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1.
J Mech Behav Biomed Mater ; 121: 104590, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34077907

RESUMO

Treatment the deeper and remineralizable carious zone (DRCZ) in dentin with various remineralizing methods, either with classic top-down or biomimetic bottom-up remineralization approaches, has remained a constant main issue to enhance dentin substrate bonding quality. The concern of remineralizing the remaining, partially demineralized and physiologically re-mineralizable collagen fibrils was the optimum target. However, applying already mineralized type I collage fibrils which have the ability to chemically cross-link with remaining collagen and minerals did not gain much interest. Synthesis of collagen/hydroxyapatite (Col/Hap) nanocomposite was done with self-assembling Hap in situ onto Col fibrils with different % (70/30, 50/50, 30/70% of Col/Hap, respectively). Micro-tensile bond strength (µTBS) was evaluated after pre-treatment of artificially demineralized dentin with these suggested protocols [nanocomposite together with grape seed extract (GSE; 6.5%) cross-linker for two periods, 10min and 1 h] then applying self-adhesive bonding system. Applied Col/Hap (30/70%) together with GSE (6.5%) gave the significantly highest µTBS (25.04 ± 5.47 and 25.53 ± 7.64 MPa, for 10min and 1 h application times, respectively). After thermocycling for 10,000 cycles at 5 and 55 °C, µTBS for all protocols and both application times substantially decreased especially for the two control groups. Using the suggested dentin pre-treatment protocols, in chair-side, may possibly enhance the bond strength to DRCZ and its durability.


Assuntos
Colagem Dentária , Nanocompostos , Colágeno , Dentina , Adesivos Dentinários , Durapatita , Teste de Materiais , Cimentos de Resina , Resistência à Tração
2.
J Genet Eng Biotechnol ; 19(1): 57, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33860859

RESUMO

BACKGROUND: Bio-nanotechnology is considered as one of the low-cost approaches that have been utilized in production of nanomaterials. The current research aimed at investigating the influence of different types of Actinomycete strains on the final properties of silver nanoparticles (AgNPs) such as size, shape, polydispersity, and antibacterial properties. For this purpose, the following techniques were employed UV spectrophotometer, SDS-PAGE electrophoresis, TEM, FTIR, antibacterial agar diffusion test, and Zetasizer. RESULTS: It was found that among 34 Streptomyces isolates collected from the soil, Streptomyces spiralis and Streptomyces rochei were able to reduce silver nitrate into sliver nanoparticles. The diversity and molecular weights of extracellular proteins secreted by these stains were different as proved by SDS-PAGE technique. This consequently resulted in differences in polydispersity of AgNPs which indicate that the sizes of AgNPs were highly dependent on the amount, molecular sizes, and diversity of extracellular matrix proteins of the microorganism. CONCLUSION: This article might give an insight about the importance of molecular sizes of biomacromolecules such as proteins on the physical properties of biogenic synthesized nanoparticles.

3.
Biotechnol Bioeng ; 117(6): 1789-1804, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32068251

RESUMO

During evolution, sponges (Porifera) have honed the genetic toolbox and biosynthetic mechanisms for the fabrication of siliceous skeletal components (spicules). Spicules carry a protein scaffold embedded within biogenic silica (biosilica) and feature an amazing range of optical, structural, and mechanical properties. Thus, it is tempting to explore the low-energy synthetic pathways of spiculogenesis for the fabrication of innovative hybrid materials. In this synthetic biology approach, the uptake of multifunctional nonbiogenic nanoparticles (fluorescent, superparamagnetic) by spicule-forming cells of bioreactor-cultivated sponge primmorphs provides access to spiculogenesis. The ingested nanoparticles were detected within intracellular vesicles resembling silicasomes (silica-rich cellular compartments) and as cytosolic clusters where they lent primmorphs fluorescent/magnetic properties. During spiculogenesis, the nanoparticles initially formed an incomplete layer around juvenile, intracellular spicules. In the mature, extracellular spicules the nanoparticles were densely arranged as a surface layer that rendered the resulting composite fluorescent and magnetic. By branching off the conventional route of solid-state materials synthesis under harsh conditions, a new pathway has been opened to a versatile platform that allows adding functionalities to growing spicules as templates in living cells, using nonbiogenic nanoscale building blocks with multiple functionalities. The magnet-assisted alignment renders this composite with its fluorescent/magnetic properties potentially suitable for application in biooptoelectronics and microelectronics (e.g., microscale on-chip waveguides for applications of optical detection and sensing).


