Ascorbic Acid/Retinol and/or Inflammatory Stimuli's Effect on Proliferation/Differentiation Properties and Transcriptomics of Gingival Stem/Progenitor Cells.

The present study explored the effects of ascorbic-acid (AA)/retinol and timed inflammation on the stemness, the regenerative potential, and the transcriptomics profile of gingival mesenchymal stem/progenitor cells' (G-MSCs). STRO-1 (mesenchymal stem cell marker) immuno-magnetically sorted G-MSCs were cultured in basic medium (control group), in basic medium with IL-1ß (1 ng/mL), TNF-α (10 ng/mL) and IFN-γ (100 ng/mL, inflammatory-medium), in basic medium with AA (250 µmol/L) and retinol (20 µmol/L) (AA/retinol group) or in inflammatory medium with AA/retinol (inflammatory/AA/retinol group; n = 5/group). The intracellular levels of phosphorylated and total ß-Catenin at 1 h, the expression of stemness genes over 7 days, the number of colony-forming units (CFUs) as well as the cellular proliferation aptitude over 14 days, and the G-MSCs' multilineage differentiation potential were assessed. Next-generation sequencing was undertaken to elaborate on up-/downregulated genes and altered intracellular pathways. G-MSCs demonstrated all mesenchymal stem/progenitor cells characteristics. Controlled inflammation with AA/retinol significantly elevated NANOG (p < 0.05). The AA/retinol-mediated reduction in intracellular phosphorylated ß-Catenin was restored through the effect of controlled inflammation (p < 0.05). Cellular proliferation was highest in the AA/retinol group (p < 0.05). AA/retinol counteracted the inflammation-mediated reduction in G-MSCs' clonogenic ability and CFUs. Amplified chondrogenic differentiation was observed in the inflammatory/AA/retinol group. At 1 and 3 days, the differentially expressed genes were associated with development, proliferation, and migration (FOS, EGR1, SGK1, CXCL5, SIPA1L2, TFPI2, KRATP1-5), survival (EGR1, SGK1, TMEM132A), differentiation and mineral absorption (FOS, EGR1, MT1E, KRTAP1-5, ASNS, PSAT1), inflammation and MHC-II antigen processing (PER1, CTSS, CD74) and intracellular pathway activation (FKBP5, ZNF404). Less as well as more genes were activated the longer the G-MSCs remained in the inflammatory medium or AA/retinol, respectively. Combined, current results point at possibly interesting interactions between controlled inflammation or AA/retinol affecting stemness, proliferation, and differentiation attributes of G-MSCs.

A Bacteria and Cell Repellent Zwitterionic Polymer Coating on Titanium Base Substrates towards Smart Implant Devices.

Biofouling and biofilm formation on implant surfaces are serious issues that more than often lead to inflammatory reactions and the necessity of lengthy post-operation treatments or the removal of the implant, thus entailing a protracted healing process. This issue may be tackled with a biocompatible polymeric coating that at the same time prevents biofouling. In this work, oxygen plasma-activated silanized titanium substrates are coated with poly(sulfobetaine methacrylate), a zwitterionic antibiofouling polymer, using photopolymerization. The characterization of polymer films includes FT-IR, AFM, and adhesion strength measurements, where adhesion strength is analyzed using a cylindrical flat punch indenter and water contact angle (WCA) measurements. Both cytotoxicity analysis with primary human fibroblasts and fluorescence microscopy with fibroblasts and plaque bacteria are also performed is this work, with each procedure including seeding on coated and control surfaces. The film morphology obtained by the AFM shows a fine structure akin to nanoropes. The coatings can resist ultrasonic and sterilization treatments. The adhesion strength properties substantially increase when the films are soaked in 0.51 M of NaCl prior to testing when compared to deionized water. The coatings are superhydrophilic with a WCA of 10° that increases to 15° after dry aging. The viability of fibroblasts in the presence of coated substrates is comparable to that of bare titanium. When in direct contact with fibroblasts or bacteria, marginal adhesion for both species occurs on coating imperfections. Because photopolymerization can easily be adapted to surface patterning, smart devices that promote both osseointegration (in non-coated areas) and prevent cell overgrowth and biofilm formation (in coated areas) demonstrate practical potential.

A Novel Surface Modification Strategy via Photopolymerized Poly-Sulfobetaine Methacrylate Coating to Prevent Bacterial Adhesion on Titanium Surfaces.

