scholarly journals Preparation and Preliminary Evaluation of Silver-Modified Anodic Alumina for Biomedical Applications

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 51
Author(s):  
Denitsa Kiradzhiyska ◽  
Nikolina Milcheva ◽  
Rositsa Mancheva ◽  
Tsvetelina Batsalova ◽  
Balik Dzhambazov ◽  
...  
Keyword(s):  
Biomedical Application ◽  
Pure Aluminum ◽  
Human Fibroblasts ◽  
Cell Monolayer ◽  
Anodic Alumina ◽  
Silver Coating ◽  
Specific Method ◽  
Preliminary Evaluation ◽  
Silver Deposition ◽  
Nih 3T3

The present study reports a specific method for preparation of silver-modified anodic alumina substrates intended for biomaterial applications. Al2O3 coatings were obtained by anodization of technically pure aluminum alloy in sulfuric acid electrolyte. Silver deposition into the pores of the anodic structures was carried out employing in situ thermal reduction for different time periods. The obtained coatings were characterized using scanning electron microscopy (SEM), potentiodynamic scanning after 168 h in 3.5% NaCl solution and bioassays with human fibroblast and NIH/3T3 cell lines. The modified alumina substrates demonstrated better biocompatibility compared to the control anodic Al2O3 pads indicated by increased percent cell survival following in vitro culture with human and mouse fibroblasts. The Ag-deposition time did not affect considerably the biocompatibility of the investigated anodic layers. SEM analyses indicated that mouse NIH/3T3 cells and human fibroblasts adhere to the silver-coated alumina substrates retaining normal morphology and ability to form cell monolayer. Therefore, the present studies demonstrate that silver coating of anodic alumina substrates improves their biocompatibility and their eventual biomedical application.

Metallographic effects of pure aluminum on properties of nanoporous anodic alumina (NPAA)

2013 ◽  
Vol 45 (10) ◽  
pp. 1490-1496 ◽  
Author(s):  
Fereshteh Rashidi ◽  
Tatsuya Masuda ◽  
Hidetaka Asoh ◽  
Sachiko Ono
Keyword(s):  
Pure Aluminum ◽  
Anodic Alumina ◽  
Nanoporous Anodic Alumina

THE EFFECT OF ALUMINUM ELECTROPOLISHING ON NANO-PORES ARRANGEMENT IN ANODIC ALUMINA MEMBRANES

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3267-3277 ◽  
Author(s):  
M. H. RAHIMI ◽  
S. H. TABAIAN ◽  
S. P. HOVEYDA MARASHI ◽  
M. AMIRI ◽  
M. M. DALALY ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Pure Aluminum ◽  
Optical Microscope ◽  
Anodic Alumina ◽  
The Other ◽  
Sem Images ◽  
Current Time ◽  
Nanoporous Anodic Alumina ◽  
Alumina Membranes ◽  
Stress Relieving

Surface conditions of aluminum can influence the final arrangement of nano-pores in fabrication of ordered nanoporous anodic alumina membranes (AAMs). This study is mainly focused on the different applied voltages of aluminum electropolishing by keeping all the other parameters constant. After heat treatment (stress relieving and annealing at 500°C) of pure aluminum sheets, the samples were electropolished at different voltages (10-60V) to obtain desirable surface smoothness, while the temperature of the container was kept constant. The current-time curves were recorded during electropolishing process. The surface roughness obtained in each applied voltage was examined using optical microscope and atomic force microscope (AFM). The process was followed by two-step anodization in order to reach ordered nano-pores. Finally, the influence of surface roughness on regularity of nano-pores was observed using scanning electron microscope (SEM). The SEM images were analyzed to investigate the morphology and the degree of self ordering of pores of the samples by using a new designed analytical method aiming MATLAB and fast Fourier transform (FFT) technique. It was concluded that the electropolishing voltage and the resulted surface roughness and also formed defects can competitively affect the arrangement of membrane's nano-pores. A desired smoothness obtained from electropolishing voltage of 30V. Also 40V provided the best order with respect to the other voltages.

scholarly journals Analysis of Nitric Oxide-Stabilized mRNAs in Human Fibroblasts Reveals HuR-Dependent Heme Oxygenase 1 Upregulation

2009 ◽  
Vol 29 (10) ◽  
pp. 2622-2635 ◽  
Author(s):  
Yuki Kuwano ◽  
Ariel Rabinovic ◽  
Subramanya Srikantan ◽  
Myriam Gorospe ◽  
Bruce Demple
Keyword(s):  
Nitric Oxide ◽  
Heme Oxygenase ◽  
Rna Binding ◽  
De Novo ◽  
Human Fibroblasts ◽  
Heme Oxygenase 1 ◽  
Protein Levels ◽  
3T3 Fibroblasts ◽  
The Stability ◽  
Nih 3T3