Assuntos
Corantes Fluorescentes/química , Imãs/química , Poríferos/química , Poríferos/crescimento & desenvolvimento , Dióxido de Silício/química , Animais , Reatores Biológicos , Corantes Fluorescentes/metabolismo , Nanopartículas Magnéticas de Óxido de Ferro/química , Poríferos/metabolismo , Dióxido de Silício/metabolismo , Biologia Sintética/métodos
4.
Nanomedicine (Lond) ; 15(4): 337-353, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31950875

RESUMO

Aim: Previously, different results have been achieved regarding effects of silver nanoparticles (Ag NPs) on osteogenesis of stem cells and the mechanisms have not been disclosed yet, which are quite important for potential application of Ag NPs in bone reconstruction. Materials & methods: Effects of Ag NPs on osteogenesis of human mesenchymal stem cells (hMSCs) with underlying mechanisms were investigated. Results: Ag NPs at 2.5 and 5 µg/ml increased osteogenic proteins expression and mineralization of hMSCs. Meanwhile, autophagy was activated by Ag NPs and it could be inhibited by 3-methyladenine. Furthermore, osteogenesis induced by Ag NPs could also be reversed by 3-methyladenine. Conclusion: These findings suggest that autophagy is involved in stimulating osteogenesis of hMSCs induced by Ag NPs.


Assuntos
Nanopartículas Metálicas/química , Prata/química , Autofagia/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Prata/farmacologia
5.
Heliyon ; 5(12): e02986, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31886428

RESUMO

Formation of bacterial biofilm on indwelling urinary catheters usually causes catheter-associated urinary tract infections (CAUTIs) that represent high percent of nosocomial infections worldwide. Therefore, coating urinary catheter with antibacterial and antifouling coating using facile technique is in great demand. In this study, commercial urinary catheter was coated with a layer of the self-polymerized polydopamine which acts as active platform for the in situ formation of silver nanoparticle (AgNPs) on catheter surface. The formed coating was intensively characterized using spectroscopic and microscopic techniques. The coated catheter has the potential to release silver ion in a sustained manner with a concentration of about 2-4 µg ml-1. Disk diffusion test and colony forming unites assay verified the significant bactericidal potential of the AgNPs coated catheter against both gram-positive and gram-negative bacteria as a consequence of silver ion release. In contrast to commercial catheter, the AgNPs coated catheter prevented the adherence of bacterial cells and biofilm formation on their surfaces. Interestingly, scanning electron microscope investigations showed that AgNPs coated catheter possess greater antifouling potential against gram-positive bacteria than against gram-negative bacteria. Overall, the remarkable antibacterial and antifouling potential of the coated catheter supported the use of such facile approach for coating of different medical devices for the prevention of nosocomial infections.

6.
Colloids Surf B Biointerfaces ; 171: 276-284, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30041151

RESUMO

The implant materials with proper anti-inflammatory and osteogenic properties may be promising for orthopedic applications. The inflammatory response induced by biomaterials has been regarded as one of the critical factors in determining in vivo fate of implants. Therefore, a novel bone biomaterial should have inflammation regulatory effects instead of being completely bio-inert. In the present work, the inflammation regulatory effects of exogenous magnesium (Mg) ions were investigated. Under the stimulation of lipopolysaccharide (LPS), macrophages exposed to Mg2+ exhibited down-regulated gene expressions of M1 markers (CD86, CD11c and inducible nitric oxide synthase (iNOS)) and pro-inflammatory cytokines (tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1ß), up-regulated gene expression of M2 marker CD163 and decreased TNF-α release, indicating that Mg2+ could switch macrophages from M1 to M2 phenotype. Thereafter, micro-arc oxidation (MAO) technique was employed to fabricate Mg-containing ceramic coatings on titanium substrates. Macrophages grown on Mg-containing surface were switched from M1 to M2 phenotype with the stimulation of LPS, evidenced by suppressed gene expressions of M1 markers (CD86, CD11c and iNOS) and pro-inflammatory cytokines (TNF-α and IL-1ß), promoted gene expression of M2 marker CD163 and decreased TNF-α release. Moreover, gene expressions of bone morphogenetic protein-2 (BMP-2), BMP-6 and vascular endothelial growth factor (VEGF) were up-regulated on Mg incorporated MAO surface without LPS stimulation. Together, Mg could be used as an anti-inflammatory agent for suppressing inflammation and mediating osteogenesis. The integration of Mg in biomaterials could endow bone biomaterials with anti-inflammatory property.


