Osteoblast-like Saos-2 Cells Research Articles

Enhancement of Biomimetic Enzymatic Mineralization of Gellan Gum Polysaccharide Hydrogels by Plant-Derived Gallotannins.

Mineralization of hydrogel biomaterials with calcium phosphate (CaP) is considered advantageous for bone regeneration. Mineralization can be both induced by the enzyme alkaline phosphatase (ALP) and promoted by calcium-binding biomolecules, such as plant-derived polyphenols. In this study, ALP-loaded gellan gum (GG) hydrogels were enriched with gallotannins, a subclass of polyphenols. Five preparations were compared, namely three tannic acids of differing molecular weight (MW), pentagalloyl glucose (PGG), and a gallotannin-rich extract from mango kernel (Mangifera indica L.). Certain gallotannin preparations promoted mineralization to a greater degree than others. The various gallotannin preparations bound differently to ALP and influenced the size of aggregates of ALP, which may be related to ability to promote mineralization. Human osteoblast-like Saos-2 cells grew in eluate from mineralized hydrogels. Gallotannin incorporation impeded cell growth on hydrogels and did not impart antibacterial activity. In conclusion, gallotannin incorporation aided mineralization but reduced cytocompatibility.

Response of Saos-2 osteoblast-like cells to kilohertz-resonance excitation in porous metallic scaffolds

Post-operative therapy for joint replacement is often performed to optimize bone volume and bone-implant contact. Methods, such as pulsed therapeutic ultrasound, have been shown to be a valuable addition to regular physiotherapy to increase bone regeneration. To evaluate the efficacy of kilohertz-frequency (kHz) resonant stimuli to additively manufactured implant analogues, Saos-2 cells were seeded onto porous stainless steel scaffolds and flat substrates. Resonant frequency modes were mapped in the low kHz range, and cells were subjected to daily stimulus for 10 min at a frequency of 1.278 kHz. kHz-frequency excitation was found to increase normalized alkaline phosphatase production by almost twofold on metallic substrates relative to non-vibrated control scaffolds, while peak velocity influenced alkaline phosphatase production on porous scaffolds but not flat substrates. Total cell proliferation was downregulated by excitation, and all excited samples displayed larger variability. This work indicates that vibration within the range of 0.16–0.48 mm/s may reduce cell proliferation, but favour osteogenic gene expression. This study highlights the potential of using kHz-resonance therapy to mitigate early-onset pore occlusion to achieve uniform osseointegration through porous metallic scaffolds.

TRPM7 and MagT1 regulate the proliferation of osteoblast-like SaOS-2 cells through different mechanisms.

A correct magnesium (Mg2+) intake is essential for bone health. In particular, Mg2+ deficiency inhibits the proliferation of osteoblast-like SaOS-2 cells by increasing nitric oxide (NO) production through the upregulation of inducible NO synthase. At the moment, little is known about the expression and the role of TRPM7, a channel/enzyme involved in Mg2+ uptake, and MagT1, a Mg2+ selective transporter, in SaOS-2 cells. Here, we demonstrate that TRPM7 is not modulated by different extracellular concentrations of Mg2+ and its silencing exacerbates growth inhibition exerted by low Mg2+ through the activation of inducible NO synthase and consequent accumulation of NO. Moreover, MagT1 is upregulated in SaOS-2 cultured in high Mg2+ and its silencing inhibits the growth of SaOS-2 cultured in media containing physiological or high Mg2+, without any modulation of NO production. We propose that TRPM7 and MagT1 are both involved in regulating SaOS-2 proliferation through different mechanisms.

Blueberry Juice Antioxidants Protect Osteogenic Activity against Oxidative Stress and Improve Long-Term Activation of the Mineralization Process in Human Osteoblast-Like SaOS-2 Cells: Involvement of SIRT1.

