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1.
J Phys Chem Lett ; 10(15): 4185-4191, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31295998

RESUMO

The treatment of massive bone defects is still a significant challenge for orthopedists. Here we have engineered synthetic porous AuPd alloy nanoparticles (pAuPds) as a hyperthermia agent for in situ bone regeneration through photothermal therapy (PTT). After being swallowed by cells, pAuPds produced a mild localized heat (MLH) (40-43 °C) under the irradiation of a near-infrared laser, which can greatly accelerate cell proliferation and bone regeneration. Almost 97% of the cranial defect area (8 mm in diameter) was covered by the newly formed bone after 6 weeks of PTT. RNA sequencing analysis was used to obtain insight into the molecular mechanism of the MLH on cell proliferation and bone formation. These results demonstrated that the Wnt signaling pathway was involved in the MLH. This Letter provides a unique strategy with mild heat stimulation and high efficiency for in situ bone regeneration.


Assuntos
Ligas/química , Regeneração Óssea , Ouro/química , Nanopartículas Metálicas/química , Paládio/química , Animais , Materiais Biocompatíveis/química , Linhagem Celular , Proliferação de Células , Sobrevivência Celular , Hipertermia Induzida , Raios Infravermelhos , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/toxicidade , Camundongos , Fototerapia , Porosidade , Ratos , Crânio/patologia
2.
Anal Bioanal Chem ; 411(17): 3829-3838, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31172234

RESUMO

The rapid detection of bacterial strains has become a major topic thoroughly discussed across the biomedical field. Paired with the existence of nosocomial pathogen agents that imply extreme medical and financial challenges throughout diagnosis and treatment, the development of rapid and easy-to-use sensing devices has gained an increased amount of attention. Moreover, antibiotic resistance considered by World Health Organization as one of the "biggest threats to global health, food security, and development today" enables this topic as high priority. Pseudomonas aeruginosa, one of the most ubiquitous bacterial strains, has various quorum-sensing systems that are a direct cause of their virulence. One of them is represented by pyocyanin, a blue pigment with electroactive properties that is synthesized from early stages of bacterial colonization. Thus, the sensitive detection of this biomarker could enable a personalized and efficient therapy. It was achieved with the development of an electrochemical sensor based on a thermosensitive polymer, modified with Au/Ag nanoalloy for the rapid and accurate detection of pyocyanin, a virulence biomarker of Pseudomonas aeruginosa. The sensor displayed a linear range from 0.12 to 25 µM, and a limit of detection of 0.04 µM (signal/noise = 3). It was successfully tested in real samples spiked with the target analyte without any pretreatment other than a dilution step. The detection of pyocyanin with high recovery in whole blood in a time frame of 5-10 min from the moment of collection was performed with this electrochemical sensor. Graphical abstract.


Assuntos
Ligas/química , Ouro/química , Hidrogéis/química , Nanopartículas Metálicas/química , Piocianina/análise , Prata/química , Ágar/química , Artefatos , Biomarcadores/análise , Técnicas Biossensoriais , Técnicas Eletroquímicas/métodos , Limite de Detecção , Sistemas Automatizados de Assistência Junto ao Leito , Pseudomonas aeruginosa/isolamento & purificação , Piocianina/sangue , Reprodutibilidade dos Testes , Temperatura Ambiente
3.
Bioelectrochemistry ; 129: 106-115, 2019 Oct.
Artigo em Espanhol | MEDLINE | ID: mdl-31153125

