Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 147
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Mater Sci Eng C Mater Biol Appl ; 105: 110034, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546451

RESUMO

The efficacy of surface topology and chemistry on the ability for a surface to retain antimicrobial performance via the immobilization of a peptide was evaluated. A nanosecond pulsed laser was used to create oxide films on Ti-6Al-4V and 304L stainless steel. The laser conditions employed created a mudflat cracked surface on titanium, but no cracks on the steel. An antimicrobial peptide, nisin, was infused into the cracked and uncracked oxide surfaces to provide antimicrobial activity against Gram-positive bacteria; Listeria monocytogenes was chosen as the model microorganism. Release tests in distilled water at room temperature show that nisin is slowly liberated from the uncracked stainless steel surface, while there was no evidence of nisin liberation from the cracked titanium alloy surfaces, likely due to immobilization of the peptide into the artificially created micro-cracks on the surface of this alloy. Surfaces treated with nisin became active and exhibit anti-microbial performance against L. monocytogenes; this behavior is mostly retained after scrubbing/washing and simple immersion in water.


Assuntos
Antibacterianos/farmacologia , Metais/química , Nisina/farmacologia , Óxidos/química , Testes de Sensibilidade Microbiana , Espectroscopia de Infravermelho com Transformada de Fourier , Aço Inoxidável/farmacologia , Propriedades de Superfície , Titânio/farmacologia
2.
Mater Sci Eng C Mater Biol Appl ; 100: 396-410, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948076

RESUMO

Stainless steel (SS) has been widely applied as one of the most efficient implant metal materials, although corrosion and infection in body environment are still challenging. Herein, an antibacterial passivation method was employed to enhance the antibacterial performance and corrosion resistance of the medical 316L SS. The result proved that the antibacterial-passivated 316L SS exhibited stable antibacterial activity and effectively inhibited the formation of bacterial biofilm. Electrochemical measurements combined with X-ray photoelectron spectroscopy technique were used to study the corrosion resistance and semiconductor behavior of passivated 316L SS immersed in simulated physiological environment. The results indicated that the 316L SS after antibacterial passivation treatment for 1 h, soaking in the medium for 10 days, showed satisfactory corrosion resistance attributing to proper Cu deposition in the passive film. The anodic stripping voltammetry measurement further confirmed that the Cu-bearing passive film could continuously release Cu ions into medium. The zebrafish test demonstrated an excellent in vivo biocompatibility for the 316L SS with antibacterial passivation for 0.5 and 1 h, respectively. In addition, changes of surface roughness, contact angle and chemical composition after antibacterial passivation played an important role in explaining the antibacterial mechanism, which could be clearly divided into contact killing and ionic release killing. Hence, the antibacterial passivation treatment was preliminarily proved as a potential way for enhancing the persistent antibacterial activity and corrosion resistance of 316L SS.


Assuntos
Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Aço Inoxidável/farmacologia , Animais , Biofilmes/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Cobre/análise , Corrosão , Espectroscopia Dielétrica , Eletroquímica , Eletrodos , Embrião não Mamífero/citologia , Embrião não Mamífero/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Microscopia de Força Atômica , Espectroscopia Fotoeletrônica , Propriedades de Superfície , Água/química , Peixe-Zebra/embriologia
3.
PLoS One ; 14(3): e0214384, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30913254

RESUMO

Optimal treatment of bone fractures with minimal complications requires implant alloys that combine high strength with high ductility. Today, TiAl6V4 titanium and 316L steel are the most applied alloys in bone surgery, whereas both share advantages and disadvantages. The nickel-free, high-nitrogen austenitic steel X13CrMnMoN18-14-3 (1.4452, brand name: P2000) exhibits high strength in combination with superior ductility. In order to compare suitable alloys for bone implants, we investigated titanium, 316L steel, CoCrMo and P2000 for their biocompatibility and hemocompatibility (according to DIN ISO 10993-5 and 10993-4), cell metabolism, mineralization of osteoblasts, electrochemical and mechanical properties. P2000 exhibited good biocompatibility of fibroblasts and osteoblasts without impairment in vitality or changing of cell morphology. Furthermore, investigation of the osteoblasts function by ALP activity and protein levels of the key transcription factor RUNX2 revealed 2x increased ALP activity and more than 4x increased RUNX2 protein levels for P2000 compared to titanium or 316 steel, respectively. Additionally, analyses of osteoblast biomineralization by Alizarin Red S staining exhibited more than 6x increased significant mineralization of osteoblasts grown on P2000 as compared to titanium. Further, P2000 showed no hemolytic effect and no significant influence on hemocompatibility. Nanoindentation hardness tests of Titanium and 316L specimens exposed an indentation hardness (HIT) of about 4 GPa, whereas CoCrMo and P2000 revealed HIT of 7.5 and 5.6 GPa, respectively. Moreover, an improved corrosion resistance of P2000 compared to 316L steel was observed. In summary, we could demonstrate that the nickel-free high-nitrogen steel P2000 appears to be a promising alternative candidate for applications in bone surgery. As to nearly all aspects like biocompatibility and hemocompatibility, cell metabolism, mineralization of osteoblasts and mechanical properties, P2000 was similar to or revealed advantages against titanium, 316L or CoCrMo.