Diets rich in fruits and vegetables with many antioxidants can be very important in the prevention and treatment of osteoporosis. Studies show that oxidative stress, often due to lack of antioxidants, is involved in alteration of bone remodeling and reduction in bone density. This study demonstrates in human osteoblast-like SaOS-2 cells that blueberry juice (BJ), containing 7.5 or 15 μg∙mL−1 total soluble polyphenols (TSP), is able to prevent the inhibition of osteogenic differentiation and the mineralization process due to oxidative stress induced by glutathione depletion. This situation mimics a metabolic condition of oxidative stress that may occur during estrogen deficiency. The effect of BJ phytochemicals occurs through redox- and non-redox-regulated mechanisms. BJ protects from oxidative damage factors related to bone remodeling and bone formation, such as alkaline phosphatase and Runt-related transcription factor 2. It upregulates these factors by activation of sirtuin type 1 deacetylase expression, a possible molecular target for anti-osteoporotic drugs. Quantitative analysis of TSP in BJ shows high levels of anthocyanins with high antioxidant capacity and bioavailability. These novel data may be important to elucidate the molecular and cellular beneficial effects of blueberry polyphenols on bone regeneration, and they suggest their use as a dietary supplement for osteoporosis prevention and therapies.

Graphene nanoplatelets-reinforced magnesium metal matrix nanocomposites with superior mechanical and corrosion performance for biomedical applications

Magnesium (Mg) metal matrix composites (MMCs) reinforced with graphene nanoplatelets (GNPs) have been developed by powder metallurgy (PM). GNPs with different concentrations (0.1, 0.2, and 0.3 wt.%), layer thicknesses (5 nm and 9 nm), and particle sizes (15 µm and 5 µm) were dispersed into Mg powder by high-energy ball-milling processes. The microstructure and mechanical properties of the fabricated composites were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy (RS), and compression tests. The corrosion resistance was evaluated by electrochemical tests and hydrogen evolution measurements. The cytotoxicity of Mg-GNPs composites was assessed using osteoblast-like SaOS2 cells. The results indicate that GNPs are excellent candidates as reinforcements in Mg matrices for the manufacture of biodegradable Mg-based composite implants. GNP addition improved the mechanical properties of Mg via synergetic strengthening modes. Moreover, retaining the structural integrity of GNPs during processing improved the ductility, compressive strength, and corrosion resistance of the Mg-GNP composites. Cytotoxicity assessments did not reveal any significant toxicity with the addition of GNPs to Mg matrices. This study demonstrates that Mg-xGNPs with x < 0.3 wt.%, may constitute novel biodegradable implant materials for load-bearing applications.

Perfusion-based co-culture model system for bone tissue engineering.

In this work, we report on a perfusion-based co-culture system that could be used for bone tissue engineering applications. The model system is created using a combination of Primary Human Umbilical Vein Endothelial Cells (HUVECs) and osteoblast-like Saos-2 cells encapsulated within a Gelatin Methacrylate (GelMA)-collagen hydrogel blend contained within 3D printed, perfusable constructs. The constructs contain dual channels, within a custom-built bioreactor, that were perfused with osteogenic media for up to two weeks in order to induce mineral deposition. Mineral deposition in constructs containing only HUVECs, only Saos-2 cells, or a combination thereof was quantified by microCT to determine if the combination of endothelial cells and bone-like cells increased mineral deposition. Histological and fluorescent staining was used to verify mineral deposition and cellular function both along and between the perfused channels. While there was not a quantifiable difference in the amount of mineral deposited in Saos-2 only versus Saos-2 plus HUVEC samples, the location of the deposited mineral differed dramatically between the groups and indicated that the addition of HUVECs within the GelMA matrix allowed Saos-2 cells, in diffusion limited regions of the construct, to deposit bone mineral. This work serves as a model on how to create perfusable bone tissue engineering constructs using a combination of 3D printing and cellular co-cultures.