RESUMO

Due to their desirable elastic modulus and density that are similar to natural bone, non-toxic element containing magnesium alloys are regarded as promising bio-degradable materials. A biodegradable HA-particle-reinforced magnesium-matrix composite Mg-3Zn-0.2Ca-1HA (wt%) was fabricated for biomedical application by a combination of high shear solidification (HSS) and hot extrusion technology. The microstructure, mechanical properties, corrosion resistance and cell biocompatibility of the composite were subsequently investigated. In comparison with the matrix alloy, the as-cast Mg-3Zn-0.2Ca-1HA composite obtained by HSS technology exhibited a uniform and fine grained structure, further refined after a hot extrusion ratio of 36:1. The yield strength (0.2%YS), ultimate tensile strength and elongation of the extruded composite were 322 MPa, 341 MPa and 7.6%, respectively. The corrosion rate of the as-extruded Mg-3Zn-0.2Ca-1HA composite was measured to be 1.52 mm/y. Electrochemical and immersion tests showed that the corrosion resistance of the composite is slightly improved comparing to that of the matrix alloy.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Durapatita/química , Magnésio/química , Zinco/química , Animais , Linhagem Celular , Corrosão , Fibroblastos/citologia , Teste de Materiais , Camundongos , Resistência à Tração
4.
Bioelectrochemistry ; 129: 235-241, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31226524

RESUMO

During tribocorrosion of biomedical alloys, potentials may shift cathodically across the metal-oxide-electrolyte interface resulting in the increased reduction of local oxygen and water molecules. The products of reduction are thought to include reactive oxygen species (ROS) as well as hydroxide ions. Using fluorescent probes, developed for labeling intracellular ROS-based hydroxyl radicals (OH·) and hydrogen peroxide (H2O2), ROS generation due to reduction reactions at cathodically biased CoCrMo alloy surfaces was measured directly. Using terephthalic acid (TA) and pentafluorosulfonylbenzene-fluorescein (PFF) as fluorescent dosimeters, it was found that OH· and H2O2 concentrations increased up to 16 h and 2 h, respectively. Decreases in fluorescence past these time points were attributed to the continuous onset of reduction reactions consuming both the ROS and/or dosimeter. It was also found that voltages below and including -600 mV (vs. Ag/AgCl) produced measurable quantities of H2O2 after two hours of polarization, with concentrations increasing with decreasing potentials up to -1000 mV. The detection and quantification of ROS in a clinical setting could help us better understand the role of ROS in the inflammatory response as well as their impact on corrosion behavior of biomedical alloys.


Assuntos
Cromo/química , Cobalto/química , Corantes Fluorescentes/química , Peróxido de Hidrogênio/análise , Radical Hidroxila/análise , Molibdênio/química , Espécies Reativas de Oxigênio/análise , Ligas/química , Eletrodos , Fluoresceína/química , Oxirredução , Ácidos Ftálicos/química , Espectrometria de Fluorescência/métodos
5.
Chem Asian J ; 14(15): 2662-2675, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31149777

RESUMO

Chicken feather-derived high-surface-area porous activated carbon (CFAC) material was prepared using chemical activation. A new composite composed of Ru-Pd nanoparticles supported on CFAC (Ru-Pd@CFAC) has been prepared by microwave-thermal reduction in the presence of the support. Characterization by XRD, Raman, BET, FE-SEM/TEM, FT-IR, TGA, XPS, HAADF-STEM-EDS, H2 -chemisorption, H2 -TPR, and ICP-AES was used to analyze the catalyst. This catalyst is found to be efficient for the reduction of hexavalent chromium (CrVI ), potassium ferricyanide (K3 [Fe(CN)6 ]), 4-nitrophenol (4-NP), and pendimethalin (PDM), at room temperature, and remains stable, even after several repeated runs. Moreover, it showed excellent catalytic activity compared with the monometallic counterparts.


Assuntos
Ligas/química , Carbono/química , Nanopartículas Metálicas/química , Paládio/química , Rutênio/química , Compostos de Anilina/química , Animais , Catálise , Galinhas , Cromo/química , Ferricianetos/química , Nitrofenóis/química , Oxirredução , Porosidade , Reciclagem , Espectrofotometria , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Eliminação de Resíduos Líquidos
6.
Anal Chim Acta ; 1070: 88-96, 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31103171