ABSTRACT We previously observed that nitric oxide (NO) exposure increases the stability of mRNAs encoding heme oxygenase 1 (HO-1) and TIEG-1 in human and mouse fibroblasts. Here, we have used microarrays to look broadly for changes in mRNA stability in response to NO treatment. Using human IMR-90 and mouse NIH 3T3 fibroblasts treated with actinomycin D to block de novo transcription, microarray analysis suggested that the stability of the majority of mRNAs was unaffected. Among the mRNAs that were stabilized by NO treatment, seven transcripts were found in both IMR-90 and NIH 3T3 cells (CHIC2, GADD45B, HO-1, PTGS2, RGS2, TIEG, and ID3) and were chosen for further analysis. All seven mRNAs showed at least one hit of a signature motif for the stabilizing RNA-binding protein (RBP) HuR; accordingly, ribonucleoprotein immunoprecipitation analysis revealed that all seven mRNAs associated with HuR. In keeping with a functional role of HuR in the response to NO, a measurable fraction of HuR increased in the cytoplasm following NO treatment. However, among the seven transcripts, only HO-1 mRNA showed a robust increase in the level of its association with HuR following NO treatment. In turn, HO-1 mRNA and protein levels were significantly reduced when HuR levels were silenced in IMR-90 cells, and they were elevated when HuR was overexpressed. In sum, our results indicate that NO stabilizes mRNA subsets in fibroblasts, identify HuR as an RBP implicated in the NO response, reveal that HuR alone is insufficient for stabilizing several mRNAs by NO, and show that HO-1 induction by NO is regulated by HuR.

scholarly journals Comparison of commercial RT-PCR diagnostic kits for COVID-19

2020 ◽  
Author(s):  
Puck B. van Kasteren ◽  
Bas van der Veer ◽  
Sharon van den Brink ◽  
Lisa Wijsman ◽  
Jørgen de Jonge ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Cross Reactivity ◽  
Molecular Diagnostic ◽  
Clinical Samples ◽  
Specific Method ◽  
Preliminary Evaluation ◽  
Rt Pcr ◽  
Accurate Identification ◽  
Clinical Sensitivity ◽  
Pcr Efficiency

ABSTRACTThe final months of 2019 witnessed the emergence of a novel coronavirus in the human population. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has since spread across the globe and is posing a major burden on society. Measures taken to reduce its spread critically depend on timely and accurate identification of virus-infected individuals by the most sensitive and specific method available, i.e. real-time reverse transcriptase PCR (RT-PCR). Many commercial kits have recently become available, but their performance has not yet been independently assessed.The aim of this study was to compare basic analytical and clinical performance of selected RT-PCR kits from seven different manufacturers (Altona Diagnostics, BGI, CerTest Biotec, KH Medical, PrimerDesign, R-Biopharm AG, and Seegene).We used serial dilutions of viral RNA to establish PCR efficiency and estimate the 95% limit of detection (LOD95%). Furthermore, we ran a panel of SARS-CoV-2-positive clinical samples (n=16) for a preliminary evaluation of clinical sensitivity. Finally, we used clinical samples positive for non-coronavirus respiratory viral infections (n=6) and a panel of RNA from related human coronaviruses to evaluate assay specificity.PCR efficiency was ≥96% for all assays and the estimated LOD95% varied within a 6-fold range. Using clinical samples, we observed some variations in detection rate between kits. Importantly, none of the assays showed cross-reactivity with other respiratory (corona)viruses, except as expected for the SARS-CoV-1 E-gene.We conclude that all RT-PCR kits assessed in this study may be used for routine diagnostics of COVID-19 in patients by experienced molecular diagnostic laboratories.

scholarly journals Staggered Herringbone Microfluid Device for the Manufacturing of Chitosan/TPP Nanoparticles: Systematic Optimization and Preliminary Biological Evaluation

2019 ◽  
Vol 20 (24) ◽  
pp. 6212 ◽  
Author(s):  
Enrica Chiesa ◽  
Antonietta Greco ◽  
Federica Riva ◽  
Elena Maria Tosca ◽  
Rossella Dorati ◽  
...  
Keyword(s):  
Sodium Tripolyphosphate ◽  
Biomedical Application ◽  
Diffusion Mechanism ◽  
Chitosan Nanoparticles ◽  
Human Mesenchymal Stem Cells ◽  
Biological Properties ◽  
Biological Evaluation ◽  
Main Process ◽  
Preliminary Evaluation ◽  
Main Challenge