Animal Origin Bioactive Hydroxyapatite Thin Films Synthesized by RF-Magnetron Sputtering on 3D Printed Cranial Implants

Ti6Al4V cranial prostheses in the form of patterned meshes were 3D printed by selective laser melting in an argon environment; using a CO2 laser source and micron-sized Ti6Al4V powder as the starting material. The size and shape of prostheses were chosen based on actual computer tomography images of patient skull fractures supplied in the framework of a collaboration with a neurosurgery clinic. After optimizations of scanning speed and laser parameters, the printed material was defect-free (as shown by metallographic analyses) and chemically homogeneous, without elemental segregation or depletion. The prostheses were coated by radio-frequency magnetron sputtering (RF-MS) with a bioactive thin layer of hydroxyapatite using a bioceramic powder derived from biogenic resources (Bio-HA). Initially amorphous, the films were converted to fully-crystalline form by applying a post-deposition thermal-treatment at 500 °C/1 h in air. The X-ray diffraction structural investigations indicated the phase purity of the deposited films composed solely of a hexagonal hydroxyapatite-like compound. On the other hand, the Fourier transform infrared spectroscopic investigations revealed that the biological carbonatation of the bone mineral phase was well-replicated in the case of crystallized Bio-HA RF-MS implant coatings. The in vitro acellular assays, performed in both the fully inorganic Kokubo’s simulated body fluid and the biomimetic organic–inorganic McCoy’s 5A cell culture medium up to 21 days, emphasized both the good resistance to degradation and the biomineralization capacity of the films. Further in vitro tests conducted in SaOs-2 osteoblast-like cells showed a positive proliferation rate on the Bio-HA RF-MS coating along with a good adhesion developed on the biomaterial surface by elongated membrane protrusions.

Mechanical, corrosion, and biocompatibility properties of Mg-Zr-Sr-Sc alloys for biodegradable implant applications

Magnesium (Mg) and its alloys are considered promising biodegradable implant materials because of their strength and natural degradation in the human body. However, the high corrosion rate of pure Mg in the physiological environment leads to rapid degradation before adequate bone healing. This mismatch between bone healing and the degradation of Mg implants supports the development of new Mg alloys with the addition of other suitable alloying elements in order to achieve simultaneously high corrosion resistance and desirable mechanical properties. This study systematically investigates the microstructure, mechanical properties, corrosion behavior, and biocompatibility of Mg-based alloys with the addition of different concentrations of scandium (Sc), i.e., Mg-0.6Zr-0.5Sr-xSc (x = 0.5, 1, 2, 3 wt.%). Results indicated that high concentration of Sc in strontium (Sr)-containing Mg alloys can alter their microstructures by suppressing the intermetallic phases along the grain boundaries and improve the corrosion resistance by forming chemically stable Sc oxide layers on the surfaces of the Mg alloys. Cytotoxicity assessment revealed that the Sc containing Mg alloys did not significantly alter the viability of human osteoblast-like SaOS2 cells. This study highlights the advantages of using Sc as an alloying element to simultaneously tune Mg alloys with higher strength and slower degradation. Statement of significanceRare earth elements such as scandium (Sc) with both a high solid-solubility and strong affinity towards oxygen can improve the mechanical and corrosion properties of magnesium (Mg) alloys. However, the feasibility of Sc-containing Mg alloys as biodegradable implant materials is scarcely reported. This study investigates the effects of different Sc concentrations on the mechanical, corrosion, and biocompatibility properties of Mg-Zr-Sr-Sc alloys. Our findings indicated that the addition of Sc significantly improves the mechanical and corrosion properties of Mg-Zr-Sr alloys. Moreover, in vitro cytotoxicity assessment of the Mg-Zr-Sr-Sc alloys did not show any adverse effects on the viability of osteoblast-like cells.