Assuntos
Inflamação/tratamento farmacológico , Macrófagos/efeitos dos fármacos , Magnésio/farmacologia , Titânio/farmacologia , Adsorção , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Inflamação/metabolismo , Macrófagos/metabolismo , Magnésio/química , Camundongos , Tamanho da Partícula , Porosidade , Células RAW 264.7 , Propriedades de Superfície , Titânio/química
7.
Colloids Surf B Biointerfaces ; 170: 242-250, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-29933233

RESUMO

The implant materials with both osteogenic and anti-bacterial properties are promising for orthopedic and dental applications. Moreover, the inflammatory response induced by biomaterials has been recently recognized as one of the critical factors in determining implantation fate. A new generation of implant materials should have modulatory effects on the local inflammatory environment such that it favors osteogenesis and osteointegration instead of being bio-inert. In this study, the micro-arc oxidation (MAO) technique was employed to fabricate Cu-containing ceramic coatings on titanium substrates. The macrophages cultured on Cu-containing MAO-fabricated surfaces were polarized to M1 phenotype, evidenced by the high expression levels of inducible nitric oxide synthase (iNOS), low expression levels of arginase1 (Arg1), enhanced pro-inflammatory cytokine interleukin-6 (IL-6) release and inhibited IL-4 and IL-10 (anti-inflammatory cytokines) release. The MAO-treated surface incorporated with larger amounts of Cu (referred as Cu(h)-MAO) could modulate a favorable inflammatory microenvironment for osteoblast-like cell differentiation. Moreover, the macrophages cultured on Cu(h)-MAO surface exhibited enhanced bacteria uptake and killing rate, indicating that the Cu(h)-MAO surface promoted the bactericidal capacity of macrophages. Together, Cu could be used as a promising modulatory agent for macrophage functions. The integration of Cu in biomaterials could lead to enhanced macrophage-mediated osteogenesis and bactericidal capacity.


Assuntos
Materiais Revestidos Biocompatíveis/farmacologia , Cobre/farmacologia , Macrófagos/efeitos dos fármacos , Titânio/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Materiais Revestidos Biocompatíveis/química , Cobre/química , Citocinas/biossíntese , Inflamação/metabolismo , Macrófagos/metabolismo , Camundongos , Oxirredução , Tamanho da Partícula , Células RAW 264.7 , Propriedades de Superfície , Titânio/química
8.
Colloids Surf B Biointerfaces ; 169: 49-59, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29747030

RESUMO

It is known that good mechanical properties, low modulus to reduce stress-shielding effect, favorable osteogenic activity and limited inflammatory response are critical factors for orthopedic implants to induce excellent osteointegration. In this study, Ti-20% Ta metal-metal composite (referred as Ti-Ta) which consisted of Ti- and Ta-rich phases was fabricated via the strategy of powder metallurgy. Micro-arc oxidation (MAO) was employed to modify the surface of Ti-Ta composite. The surfaces of Ti-Ta composite after MAO treatment at an applied voltage of 250 (referred as MAO-250 V) or 300 V (referred as MAO-300 V) exhibited three distinct zones with significantly different morphological features and surface chemistry. Osteoblast-like SaOS-2 cells were found to be preferential to attach on the Ta-rich phase and its surrounding areas, exhibiting an area-dependent adhesion tendency. However, the attachment of Raw 264.7 macrophages was found to be insensitive to the surface characteristics. The proliferation and differentiation of SaOS-2 cells cultured on various surfaces basically followed the trend: MAO-modified surfaces > Ti-Ta surface > Ti surface. The Ti-Ta and MAO-modified surfaces were found to inhibit the inflammatory response and polarize macrophages to anti-inflammatory M2 phenotype compared to Ti surface. Moreover, the microenvironments created by Ti-Ta, MAO-250 V and MAO-300 V/macrophage interactions promoted the proliferation and differentiation of SaOS-2 cells compared to that created by Ti/macrophage interactions. MAO-300 V surface exhibited further enhanced positive osteo-immunomodulatory effects compared to Ti-Ta surface. Together, the Ti-20% Ta metal-metal composite modified by MAO at an applied voltage of 300 V is considered as a promising implant material for orthopedic applications.