Recent investigations on the anti-adhesive properties of polysulfobetaine methacrylate (pSBMA) coatings had shown promising potential as antifouling surfaces and have given the impetus for the present paper, where a pSBMA coating is applied via photopolymerization on a macro-roughened, sandblasted, and acid-etched titanium implant surface in order to assess its antifouling properties. Current emphasis is placed on how the coating is efficient against the adhesion of Enterococcus faecalis by quantitative assessment of colony forming units and qualitative investigation of fluorescence imaging and scanning electron microscopy. pSBMA coatings via photopolymerization of titanium surfaces seems to be a promising antiadhesion strategy, which should bring substantial benefits once certain aspects such as biodegradation and osseointegration were addressed. Additionally, commercial SAL-titanium substrates may be coated with the super-hydrophilic coating, appearing resistant to physiological salt concentrations and most importantly lowering E. faecalis colonization significantly, compared to titanium substrates in the as-received state. It is very likely that pSBMA coatings may also prevent the adhesion of other germs.

Data supporting polymerization of anti-fouling polymer brushes polymerized on the pore walls of porous aluminium and titanium oxides.

The data presented in this article affords insight into the fabrication and ensuing microstructure of the supported porous anodic aluminum oxide (AAO) and TiO2-nanotubes (NT) films that are used for the subsequent grafting of antifouling poly(oligo ethyleneglycol) methylether methacrylate (POEGMA) and poly acrylamide (PAAm) brushes. The experimental procedure for the grafting of POEGMA and PAAm via atom transfer radical polymerization (ATRP) is described in Wassel et al. (2019) https://doi.org/10.1016/j.matdes.2018.107542 [1]. The FTIR spectra of the porous oxides before and after attachment of (3-Aminopropyl)trimethoxysilane (APTMS) are presented. Microscopic images of thick POEGMA films and PAAm on AAO are displayed, and an FTIR spectrum of AAO/PAAm is shown. An EDX mapping of carbon is shown on an AAO/POEGMA sample. The adsorption behavior of Fluorescein isothiocyanate (FITC) marked bovine serum albumin (BSA) on patterned porous TiO2-NT films is documented. Finally microscopic images are presented to compare the scratch resistance behavior of pristine porous films with those functionalized with POEGMA.

In vitro biocompatibility of orthodontic miniscrews with human gingival fibroblast and SAOS-2 osteoblast cultures.

PURPOSE: Miniscrews are an important choice for orthodontic anchorage. Yet reports on failures do exist, and attempts have been made to elucidate the causes. Clinical outcomes may be compromised not only by the mechanical implications of miniscrew design and the location of anchorage but also by poor biocompatibility. Hence, this study deals with the surface roughness and elemental composition of miniscrews and how these properties may affect the in vitro biocompatibility of four commercially available miniscrews. METHODS: Most of the currently available miniscrews are made of TiAl6V4, an alloy widely considered to be biocompatible. The samples tested in this study included four similarly dimensioned TiAl6V4 products from different manufacturers: tomas® by Dentaurum, OrthoEasy® by Forestadent®, Dual Top™ by Jeil Medical/Promedia, and LOMAS by Mondeal®. The surface properties of these products were characterized by scanning electron microscopy (SEM) and energy-dispersive X­ray spectroscopy (EDX). Cytotoxicity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and agar overlay assays according to ISO 10993-5. RESULTS: The miniscrew products were found to show variations in surface-finish quality pertaining to topography and chemical composition, with the latter departing slightly from the manufacturers' specifications. MTT assays yielded rates of cell culture viability in excess of 90%, and agar overlay assays did not reveal decoloration beyond the specimen outlines in any of the experimental groups tested. CONCLUSIONS: The four miniscrew products exhibited some minor, but statistically significant, differences in microtopography, alloy composition, and biological inertness. Cytotoxicity testing revealed that all four products should be considered non-cytotoxic, thus, ruling out poor biocompatibility as a cause of miniscrew failure.

Nanocomposite Films of Laponite/PEG-Grafted Polymers and Polymer Brushes with Nonfouling Properties.