Effects of laser processing conditions on wettability and proliferation of Saos-2 cells on CoCrMo alloy surfaces

Abstract Any processing disturbances in laser surface texturing (LST) could compromise the resulting surface topography and their desired functional response. Disturbances such as focal plane offsets and beam incident angle variations are always present in LST processing of 3D parts and can affect the surface morphology. In this research the effects of these laser processing disturbances in producing laser induced surface structures (LIPSS) on CoCrMo alloy substrates were investigated. In particular, these two disturbances were considered as laser processing variables to determine their effects on functional responses of LIPSS treated surfaces, i.e. surface wettability and the proliferation of Saos-2 osteoblast-like cells were evaluated. It was found that the changes of laser processing conditions led to a decrease in surface wettability and Saos-2 cells proliferation. In addition, a correlation between surface wettability and cell proliferation on LIPSS treated surface was identified and conclusions made about the effects of investigated process disturbances on the functional response of LIPSS treated CoCrMo substrates.

Activating macrophages for enhanced osteogenic and bactericidal performance by Cu ion release from micro/nano-topographical coating on a titanium substrate

In the field of orthopaedics, inflammation-modulatory biomaterials are receiving increasing attentions due to their abilities to regulate innate immune response and mediate wound healing. In the current work, a Cu-containing micro/nano-topographical bio-ceramic surface (Cu-Hier-Ti surface) was employed as material model to explore the role played by Cu2+ release or material surface in regulating macrophage polarization as well as macrophage-mediated osteogenic and bactericidal effect. A Cu-free micro-topographical surface (Micro-Ti surface) generated by micro-arc oxidation was employed as control. The results showed that Cu2+ supplemented directly into the culture medium or released from Cu-Hier-Ti surface could polarize macrophages to pro-inflammatory M1 phenotype by activating Cu-transport signaling (copper transporter 1 (CTR1) and ATP7A) in macrophages, while the material characteristics exhibited anti-inflammatory effect to some extent by regulating integrin (α5, αM, β1 and β2) and TLR (TLR-3, TLR-4, Myd88 and Ticam-1/2) signaling. Macrophages grown on Cu-Hier-Ti surface or treated by Cu2+ could create a favorable inflammatory microenvironment for osteoblast-like SaOS-2 cell proliferation and differentiation. Moreover, Cu-Hier-Ti surface promoted macrophage capacity to engulf and kill bacteria, even though it did not show direct bactericidal effect against Staphylococcus aureus. In vivo results showed that Cu-Hier-Ti surface could lead to promoted osteointegraion and enhanced expression levels of M1 surface marker CD11c, growth factor BMP-6 and osteogenic makers including osteocalcin (OCN) and Runx-2 at the biomaterial/bone tissue interface in a rat model. The results indicate that Cu could be employed as a promising inflammation-modulatory agent to activate macrophages for enhanced osteogenic and bactericidal effect. Statement of significanceThe next generation of bone biomaterials should be active to regulate the local inflammatory environment such that it favors bone regeneration. For the design and development of Cu-containing inflammation-modulatory biomaterials, it is of great importance to recognize the exact role played by Cu2+ release or material surface characteristics. So far, relatively little is known about the regulatory role of Cu2+ or micro/nano-topographical surface on macrophages. The results in the current work suggest that Cu2+ release and material surface characteristics of Cu-containing micro/nano-topographical coating could activate distinct signaling pathways in macrophages. The activated M1 macrophages exhibited stimulatory effect on osteoblast maturation and enhanced bactericidal capacity against Staphylococcus aureus. This study might provide new thoughts for the development of multi-functional Cu-containing biomaterials.

In vitro studies of α-TCP and β-TCP produced from Clinocardium ciliatum seashells

In this study, α-TCP and β-TCP were successfully produced via a mechanochemical method from aragonite structures, Clinocardium ciliatum seashells, at 850 °C, 1000 °C, and 1200 °C sintering temperatures. The characterization of the obtained materials was carried out via FT-IR, SEM/EDX, BET, XRD, ICP-OES analysis. Samples were soaked for 21 days in simulated body fluid (SBF) for a bioactivity test. Additionally, MTT assay was applied to determine the cell viability of samples. Bioactivity in vitro tests showed that bone-like hydroxyapatite formed when the α-TCP and β-TCP were soaked in SBF. TCP bioceramics had a noncytotoxicity effect on SAOS-2 osteoblast-like cells and cell viability increased in 1 to 7 days. The produced bioceramics have ideal pore sizes and properties that are suitable for supporting biological activities. Tris-HCl buffer solution was used to obtain the level of biodegradation. It was seen that α-TCP exhibited better dissolution features than β-TCP.