Assuntos
Materiais Revestidos Biocompatíveis/farmacologia , Inflamação/tratamento farmacológico , Osteogênese/efeitos dos fármacos , Animais , Cálcio/química , Cálcio/farmacologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Materiais Revestidos Biocompatíveis/química , Citocinas/biossíntese , Humanos , Camundongos , Tamanho da Partícula , Células RAW 264.7 , Silício/química , Silício/farmacologia , Propriedades de Superfície , Tantálio/química , Tantálio/farmacologia , Titânio/química , Titânio/farmacologia
9.
Biomed Mater ; 13(4): 045013, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29657156

RESUMO

Osteoblastic lineage cells are commonly used to evaluate the in vitro osteogenic ability of bone biomaterials. However, contradictory results obtained from in vivo and in vitro studies are not uncommon. With the increasing understanding of osteoimmunology, the immune response has been recognized as playing an important role in bone regeneration. In this study, we examined the effect of submicron-scaled titanium surface roughness (ranging from approximately 100 to 400 nm) on the response of osteoblasts and macrophages. The results showed that osteoblast differentiation enhanced with increased surface roughness of titanium substrates. The cytoskeleton of macrophages altered with the variation in titanium surface roughness. The production of cytokines (TNF-α, IL-6, IL-4 and IL-10) could be regulated by titanium surface roughness. Moreover, macrophages cultured on titanium surfaces exhibited a tendency to polarize to M1 phenotype with the increase of surface roughness. Material/macrophage conditioned medium tended to promote osteoblast differentiation with the increase of surface roughness. The results indicate that increasing surface roughness in the submicron range is beneficial for osteogenesis via modulating the immune response of macrophages. Modifying biomaterial surfaces based on their immunomodulatory effects is considered as a novel strategy for the improvement of their biological performance.


Assuntos
Macrófagos/imunologia , Osteogênese/efeitos dos fármacos , Titânio/química , Fosfatase Alcalina/metabolismo , Animais , Materiais Biocompatíveis/química , Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/patologia , Diferenciação Celular/efeitos dos fármacos , Linhagem da Célula , Proliferação de Células , Colágeno/química , Meios de Cultivo Condicionados , Citocinas/metabolismo , Humanos , Sistema Imunitário , Camundongos , Osteoblastos/citologia , Fenótipo , Células RAW 264.7 , Propriedades de Superfície
10.
J Biomed Mater Res A ; 106(7): 1896-1902, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29520936

RESUMO

To improve the success of medical devices, implants with strong surface bioactivity are urgently required. Coatings with a macroporous structure produced by micro-arc oxidation possess advantages, such as strong adhesion to substrate and excellent resistance to wear and corrosion. Mesoporous structures contain pores with sizes of 2-50 nm, which can endow the biomaterials with the ability to enhance osteogenesis and to be loaded with diverse drugs. Thus, in this study, we aimed to evaluate the effects of both macroporous and mesoporous structures using a hierarchical macro/mesoporous structure to modify the titanium implant surface. The behaviors of SaOS-2 human osteosarcoma cells on the macro/mesoporous structure, including initial adhesion, proliferation, alkaline phosphatase (ALP) activity, and collagen secretion, were investigated. Cells that attached on the macro/mesoporous surface showed the highest cell numbers and greatest spreading area after incubation for 1, 2, and 4 h compared with the polished smooth substrate and macroporous surface in the presence of fetal bovine serum (FBS). However, in the absence of FBS, cell adhesion on the polished substrate, macroporous structure, and macro/mesoporous structure did not differ significantly. Cell proliferation on the macroporous and macro/mesoporous surfaces increased compared with that on the smooth substrate surface. Furthermore, ALP activity and collagen secretion were enhanced on the macro/mesoporous structure. Our findings provided important insights into the cellular responses to macro/mesoporous structures in the field of implant surface modification. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1896-1902, 2018.