We explore the suitability of nanocomposite thin films based on laponite nanomaterial and grafted antiadhesive polymers as transparent nonfouling surfaces. For this purpose, two polymers were chosen: a linear poly(ethylene glycol) (PEG) silane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane), and thermoresponsive poly(oligo ethylene glycol)-methyl ether-methacrylate (POEGMA) brushes. PEG silane was grafted on the laponite nanoparticles in solution yielding homogeneous and transparent thin films via a dip coating procedure on glass and silicon substrates. POEGMA was grafted on laponite-(3-Aminopropyl)trimethoxysilane (APTMS) nanocomposite films that were processed similarly to PEG-silane using atom transfer radical polymerization (ATRP). Film characterization with, among others, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and atomic force microscopy (AFM) attests to successful grafting of the polymers to the laponite nanoparticles. In particular, evidence of basal plane expansion of laponite with increasing silane concentration are obtained using XRD, while patent morphological changes are revealed with AFM. The results are discussed in terms of the different grafting sites on laponite and compared with literature. While LP-PEG-silane is easily applied to a surface from a precursor solution via a dip coating procedure LP-APTMS-OEGMA requires lots more chemicals, a thorough control of reaction parameters, and longer reaction time in order to generate films with the desirable properties. We therefore also addressed the antifouling properties of the films. These were tested together with control samples of bare glass and laponite thin films for 30 days in an algae container. More tests were conducted with fibroblast cell cultures. Our preliminary results show that grafting of PEG containing polymers and polymer brushes alters the properties of the laponite films from fouling to nonfouling surfaces. As a first estimate, the adhesion of particles (diatoms, algae, etc.) to surfaces is reduced by approximately 85% in the case of LP-PEG-silane and up to 92% in the case of LP-APTMS-POEGMA, in comparison to the control surfaces. Furthermore, practically no cell adhesion on such surfaces could be observed.

Mesoporous and macroporous brookite thin films having a large thermal stability range.

A sol-gel chemistry approach is employed to generate mesoporous and macroporous brookite thin films using Ag ions as dopant species whose thermal stability is well above previously reported literature values for thin films. The Ag ions not only induce the formation of brookite but also participate in its enhanced thermal stability. Despite brookite being metastable in nature, which renders it a challenge to synthesize, it has been prescribed as a potential competitor to anatase. We have used a layer-by-layer approach to generate a mesoporous Ag-doped brookite structure at 500 °C with 95% composition by XRD. This tightly packed mesoporous structure can be described as striated grains of brookite protruding from the surface to form an interlocked network whose thermal stability spans up to 800 °C. The open structure of brookite makes it an apt host for the intercalant Ag species, whose inclusion within the brookite framework is improved by the presence of a stabilizing agent. Both the morphology of the surface and the presence of a stabilization agent for Ag contribute to enhancing its thermal stability. This is in contrast to the thermal stability of the macroporous brookite thin film, which was found to be lower (<700 °C) than that of the mesoporous brookite thin film. The reagents are deliberately chosen to produce a macroporous film in the absence of a stabilizing agent. Ag nodules are observed to be formed at 700 °C, which implies their limited intercalation into the brookite structure, thus rendering them relatively less stable. Moreover, the macroporous film being relatively more relaxed is more susceptible to phase transformation at a higher calcination temperature. Our results provide a platform that paves the way toward better control, thereby leading to a broader technological application of brookite.

Human gingival fibroblast response to electropolished NiTi surfaces.

In the present study the in vitro biocompatibility of electropolished NiTi sheets is investigated. The assessment of cytotoxic effects due to potential Ni leaching from metal sheets was performed in direct contact with primary human fibroblast cultures using the 5-bromo-2'-deoxyuridine cell proliferation assay and morphologic studies via light microscopy and scanning electron microscopy. To assess toxic effects related to Ni-ions release, cells cultured in the presence of increasing concentrations of Ni(2+) (NiSO(4).6H(2)O) served as positive controls. It is shown that while the addition of NiSO(4) caused severe proliferation decrease (approximately 80%) and morphologic damage at a concentration of 50 mg/L Ni(2+) no negative effects were observed in fibroblasts cultured in the presence of electropolished NiTi sheets. The results are discussed in terms of surface topography effects on the biocompatibility of NiTi shape memory alloys.

Assessing the biocompatibility of NiTi shape memory alloys used for medical applications.

The present paper reviews aspects related to the biocompatibility of NiTi shape memory alloys used for medical applications. These smart metallic materials, which are characterised by outstanding mechanical properties, have been gaining increasing importance over the last two decades in many minimal invasive surgery and diagnostic applications, as well as for other uses, such as in orthodontic appliances. Due to the presence of high amounts of Ni, the cytotoxicity of such alloys is under scrutiny. In this review paper we analyse work published on the biocompatibility of NiTi alloys, considering aspects related to: (1) corrosion properties and the different methods used to test them, as well as specimen surface states; (2) biocompatibility tests in vitro and in vivo; (3) the release of Ni ions. It is shown that NiTi shape memory alloys are generally characterised by good corrosion properties, in most cases superior to those of conventional stainless steel or Co-Cr-Mo-based biomedical materials. The majority of biocompatibility studies suggest that these alloys have low cytotoxicity (both in vitro and in vivo) as well as low genotoxicity. The release of Ni ions depends on the surface state and the surface chemistry. Smooth surfaces with well-controlled structures and chemistries of the outermost protective TiO2 layer lead to negligible release of Ni ions, with concentrations below the normal human daily intake.

On the in vitro biocompatibility of Elgiloy, a co-based alloy, compared to two titanium alloys.

AIM: The aim of the present investigation was to contribute to an understanding of the effects of surface topography and chemical composition on the corrosion behavior and thus the biocompatibility of Elgiloy (RMO, Denver, CO, USA), a common Co-based alloy. MATERIAL AND METHODS: The results are compared with those obtained for a binary NiTi alloy, Neo Sentalloy (GAC, Central Islip, NY, USA) and a beta-III-Ti alloy, TMA (Ormco, Glendora, CA, USA). In the present study, the surface topography and the chemical composition of two different grades of Elgiloy, Blue Elgiloy (soft) and Yellow Elgiloy (ductile), were examined by means of scanning electron microscopy (SEM) and energy-dispersive spectroscopy analysis (EDS). Their corrosion behavior in half-strength Ringer solution and in an artificial saliva solution according to Barrett [1] was investigated using potentiodynamic corrosion testing (PDC). The photometry-based PAN method was used to quantify the released Ni and Co ions. The in vitro biocompatibility of the two grades of Elgiloy was tested in three different cell cultures: in L929, a commercially available mouse fibroblast cell line, and in primary human epithelial cells and fibroblasts. RESULTS: The results of the corrosion testing showed satisfactorily high pitting corrosion potentials but lower repassivation potentials and a strong increase in current density once pitting had occurred. The photometric results revealed the release of Ni and Co ions in both tested electrolytes. The tested native surfaces exhibited numerous grinding and polishing grooves, inclusions and inhomogeneities of the microstructure. After corrosion testing the same surfaces displayed numerous signs of corrosion, especially in areas with microstructural inhomogeneities. In vitro biocompatibility testing showed a substantially reduced dehydrogenase activity in the presence of Elgiloy. The reduced quality of surface finish resulting from the manufacturing process led in the case of the tested Elgiloy types to decreased corrosion resistance with consequently reduced in vitro biocompatibility. CONCLUSIONS: In this context it is also conceivable that patients with a proven allergy to nickel, cobalt or chromium may react sensitively to the deployment of this alloy, at least in the surface quality tested by us. From this aspect, the introduction of a binding standard for the surface quality of materials used in orthodontic appliances is urgently recommended.

On the interaction of polyacrylic acid as a conditioning agent with bovine enamel.

In the present paper, the effects of polyacrylic acid (PAA) conditioning on the morphology and chemistry of bovine enamel surface and the resulting interfacial reactions are being investigated using photometric, microscopic (SEM, AFM), electron spectroscopic (XPS) and staining methods (neutral red dye). The results are compared to two reference surfaces obtained by simple grinding and by etching with a phosphoric acid solution. It is shown that PAA conditioning leads to the leaching of calcium and phosphorus ions, to the smoothening of the surface and probably to the formation of a polymeric film at the surface. A mechanism by which a preliminary PAA conditioning of the enamel leads to the reported higher bonding strength between enamel and glass ionomer cements is proposed.

On the properties of two binary NiTi shape memory alloys. Effects of surface finish on the corrosion behaviour and in vitro biocompatibility.

The present paper compares the transformation behaviour and mechanical properties of two orthodontic wires of close chemical compositions. The effects of surface topography and surface finish residues on the potentiodynamic corrosion behaviour and biocompatibility are also reported. The cytotoxicity tests were performed on both alloys in fibroblast cell cultures from human gingiva using the MTT test. It is shown that the surface finish and the amounts of surface finish residues affect dramatically the corrosion resistance. Bad surface finish results in lower corrosion resistance. The in vitro biocompatibility, though not affected to the extent of corrosion resistance, is also reduced as the surface roughness and the amounts of residues increase. This is thought to be due to surface effects on corrosion and metallic ions release.