Assuntos
Substitutos Ósseos/química , Nitrogênio/química , Aço Inoxidável/química , Fosfatase Alcalina/metabolismo , Ligas/química , Ligas/farmacologia , Animais , Doenças Ósseas/cirurgia , Doenças Ósseas/terapia , Substitutos Ósseos/farmacologia , Substitutos Ósseos/uso terapêutico , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Subunidades alfa de Fatores de Ligação ao Core/metabolismo , Corrosão , Dureza , Camundongos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Próteses e Implantes , Aço Inoxidável/farmacologia , Propriedades de Superfície
4.
Eur J Orthop Surg Traumatol ; 29(5): 1141-1145, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30848379

RESUMO

Operative fixation of acetabular fractures involving the quadrilateral surface presents a challenging clinical scenario. Classically, quadrilateral plate buttress was achieved via the use of a "seven" plate. More recently, the use of an anatomic, pre-contoured design has been gaining popularity due to its pre-contoured shape and larger footprint, allowing for a wider quadrilateral plate buttress. The current study presents using a stainless steel locking calcaneal plate to obtain similar surface area coverage as the modern pre-contoured quadrilateral plate, but at a lower cost.Level of evidence IV.


Assuntos
Acetábulo , Placas Ósseas , Fixação Interna de Fraturas , Fraturas Ósseas , Complicações Pós-Operatórias/prevenção & controle , Acetábulo/diagnóstico por imagem , Acetábulo/lesões , Acetábulo/cirurgia , Adulto , Fenômenos Biomecânicos , Parafusos Ósseos , Fixação Interna de Fraturas/instrumentação , Fixação Interna de Fraturas/métodos , Fixação Interna de Fraturas/reabilitação , Consolidação da Fratura , Fraturas Ósseas/diagnóstico , Fraturas Ósseas/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Aço Inoxidável/farmacologia , Resultado do Tratamento
5.
Colloids Surf B Biointerfaces ; 173: 470-477, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30326363

RESUMO

To solve the thrombosis and restenosis problem in cardiovascular stent implantation for cardiovascular artery disease, chondroitin 6-sulfate (ChS) with heparin (HEP) have been used as drug carrier layers and alternatively covalently bonded on gold (Au)-dimercaptosuccinic acid (DMSA)-thiolized cardiovascular metallic (SUS316 L stainless steel, SS) stents. Sirolimus, a model drug, was encapsulated in the ChS-HEP alternative layers. The behavior of the drug in releasing and suppressing the growth of smooth-muscle cells (SMCs) was evaluated with 5-layer CHS-HEP coating on the SS stents. Moreover, hemocompatibility of blood clotting time and platelet adhesion was performed. The results showed that the 5-layer ChS-HEP-modified SS stents displayed the greatest hemocompatibility, showing prolonged blood clotting time of the activated partial thrombin time (> 500 s) and less platelet adhesion to reduce thrombosis. Furthermore, sirolimus can be released continuously for more than 40 days with the 5-layer ChS-HEP coating and is beneficial for inhibiting the growth of SMCs; however, it does not affect the proliferation of endothelial cells, which can avoid restenosis formation. Therefore, the multilayers of ChS-HEP grafted onto the Au-DMSA-cardiovascular SS stents provide high potential for use as drug eluting stents.


Assuntos
Sulfatos de Condroitina/química , Materiais Revestidos Biocompatíveis/química , Stents Farmacológicos , Ouro/química , Heparina/química , Sirolimo/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Materiais Revestidos Biocompatíveis/farmacologia , Composição de Medicamentos/métodos , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/efeitos dos fármacos , Tempo de Tromboplastina Parcial , Adesividade Plaquetária/efeitos dos fármacos , Plasma Rico em Plaquetas , Sirolimo/química , Aço Inoxidável/química , Aço Inoxidável/farmacologia , Succímero/química
6.
Carbohydr Polym ; 202: 600-610, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30287041