Chitosan nanoparticles (CS NPs) showed promising results in drug, vaccine and gene delivery for the treatment of various diseases. The considerable attention towards CS was owning to its outstanding biological properties, however, the main challenge in the application of CS NPs was faced during their size-controlled synthesis. Herein, ionic gelation reaction between CS and sodium tripolyphosphate (TPP), a widely used and safe CS cross-linker for biomedical application, was exploited by a microfluidic approach based on a staggered herringbone micromixer (SHM) for the synthesis of TPP cross-linked CS NPs (CS/TPP NPs). Screening design of experiments was applied to systematically evaluate the main process and formulative factors affecting CS/TPP NPs physical properties (mean size and size distribution). Effectiveness of the SHM-assisted manufacturing process was confirmed by the preliminary evaluation of the biological performance of the optimized CS/TPP NPs that were internalized in the cytosol of human mesenchymal stem cells through clathrin-mediated mechanism. Curcumin, selected as a challenging model drug, was successfully loaded into CS/TPP NPs (EE% > 70%) and slowly released up to 48 h via the diffusion mechanism. Finally, the comparison with the conventional bulk mixing method corroborated the efficacy of the microfluidics-assisted method due to the precise control of mixing at microscales.

Mechanical Properties of Free-Standing Porous Anodic Alumina Films

2013 ◽  
Vol 200 ◽  
pp. 54-59
Author(s):  
Eugene Ignashev ◽  
Vladimir Shulgov
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Film Thickness ◽  
Pure Aluminum ◽  
Heat Removal ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Free Standing ◽  
Alumina Films ◽  
The One

The flexural strength and microhardness of free-standing anodic alumina films obtained from the one-sided anodization of aluminum are discussed. The films formed of high-pure aluminum were shown to have maximum flexural strength. Even a small amount of impurities decreases the flexural strength of the resulting free-standing anodic alumina films to be associated with their higher defectiveness. The microhardness of thick films of anodic alumina measured on the side of a barrier layer is independent of the film thickness, and this measured on the side of the porous layer decreases continuosly from 5.39-5.88 GPa to 2.94 GPa when the film thickness increases from 50 to 500 μm. The microhardness of thin (<100 μm) films of porous anodic alumina was studied as well. When the samples were immovable in the electrolyte during the anodization, the microhardness of the resulting films is low and varies from 0.93 to 1.86 GPa. When the samples moved in the electrolyte occasionally during the anodization, the microhardness of the resulting films increases to 1.67 – 2.45 GPa. When the samples moved in the electrolyte continuously during the anodization, the microhardness of the resulting films increases to 2.45 - 3.43 GPa. This is associated with the rate of the heat removal from the sample (the oxidation rate) during the anodization. The microhardness of the free-standing porous anodic alumina films formed of low binary alloys of aluminum is lower than one of films formed of high-pure aluminum.

scholarly journals Cytotoxicity evaluation of chlorhexidine gluconate on human fibroblasts, myoblasts, and osteoblasts

2018 ◽  
Vol 3 (4) ◽  
pp. 165-172 ◽  
Author(s):  
James X. Liu ◽  
Jordan Werner ◽  
Thorsten Kirsch ◽  
Joseph D. Zuckerman ◽  
Mandeep S. Virk
Keyword(s):  
Cell Migration ◽  
Cell Survival ◽  
Human Fibroblasts ◽  
Cell Monolayer ◽  
Survival Rates ◽  
Chlorhexidine Gluconate ◽  
Cell Counting ◽  
In Vivo Studies ◽  
Wound Irrigation

Abstract. Introduction: Chlorhexidine gluconate (CHX) is widely used as a preoperative surgical skin-preparation solution and intra-wound irrigation agent, with excellent efficacy against wide variety of bacteria. The cytotoxic effect of CHX on local proliferating cells following orthopaedic procedures is largely undescribed. Our aim was to investigate the in vitro effects of CHX on primary fibroblasts, myoblasts, and osteoblasts.Methods: Cells were exposed to CHX dilutions (0%, 0.002%, 0.02%, 0.2%, and 2%) for either a 1, 2, or 3-minute duration. Cell survival was measured using a cytotoxicity assay (Cell Counting Kit-8). Cell migration was measured using a scratch assay: a “scratch” was made in a cell monolayer following CHX exposure, and time to closure of the scratch was measured.Results: All cells exposed to CHX dilutions of ≥ 0.02% for any exposure duration had cell survival rates of less than 6% relative to untreated controls (p < 0.001). Cells exposed to CHX dilution of 0.002% all had significantly lower survival rates relative to control (p < 0.01) with the exception of 1-minute exposure to fibroblasts, which showed 96.4% cell survival (p = 0.78). Scratch defect closure was seen in < 24 hours in all control conditions. However, cells exposed to CHX dilutions ≥ 0.02% had scratch defects that remained open indefinitely.Conclusions: The clinically used concentration of CHX (2%) permanently halts cell migration and significantly reduces survival of in vitro fibroblasts, myoblasts, and osteoblasts. Further in vivo studies are required to examine and optimize CHX safety and efficacy when applied near open incisions or intra-wound application.