Assuntos
Osteoblastos/citologia , Adesão Celular , Diferenciação Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Proliferação de Células , Forma Celular , Citoesqueleto/metabolismo , Humanos , Osteoblastos/ultraestrutura , Oxirredução , Porosidade , Propriedades de Superfície
11.
Biochem Biophys Rep ; 11: 161-173, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28955781

RESUMO

The mesencephalic astrocyte-derived neurotrophic factor (MANF) belongs to a recently discovered family of neurotrophic factors. MANF can be secreted but is generally resident within the endoplasmic reticulum (ER) in neuronal and non-neuronal cells, where it is involved in the ER stress response with pro-survival effects. Here we report the discovery of the MANF homolog SDMANF in the sponge Suberites domuncula. The basal positioning of sponges (phylum Porifera) in the animal tree of life offers a unique vantage point on the early evolution of the metazoan-specific genetic toolkit and molecular pathways. Since sponges lack a conventional nervous system, SDMANF presents an enticing opportunity to investigate the evolutionary ancient role of these neurotrophic factors. SDMANF shares considerable sequence similarity with its metazoan homologs. It also comprises a putative protein binding domain with sequence similarities to the Bcl-2 family of apoptotic regulators. In Suberites, SDMANF is expressed in the vicinity of bacteriocytes, where it co-localizes with the toll-like receptor SDTLR. In transfected human cells, SDMANF was detected in both the organelle protein fraction and the cell culture medium. The intracellular SDMANF protein level was up-regulated in response to both a Golgi/ER transport inhibitor and bacterial lipopolysaccharides (LPS). Upon LPS challenge, transfected cells revealed a decreased caspase-3 activity and increased cell viability with no inducible Bax expression compared to the wild type. These results suggest a deep evolutionary original cytoprotective role of MANF, at the crossroads of innate immune and apoptotic pathways, of which a neurotrophic function might have arisen later in metazoan evolution.

12.
Mater Sci Eng C Mater Biol Appl ; 78: 443-451, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28576007

RESUMO

A dual-layer TiO2 surface with hierarchical macro and mesoporous structure was prepared by a combinational approach of micro-arc oxidation followed by evaporation-induced self-assembly of nano-crystallites. The mesoporous layer contains pores with an average size of <10nm and consists of anatase TiO2 nanocrystallites. The dual-layer hierarchical macro/mesoporous structured TiO2 surface improves the hydrophilicity and fibronectin adsorption ability in comparison with the sole macroporous or smooth TiO2 surface. With the formation of an additional mesoporous layer on macroporous TiO2 surface, the attached number of human osteogenic sarcoma cells (SaOS-2) increases in the initial incubation of 4h but it does not show significant difference after 24h compared to that attached on the macroporous or smooth surfaces. Whereas, it was noticed that SaOS-2 cells have larger spread area and more stress fibers on the macro/mesoporous structured surface than those on the other surfaces. To understand the intracellular mechanism of the initial cell adhesion on the macro/mesoporous surface, the Rho/ROCK pathway was investigated to reveal the topography-induced biological functions by introducing the ROCK inhibitor Y-27632 during cell culture. In the presence of Y-27632, cells on the macroporous surface and macro/mesoporous surface both show stellate appearance, with poor assembly stress fibers and long cell membrane protrusions. Cells on the smooth surface have larger spread areas compared to the former two surfaces. And the attached cells significantly reduced but there are no differences among the three surfaces. It reveals that the ROCK inhibitor invalidates the promotion of initial cell adhesion on the macro/mesoporous structure. This study may shed light on the mechanism behind the enhancement effect of macro/mesoporous structure for initial cell adhesion.


Assuntos
Osteoblastos , Amidas , Adesão Celular , Humanos , Porosidade , Piridinas , Titânio
13.
Mater Sci Eng C Mater Biol Appl ; 67: 195-204, 2016 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-27287114