RESUMO

This work focuses on the structure, bioactivity, corrosion, and biocompatibility characteristics of chitosan-matrix composites reinforced with various amounts of fluoride-doped diopside nanoparticles (at 20, 40, 60, and 80 wt%) deposited on stainless steel 316 L. Bioactivity studies reveal that the presence of the nanoparticles in the coatings induces apatite-forming ability to the surfaces. Based on electrochemical impedance spectroscopy and polarization experiments, the in vitro corrosion resistance of the substrate was enhanced by increasing the level of the nanoparticles in the coating. The sample containing 60% of the nanoparticles presented the highest osteoblast-like MG63 cell viability, in comparison to the other prepared and even control samples. Also, the cell attachment on the surfaces was improved with increasing the amount of the nanoparticles in the coatings. It is eventually concluded that the application of chitosan/fluoride-doped diopside nanocomposite coatings improves the bioperformance of metallic implants.


Assuntos
Quitosana/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Fluoretos/farmacologia , Nanocompostos/química , Aço Inoxidável/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Materiais Revestidos Biocompatíveis/síntese química , Materiais Revestidos Biocompatíveis/química , Espectroscopia Dielétrica , Fluoretos/química , Humanos , Tamanho da Partícula , Aço Inoxidável/química , Propriedades de Superfície
7.
Tissue Eng Part A ; 24(13-14): 1157-1166, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29431053

RESUMO

Incomplete endothelialization of intracoronary stents has been associated with stent thrombosis and recurrent symptoms, whereas prolonged use of dual antiplatelet therapy increases bleeding-related adverse events. Facilitated endothelialization has the potential to improve clinical outcomes in patients who are unable to tolerate dual antiplatelet therapy. The objective of this study was to demonstrate the feasibility of magnetic cell capture to rapidly endothelialize intracoronary stents in a large animal model. A novel stent was developed from a magnetizable duplex stainless steel (2205 SS). Polylactic-co-glycolic acid and magnetite (Fe3O4) were used to synthesize biodegradable superparamagnetic iron oxide nanoparticles, and these were used to label autologous blood outgrowth endothelial cells. Magnetic 2205 SS and nonmagnetic 316L SS control stents were implanted in the coronary arteries of pigs (n = 11), followed by intracoronary delivery of magnetically labeled cells to 2205 SS stents. In this study, we show extensive endothelialization of magnetic 2205 SS stents (median 98.4% cell coverage) within 3 days, whereas the control 316L SS stents exhibited significantly less coverage (median 48.9% cell coverage, p < 0.0001). This demonstrates the ability of intracoronary delivery of magnetic nanoparticle labeled autologous endothelial cells to improve endothelialization of magnetized coronary stents within 3 days of implantation.


Assuntos
Células Endoteliais/citologia , Metais/química , Nanopartículas/química , Stents , Animais , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/ultraestrutura , Feminino , Nanopartículas/ultraestrutura , Fenótipo , Aço Inoxidável/farmacologia , Suínos
8.
J Biomed Mater Res B Appl Biomater ; 106(2): 569-577, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28245086

RESUMO

Medical grade 316L stainless steel was laser surface melted (LSM) using continuous wave Nd-YAG laser in argon atmosphere at 1 and 5 mm/s. The treated surfaces were characterized using electron backscatter diffraction to study the influence of top surface crystallographic orientation and type of grain boundaries on corrosion resistance, wettability, and biocompatibility. The laser scan velocity was found to have a marginal influence on the surface roughness and the type of grain boundaries. However, the crystal orientation density was found to be relatively high in 1 mm/s samples. The LSM samples showed a higher concentration of {101} and {123} planes parallel to the sample surface as well as a higher fraction of low-angle grain boundaries. The LSM samples were found to exhibit better surface wettability and enhanced the viability and proliferation of human fetal osteoblast cells in vitro when compared to the untreated samples. Further, the corrosion protection efficiency of 316L stainless steel was improved up to 70% by LSM in as-processed condition. The increased concentration of {101} and {123} planes on surfaces of LSM samples increases their surface energy, which is believed to be responsible for the improved in vitro cell proliferation. Further, the increased lattice spacing of these planes and high concentration of low-energy grain boundaries in LSM samples would have contributed to the better in vitro corrosion resistance than untreated 316L stainless steel. Our results indicate that LSM can be a potential treatment option for 316L stainless steel-based biomedical devices to improve biocompatibility and corrosion resistance. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 569-577, 2018.