Nanopillared Chitosan/Gelatin Films: A Biomimetic Approach for Improved Osteogenesis

Biomimicry strategies, inspired from natural organization of living organisms, are being widely used in the design of nanobiomaterials. Particularly, nonlithographic techniques have shown immense potential in the facile fabrication of nanostructured surfaces at large-scale production. Orthopedic biomaterials or coatings possessing extracellular matrix-like nanoscale features induce desirable interactions between the bone tissue and implant surface, also known as osseointegration. In this study, nanopillared chitosan/gelatin (C/G) films were fabricated using nanoporous anodic alumina molds, and their antibacterial properties as well as osteogenesis potential were analyzed by comparing to the flat C/G films and tissue culture polystyrene as controls. In vitro analysis of the expression of RUNX2, osteopontion, and osteocalcin genes for mesenchymal stem cells as well as osteoblast-like Saos-2 cells was found to be increased for the cells grown on nano C/G films, indicating early-stage osteogenic differentiation. Moreover, the mineralization tests (quantitative calcium analysis and alizarin red staining) showed that nanotopography significantly enhanced the mineralization capacity of both cell lines. This work may provide a new perspective of biomimetic surface topography fabrication for orthopedic implant coatings with superior osteogenic differentiation capacity and fast bone regeneration potential.

Bone protective effects of purified extract from Ruscus aculeatus on ovariectomy-induced osteoporosis in rats

Ruscus aculeatus is a source of steroidal saponins that could mimic sex hormones and could help alleviate the risk of fracture in osteoporotic patients. The aim of the present study was to evaluate the in vitro effects of an extract from R. aculeatus (ERA) on the proliferation of human osteoblast-like SaOS-2 cell line and to investigate the effects of the ERA administered orally for 10 weeks at three doses (50, 100 and 200 mg/kg) on the bone structure of rats with estrogen deficiency induced by bilateral ovariectomy. Bone turnover markers, hormones, histopathological and radiological disturbances were evidenced in the ovariectomized rats. ERA recovered most of the affected parameters in a dose-dependent manner similar to diosgenin and alendronate used as positive comparators. The main active compounds of ERA (ruscogenin and neoruscogenin) were docked into the Vit. D receptor and oestrogen receptors alpha and beta, and stable complexes were found with binding scores equal to those of estradiol and diosgenin.The findings of this study provide for the first time an insight into the effects of ERA on bone structure and suggest that ERA could be developed as a potential candidate for the prevention of postmenopausal osteoporotic complications.

Biodegradable polymer promotes osteogenic differentiation in immortalized and primary osteoblast-like cells

Biodegradable polymers have been broadly used as agents that can complex with and deliver osteoinductive agents, but osteoinductivity of the polymers themselves has been rarely studied. Here we report the osteoinductivity of poly(4-hydroxy-L-proline ester) (PHPE), a biodegradable cationic polymer with cell penetrating properties. Under physiological conditions, PHPE degrades into trans-4-hydroxy-L-proline (trans-Hyp), a non-coded amino acid with essential functions in collagen fibril formation and fibril stability. Treatment of SaOS-2 osteoblast-like cells and hFOB 1.19 primary osteoblast cells with PHPE promoted earlier collagen nodule formation and mineralization of the extracellular matrix compared to untreated cells, even when mineralization activators were absent in the growth medium. Our results indicate that PHPE is a potential osteoinductive agent in vitro that can favor bone regeneration. Moreover, this osteoinductive property could be partly attributed to the degradation product trans-Hyp, which could recapitulate some, but not all of the osteogenic activity. The primary findings of this study can be summarized as follows: treatment of cells with PHPE led to (1) the induction of COL1A1 expression, collagen synthesis and secretion in osteoblast-like cells, (2) mineralization of the ECM in both SaOS-2 and hFOB 1.19 primary osteoblasts, and (3) induction of BMP2 gene and protein expression in osteoblast-like cells, which can promote mineralization of the ECM and regeneration of the bone tissue. Our results suggest that PHPE is a non-cytotoxic polymer and can be potentially used to overcome collagenopathies such as osteogenesis imperfecta.