RESUMO

Herein, we developed a simple and rapid strategy to synthesize gold/silver bimetallic nanoclusters (Au/Ag NCs) with highly biochemical stability by a one-pot route. The Au/Ag NCs were obtained via a chemical reduction procedure in alkaline aqueous solution at 75 °C within only 20 min by employing bovine serum albumin (BSA) as both ligand and reductant. The as-obtained Au/Ag NCs displayed bright orange fluorescence with an emission peak located at 570 nm and temperature-dependent fluorescence property, which were utilized as fluorescent thermometer directly. More intriguingly, the Au/Ag NCs were very stable against various pH values, ions, biothiols, H2O2, fetal bovine serum (FBS), RPMI 1640 medium and amino acids. Taking advantage of the excellent biochemical stability, a ratiometric fluorescence biosensor, fluorescein-5-isothiocyanate (FITC)-Au/Ag NCs, was constructed for pH sensing based on the incorporation of FITC into the Au/Ag NCs. Furthermore, the ratiometric pH sensor was also successfully applied on the model of HeLa cells.


Assuntos
Ligas/química , Ouro/química , Nanopartículas Metálicas/química , Prata/química , Temperatura Ambiente , Ligas/síntese química , Animais , Técnicas Biossensoriais , Bovinos , Fluoresceína-5-Isotiocianato/química , Fluorescência , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Soroalbumina Bovina/química , Espectrometria de Fluorescência
7.
World J Microbiol Biotechnol ; 35(5): 73, 2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31037431

RESUMO

Metal corrosion is a major global concern in many economic sectors. The degradation of metal surfaces is responsible for losses in values that account for about 3% of gross domestic product (GDP) only in the US. Parts of all corrosion processes described in different environments are present mainly in marine environments. The marine environment is characterized as favoring the corrosion processes of several metallic alloys, damaging structures used in the construction of ships, ports, oil pipelines, and others. Despite chemical corrosion being the most frequently described in these environments, studies show the participation of microorganisms in direct corrosion processes or in the acceleration/influence of the corrosive action, through the formation of complex biofilms. These structures create favorable conditions for microorganisms to degrade metal surfaces, causing damage known as pitting and crevices. Currently, diverse technicians are employed in biocorrosion research, e.g. electronic microscopy, and DNA sequencing. These techniques have clarified the dynamic process of the formation of biofilm structures, allowing understanding of the succession of different species during the evolution of the structure. Improving the understanding of how this interaction between biofilm and metallic surface occurs will enable better evaluation of strategies to avoid or decelerate the degradation of metallic structures in marine environments.


Assuntos
Biofilmes/crescimento & desenvolvimento , Água do Mar/microbiologia , Aço/química , Ligas/química , Bactérias/metabolismo , Aderência Bacteriana/fisiologia , Fenômenos Fisiológicos Bacterianos , Corrosão , Eletroquímica , Metais/química , Propriedades de Superfície
8.
Bioelectrochemistry ; 129: 10-17, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31075534

RESUMO

In this study, the corrosion behavior of 7075-T6 aluminum alloy in a high salinity environment containing Aspergillus niger was investigated using high-performance liquid chromatography tandem mass spectrometry, gas chromatography, surface analysis and electrochemical measurement. Results demonstrated that uniform and localized corrosion rates of the alloy in the presence of A. niger were approximately 3.7 and 22.4 times, respectively, of that in the absence A. niger. This higher corrosion rate was attributed to accelerated anode and cathode reactions from the actions of A. niger biofilm. Additionally, organic acid corrosion caused by the presence of A. niger was confirmed to be the main cause for the corrosion of aluminum alloy.


Assuntos
Ligas/química , Alumínio/química , Aspergillus niger/fisiologia , Biofilmes/crescimento & desenvolvimento , Corrosão , Técnicas Eletroquímicas , Eletrodos/microbiologia , Salinidade , Propriedades de Superfície
9.
Bioelectrochemistry ; 128: 133-139, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30991309

RESUMO

In addition to being environmentally friendly and ecologically acceptable, starch-based materials are inexpensive, readily available and renewable. The capability of starch, therefore, to inhibit the corrosion of Al-Mg-Si alloy processed via micro arc oxidation (MAO) process was investigated. For this aim, MAO coating was carried out on the present sample under AC conditions in an alkaline electrolyte with and without starch. The oxide layer formed on an Al-Mg-Si alloy created from electrolyte with starch was denser and thicker than that without starch. Whilst the oxide layer formed from electrolyte without starch was only composed of γ-Al2O3, the addition of starch into the electrolyte helped to decelerate the rate of cooling during the solidification of molten alumina, resulting in the formation of α-Al2O3 as well. Accordingly, the inhibiting action in the sample coated from the electrolyte containing starch was superior to that without starch.