Assuntos
Lasers , Teste de Materiais , Aço Inoxidável/química , Aço Inoxidável/farmacologia , Molhabilidade , Argônio/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Corrosão , Humanos , Soluções Isotônicas/química , Soluções Isotônicas/farmacologia , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Água/química
9.
Clin Oral Investig ; 22(6): 2149-2160, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29280076

RESUMO

OBJECTIVES: The objective of this study is to evaluate the effects of treatment modalities on titanium surface characteristics and surrounding tissues. MATERIALS AND METHODS: Eighteen participants each had four titanium healing caps (HC) attached to four newly inserted implants. After healing, each HC was randomly assigned to either (1) titanium curettes (TC), (2) stainless steel ultrasonic tip (PS), (3) erythritol air-polishing powder (EP), or (4) only rubber cup polishing (CON). Probing depths (PD), bleeding on probing (BOP), matrix metalloproteinase 8 (MMP-8), and periopathogens were recorded before and 3 months following instrumentation. After final assessments, HCs were removed, cleaned, and subjected to (a) bacterial colonization (Streptococcus gordonii, 24 h; mixed culture, 24 h) and (b) gingival fibroblasts (5 days). HC surfaces were analyzed with a scanning electron microscope (SEM). RESULTS: No significant differences between the groups were evident before or after instrumentation for PD and BOP (except TC showed a significant decrease in PD; p = 0.049). MMP-8 levels and bacterial loads were always very low. MMP-8 decreased further after instrumentation, while bacteria levels showed no change. No significant differences (p > 0.05) were evident in bacterial colonization or fibroblast attachment. A comparison of the overall mean SEM surface roughness scores showed a significant difference between all groups (p < 0.0001) with the lowest roughness after EP. CONCLUSIONS: All treatments performed yielded comparable outcomes and may be implemented safely. CLINICAL RELEVANCE: Clinicians may fear implant surface damage, but all instrumentation types are safe and non-damaging. They can be implemented as needed upon considering the presence of staining and soft and hard deposits.


Assuntos
Implantação Dentária Endo-Óssea , Implantes Dentários , Profilaxia Dentária/instrumentação , Titânio/farmacologia , Adulto , Idoso , Eritritol/farmacologia , Fibroblastos , Humanos , Metaloproteinase 8 da Matriz/análise , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Mucosite/microbiologia , Mucosite/prevenção & controle , Peri-Implantite/microbiologia , Peri-Implantite/prevenção & controle , Índice Periodontal , Pós/farmacologia , Estudos Prospectivos , Aço Inoxidável/farmacologia , Streptococcus gordonii , Propriedades de Superfície , Cicatrização
10.
Int J Nanomedicine ; 12: 8443-8457, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29225463

RESUMO

Treatment for fractures requires internal fixation devices, which are mainly produced from stainless steel or titanium alloy without biological functions. Therefore, we developed a novel nano-copper-bearing stainless steel with nano-sized copper-precipitation (317L-Cu SS). Based on previous studies, this work explores the effect of 317L-Cu SS on fracture healing; that is, proliferation, osteogenic differentiation, osteogenesis-related gene expression, and lysyl oxidase activity of human bone mesenchymal stem cells were detected in vitro. Sprague-Dawley rats were used to build an animal fracture model, and fracture healing and callus evolution were investigated by radiology (X-ray and micro-CT), histology (H&E, Masson, and safranin O/fast green staining), and histomorphometry. Further, the Cu2+ content and Runx2 level in the callus were determined, and local mechanical test of the fracture was performed to assess the healing quality. Our results revealed that 317L-Cu SS did not affect the proliferation of human bone mesenchymal stem cells, but promoted osteogenic differentiation and the expression of osteogenesis-related genes. In addition, 317L-Cu SS upregulated the lysyl oxidase activity. The X-ray and micro-CT results showed that the callus evolution efficiency and fracture healing speed were superior for 317L-Cu SS. Histological staining displayed large amounts of fibrous tissues at 3 weeks, and cartilage and new bone at 6 weeks. Further, histomorphometric analysis indicated that the callus possessed higher osteogenic efficiency at 6 weeks, and a high Cu2+ content and increased Runx2 expression were observed in the callus for 317L-Cu SS. Besides, the mechanical strength of the fracture site was much better than that of the control group. Overall, we conclude that 317L-Cu SS possesses the ability to increase Cu2+ content and promote osteogenesis in the callus, which could accelerate the callus evolution process and bone formation to provide faster and better fracture healing.