Template-assisted, Sol-gel Fabrication of Biocompatible, Hierarchically Porous Hydroxyapatite Scaffolds.

Hierarchically porous hydroxyapatite (HHA) scaffolds were synthesized by template-assisted sol-gel chemistry. Polyurethane foam and a block copolymer were used as templates for inducing hierarchically porous structures. The HHA scaffolds exhibited open porous structures with large pores of 400–600 µm and nanoscale pores of ~75 nm. In comparison with conventional hydroxyapatite (CHA), HHA scaffolds exhibited significantly higher surface areas and increased protein adsorption for bovine serum albumin and vitronectin. Both the HHA and CHA scaffolds exhibited well in vitro biocompatibility. After 1 day, Saos-2 osteoblast-like cells bound equally well to both HHA and CHA scaffolds, but after 7 days in culture, cell proliferation was significantly greater on the HHA scaffolds (p < 0.01). High surface area and hierarchical porous structure contributed to the selective enhancement of osteoblast proliferation on the HHA scaffolds.

Heat-treated carbon coatings on poly (l-lactide) foils for tissue engineering

Carbon-based materials have emerged as promising candidates for a wide variety of biomedical applications, including tissue engineering. We have developed a simple but unique technique for patterning carbon-based substrates in order to control cell adhesion, growth and phenotypic maturation. Carbon films were deposited on PLLA foils from distances of 3 to 7 cm. Subsequent heat-treatment (60 °C, 1 h) created lamellar structures with dimensions decreasing from micro- to nanoscale with increasing deposition distance. All carbon films improved the spreading and proliferation of human osteoblast-like MG 63 cells, and promoted the alignment of these cells along the lamellar structures. Similar alignment was observed in human osteoblast-like Saos-2 cells and in human dermal fibroblasts. Type I collagen fibers produced by Saos-2 cells and fibroblasts were also oriented along the lamellar structures. These structures increased the activity of alkaline phosphatase in Saos-2 cells. Carbon coatings also supported adhesion and growth of vascular endothelial and smooth muscle cells, particularly flatter non-heated carbon films. On these films, the continuity of the endothelial cell layer was better than on heat-treated lamellar surfaces. Heat-treated carbon-coated PLLA is therefore more suitable for bone and skin tissue engineering, while carbon-coated PLLA without heating is more appropriate for vascular tissue engineering.