RESUMO

The aims of the present study were to develop boron-incorporated TiO2 coating (B-TiO2 coating) through micro-arc oxidation (MAO) and subsequently evaluate the effect of boron incorporation on the in vitro biological performance of the coatings. The physicochemical properties of B-TiO2 coating and its response to osteoblast like cells (SaOS-2) were investigated compared to the control group without boron (TiO2 coating). The morphological and X-ray diffraction results showed that both coatings exhibited similar surface topography and phase composition, respectively. However, the incorporation of B led to an enhancement in the surface hydrophilicity of B-TiO2 coating. The spreading of SaOS-2 cells on B-TiO2 coating was faster than that on TiO2 coating. The proliferation rate of SaOS-2 cells cultured on B-TiO2 decreased after 5days of culture compared to that on TiO2 coating. SaOS-2 cells cultured on B-TiO2 coating exhibited an enhanced alkaline phosphatase (ALP) activity, Collagen I synthesis and in vitro mineralization compared to those on TiO2 coating. The present findings suggest that B-TiO2 coating is a promising candidate surface for orthopedic implants.


Assuntos
Boro/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Teste de Materiais/métodos , Titânio/farmacologia , Actinas/metabolismo , Fosfatase Alcalina/metabolismo , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Fluorescência , Imunofluorescência , Humanos , Oxirredução , Porosidade , Difração de Raios X
14.
J Biomed Nanotechnol ; 12(3): 525-35, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27280250

RESUMO

With the combined use of silver nanoparticles (Ag NPs) and human bone marrow derived mesenchymal stem cells (hMSCs) in bone tissue engineering, more knowledge of the effects of Ag NPs on hMSCs is required. Up to date, researches mainly focused on the cytotoxicity and genotoxicity of Ag NPs, only few studies discussed their influence on the differentiation of stem cells, especially adipogenic differentiation. In the present study, we investigated the in vitro uptake of 30 nm PVP-coated Ag NPs in hMSCs and their effects on cell viability, cell morphology and adipogenic differentiation of hMSCs. HMSCs were exposed to Ag NPs at concentrations of 25 and 50 µg/mL for 24 hours and at concentrations of 5 and 10 µg/mL throughout the whole differentiation period. Results of cell viability showed that Ag NPs caused time- and dose-dependent toxicity in hMSCs. Transmission electron microscopy (TEM) confirmed the uptake of Ag NPs into cytoplasm of hMSCs. No influence on cell morphology was observed. The 30 nm sized Ag NPs had no effects on adiponectin secretion, lipid droplet formation and the expression of adipogenic marker genes. It is concluded that under our experimental conditions, 30 nm PVP-coated Ag NPs do not influence the adipogenic differentiation of hMSCs in vitro. The present results provide a reference for the usage of 30 nm Ag NPs in the presence of hMSCs in bone tissue engineering.


Assuntos
Adipócitos/efeitos dos fármacos , Adipócitos/patologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/patologia , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Adipogenia/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Células Cultivadas , Humanos , Teste de Materiais , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Tamanho da Partícula
15.
Bioprocess Biosyst Eng ; 39(9): 1477-86, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27151092

RESUMO

The fundamental mechanisms of biomineralization and their translation into innovative synthetic approaches have yielded promising perspectives for the fabrication of biomimetic and bioinspired organic-inorganic hybrid materials. In siliceous sponges, the enzyme silicatein catalyzes the polycondensation of molecular precursors to nano-structured SiO2 that is deposited on self-assembled filaments consisting of the two silicatein isoforms (silicatein-α and -ß) and the scaffold protein silintaphin-1. Due to its broad substrate specificity silicatein is also able to convert in vitro various other precursors to non-biogenic materials (e.g., hydrolysis of titanium bis(ammonium lactato)-dihydroxide [TiBALDH] and subsequent polycondensation to titania [TiO2]). In the present approach, silicatein was bioengineered to carry a protein tag (Arg-tag) that confers binding affinity to TiO2. Then, by combining Arg-tagged silicatein-α with silicatein-ß and silintaphin-1, self-assembled branched hybrid protein microfilaments were fabricated. Upon subsequent incubation with TiBALDH the filaments were decorated with TiO2 and assayed for photocatalytic activity through photodegradation of the dye methylene blue. This is the first approach that considers concomitant application of two silicatein isoforms for the synthesis of bioinspired organic-inorganic hybrid materials. It is also the first time that the biocatalytic activity of the enzymes has been combined with both the structure-providing properties of silintaphin-1 and a TiO2 affinity protein tag to fabricate self-assembled branched protein filaments as template for a silicatein-synthesized TiO2 photocatalyst. The TiO2-decorated filaments might be explored as a practical alternative to approaches where biotemplates have to be laboriously isolated from their original biological source prior to TiO2 immobilization.


