do Quadril/diagnóstico por imagem , Prognóstico , Análise Radioestereométrica , Medição de Risco , Índice de Gravidade de Doença , Fatores Sexuais , Estatísticas não Paramétricas , Suécia , Vitamina E/farmacologia
2.
Bone Joint J ; 101-B(10): 1238-1247, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31564153

RESUMO

AIMS: Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function. MATERIALS AND METHODS: A total of 18 New Zealand rabbits underwent bilateral anterior cruciate ligament reconstruction by autograft, FiberTape, or FiberTape-augmented autograft. Primary outcomes were biomechanical assessment (n = 17), microCT (µCT) assessment (n = 12), histological evaluation (n = 12), and quantitative polymerase chain reaction (qPCR) analysis (n = 6). RESULTS: At eight weeks, FiberTape alone or FiberTape-augmented autograft demonstrated increased biomechanical stability compared with autograft regarding ultimate load to failure (p = 0.035), elongation (p = 0.006), and energy absorption (p = 0.022). FiberTape-grafted samples also demonstrated increased bone mineral density in the bone tunnel (p = 0.039). Histological evaluation showed integration of all grafts in the bone tunnels by new bone formation, and limited signs of inflammation overall. A lack of prolonged inflammation in all samples was confirmed by quantification of inflammation biomarkers. However, no regeneration of ligament-like tissue was observed along the suture tape materials. Except for one autograft failure, no adverse events were detected. CONCLUSION: Our results indicate that FiberTape increases the biomechanical performance of intra-articular ligament reconstructions in a verified rabbit model at eight weeks. Within this period, FiberTape did not adversely affect bone tunnel healing or invoke a prolonged elevation in inflammation. Cite this article: Bone Joint J 2019;101-B:1238-1247.


Assuntos
Lesões do Ligamento Cruzado Anterior/cirurgia , Reconstrução do Ligamento Cruzado Anterior/métodos , Polietilenos/química , Tendões/transplante , Resistência à Tração/fisiologia , Análise de Variância , Animais , Fenômenos Biomecânicos , Modelos Animais de Doenças , Feminino , Humanos , Peso Molecular , Coelhos , Sensibilidade e Especificidade , Estatísticas não Paramétricas , Técnicas de Sutura , Suturas , Transplante Autólogo
3.
Environ Sci Pollut Res Int ; 26(24): 25107-25116, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31254196

RESUMO

The overdosage use of pesticide was harmful to the environment and human health, which was mainly caused by the low utilization rate of the pesticide. However, the pesticide microcapsule with sustained-release and stimulating response properties could effectively solve this problem. Preparation of carboxymethyl cellulose grafting dimethyldiallylammonium chloride (CMC-g-PDMDAAC) through grafting polymerization and trapping as well as encapsulation of avermectin (AVM) via electrostatic interactions resulted in the formation of AVM/CMC-g-PDMDAAC microcapsules. The results showed that the particle size was 200~300 nm. The encapsulation efficiency was as high as 72.06%. Furthermore, the remaining rate of encapsulated AVM increased from 50.0 to 81.60% after UV irradiation for 359 min. The microcapsules exhibited significant enzyme and pH stimuli responsiveness. Finally, CMC-g-PDMDAAC had no significant difference effect on the toxicity of AVM, AVM could be found, and DMDAAC featured a synergistic effect on the toxicological effects of AVM. Graphical abstract.


Assuntos
Carboximetilcelulose Sódica/química , Ivermectina/análogos & derivados , Praguicidas/química , Polietilenos/química , Compostos de Amônio Quaternário/química , Cápsulas/química , Concentração de Íons de Hidrogênio , Ivermectina/química , Tamanho da Partícula , Polimerização , Raios Ultravioleta
4.
Artigo em Inglês | MEDLINE | ID: mdl-31046561

RESUMO

Acetaminophen, a popular NSAID (Non-steroidal anti-inflammatory drug), was studied for efficacy of removal from aqueous solutions. While Octolig® (a polyethylenediimine covalently attached to silica gel) is able to remove many simple anions and some acidic pharmaceuticals having a pKa value less than 4.5, it lacked efficacy with acetaminophen. Accordingly different transition- metal derivatives of Octolig® were tested by column chromatography using as substrates Octolig® derivatives of copper(II), cobalt(II), iron(III), manganese(II), nickel(II), and zinc(II).