Cross-linked cellulose nanocrystal aerogels as viable bone tissue scaffolds

Chemically cross-linked cellulose nanocrystal (CNC) aerogels possess many properties beneficial for bone tissue scaffolding applications. CNCs were extracted using sulfuric acid or phosphoric acid, to produce CNCs with sulfate and phosphate half-ester surface groups, respectively. Hydrazone cross-linked aerogels fabricated from the two types of CNCs were investigated using scanning electron microscopy, X-ray micro-computed tomography, X-ray photoelectron spectroscopy, nitrogen sorption isotherms, and compression testing. CNC aerogels were evaluatedin vitrowith osteoblast-like Saos-2 cells and showed an increase in cell metabolism up to 7 days while alkaline phosphatase assays revealed that cells maintained their phenotype. All aerogels demonstrated hydroxyapatite growth over 14 days while submerged in simulated body fluid solution with a 0.1 M CaCl2 pre-treatment. Sulfated CNC aerogels slightly outperformed phosphated CNC aerogels in terms of compressive strength and long-term stability in liquid environments, and were implanted into the calvarian bone of adult male Long Evans rats. Compared to controls at 3 and 12 week time points, sulfated CNC aerogels showed increased bone volume fraction of 33% and 50%, respectively, compared to controls, and evidence of osteoconductivity. These results demonstrate that cross-linked CNC aerogels are flexible, porous and effectively facilitate bone growth after they are implanted in bone defects. Statement of SignificanceDue to the potential complications associated with autografts, there is a need for synthetic bone tissue scaffolds. Here, we report a new naturally-based aerogel material for bone regeneration made solely from chemically cross-linked cellulose nanocrystals (CNC). These highly porous CNC aerogels were shown to promote the proliferation of bone-like cells and support the growth of hydroxyapatite on their surface in vitro. The first in vivo study on these materials was conducted in rats and showed their osteconductive properties and an increase in bone volume up to 50% compared to sham sites. This study demonstrates the potential of using functionalized cellulose nanocrystals as the basis for aerogel scaffolds for bone tissue engineering.

Electronic cigarette liquid exposure induces flavor-dependent osteotoxicity and increases expression of a key bone marker, collagen type I.

Electronic cigarettes (e-cigarettes) are nicotine delivery devices advertised as a healthier alternative to conventional tobacco products, but their rapid rise in popularity outpaces research on potential health consequences. As conventional tobacco use is a risk factor for osteoporosis, this study examines whether exposure to electronic liquid (e-liquid) used in e-cigarettes affects bone-forming osteoblasts. Human MG-63 and Saos-2 osteoblast-like cells were treated for 48hours with 0.004%-4.0% dilutions of commercially available e-liquids of various flavors with or without nicotine. Changes in cell viability and key osteoblast markers, runt-related transcription factor 2 and Col1a1, were assessed. With all e-liquids tested, cell viability decreased in a dose-dependent manner, which was least pronounced in flavorless e-liquids, most pronounced in cinnamon-flavored e-liquids and occurred independently of nicotine. Col1a1, but not runt-related transcription factor 2, mRNA expression was upregulated in response to coffee-flavored and fruit-flavored e-liquids. Cells treated with a non-cytotoxic concentration of fruit-flavored Mango Blast e-liquid with or without nicotine showed significantly increased collagen type I protein expression compared to culture medium only. We conclude that the degree of osteotoxicity is flavor-dependent and occurs independently of nicotine and that flavored e-liquids reveal collagen type I as a potential target in osteoblasts. This study elucidates potential consequences of e-cigarette use in bone.

Response of Saos-2 osteoblast-like cells to laser surface texturing, sandblasting and hydroxyapatite coating on CoCrMo alloy surfaces

Cobalt chrome alloys are commonly used in orthopaedic implants where high stiffness and wear resistance are required. This study proposes Laser Surface Texturing (LST) as a cost-effective mean for producing bioinspired surface textures in order to improve the performance of CoCrMo orthopaedic implants. Cobalt-chrome alloy disks were modified using three different LST strategies: i) micro-scale texturing using a nanosecond laser source; (ii) micro-scale texturing with an ultrashort laser source and (iii) bioinspired sub-micron scale texturing with an ultrashort laser source. The modified disks were characterized and compared to blasted, hydroxyapatite coated and polished surface finishes. Saos-2 osteoblast-like cells were seeded on the different surfaces and their proliferation and morphology was assessed. The laser modification increases the surface energy of the CoCrMo alloy disks when compared to their untreated counterparts. The bioinspired sub-micron textured surfaces exhibited the highest cell metabolic activity on day 7 of the MTT assay.

Co-culture of human chondrogenic microtissues with osteoblast-like Saos-2 cells or HFF-1 fibroblasts influence the differentiation potential of spheroids

Co-culture of human chondrogenic microtissues with osteoblast-like Saos-2 cells or HFF-1 fibroblasts influence the differentiation potential of spheroids