Assuntos
Catepsinas/química , Nanopartículas Metálicas/química , Titânio/química , Marcadores de Afinidade , Catálise , Eletroforese em Gel de Poliacrilamida , Processos Fotoquímicos
16.
Colloids Surf B Biointerfaces ; 145: 37-45, 2016 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-27137801

RESUMO

Coating the surfaces of titanium-based implants with appropriate hierarchical micro/nano-topographies resembling the structure of natural bone significantly enhances their biological performance. However, the relationship between nanostructures surfaces and their effects on modulating cellular response is not clearly understood. Moreover, it is not clear whether the surface chemistry or topography is the main factor on modulating cellular behavior, because the commonly used surface modification techniques for titanium-based implants simultaneously modify surface topography and chemistry. The aim of this study is to investigate osteoblast-like cell adhesion, proliferation and differentiation on hierarchical micro/nano-topographies with similar surface chemistry but different nano-scale features. Micro-arc oxidation and post hydrothermal treatment were employed to fabricate micro/nano-topographies on titanium. According to the morphological features, they were classified as microcrater (micro-topography), nanoplate (hierarchical topography with nanoplates) and nanoleaf (hierarchical topography with nanoleaves). The response of osteoblast like cells (SaOS-2) was studied on each surface after sputtering with a thin layer of gold (Au) to minimize the influence of surface chemistry. The morphological evaluation after histochemical staining revealed that the adherent cells were polygonal-shaped on microcrater surface, roundish on nanoplate surface and elongated on nanoleaf surface. Additionally, compared to microcrater surface, nanoplate surface slowed down cell proliferation and exhibited no enhancement on cell differentiation. However, nanoleaf surface supported cell proliferation and promoted cell differentiation. The results indicate that tuning morphological features of nanostructures on micro-topography can serve as a promising strategy to specifically modulate cellular response, such as cell morphology, proliferation, differentiation and mineralization.


Assuntos
Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Osteoblastos/citologia , Materiais Biocompatíveis/química , Linhagem Celular Tumoral , Humanos , Nanoestruturas/química , Osteoblastos/fisiologia , Propriedades de Superfície , Titânio/química
17.
J Mater Chem B ; 4(8): 1466-1479, 2016 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32263113

RESUMO

Silver nanoparticle (AgNP) based antibacterial surfaces were fabricated using plasma polymerization technology and their effects on differentiation of human bone-marrow derived mesenchymal stem cells (hMSCs) were investigated in this study. The results showed that AgNP coated surfaces do not affect the initial adhesion, spreading and proliferation of hMSCs. Furthermore, the silver coated surface promoted adipogenic differentiation of hMSCs as demonstrated by more accumulation of lipid droplets and upregulation of adipogenesis-related genes such as peroxisome proliferator activated receptor gamma (PPARγ), adipocyte determination and differentiation factor (ADD1) and CCAAT/enhancer binding protein alpha (C/EBPα). In addition, silver incorporation activated the expression of antioxidant enzymes as a consequence of the accumulation of intracellular reactive oxygen species (ROS) in adipogenic induced cells, which was correlated with the enhanced adipogenic capacity of hMSCs. ROS generation was enhanced due to silver ion release and consequently reduced osteogenesis at the early stage after 7 days of osteogenic induction as a result of reducing alkaline phosphatase (ALP) activity. However, the differentiation and mineralization capacity of osteoblasts were restored after 14 days of osteogenic induction, which indicated that adipogenesis favors intracellular ROS accumulation mediated by silver coatings compared to osteogenesis. None of the osteogenic related genes was affected by ROS mediated by AgNP dissolution. The findings in this work are instructive for the use of silver as an antibacterial agent in the areas of tissue engineering, stem cell therapies and implantable biomedical devices.