Assuntos
Anti-Inflamatórios não Esteroides/isolamento & purificação , Sílica Gel/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Água/química , Acetaminofen/isolamento & purificação , Acetaminofen/farmacocinética , Ânions , Anti-Inflamatórios não Esteroides/farmacocinética , Cromatografia/métodos , Cobalto/química , Cobre/química , Compostos Férricos/química , Humanos , Manganês/química , Níquel/química , Polietilenos/química , Sílica Gel/metabolismo , Soluções/química , Poluentes Químicos da Água/farmacocinética , Zinco/química
5.
Food Chem ; 292: 253-259, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31054673

RESUMO

A sensitive electrochemical sensor for BPA based on the AuPd incorporated carboxylic multi-walled carbon nanotubes (MWCNT) with synergetic amplified current signal was developed, where MWCNT was used as supporter to improve electron transport and poly (diallyldimethylammonium chloride) (PDDA) was used as dispersant for MWCNT and overcome the intrinsic van der Waals interactions between MWCNT and further increase metal NPs loading. The prepared MWCNT-PDDA-AuPd showed enhanced electrocatalytic performance toward BPA, which is better than those of homologous monometallic counterparts and MWCNT-PDDA though the content of AuPd is really low. The peak currents of BPA increased with BPA concentration in linear range of 0.18-18 µM and the detection limit of 60 nM. The sensor showed high sensitivity, good stability, repeatability and can be used to detect BPA in milk and water samples with good performance, which demonstrate that MWCNTs-PDDA-AuPd nanocomposite may be an attractive material in applications of environmental and food analysis.


Assuntos
Compostos Benzidrílicos/análise , Técnicas Eletroquímicas/métodos , Nanocompostos/química , Nanotubos de Carbono/química , Fenóis/análise , Animais , Técnicas Biossensoriais , Eletrodos , Água Doce/química , Ouro/química , Limite de Detecção , Leite/química , Paládio/química , Polietilenos/química , Compostos de Amônio Quaternário/química
6.
Molecules ; 24(6)2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30934627

RESUMO

Six examples of 2-(1-arylimino)ethyl-9-arylimino-5,6,7,8-tetrahydrocycloheptapyridine-cobalt(II) chloride complexes, [2-(1-ArN)C2H3-9-ArN-5,6,7,8-C5H8C5H3N]CoCl2, (Ar = 2-(C5H9)-6-MeC6H3 Co1, 2-(C6H11)-6-MeC6H3 Co2, 2-(C8H15)-6-MeC6H3 Co3, 2-(C5H9)-4,6-Me2C6H2 Co4, 2-(C6H11)-4,6-Me2C6H2 Co5, and 2-(C8H15)-4,6-Me2C6H2 Co6), were synthesized by the direct reaction of the corresponding ortho-cycloalkyl substituted carbocyclic-fused bis(arylimino)pyridines (L1⁻L6) and cobalt(II) chloride in ethanol with good yields. All the synthesized ligands (L1⁻L6) and their corresponding cobalt complexes (Co1⁻Co6) were fully characterized by FT-IR, ¹H/13C-NMR spectroscopy and elemental analysis. The crystal structure of Co2 and Co3 revealed that the ring puckering of both the ortho-cyclohexyl/cyclooctyl substituents and the one pyridine-fused seven-membered ring; a square-based pyramidal geometry is conferred around the metal center. On treatment with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all the six complexes showed high activities (up to 4.09 × 106 g of PE mol-1 (Co) h-1) toward ethylene polymerization at temperatures between 20 °C and 70 °C with the catalytic activities correlating with the type of ortho-cycloalkyl substituent: Cyclopentyl (Co1 and Co4) > cyclohexyl (Co2 and Co5) > cyclooctyl (Co3 and Co6) for either R = H or Me and afforded strictly linear polyethylene (Tm > 130 °C). The narrow unimodal distributions of the resulting polymers are consistent with single-site active species for the precatalyst. Furthermore, compared to the previously reported cobalt analogues, the titled precatalysts exhibited good thermo-stability (up to 70 °C) and possessed longer lifetime along with a higher molecular weight of PE (Mw: 9.2~25.3 kg mol-1).