Assuntos
Calo Ósseo/efeitos dos fármacos , Cobre/farmacologia , Consolidação da Fratura/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Aço Inoxidável/farmacologia , Animais , Calo Ósseo/diagnóstico por imagem , Calo Ósseo/fisiologia , Cartilagem/efeitos dos fármacos , Cartilagem/crescimento & desenvolvimento , Diferenciação Celular/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Humanos , Implantes Experimentais , Células-Tronco Mesenquimais/citologia , Nanoestruturas/química , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Ratos , Ratos Sprague-Dawley , Aço Inoxidável/química , Microtomografia por Raio-X
11.
Astrobiology ; 17(12): 1183-1191, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29116818

RESUMO

Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth. The efficacy of wetted oxidized copper layers and pure copper surfaces as antimicrobial agents was tested by applying cultures of Escherichia coli and Staphylococcus cohnii to these metallic surfaces. Stainless steel surfaces were used as non-inhibitory control surfaces. The production of reactive oxygen species and membrane damage increased rapidly within 1 h of exposure on pure copper surfaces, but the effect on cell survival was negligible even after 2 h of exposure. However, longer exposure times of up to 4 h led to a rapid decrease in cell survival, whereby the survival of cells was additionally dependent on the exposed cell density. Finally, the release of metal ions was determined to identify a possible correlation between copper ions in suspension and cell survival. These measurements indicated a steady increase of free copper ions, which were released indirectly by cells presumably through excreted complexing agents. These data indicate that the application of antimicrobial surfaces in spaceflight facilities could improve crew health and mitigate material damage caused by microbial contamination and biofilm formation. Furthermore, the results of this study indicate that cuprous oxide layers were superior to pure copper surfaces related to the antimicrobial effect and that cell density is a significant factor that influences the time dependence of antimicrobial activity. Key Words: Contact killing-E. coli-S. cohnii-Antimicrobial copper surfaces-Copper oxide layers-Human health-Planetary protection. Astrobiology 17, 1183-1191.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Cobre/farmacologia , Escherichia coli/fisiologia , Voo Espacial , Staphylococcus/fisiologia , Contaminação de Equipamentos/prevenção & controle , Escherichia coli/efeitos dos fármacos , Íons/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Aço Inoxidável/farmacologia , Staphylococcus/efeitos dos fármacos , Propriedades de Superfície
12.
J Mater Sci Mater Med ; 28(8): 125, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28707137

RESUMO

Esophageal cancer is difficult to cure globally and possesses high mortality rate, and it is generally accepted that palliative care such as stent implantation is the main therapy method for esophageal cancer in later period. However, the restenosis caused by tumor cells and inflammatory cells seriously interferes the stent clinical application and limits its long-term services. To solve this problem, series of drug delivery stents were developed and proven rather effective in the early stage of implantation, but more serious restenosis occurred after the drug delivery was over, which endangered the patients' life. Therefore, endowing the esophageal stent continuous anti-cancer function become an ideal strategy for inhibiting the restenosis. In this contribution, the functional layer composed of polydopamine (PDA) and Poly-ethylenimine (PEI) with series of molecular weights (MW, 1.8 × 103, 1 × 104, 2.5 × 104 and 7 × 104 Da) were fabricated onto the esophageal stent material 317L stainless steel (317L SS) surface. The surface characterization including amine quantitative, atomic force microscopy (AFM) and water contact angle measurement indicated successful preparation of the PDA/PEI layer. The Eca109 cells culture results proved that the PDA/PEI layers significantly improve Eca109 cells apoptosis and necrosis, suggesting excellent anti-cancer function. In addition, we also found that the anti-cancer function of the PDA/PEI layers was positively correlated to the immobilized PEIs' MW. All the results demonstrated the potential application of the PDA/PEI layers on the surface modification of esophageal stent for continuous anti-cancer function. It is generally accepted that the restenosis caused by tumor cells seriously interferes the esophageal stent clinical application. Thus, endowing the esophageal stent continuous anti-cancer function is the ideal strategy for inhibiting the restenosis. In this work, we fabricated functional layers composed of polydopamine (PDA) and Poly-ethylenimine (PEI) with series of molecular weights (MW, 1.8 × 103, 1 × 104, 2.5 × 104 and 7 × 104 Da) onto the esophageal stent material 317L stainless steel (317L SS) surface to inhibit the tumor cells growth, and this function was related to the PEIs' molecular weights. The functional PDA/PEI layers were expected potentially applied for surface modification of esophageal stent materials.