18.
Mater Sci Eng C Mater Biol Appl ; 60: 308-316, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26706535

RESUMO

In the current work, TiO2/silicate hierarchical coatings with various nanostructure morphologies were successfully prepared on titanium substrates through micro-arc oxidation (MAO) and subsequent hydrothermal treatment (HT). Moreover, the nucleation mechanism and growth behavior of the nanostructures, hydrophilicity, protein adsorption and apatite-inducing ability of various coatings were also explored. The novel TiO2/silicate hierarchical coatings comprised calcium silicate hydrate (CSH) as an outer-layer and TiO2 matrix as an inner-layer. According to the morphological features, the nanostructures were classified as nanorod, nanoplate and nanoleaf. The morphology, degree of crystallinity and crystalline phases of CSH nanostructures could be controlled by optimizing the HT conditions. The nucleation of CSH nanostructures is caused by release and re-precipitation mechanism. The TiO2/CSH hierarchical coatings exhibited some enhanced physical and biological performances compared to MAO-fabricated coating. The improvement of the hydrophilicity, fibronectin adsorption and apatite-inducing ability was found to be morphological dependent according to the following trend: nanoleaf coating>nanoplate coating>nanorod coating>MAO coating. The results indicate that the tuning of physical and morphological properties of nanostructures coated on biomaterial surface could significantly influence the hydrophilicity, protein adsorption and in vitro bioactivity of biomaterial.


Assuntos
Materiais Revestidos Biocompatíveis/química , Silicatos/química , Titânio/química , Compostos de Cálcio/química , Propriedades de Superfície
19.
Colloids Surf B Biointerfaces ; 134: 169-77, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26196089

RESUMO

Recently, surface micron/nano-topographical modifications have attracted a great deal of attention because it is capable of mimicking the hierarchical characteristics of bone. In the current work, a novel titania/calcium silicate hydrate (CSH) bi-layer coating with hierarchical surface topography was successfully prepared on titanium substrate through micro-arc oxidation (MAO) and subsequent hydrothermal treatment (HT). MAO treatment could lead to a micron-scale topographical surface with numerous crater-like protuberances. The subsequent HT process enables the in situ nucleation and growth of CSH nanoplates on MAO-fabricated titania surface. The nucleation of CSH nanoplates is considered to follow a dissolution-precipitation mechanism. Compared to MAO-fabricated coating with single-scale surface topography, MAO-HT-fabricated coating with hierarchical surface topography exhibits enhanced hydrophilicity, fibronectin adsorption and initial MG-63 cell attachment. The process of cell-material interactions is considered to be triggered by surface properties of the coated layer and indirectly mediated by protein adsorption on coating surface. These results suggest that MAO-HT treatment is an efficient way to prepare coatings with hierarchical surface topography on titanium surface, which is essential for altering protein adsorption and initial cell attachment.


Assuntos
Compostos de Cálcio/química , Materiais Revestidos Biocompatíveis , Silicatos/química , Titânio/química , Adsorção , Linhagem Celular , Humanos , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Proteínas/química
20.
Acta Biomater ; 10(10): 4456-64, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24998774

RESUMO

Several attempts have been made in the past to fabricate hybrid materials that display the complementary properties of the polyester polycaprolactone (PCL) and the polysaccharide chitosan (CHS) for application in the field of bone regeneration and tissue engineering. However, such composites generally have no osteogenic activity per se. Here we report the synthesis of a chitosan-graft-polycaprolactone (CHS-g-PCL) and its subsequent characterization, including crystallinity, chemical structure and thermal stability. Upon surface-functionalization of CHS-g-PCL with osteogenic biosilica via the surface-immobilized enzyme silicatein, protein adsorption, surface morphology and wettability were assessed. Finally, the cultivation of osteoblastic SaOS-2 cells on the surface-functionalized CHS-g-PCL was followed by analyses of cell viability, mineral deposition and alkaline phosphatase activity. These characterizations revealed a composite that combines the versatile properties of CHS-g-PCL with the osteogenic activity of the silicatein/biosilica coating and, hence, represents an innovative alternative to conventionally used CHS/PCL composites for biomedical applications, where stable bone-material interfaces are required.


Assuntos
Regeneração Óssea/efeitos dos fármacos , Quitosana , Materiais Revestidos Biocompatíveis , Osteoblastos/metabolismo , Osteogênese/efeitos dos fármacos , Poliésteres , Dióxido de Silício , Fosfatase Alcalina/metabolismo , Linhagem Celular Tumoral , Quitosana/química , Quitosana/farmacologia , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Humanos , Osteoblastos/citologia , Poliésteres/química , Poliésteres/farmacologia , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Engenharia Tecidual/métodos
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