Assuntos
Ligas/química , Alumínio/química , Corrosão , Eletrólitos/química , Magnésio/química , Silício/química , Amido/química , Óxido de Alumínio/química , Oxirredução , Porosidade , Propriedades de Superfície , Difração de Raios X
10.
Mater Sci Eng C Mater Biol Appl ; 100: 38-47, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948074

RESUMO

In-vivo antibacterial property of Ti10Cu sintered alloy was investigated in comparison with pure titanium (cp-Ti) by implanting the alloys with S. aureus suspension in the muscles of rabbits. The general appearance, the white blood cell (WBC) number, the bacteria number were checked and the pathological examination were analyzed. It has been shown that serious inflammation at day 4 and fester at day 14 were observed after implantation in cp-Ti group while only mild infection was observed at day 4 in the case of Ti10Cu implants. Bacterial incubation results have also shown that lots of S. aureus were found in cp-Ti group at all intervals while only several bacteria at day 1 and day 4 and no bacteria after 7 days postimplantation can be found in Ti10Cu group. All these results demonstrate the strong in vivo antibacterial property of Ti10Cu alloy. The strong antibacterial property suggests that Ti10Cu alloy might have potential application in orthopedic surgery and dental implant to reduce the implant-related infection or inflammation.


Assuntos
Ligas/química , Cobre/química , Próteses e Implantes/microbiologia , Titânio/química , Ligas/farmacologia , Animais , Leucócitos/citologia , Leucócitos/efeitos dos fármacos , Leucócitos/metabolismo , Teste de Materiais , Testes de Sensibilidade Microbiana , Músculos/patologia , Coelhos , Staphylococcus aureus/efeitos dos fármacos
11.
Molecules ; 24(8)2019 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-31010195

RESUMO

As a hydrogen storage material, Zr2Fe alloy has many advantages such as fast hydrogen absorption speed, high tritium recovery efficiency, strong anti-pulverization ability, and difficulty self-igniting in air. Zr2Fe alloy has lower hydrogen absorption pressure at room temperature than LaNi5 alloy. Compared with the ZrVFe alloy, the hydrogen release temperature of Zr2Fe is lower so that the material can recover hydrogen isotopes at lower hydrogen concentration efficiently. Unfortunately, the main problem of Zr2Fe alloy in application is that a disproportionation reaction is easy to occur after hydrogen absorption at high temperature. At present, there is little research on the generation and influencing factors of a disproportionation reaction in Zr2Fe alloy. In this paper, the effects of temperature and hydrogen pressure on the disproportionation of Zr2Fe alloy were studied systematically. The specific activation conditions and experimental parameters for reducing alloy disproportionation are given, which provide a reference for the specific application of Zr2Fe alloy.


Assuntos
Ligas/química , Hidrogênio/química , Temperatura Ambiente
12.
Mater Sci Eng C Mater Biol Appl ; 100: 706-714, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948108

RESUMO

The current study explored the degradation behavior of a WE43 Mg alloy during immersion tests in Dulbecco's Modified Eagle's Medium (DMEM) for 3d and 7d, for a bare alloy surface as well as for samples with surface pre-treatment, and finally for samples coated with chitosan-bioactive glass. The immersion tests were conducted with and without addition of serum, to study the influence of proteins on the degradation process. Mass-loss was measured to determine the corrosion rate after 3d and 7d of immersion. The samples were analyzed by SEM with respect to their surface morphology and the chemical composition was screened by high-resolution XPS. The results demonstrate not only a significant, time-dependent influence of serum addition on the corrosion behavior of the materials studied, but noteworthy is that depending on the sample type, proteins in solution were observed to either accelerate or inhibit corrosion. These results are discussed in correlation to observed changes in surface chemistry taking place upon immersion in the absence and presence of proteins.