Preparation and Characterization of Anodic Alumina Membrane with Nanopore Arrays

2012 ◽  
Vol 549 ◽  
pp. 358-361
Author(s):  
Xiao Hong Tang ◽  
Wen Bin Yang ◽  
Ya Fei Cheng ◽  
Quan Guo Huang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Pure Aluminum ◽  
Aluminum Foil ◽  
Honeycomb Structure ◽  
Anodic Alumina ◽  
Alumina Membrane ◽  
Energy Dispersion Spectroscopy ◽  
X Ray ◽  
Alumina Membranes ◽  
Nanopore Arrays

Anodic alumina membranes (AAM) with nanopore arrays were prepared by one-step anodization of highly pure aluminum foil. Morphology, structure and composition of AAM were characterized by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Results showed that AAM owned honeycomb structure which was characterized by close-packed arrays of columnar hexagonal cells, each containing a central pore normal to the substrate. The diameter of pores and the size of cells changed under different anodic conditions, such as temperature, concentration of H2C2O4 solution, voltage and time of anodization. The walls of AAM were composed of two strains of nanoparticles of alumina. Furthermore, the chemical composition of AAM was found to be amorphous alumina. The prepared AAM with nanopore arrays is a kind of ideal template for preparation of many one-dimensional nanomaterials.

scholarly journals Biocidal and bioresorbable chitosan/triclosan/collagen matrixes

Innovation ◽  
2019 ◽  
pp. 1
Author(s):  
GE Villanueva-Ornelas ◽  
RE Núñez-Anita ◽  
MC Arenas-Arrocena ◽  
GH Luévano-Colmenero
Keyword(s):  
Biomedical Application ◽  
Antimicrobial Effect ◽  
Matrix Group ◽  
Dental Surgery ◽  
Culture Cells ◽  
Antimicrobial Materials ◽  
The Matrix ◽  
Bioresorbable Material ◽  
Nih 3T3 ◽  
Over Time

Biomedical application of biomaterials has increased in recent years. Some preferred characteristics of these materials are biocompatibility, biodegradability and antimicrobial effect. We are facing a constant search for antimicrobial materials to be used instead of antibiotics therapy to reduce the possibility of dental surgery contamination. In this study, biocidal, bioresorbable and non-toxic matrixes were synthesized from chitosan, triclosan and collagen. Three experimental groups received different chitosan/collagen combinations, (0.5:1, 0.75:1 and 1:1), all with the same dose of triclosan (0.1%). Antimicrobial effect was measured by the inhibition of S. aureus growth. Moreover, matrixes were placed in a PBS-collagenase solution to measure degradation over time; matrix residues were evaluated at 1, 4, and 7 days. Finally, cell toxicity of each matrix was analyzed on NIH-3T3 fibroblast cells. As a result, inhibition of S. aureus growth was similar in the three established experimental groups of matrixes vs vancomycin antibiotic as control. These data suggest potent antimicrobial effect of chitosan/triclosan/collagen matrixes. Degradation over time showed that 80% of the matrix was degraded after 4 days, thus suggesting that chitosan/triclosan/collagen matrixes are bioresorbable material. On the other hand, viability of NIH-3T3 cells was between 60% to 74% after 24 h and prior to matrix exposition to culture cells. These data indicate light toxicity in the 0.5:1 and 0.75:1 matrix groups and non-toxic effect in the 1:1 matrix group. By taking together these data, we propose the application of chitosan/triclosan/collagen matrixes to prevent bacterial contamination after dental surgery.

scholarly journals Synthesis and study of composite based on porous anodic alumina modified by silver nanowires

2021 ◽  
Vol 13 (1) ◽  
pp. 39-44
Author(s):  
Mikhail Yu. Vasilkov ◽  
◽  
Ilya N. Mikhailov ◽  
Alexander E. Isaev ◽  
David Z. Safoshkin ◽  
...  
Keyword(s):  
Experimental Study ◽  
Surface Morphology ◽  
Silver Nanowires ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Nanocomposite Membranes ◽  
Silver Deposition ◽  
Technological Methods

The paper presents the results of an experimental study of the deposition of modified silver into the pores of ceramic Ag&Al2O3 membranes, laboratory samples of thin nanocomposite membranes were obtained based on the developed technological methods of silver deposition, and their composition and surface morphology were studied.

Sign in / Sign up

Export Citation Format

Share Document