Assuntos
Antineoplásicos/administração & dosagem , Materiais Revestidos Biocompatíveis/química , Stents Farmacológicos , Neoplasias Esofágicas/tratamento farmacológico , Esôfago , Polietilenoimina/química , Antineoplásicos/farmacocinética , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/farmacologia , Sistemas de Liberação de Medicamentos , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/patologia , Esôfago/efeitos dos fármacos , Esôfago/metabolismo , Esôfago/patologia , Humanos , Indóis/química , Indóis/farmacologia , Teste de Materiais , Necrose/patologia , Polietilenoimina/farmacologia , Polímeros/química , Polímeros/farmacologia , Aço Inoxidável/química , Aço Inoxidável/farmacologia , Propriedades de Superfície , Água/metabolismo
13.
Artigo em Inglês | MEDLINE | ID: mdl-28726753

RESUMO

Background: Hospital equipment made from copper alloys can play an important role in complementing traditional methods of disinfection. Aims of the study: The aim of this study was to assess the dynamics of the antimicrobial properties of selected copper alloys in different simulations of environmental conditions (with organic contamination vs. without organic contamination), and to test alternatives to the currently used testing methods. Materials and Methods: A modification of Japanese standard JIS Z 2801 as well as Staphylococcus aureus (SA) and Escherichia coli (EC) suspended in NaCl vs. tryptic soy broth (TSB) were used in tests performed on seven commonly used copper alloys, copper, and stainless steel. Results: A much faster reduction of the bacterial suspension was observed for the inoculum prepared in NaCl than in TSB. A faster reduction for EC than for SA was observed in the inoculum prepared in NaCl. The opposite results were found for the inoculum based on TSB. A significant correlation between the copper concentration in the copper alloys and the time and degree of bacterial suspension reduction was only observed in the case of EC. Conclusions: This study confirmed the antimicrobial properties of copper alloys, and additionally showed that Staphylococcus aureus was more resistant than Escherichia coli in the variant of the experiment without organic contamination. However, even for SA, a total reduction of the bacterial inoculum's density took no longer than 2 h. Under conditions simulating organic contamination, all of the tested alloys were shown to have bactericidal or bacteriostatic properties, which was contrary to the results from stainless steel.


Assuntos
Ligas/farmacologia , Antibacterianos/farmacologia , Cobre/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Caseínas/farmacologia , Desinfecção , Hidrolisados de Proteína/farmacologia , Cloreto de Sódio/farmacologia , Aço Inoxidável/farmacologia
14.
Int J Food Microbiol ; 257: 254-261, 2017 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-28710947

RESUMO

Listeria monocytogenes is a pathogenic foodborne microorganism noted for its ability to survive in the environment and food processing facilities. Survival may be related to the phenotype of individual strains including the ability to form biofilms and resist desiccation and/or sanitizer exposure. The objectives of this research were to compare 14 L. monocytogenes strains isolated from blood (3), food (6) and water (5) with respect to their benzalkonium chloride (BAC) sensitivity, desiccation resistance, and ability to form biofilm. Correlations were tested between those responses, and the presence of the SSI-1 (Stress Survival Islet) and LGI1/CC8 (Listeria Genomic Island 1 in a clonal complex 8 background) genetic markers. Genetic sequences from four strains representing different phenotypes were also probed for predicted amino acid differences in biofilm, desiccation, and membrane related genes. The water isolates were among the most desiccation susceptible strains, while strains exhibiting desiccation resistance harboured SSI-1 or both the SSI-1 and LGI1/CC8 markers. BAC resistance was greatest in planktonic LGI1/CC8 cells (relative to non-LGI1/CC8 cells), and higher BAC concentrations were also needed to inhibit the formation of biofilm by LGI1/CC8 strains during incubation for 48h and 6days compared to other strains. Formation of biofilm on stainless steel was not significantly (p>0.05) different among the strains. Analysis of genetic sequence data from desiccation and BAC sensitive (CP4 5-1, CP5 2-3, both from water), intermediate (Lm568, food) and desiccation and BAC resistant (08 5578, blood, human outbreak) strains led to the finding of amino acid differences in predicted functional protein domains in several biofilm, desiccation and peptidoglycan related genes (e.g., lmo0263, lmo0433, lmo0434, lmo0771, lmo0973, lmo1080, lmo1224, lmo1370, lmo1744, and lmo2558). Notably, the LGI1/CC8 strain 08-5578 had a frameshift mutation in lmo1370, a gene previously associated with desiccation resistance. In conclusion, the more desiccation and BAC resistant LGI1/CC8 isolates may pose a challenge for sanitation efforts.