Assuntos
Cobalto/química , Polietilenos/química , Termodinâmica , Catálise , Técnicas de Química Sintética , Ligantes , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Polimerização , Relação Estrutura-Atividade
7.
J Colloid Interface Sci ; 549: 72-79, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31022525

RESUMO

Overuse and abuse of antibiotics greatly hasten the development of microbial drug resistance and substantially threat to global public health. Developing alternative methods for combating bacterial infections is urgently required. In this work, a simple hydrothermal approach was employed to prepare the protoporphyrin IX-polyethylenimine nanoparticles (PPIX-PEI NPs) containing abundant amine groups and PPIX moieties. The as-obtained PPIX-PEI NPs exhibit antibacterial properties against both Gram-positive and Gram-negative bacteria. The presence of PPIX in the PPIX-PEI NPs can generate reactive oxygen species (ROS) under 635 nm laser irradiation, which enhance the antibacterial properties of the PPIX-PEI NPs against Gram-positive bacteria. Thus, the PPIX-PEI NPs display a synergistic antibacterial activity against Gram-positive bacteria in the combination of antibacterial photodynamic therapy (PDT). In addition, emission of red fluorescence by the PPIX-PEI NPs can help to differentiate bacteria and observe the bacterial morphologies using a confocal laser scanning microscope (CLSM).


Assuntos
Antibacterianos/química , Nanopartículas/química , Fármacos Fotossensibilizantes/química , Protoporfirinas/química , Antibacterianos/farmacologia , Corantes Fluorescentes/química , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/metabolismo , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/metabolismo , Humanos , Iminas/química , Imagem Óptica/métodos , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Polietilenos/química , Protoporfirinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo
8.
Mater Sci Eng C Mater Biol Appl ; 100: 411-423, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948077

RESUMO

The low interaction between ultra high molecular weight polyethylene (UHMWPE) and hydroxyapatite (HA) has been one of the problems that results in a composite material with low mechanical and tribological performance due to the formation of agglomerates and microstructural defects. These properties affect the quality of the material when used for total joint implants and other applications in hard tissue engineering. This study investigated the effect of the addition of organophilic bentonite (BO) into the interface HA and UHMWPE. The composite was prepared by wet milling in a planetary mill and then by compression molding. The composites samples were characterized by XRD, FTIR, SEM and DSC. The tensile and tribological mechanical properties were also evaluated. Furthermore, in vitro degradation using simulated blood fluid (SBF) and hemocompatibility was performed. The results suggest that the addition of 10 wt% of organophilic bentonite improved the interface between the UHMWPE and HA by exfoliation/intercalation, presenting the best results of modulus of elasticity, tensile strength, coefficient of friction and rate of wear. The composite UHMWPE/HA/BO-10 wt% presented low water absorption and induced the growth of apatite crystals on its surface. Additionally, its hemocompatibility index is within normal limits and induced a low adhesion and agglomeration of platelets in contact with human blood, evidencing that the UHMWPE/HA/BO-10 wt% composite is promising for application in bone tissue engineering.


Assuntos
Bentonita/química , Materiais Biocompatíveis/química , Sangue , Durapatita/química , Teste de Materiais , Polietilenos/química , Animais , Varredura Diferencial de Calorimetria , Camundongos , Adesividade Plaquetária , Resistência à Tração
9.
J Nanobiotechnology ; 17(1): 51, 2019 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-30954085

RESUMO

BACKGROUND: Children born with a small or absent ear undergo surgical reconstruction to create a suitable replacement using rib cartilage. To overcome the donor site morbidity and long-term pain of harvesting rib cartilage, synthetic materials can be a useful alternative. Medpor, is the currently used synthetic polyethylene material to replace missing facial cartilage but unfortunately it has high levels of surgical complications including infection and extrusion, making it an unsuitable replacement. New materials for facial cartilage reconstruction are required to improve the outcomes of surgical reconstruction. This study has developed a new nanomaterial with argon surface modification for auricular cartilage replacement to overcome the complications with Medpor. RESULTS: Polyurethanes nanocomposites scaffolds (PU) were modified with argon plasma surface modification (Ar) and compared to Medpor in vitro and in vivo. Ar scaffolds allowed for greater protein adsorption than Medpor and PU after 48 h (p < 0.05). Cell viability and DNA assays demonstrated over 14-days greater human dermal fibroblast adhesion and cell growth on Ar than PU and Medpor nanocomposites scaffolds (p < 0.05). Gene expression using RT-qPCR of collagen-I, fibronectin, elastin, and laminin was upregulated on Ar scaffolds compared to Medpor and PU after 14-days (p < 0.05). Medpor, unmodified polyurethane and plasma modified polyurethane scaffolds were subcutaneously implanted in the dorsum of mice for 12 weeks to assess tissue integration and angiogenesis. Subcutaneous implantation of Ar scaffolds in mice dorsum, demonstrated significantly greater tissue integration by H&E and Massons trichrome staining, as well as angiogenesis by CD31 vessel immunohistochemistry staining over 12-weeks (p < 0.05). CONCLUSIONS: Argon modified polyurethane nanocomposite scaffolds support cell attachment and growth, tissue integration and angiogenesis and are a promising alternative for facial cartilage replacement. This study demonstrates polyurethane nanocomposite scaffolds with argon surface modification are a promising biomaterial for cartilage tissue engineering applications.


Assuntos
Argônio/química , Cartilagem da Orelha , Nanocompostos/química , Gases em Plasma/química , Poliuretanos/química , Adsorção , Animais , Materiais Biocompatíveis/química , Colágeno Tipo I/química , Elastina/química , Fibroblastos/citologia , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Tamanho da Partícula , Polietilenos/química , Engenharia Tecidual/métodos , Tecidos Suporte/química
10.
J Mater Sci Mater Med ; 30(4): 46, 2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-30953223

RESUMO

Degeneration of the intervertebral disc (IVD) is a leading source of chronic low back pain or neck pain, and represents the main cause of long-term disability worldwide. In the aim to relieve pain, total disc replacement (TDR) is a valuable surgical treatment option, but the expected benefit strongly depends on the prosthesis itself. The present contribution is focused on the synthetic mimic of the native IVD in the aim to optimally restore its functional anatomy and biomechanics, and especially its time-dependency. Semi-crystalline polyethylene (PE) materials covering a wide spectrum of the crystallinity are used to propose new designs of TDR. The influence of the crystallinity on various features of the time-dependent mechanical response of the PE materials is reported over a large strain range by means of dynamic mechanical thermo-analysis and video-controlled tensile mechanical tests. The connection of the stiffness and the yield strength with the microstructure is reported in the aim to propose a model predicting the crystallinity dependency of the response variation with the frequency. New designs of TDR are proposed and implemented into an accurate computational model of a cervical spine segment in order to simulate the biomechanical response under physiological conditions. Predicted in-silico motions are found in excellent agreement with experimental data extracted from published in-vitro studies under compression and different neck movements, namely, rotation, flexion/extension and lateral bending. The simulation results are also criticized by analyzing the local stresses and the predicted biomechanical responses provided by the different prosthetic solutions in terms of time-dependency manifested by the hysteretic behavior under a cyclic movement and the frequency effect.


Assuntos
Fenômenos Biomecânicos/fisiologia , Substitutos Ósseos/química , Disco Intervertebral , Polietileno/química , Desenho de Prótese , Substituição Total de Disco , Alcenos/química , Cristalização , Testes de Dureza , Humanos , Disco Intervertebral/química , Disco Intervertebral/cirurgia , Vértebras Lombares , Teste de Materiais , Polietilenos/química , Polímeros/química , Amplitude de Movimento Articular/fisiologia , Estresse Mecânico , Fatores de Tempo , Substituição Total de Disco/instrumentação , Substituição Total de Disco/métodos , Suporte de Carga/fisiologia
11.
Mater Sci Eng C Mater Biol Appl ; 98: 452-460, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30813047

RESUMO

The artificial joints would go through serious wear after implantation surgery due to the poor lubrication of the body fluid, and the biomimetic lubricants directly injected in vitro is easy to be absorbed by human tissues, and after a period of time, it will lose its lubrication effect. However, the composite hydrogel with slow-release lubrication effect provides a new way for the lubrication of artificial joints. In this study, Graphene oxide/Poly(ethylene glycol) (GO/PEG) composites were prepared to improve the artificial joint lubrication, and through wrapped in the Chitosan/Sodium glycerophosphate (CS/GP) hydrogel, the GO/PEG lubricant will be released under the squeezing action, thus to prolong the service time of biomimetic lubricants. The friction experimental results showed that GO/PEG had better lubrication effect, and the average friction coefficient of the slow-release solution was below 0.03, especially with the pressure increasing. GO, PEG and small molecule GP in the slow-release solution through hydrogen-bond interaction might form a particular structure, which led to the good lubricating effect. The experiments of cell and acute toxicity in vivo showed that GO and its composite hydrogel had good biocompatibility.


Assuntos
Órgãos Artificiais , Quitosana/farmacologia , Glicerofosfatos/farmacologia , Grafite/farmacologia , Hidrogéis/farmacologia , Articulações/efeitos dos fármacos , Lubrificação , Polietilenoglicóis/farmacologia , Alanina Transaminase/sangue , Ligas/química , Animais , Aspartato Aminotransferases/sangue , Morte Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Creatinina/sangue , Módulo de Elasticidade , Fricção , Camundongos , Polietilenos/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Mecânico , Ácido Úrico/sangue , Difração de Raios X
12.
Nat Commun ; 10(1): 490, 2019 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-30700721

RESUMO

Membraneless compartments, such as complex coacervates, have been hypothesized as plausible prebiotic micro-compartments due to their ability to sequester RNA; however, their compatibility with essential RNA World chemistries is unclear. We show that such compartments can enhance key prebiotically-relevant RNA chemistries. We demonstrate that template-directed RNA polymerization is sensitive to polycation identity, with polydiallyldimethylammonium chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in polycation/RNA coacervates. Differences in RNA diffusion rates between PDAC/RNA and oligoarginine/RNA coacervates imply distinct biophysical environments. Template-directed RNA polymerization is relatively insensitive to Mg2+ concentration when performed in PDAC/RNA coacervates as compared to buffer, even enabling partial rescue of the reaction in the absence of magnesium. Finally, we show enhanced activities of multiple nucleic acid enzymes including two ribozymes and a deoxyribozyme, underscoring the generality of this approach, in which functional nucleic acids like aptamers and ribozymes, and in some cases key cosolutes localize within the coacervate microenvironments.


Assuntos
Peptídeos/metabolismo , Polilisina/metabolismo , RNA Catalítico/metabolismo , Conformação de Ácido Nucleico , Peptídeos/química , Polietilenos/química , Polilisina/química , Polimerização , Compostos de Amônio Quaternário/química , RNA Catalítico/genética
13.
Biosens Bioelectron ; 129: 147-154, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30690179

RESUMO

Deep Vein Thrombosis and pulmonary embolism (DVT/PE) is one of the most common causes of unexpected death for hospital in-patients. D-dimer is used as a biomarker within blood for the diagnosis of DVT/PE. We report a low-cost microfluidic device with a conveniently biofunctionalised interdigitated electrode (IDE) array and a portable impedimetric reader as a point-of-care (POC) device for the detection of D-dimer to aid diagnosis of DVT/PE. The IDE array elements, fabricated on a polyethylenenaphtalate (PEN) substrate, are biofunctionalised in situ after assembly of the microfluidic device by electropolymerisation of a copolymer of polypyrrole to which is immobilised a histidine tag anti-D-Dimer antibody. The most consistent copolymer films were produced using chronopotentiometry with an applied current of 5µA for a period of 50 s using a two-electrode system. The quality of the biofunctionalisation was monitored using optical microscopy, chronopotentiometry curves and impedimetric analysis. Measurement of clinical plasma sample with a D-dimer at concentration of 437 ng/mL with 15 biofunctionalised IDE array electrodes gave a ratiometric percentage of sample reading against the blank with an average value of 124 ±â€¯15 at 95% confidence. We have demonstrated the concept of a low cost disposable microfluidic device with a receptor functionalised on the IDE array for impedimetric detection towards POC diagnostics. Changing the receptor on the IDE array would allow this approach to be used for the direct detection of a wide range of analytes in a low cost manner.


Assuntos
Anticorpos Imobilizados/química , Técnicas Biossensoriais/instrumentação , Produtos de Degradação da Fibrina e do Fibrinogênio/análise , Dispositivos Lab-On-A-Chip , Sistemas Automatizados de Assistência Junto ao Leito , Polietilenos/química , Polímeros/química , Pirróis/química , Biomarcadores/análise , Biomarcadores/sangue , Impedância Elétrica , Eletrodos , Desenho de Equipamento , Humanos , Limite de Detecção , Polimerização , Embolia Pulmonar/sangue , Trombose Venosa/sangue
14.
Mikrochim Acta ; 186(2): 100, 2019 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-30635742

RESUMO

A method is described for the determination of the activity of endonuclease. It based on the deaggregation of gold nanoparticles (AuNPs) aggregated by the action of poly(diallyldimethylammonium chloride) (PDDA). A single-stranded DNA (ssDNA) is released after enzymatic cleavage catalyzed by endonuclease. The released fragments bind electrostatically to PDDA and inhibit the PDDA-induced aggregation of AuNPs. This is accompanied by a color change from blue to red and a decrease in the absorption ratio (A630/A520). Under the optimal conditions, this ratio increases linearly in the 0.001 to 1 U·µL-1 EcoRI endonuclease activity range. The detection limit is of 2 × 10-4 U·µL-1 which is much better or at least comparable to previous reports. The method is deemed to have wide scope in that it may be used to study other endonuclease activity (such as BamHI) by simply changing the specific recognition site of the hairpin-like DNA probe. The assay may also be employed to screening for inhibitors of EcoRI endonuclease. Graphical abstract Schematic presentation of the colorimetric assay based on the deaggregation of AuNPs for the detection of endonuclease activity. A single-stranded sequence (ssDNA) is released by the EcoRI cleavage, which electrostatically binds to PDDA and inhibits the PDDA-induced aggregation of AuNPs accompanying with a color change from blue to red.


Assuntos
Colorimetria/métodos , Sondas de DNA/química , Endonucleases/metabolismo , Ouro , Sequências Repetidas Invertidas , Nanopartículas Metálicas/química , Colorimetria/normas , Desoxirribonuclease EcoRI/antagonistas & inibidores , Desoxirribonuclease EcoRI/metabolismo , Endonucleases/antagonistas & inibidores , Limite de Detecção , Polietilenos/química , Polietilenos/metabolismo , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/metabolismo
15.
Mater Sci Eng C Mater Biol Appl ; 96: 479-486, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30606557

RESUMO

Surface of ultra-high-molecular-weight polyethylene (UHMWPE) was modified by chemical methods. Surface was firstly activated by Piranha solution and then grafted with selected amino-compounds (cysteamine, ethylenediamine or chitosan). The next step was grafting of some borane cluster compounds, highly fluorescent borane hydride cluster anti-B18H22 or its thiolated derivative 4,4'-(HS)2-anti-B18H20. Polymer foils were studied using various methods to characterize surface chemistry (X-ray photoelectron spectroscopy), roughness and morphology (atomic force microscopy, scanning electron microscopy), chemistry and polarity (electrokinetic analysis), wettability (goniometry) and photophysical properties (UV-Vis spectroscopy) before and after modification steps. Subsequently some kinds of antimicrobial tests were performed. Immobilization of anti-B18H22 in small quantities onto UHMWPE surface leads to materials with a luminescence. Samples grafted with borane clusters showed significant inhibition of growth for gram-positive bacteria (S. epidermidis). These approaches can be used for (i) luminophores on the base of polymers nanocomposites development and/or (ii) preparation of materials with antimicrobial effects.


Assuntos
Anti-Infecciosos , Nanocompostos/química , Polietilenos , Staphylococcus epidermidis/crescimento & desenvolvimento , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Boranos/química , Polietilenos/química , Polietilenos/farmacologia , Molhabilidade
16.
ACS Appl Mater Interfaces ; 11(1): 1201-1208, 2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30565453

RESUMO

Polyelectrolyte multilayers (PEMs) assembled layer-by-layer have emerged as functional polymer films that are both stable and capable of containing drug molecules for controlled release applications. Most of these applications concentrate on sustained release, where the concentration of the released molecules remains rather constant with time. However, high-efficiency delivery requires obtaining high local concentrations at the vicinity of the cells, which is achieved by triggered release. Here, we show that a nanopatterned PEM platform demonstrates superior properties with respect to drug retention and triggered delivery. A chemically modified block copolymer film was used as a template for the selective deposition of poly(ethylene imine) and a charged derivative of the electroactive poly(3,4-ethylenedioxythiophene) together with a drug molecule. This nanopatterned PEM shows the following advantages: (1) high drug loading; (2) enhanced retention of the bioactive molecule; (3) release triggered by an electrochemical stimulus; (4) high efficacy of drug delivery to cells adsorbed on the surface compared to the delivery efficacy of a similar concentration of drug to cells suspended in a solution.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Técnicas Eletroquímicas/métodos , Iminas , Membranas Artificiais , Polietilenos , Animais , Iminas/química , Iminas/farmacologia , Camundongos , Células NIH 3T3 , Polietilenos/química , Polietilenos/farmacologia
17.
Mater Sci Eng C Mater Biol Appl ; 94: 211-219, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30423703

RESUMO

Despite being currently state-of-the-art to prevent the oxidation of irradiated ultrahigh molecular weight polyethylene (UHMWPE) bearings, vitamin E (VE) poses concerns in the loss of cross-linking efficiency and is limited to be used at very low concentrations. It thus emphasizes the urgent demand for more efficient stabilizers. In this study, oxidation stability of highly cross-linked UHMWPE was demonstrated to be enhanced by tea polyphenols, such as lipid-soluble tea polyphenols (lsPPT), epigallocatechin gallate (EGCG), and lipid-soluble epigallocatechin gallate (lsEGCG). These antioxidants were blended with UHMWPE granules and consolidated by compression molding prior to E-beam irradiation. The presence of tea polyphenols substantially prolonged oxidation induction time of the irradiated UHMWPE before and after accelerated aging. Especially, lsEGCG was significantly superior to VE in terms of stabilizing capacity. Explained by the hydrogen donation mechanism, tea polyphenols with multiple phenolic hydroxyls could scavenge more radiation-induced free radicals than VE with only one phenolic hydroxyl, which was verified by the electron spin resonance spectra. Intriguingly, tea polyphenols showed less inhibitive effect on the cross-link density of irradiated UHMWPE than VE. Besides, there is no significant difference in crystallinity, mechanical performance as well as in vitro biocompatibility between the irradiated UHMWPE stabilized by tea polyphenols and VE. These findings highlight tea polyphenols, especially lsEGCG, are promising alternatives to extend the life span of UHMWPE implants.


Assuntos
Reagentes para Ligações Cruzadas/química , Prótese Articular , Polietilenos/química , Polifenóis/farmacologia , Chá/química , Animais , Linhagem Celular , Espectroscopia de Ressonância de Spin Eletrônica , Camundongos , Oxirredução , Polifenóis/química , Resistência à Tração
18.
Nanoscale ; 10(38): 18370-18377, 2018 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-30255897

RESUMO

Long-term operation of wearable pressure sensors to detect body movement requires self-powered human-based energy sources to minimize the need for recharging. Recently, pressure sensors with thermoelectric properties based on conducting polymers have been reported; however, these devices are limited in their ability to simultaneously achieve sufficient power generation and sensitivity of the sensor. In this article, we suggest a coaxial strut structure of poly(styrene-ethylene/butylene-styrene)(SEBS)-poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)-melamine foam (MF) with a fractured microstructure for a highly sensitive, efficient self-powered pressure sensor. In the coaxial struts, the MF core provides a compressible and elastic framework; the intermediate PEDOT:PSS acts as a conductor and a thermoelectric material; and the SEBS shell ensures mechanical stability and resilience to stabilize the brittle PEDOT:PSS layer under high loading conditions. Additionally, by compressing the coaxial foam to 1/20, partial microfracture of PEDOT:PSS occurs only in the SEBS shell; thus, the pressure sensitivity increases significantly while maintaining high conductivity and thermoelectric performance. The coaxial foam was assembled into a wearable TEG to generate 338 nW from the forearms and demonstrate the high sensitivity of pressure sensors without an external power supply.


Assuntos
Fontes Geradoras de Energia , Polímeros/química , Pressão , Condutividade Térmica , Impedância Elétrica , Fraturas de Estresse , Polietilenos/química , Polímeros/síntese química , Poliestirenos/química , Tiofenos/química , Triazinas/química , Dispositivos Eletrônicos Vestíveis
19.
Int J Nanomedicine ; 13: 4607-4625, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30127609