Assuntos
Ligas/química , Quitosana/química , Materiais Revestidos Biocompatíveis/química , Vidro/química , Magnésio/química , Soroalbumina Bovina/química , Animais , Bovinos , Corrosão , Espectroscopia Fotoeletrônica , Propriedades de Superfície
13.
J Colloid Interface Sci ; 547: 309-317, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30965229

RESUMO

Magnesium (Mg) alloys have received considerable attentions as the emerging biodegradable implant materials in orthopedic surgery applications. However, the rapid corrosion rate and the susceptibility to bacterial infection have prevented their wide spread applications to date. In this work, the gentamicin-loaded multilayers have been constructed on Mg alloys through spin-assisted layer-by-layer (SLbL) assembly. Heat treatment is applied for improving the corrosion resistance and prolonging the drug release profile. In addition, the treated multilayer can promote the formation of hydroxyapatite (HA) during the long-time immersion in Hank's balanced salt solution (HBSS).


Assuntos
Ligas/química , Gentamicinas/química , Temperatura Alta , Magnésio/química , Polieletrólitos/química , Liberação Controlada de Fármacos , Resistência a Medicamentos , Hidroxiapatitas/síntese química , Hidroxiapatitas/química , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
14.
Nanoscale ; 11(18): 8651-8664, 2019 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-31011743

RESUMO

Subwavelength metal nanoislands thermally dewetted from a thin film emerge as a powerful and cost-effective photonic material, due to the formation of substantially strong nano-gap-based plasmonic hot spots and their simple large-area nanofabrication. Unlike conventional nanostructures, nanoislands dewetted from thin metal films can be formed on a large scale at the wafer level and show substrate-dependent plasmonic phenomena across a broad spectral range from ultraviolet to infrared. Substrate-selective dewetting methods for metal nanoislands enable diverse nanophotonic and optoelectronic technologies, underlining mechanical, structural, and material properties of a substrate. Emerging bioplasmonic technology using metal nanoislands also serves as a high-throughput and surface-sensitive analytical technique with wide-ranging application in rapid, real-time, and point-of-care medical diagnostics. This review introduces an assortment of dewetting fabrication methods for metal nanoislands on distinct substrates from glass to cellulose fibers and provides novel findings for metal nanoislands on a substrate by three-dimensional numerical modeling. Furthermore, the plasmonic properties of metal nanoislands and recent examples for their photonic applications, in particular, biological sensing, are technically summarized and discussed.


Assuntos
Nanoestruturas/química , Ligas/química , Eletrônica , Metais/química , Nanomedicina , Óptica e Fotônica , Sistemas Automatizados de Assistência Junto ao Leito
15.
Mater Sci Eng C Mater Biol Appl ; 101: 92-102, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31029368

RESUMO

In this work, microstructures and corrosion behaviors of novel ZrTiAl-χV (χ = 0, 1, 3, 5, 7 wt%) alloys have been investigated. Phase composition and microstructures of the specimens are characterized using X-ray diffraction, optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results show that phase composition of the alloys change by α' → α″ → α″ + ßâ€¯â†’â€¯ß as V is added gradually. Meanwhile, the mean size of the α' phase, α″ martensite and ß phase decreases as V content increases. In order to test the corrosion performance of the specimens, potentiodynamic polarization tests in NaCl and HCl solutions and immersion tests in HCl solution are performed. Analysis of potentiodynamic potential curves indicates that corrosion potential increases and corrosion current density decreases with adding V content in the examined alloys. From the results of weight loss tests, it can be observed that the weight loss of the examined alloys decreases along with the increase of V content. In addition, when the content of V is added from 3 to 7 wt%, the metastable corrosion pits are replaced with the stable corrosion pits. The phase composition as well as the grain size can be identified as the main factor affecting the corrosion performance of the alloys.