Assuntos
Anti-Infecciosos Locais/farmacologia , Compostos de Benzalcônio/farmacologia , Biofilmes/crescimento & desenvolvimento , Dessecação , Contaminação de Alimentos/análise , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Sequência de Bases , Biofilmes/efeitos dos fármacos , Canadá , DNA Bacteriano/genética , Tolerância a Medicamentos/genética , Tolerância a Medicamentos/fisiologia , Manipulação de Alimentos/métodos , Humanos , Listeria monocytogenes/classificação , Análise de Sequência de DNA , Aço Inoxidável/farmacologia
15.
Acta Biomater ; 59: 108-116, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28655657

RESUMO

The modification of the surface of surgical implants with cell adhesion ligands has emerged as a promising approach to improve biomaterial-host interactions. However, these approaches are limited by the non-specific adsorption of biomolecules and uncontrolled presentation of desired bioactive ligands on implant surfaces. This leads to sub-optimal integration with host tissue and delayed healing. Here we present a strategy to grow non-fouling polymer brushes of oligo(ethylene glycol) methacrylate by atom transfer radical polymerization from dopamine-functionalized clinical grade 316 stainless steel. These brushes prevent non-specific adsorption of proteins and attachment of cells. Subsequently, the brushes can be modified with covalently tethered adhesive peptides that provide controlled cell adhesion. This approach may therefore have broad application to promote bone growth and improvements in osseointegration. STATEMENT OF SIGNIFICANCE: Stainless steel (SS) implants are widely used clinically for orthopaedic, spinal, dental and cardiovascular applications. However, non-specific adsorption of biomolecules onto implant surfaces results in sub-optimal integration with host tissue. To allow controlled cell-SS interactions, we have developed a strategy to grow non-fouling polymer brushes that prevent protein adsorption and cell adhesion and can be subsequently functionalized with adhesive peptides to direct cell adhesion and signaling. This approach has broad application to improve osseointegration onto stainless steel implants in bone repair.


Assuntos
Materiais Revestidos Biocompatíveis , Dopamina , Células-Tronco Mesenquimais/metabolismo , Metacrilatos , Peptídeos , Polietilenoglicóis , Aço Inoxidável , Adesão Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Dopamina/química , Dopamina/farmacologia , Humanos , Células-Tronco Mesenquimais/citologia , Metacrilatos/química , Metacrilatos/farmacologia , Peptídeos/química , Peptídeos/farmacologia , Polietilenoglicóis/química , Polietilenoglicóis/farmacologia , Ácidos Polimetacrílicos , Aço Inoxidável/química , Aço Inoxidável/farmacologia
16.
Biointerphases ; 12(2): 020301, 2017 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-28407716

RESUMO

The killing of bacteria on metallic copper surfaces in minutes to hours is referred to as contact killing. Why copper possesses such strong antimicrobial activity has remained enigmatic. Based on the physicochemical properties of metals, it was recently predicted that cadmium should also be active in contact killing [Hans et al., Biointerphases 11, 018902 (2010)]. Here, the authors show that cadmium is indeed antimicrobial. It kills three logs of bacteria in 9 h, compared to copper which kills eight logs of bacteria. Metallic silver kills less than one log of bacteria in 9 h. These findings support the novel concept whereby oxide formation, metal ion dissolution, and a Pearson soft character are the key factors for a metal to be antibacterial. Based on these parameters, copper and cadmium are expected to be the two most antibacterial metals.


Assuntos
Antibacterianos/farmacologia , Cádmio/farmacologia , Fenômenos Químicos , Cobre/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Prata/farmacologia , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Aço Inoxidável/farmacologia , Propriedades de Superfície
17.
Mater Sci Eng C Mater Biol Appl ; 73: 198-205, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28183598

RESUMO

Thrombosis formation, restenosis, and delayed endothelium regeneration continue to be a challenge for coronary artery stent therapy. To improve the hemocompatibility of cardiovascular implants and to selectively direct vascular cell behavior, a novel heparin/poly-l-lysine microsphere was developed and immobilized on a dopamine-coated surface. We chose medical grade high nitrogen nickel-free austenitic stainless steel as the stent material since it has better biocompatibility. The stability and structural characteristics of the microspheres changed with the heparin: poly-l-lysine concentration ratio. Antithrombin III binding was significantly enhanced. Furthermore, for plasma coagulation tests, the activated partial thromboplastin time and thrombin time were prolonged and depended on the heparinfunction. The modified exhibited excellent stability and anticoagulant activity, and efficiently accelerated endothelialization and anticoagulation. This work has potential application for the design of coronary artery stent surfaces tailored for vascular cell behavior.