RESUMO

Background: The development of T1-T2 dual contrast agent (CA) favors the visualization of the lesion in a more accurate and reliable manner by magnetic resonance imaging (MRI). The relaxivity and the interference between T1 and T2 CA are the main concerns for their design. Methods: In this work, we constructed an Fe3O4@mSiO2/PDDA/BSA-Gd2O3 nanocomplex where BSA-Gd2O3 NPs and Fe3O4 NPs were chosen as T1 and T2 MRI CAs and a 20 nm mesoporous silica (mSiO2) nanoshell was introduced to reduce the interference between them. We performed transmis sion electron microscopy, X-ray powder diffraction, UV-vis absorption spectra, and Fourier transform infrared absorption (FTIR) spectra to characterize the prepared nanocom-plex and MRI scanning to evaluate their MRI behaviors. Furthermore, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and hematologic and biochemical analyses were introduced to evaluate their in vitro and in vivo toxicity. Finally, the specific MRI of 786-0 cells with Fe3O4@mSiO2/PDDA/BSA-Gd2O3-AS1411 nanoprobe in vitro was realized. In vivo biodistribution of Fe3O4@mSiO2/PDDA/BSA-Gd2O3 nanocomplex in the mouse was determined by the quantification of the Gd element by inductively coupled plasma-mass spectrometry. Results: The prepared Fe3O4@mSiO2/PDDA/BSA-Gd2O3 nanocomplex possessed high longitudinal (r1=11.47 mM s-1 Gd) and transverse (r2=195.1 mM s-1 Fe) relaxivities, enabling its use as a T1-T2 dual contrast agent for MRI. MTT testing and hematologic and biochemical analysis indicated the good biocompatibility of Fe3O4@mSiO2/PDDA/BSA-Gd2O3 nanocomplex in vitro and in vivo. After further conjugation with AS1411 aptamer, they could target tumor cells successfully by T1 and T2 MRI in vitro. The possible metabolic pathway of the tail vein-injected Fe3O4@mSiO2/PDDA/BSA-Gd2O3 nanocomplex in mouse was mainly via kidney. Conclusion: A T1-T2 dual-mode contrast agent, Fe3O4@mSiO2/PDDA/BSA-Gd2O3 nano-complex, was developed and its good performance for tumor cell targeting in vitro and kidney contrast-enhanced MRI in mice indicated its promising potential as an effective T1-T2 dual-mode contrast agent for in vivo MRI with self-confirmation.


Assuntos
Meios de Contraste/química , Neoplasias Renais/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Nanopartículas/química , Animais , Bovinos , Morte Celular , Linhagem Celular Tumoral , Sobrevivência Celular , Compostos Férricos/química , Gadolínio/química , Camundongos , Camundongos Endogâmicos BALB C , Células NIH 3T3 , Polietilenos/química , Porosidade , Compostos de Amônio Quaternário/química , Soroalbumina Bovina/metabolismo , Dióxido de Silício/química , Distribuição Tecidual , Testes de Toxicidade
20.
Int J Nanomedicine ; 13: 3011-3026, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29861633

RESUMO

Introduction: Deep penetration of large-sized drug nanocarriers into tumors is important to improve the efficacy of tumor therapy. Methods: In this study, we developed a size-changeable "Trojan Horse" nanocarrier (THNC) composed of paclitaxel (PTX)-loaded Greek soldiers (GSs; ~20 nm) assembled in an amphiphilic gelatin matrix with hydrophilic losartan (LST) added. Results: With amphiphilic gelatin matrix cleavage by matrix metalloproteinase-2, LST showed fast release of up to 60% accumulated drug at 6 h, but a slow release kinetic (~20%) was detected in the PTX from the GSs, indicating that THNCs enable controllable release of LST and PTX drugs for penetration into the tumor tissue. The in vitro cell viability in a 3D tumor spheroid model indicated that the PTX-loaded GSs liberated from THNCs showed deeper penetration as well as higher cytotoxicity, reducing a tumor spheroid to half its original size and collapsing the structure of the tumor microenvironment. Conclusion: The results demonstrate that the THNCs with controlled drug release and deep penetration of magnetic GSs show great potential for cancer therapy.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Nanopartículas/química , Paclitaxel/administração & dosagem , Polietilenos/química , Polipropilenos/química , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/farmacocinética , Linhagem Celular Tumoral , Preparações de Ação Retardada , Gelatina/química , Células HeLa , Humanos , Interações Hidrofóbicas e Hidrofílicas , Losartan/administração & dosagem , Losartan/química , Nanomedicina/métodos , Nanopartículas/administração & dosagem , Paclitaxel/farmacocinética , Esferoides Celulares/efeitos dos fármacos , Esferoides Celulares/patologia , Microambiente Tumoral
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