Assuntos
Ligas/química , Corrosão , Eletroquímica , Fatores de Tempo , Difração de Raios X
16.
Biofouling ; 35(2): 173-186, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30935231

RESUMO

The chemical composition of biomaterials can drive their biological responses; therefore, this in vitro study aimed to evaluate the proteomic profile of the salivary pellicle formed on titanium (Ti) alloys containing niobium (Nb) and zirconium (Zr). The experimental groups consisted of Ti35NbxZr (x = 5 and 10 wt%) alloys, and commercially pure titanium (cpTi); titanium aluminium vanadium (Ti6Al4V) alloys were used as controls. The physical and chemical characteristics of the Ti materials were analysed. The proteomic profile was evaluated by liquid chromatography coupled with tandem mass spectrometry. Bacterial adhesion (2 h) of mixed species (Streptococcus sanguinis and Actinomyces naeslundii) was investigated as colony-forming units (n = 6). This paper reports the finding that salivary pellicle composition can be modulated by the composition of the Ti material. The Ti35NbxZr group showed a significant ability to adsorb proteins from saliva, which can favour interactions with cells and compatibility with the body.


Assuntos
Ligas/química , Película Dentária/química , Nióbio/química , Proteoma/análise , Proteínas e Peptídeos Salivares/análise , Titânio/química , Zircônio/química , Adsorção , Aderência Bacteriana , Materiais Biocompatíveis/química , Proteômica
17.
Mater Sci Eng C Mater Biol Appl ; 98: 1073-1086, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30812991

RESUMO

Large bone defects or fractures must be treated with an implant or transplant. Resorbable implants are attractive as these require only one surgery, whereas bone autografts, which can be cut off from the same person's hip, require more than one procedure. Moreover, porous structures promote the ingrowth of the patient's bone. Thus, the objective of the present study was to develop open-pored biodegradable implant structures with different pore sizes that provide for both adequate degradation behaviour and mechanical properties that match with those of bone. The magnesium alloys LAE442 and La2 were employed in this study, as these materials are known to feature good biocompatibility and mechanical properties close to bone. It was possible to cast magnesium sponges with different pore sizes using the alloy LAE442. However, with the MgLa2 alloy, only sponges with a minimum pore size of 0.5 mm could be produced. Overall, the sponges cast with the LAE442 alloy showed higher strength, even though the strengths of the dense parts were similar in both alloys tested. In terms of castability and mechanical behaviour, the LAE442 alloy turned out to be more favourable. In order to adapt the implant degradation behaviour to the bone ingrowth behaviour, coating of the magnesium sponges with calcium phosphate and polylactic acid was also investigated. Additionally, the different coatings were tested on their adhesive forces and influences to the in-vitro degradation behaviour.


Assuntos
Materiais Biocompatíveis/química , Osso e Ossos/metabolismo , Magnésio/química , Implantes Absorvíveis , Ligas/química , Transplante Ósseo/métodos , Fosfatos de Cálcio/química , Humanos , Teste de Materiais/métodos , Porosidade
18.
Mater Sci Eng C Mater Biol Appl ; 98: 279-287, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30813028

RESUMO

The present study reports the results of the microstructure, mechanical properties and in vitro bioactivity of the Ti-13Nb-13Zr based composite with 10 wt% CPP (calcium pyrophosphate), densified using spark plasma sintering process (SPS) at different sintering temperatures (900-1200 °C). The results show that the sintered composites mainly consist of ß-Ti, α-Ti, and ceramic interphases (Ti2O, CaTiO3, CaZrO3, CaO, TixPy). With the sintering temperature increasing, α-Ti and ceramic interphases gradually increase, and relative density, elastic modulus, compressive strength and yield strength of the composites also reveal an increasing tendency. However, Ti-13Nb-13Zr-10CPP composite sintered at 1000 °C exhibits high matching elastic modulus (46 GPa) and compressive strength (1617 MPa) due to uniform structure and high density. In addition, in vitro mineralization assays demonstrate the apatite-forming ability of the composite (1000 °C) and its higher surface bioactivity as compared to the Ti-13Nb-13Zr alloy. Furthermore, ROS1728 osteoblast culture evidences that the composite (1000 °C) stimulates cell adhesion and growth due to the pore characteristics and ceramic interphases. Therefore, the prepared Ti-13Nb-13Zr-10CPP composite at 1000 °C exhibits immense potential as a biomedical material.