Assuntos
Materiais Biocompatíveis/farmacologia , Heparina/farmacologia , Microesferas , Níquel/farmacologia , Nitrogênio/farmacologia , Polilisina/farmacologia , Aço Inoxidável/farmacologia , Trombose/prevenção & controle , Animais , Antioxidantes/metabolismo , Plaquetas/efeitos dos fármacos , Plaquetas/ultraestrutura , Contagem de Células , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Ligas Dentárias , Dopamina/análise , Fibrinogênio/metabolismo , Hemólise/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Óxido Nítrico/metabolismo , Tempo de Tromboplastina Parcial , Tamanho da Partícula , Adesividade Plaquetária/efeitos dos fármacos , Tempo de Protrombina , Coelhos , Eletricidade Estática , Propriedades de Superfície , Trombose/patologia
18.
Mater Sci Eng C Mater Biol Appl ; 73: 40-47, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28183625

RESUMO

Reducing bacterial adhesion on substrates is fundamental for various industries. In this work, new superhydrophobic surfaces are created by electrodeposition of hydrophobic polymers (PEDOT-F4 or PEDOT-H8) on stainless steel with controlled topographical features, especially at a nano-scale. Results show that anti-bioadhesive and anti-biofilm properties require the control of the surface topographical features, and should be associated with a low adhesion of water onto the surface (Cassie-Baxter state) with limited crevice features at the scale of bacterial cells (nano-scale structures).


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Listeria monocytogenes/efeitos dos fármacos , Nanoestruturas/química , Implantação de Prótese , Pseudomonas aeruginosa/efeitos dos fármacos , Aço Inoxidável/farmacologia , Aderência Bacteriana , Biofilmes/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/química , Polímeros/química , Aço Inoxidável/química , Propriedades de Superfície
19.
Mater Sci Eng C Mater Biol Appl ; 71: 1079-1085, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-27987662

RESUMO

The effects of addition of different Cu content (0, 2.5 and 3.5wt%) on mechanical properties, corrosion resistance and antibacterial performance of 316L austenitic stainless steel (SS) after solution and aging treatment were investigated by mechanical test, transmission electron microscope (TEM), X-ray diffraction (XRD), electrochemical corrosion, X-ray photoelectron spectroscopy (XPS) and antibacterial test. The results showed that the Cu addition and heat treatment had no obvious influence on the microstructure with complete austenite features. The yield strength (YS) after solution treatment was almost similar, whereas the aging treatment obviously increased the YS due to formation of tiny Cu-rich precipitates. The pitting and protective potential of the solution treated Cu-bearing 316L SS in 0.9wt% NaCl solution increased with increasing Cu content, while gradually declined after aging, owing to the high density Cu-rich precipitation. The antibacterial test proved that higher Cu content and aging were two compulsory processes to exert good antibacterial performance. The XPS results further indicated that aging enhanced the Cu enrichment in passive film, which could effectively stimulate the Cu ions release from the surface of passive film.


Assuntos
Antibacterianos , Cobre , Escherichia coli/crescimento & desenvolvimento , Aço Inoxidável , Antibacterianos/química , Antibacterianos/farmacologia , Cobre/química , Cobre/farmacologia , Corrosão , Aço Inoxidável/química , Aço Inoxidável/farmacologia
20.
Mater Sci Eng C Mater Biol Appl ; 69: 631-9, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27612756

RESUMO

Recently, porous metallic materials have been extensively studied as candidates for use in the fabrication of scaffolds and augmentations to repair trabecular bone defects, e.g. in surroundings of joint replacements. Fabricating these complex structures by using common approaches (e.g., casting and machining) is very challenging. Therefore, rapid prototyping techniques, such as selective laser melting (SLM), have been investigated for these applications. In this study, we characterized a highly porous (87 vol.%) 316L stainless steel scaffold prepared by SLM. 316L steel was chosen because it presents a biomaterial still widely used for fabrication of joint replacements and, from the practical point of view, use of the same material for fabrication of an augmentation and a joint replacement is beneficial for corrosion prevention. The results are compared to the reported properties of two representative nonporous 316L stainless steels prepared either by SLM or casting and subsequent hot forging. The microstructural and mechanical properties and the surface chemical composition and interaction with the cells were investigated. The studied material exhibited mechanical properties that were similar to those of trabecular bone (compressive modulus of elasticity ~0.15GPa, compressive yield strength ~3MPa) and cytocompatibility after one day that was similar to that of wrought 316L stainless steel, which is a commonly used biomaterial. Based on the obtained results, SLM is a suitable method for the fabrication of porous 316L stainless steel scaffolds with highly porous structures.


Assuntos
Módulo de Elasticidade/efeitos dos fármacos , Ferro/farmacologia , Lasers , Teste de Materiais/métodos , Aço Inoxidável/farmacologia , Linhagem Celular Tumoral , Forma Celular , Humanos , Espectroscopia Fotoeletrônica , Porosidade , Propriedades de Superfície , Resistência à Tração/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA