Human mesenchymal stromal cell adhesion and expansion on fluoropolymer surfaces modified with oxygen and nitrogen-rich plasma polymers.

Fluorinated ethylene propylene (FEP) vessels are of significant interest for therapeutic cell biomanufacturing applications due to their chemical inertness, hydrophobic surface, and high oxygen permeability. However, these properties also limit the adhesion and survival of anchorage-dependent cells. Here, we develop novel plasma polymer coatings to modify FEP surfaces, enhancing the adhesion and expansion of human mesenchymal stromal cells (hMSCs).

Experimental and Theoretical Assessment of Water Sorbent Kinetics.

The kinetics of water adsorption in powder sorbent layers are important to design a scaled-up atmospheric water capture device. Herein, the adsorption kinetics of three sorbents, a chromium (Cr)-based metal-organic framework (Cr-MIL-101), a carbon-based material (nanoporous sponges/NPS), and silica gel, have been tested experimentally, using powder layers ranging from ∼0 to 7.5 mm in thickness, in a custom-made calibrated environmental chamber cycling from 5 to 95% RH at 30 °C.

Synthesis and characterization of MWCNT-covered stainless steel mesh with Janus-type wetting properties.

Various multi-step methods to fabricate Janus membranes have been reported in literature. However, no article so far reports the durability of the Janus membranes when exposed to liquids. We report on a novel method to fabricate a Janus-type multi-walled carbon nanotubes (MWCNT)-covered stainless steel (SS) mesh, which retains dual-wetting properties even after exposure to water for 540 d.

VUV Photodeposition of Thiol-Terminated Films: A Wavelength-Dependent Study.

Photoinitiated chemical vapor deposition (PICVD) has become attractive for selective and specific surface functionalization, because it relies on a single energy source, the photons, to carry out (photo-) chemistry. In the present wavelength (λ)-dependent study, thiol (SH)-terminated thin film deposits have been prepared from gas mixtures of acetylene (CH) and hydrogen sulfide (HS) via PICVD using four different vacuum-ultraviolet (VUV) sources, namely, KrL (λ = 123.6 nm), XeL (λ = 147.

Adhesion of human monocytes to oxygen- and nitrogen- containing plasma polymers: Effect of surface chemistry and protein adsorption.

The interactions between monocytes and biomaterials can potentially be modulated by controlling the chemical and structural surface properties of biomaterials. The objective of this study was to determine the effect of plasma-deposited functional organic coatings on monocyte adhesion and differentiation into macrophages. Organic coatings with varying oxygen and nitrogen concentration were prepared by low-pressure plasma co-polymerization of binary gas mixtures combining a hydrocarbon (butadiene/ethylene) and a heteroatom-containing gas (carbon dioxide/ammonia) to deposit either oxygen or nitrogen-containing coatings.

The effects of femtosecond laser-textured Ti-6Al-4V on wettability and cell response.

To study the biological activity effects of femtosecond laser-induced structures on cell behavior, TA6V samples were micro-textured with focused femtosecond laser pulses generating grooves of various dimensions on the micrometer scale (width: 25-75μm; depth: 1-10μm). LIPSS (Laser Induced Periodic Surface Structures) were also generated during the laser irradiation, providing a supplementary structure (sinusoidal form) of hundreds of nanometers at the bottom of the grooves oriented perpendicular (⊥ LIPPS) or parallel (// LIPPS) to the direction of these grooves. C3H10 T1/2 murine mesenchymal stem cells were cultivated on the textured biomaterials.

Chemical and elemental depth profiling of very thin organic layers by constant kinetic energy XPS: a new synchrotron XPS analysis strategy.

We present a new synchrotron X-ray photoelectron spectroscopy strategy for surface chemical analysis of materials. Our approach is based on the acquisition of photoelectron spectra at constant kinetic energies with the help of a tunable synchrotron X-radiation source. This ensures both constant and tunable information depth for all elements in a very thin organic layer.

Ambient-ageing processes in amine self-assembled monolayers on microarray slides as studied by ToF-SIMS with principal component analysis, XPS, and NEXAFS spectroscopy.

We investigated the ageing of amine-terminated self-assembled monolayers (amine-SAMs) on different silica substrates due to exposure to different ambient gases, pressures, and/or temperatures using time-of-flight secondary ion mass spectrometry (ToF-SIMS) with principal component analysis and complementary methods of surface analysis as X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS). The goal of this study is to examine the durability of primary amine groups of amine-SAMs stored in a user laboratory prior to being used as supports for biomolecule immobilization and other applications. We prepared amine-SAMs on the native oxides of silicon wafers and glass slides using 3-aminopropyl triethoxysilane, by using optimized conditions such as anhydrous organic solvent and reaction time scale of hours to avoid multilayer growth.

Adlayers of dimannoside thiols on gold: surface chemical analysis.

Carbohydrate films on gold based on dimannoside thiols (DMT) were prepared, and a complementary surface chemical analysis was performed in detail by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), near-edge X-ray absorption fine structure (NEXAFS), FT-IR, and contact angle measurements in order to verify formation of ω-carbohydrate-functionalized alkylthiol films. XPS (C 1s, O 1s, and S 2p) reveals information on carbohydrate specific alkoxy (C-O) and acetal moieties (O-C-O) as well as thiolate species attached to gold. Angle-resolved synchrotron XPS was used for chemical speciation at ultimate surface sensitivity.

Effect of nitrogen-rich cell culture surfaces on type X collagen expression by bovine growth plate chondrocytes.

Background: Recent evidence indicates that osteoarthritis (OA) may be a systemic disease since mesenchymal stem cells (MSCs) from OA patients express type X collagen, a marker of late stage chondrocyte hypertrophy (associated with endochondral ossification). We recently showed that the expression of type X collagen was suppressed when MSCs from OA patients were cultured on nitrogen (N)-rich plasma polymer layers, which we call "PPE:N" (N-doped plasma-polymerized ethylene, containing up to 36 atomic percentage (at.% ) of N.

Novel insights into the mechanism of decreased expression of type X collagen in human mesenchymal stem cells from patients with osteoarthritis cultured on nitrogen-rich plasma polymers: implication of cyclooxygenase-1.

Recent evidence indicates that a major drawback of current cartilage- and intervertebral disc (IVD) tissue engineering is that human mesenchymal stem cells (MSCs) from patients with osteoarthritis rapidly express type X collagen (COL10A1), a marker of late stage chondrocyte hypertrophy associated with endochondral ossification. We recently demonstrated that COL10A1 expression was inhibited in MSCs from patients with osteoarthritis cultured on nitrogen-rich plasma polymerized (PPE:N) coatings. Here, we sought to understand the mechanisms of action of this effect by culturing MSCs on PPE:N surfaces in the presence of different inhibitors of kinases and cyclooxygenases.

CHO cells adhering to nitrogen-rich plasma-polymerised ethylene exhibit high production of a specific recombinant protein.

In many industrial applications, inadequate cell attachment can be a limitation, especially when serum-free media are used. Nitrogen-rich plasma-polymerised ethylene (PPE:N) exhibits high concentrations of polar groups that can help to promote the attachment of weakly adherent cell types. Tissue plasminogen activator-producing Chinese hamster ovary (CHO) cells, adapted to suspension, were grown in the presence PPE:N flakes and were found to adhere to them.

Adhesion of human U937 monocytes to nitrogen-rich organic thin films: novel insights into the mechanism of cellular adhesion.

We present a two-fold study designed to elucidate the adhesion mechanism of human U937 monocytes on novel N-rich thin films deposited by plasma- and VUV photo-polymerisation, so-called "PVP:N" materials. It is shown that there exist sharply-defined ("critical") surface-chemical conditions that are necessary to induce cell adhesion. By comparing the film chemistries at the "critical" conditions, we demonstrate the dominant role of primary amines in the cell adhesion mechanism.

The Potential of N-Rich Plasma-Polymerized Ethylene (PPE:N) Films for Regulating the Phenotype of the Nucleus Pulposus.

We recently developed a nitrogen-rich plasma-polymerized biomaterial, designated "PPE:N" (N-doped plasma-polymerized ethylene) that is capable of suppressing cellular hypertrophy while promoting type I collagen and aggrecan expression in mesenchymal stem cells from osteoarthritis patients. We then hypothesized that these surfaces would form an ideal substrate on which the nucleus pulposus (NP) phenotype would be maintained. Recent evidence using microarrays showed that in young rats, the relative mRNA levels of glypican-3 (GPC3) and pleiotrophin binding factor (PTN) were significantly higher in nucleus pulposus (NP) compared to annulus fibrosus (AF) and articular cartilage.

The effect of novel nitrogen-rich plasma polymer coatings on the phenotypic profile of notochordal cells.

Background: The loss of the notochordal cells from the nucleus pulposus is associated with ageing and disc degeneration. However, understanding the mechanisms responsible for the loss of these cells has been hampered in part due to the difficulty of culturing and maintaining their phenotype. Furthermore, little is known about the influence of the substratum on the molecular markers of notochordal cells.

Suppression of genes related to hypertrophy and osteogenesis in committed human mesenchymal stem cells cultured on novel nitrogen-rich plasma polymer coatings.

Mesenchymal stem cells (MSCs) are pluripotent progenitor cells with the ability to generate cartilage, bone, muscle, tendon, ligament, and fat. However, recent evidence indicates that a major drawback of current cartilage- and intervertebral disc-tissue engineering is that human MSCs isolated from some arthritic patients (a clinically relevant source of stem cells) express type X collagen (a marker of chondrocyte hypertrophy associated with endochondral ossification) and osteogenic markers. Some studies have attempted to use growth factors to inhibit type X collagen expression, but none has addressed the possible effect of the chemical composition of the substratum on chondrocyte hypertrophy and osteogenesis.