Assuntos
Materiais Biocompatíveis/química , Pirofosfato de Cálcio/química , Titânio/química , Ligas/química , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Humanos , Teste de Materiais , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos
19.
Mater Sci Eng C Mater Biol Appl ; 98: 635-648, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30813067

RESUMO

Titanium niobium alloys exhibit a lower stiffness compared to Ti6Al4V, the 'gold standard' for load-bearing bone implants. Thus, the critical mismatch in stiffness between the implant and adjacent bone tissue could be addressed with TiNb alloys and thereby reduce stress shielding, which can result in bone resorption and subsequent implant loosening; however, the cellular response on the specific material is crucial for sufficient osseointegration. We therefore hypothesize that the response of human mesenchymal stromal cells (hMSC) and osteoblast-like cells on Ti45Nb surfaces can be improved by a novel nanoporous surface structure. For this purpose, an etching technique using hydrogen peroxide electrolyte solution was applied to Ti45Nb. The treated surfaces were characterized using SEM, LSM, AFM, nanoindentation, and contact angle measurements. Cell culture experiments using hMCS and MG-63 were conducted. The H2O2 treatment resulted in surface nanopores, an increase in surface wettability and a reduction in surface hardness. The proliferation of MG-63 was enhanced on TiNb45 compared to Ti6Al4V. MG-63 focal adhesion complexes were detected on all Ti45Nb surfaces, whereas the nanostructures notably increased the cell area and decreased cell solidity, indicating stimulated cell spreading and pseudopodia formation. Alizarin red stainings indicated that the nanoporous surfaces stimulated the osteogenic differentiation of hMSC. It can be concluded that the proposed surface treatment could potentially help to stimulate the osseointegration behaviour of the advantageous low stiff Ti45Nb alloy.


Assuntos
Ligas/química , Células-Tronco Mesenquimais/citologia , Nanoporos/ultraestrutura , Diferenciação Celular/fisiologia , Linhagem Celular Tumoral , Humanos , Peróxido de Hidrogênio/química , Microscopia Eletrônica de Varredura , Osteogênese/fisiologia
20.
Mater Sci Eng C Mater Biol Appl ; 98: 753-763, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30813081

RESUMO

The bioactivity of anodized near-ß TiNbSn alloy with low Young's modulus prepared in sulfuric acid electrolytes was examined to explore the osseointegration mechanism with a focus on the role of anodic oxide. Hydroxyapatite (HA) precipitated on the surface of anodic oxide following immersion in Hank's solution, and precipitation accelerated with increase in the sulfuric acid concentration of the electrolyte. HA is formed on the surface of as-anodized oxide without subsequent annealing or hot water (HW) treatment. This outcome differs from that of a previous study using anodized TiNbSn alloy prepared in acetic acid electrolytes requiring for subsequent HW treatment. It was found that the oxide anodized in sulfuric acid electrolyte contains a large amount of internal pores and is highly crystallized thick TiO2, whereas the same prepared in the acetic acid electrolyte is low crystalline thin TiO2 containing a small amount of pores. The present anodized TiNbSn alloy is preferred for maintaining the low Young's modulus of the alloy and eliminating the subsequent treatment to increase the Young's modulus. A model to rationalize the bioactivity of the present anodic oxide is proposed based on the series of studies. It is concluded that the sulfuric acid electrolyte is favorable for both HA formation and low Young's modulus, and the bioactivity is attributed to the anodic TiO2 that facilitates incorporation of bone ingredients.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Eletrólitos , Ácidos Sulfúricos/química
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