Proliferation Of Osteoblast-like MG-63 Cells Research Articles

Tri-Component Hydrogel as Template for Nanocrystalline Hydroxyapatite Deposition Using Alternate Soaking Method for Bone Tissue Engineering Applications.

Composite hydrogels containing apatite-like particles can act as scaffolds for osteoblast proliferation, with applications in bone tissue engineering. In this respect, porous biocompatible hydrogels were obtained from chitosan, oxidized pullulan, and PVA in different ratios. The stability of the hydrogels was ensured both by covalent bonds between aldehyde groups of oxidized pullulan and free amino groups of chitosan, and by physical bonds formed during freeze-thaw cycles and lyophilization. The deposition of calcium phosphates was performed by alternate soaking of the porous hydrogels into solutions with calcium and phosphate ions, assuring a basic pH required for hydroxyapatite formation. The mineralized hydrogels were characterized using FTIR spectroscopy, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis, showing that inorganic particles containing between 80 and 92% hydroxyapatite were deposited in a high amount on the pore walls of the polymeric matrix. The composition of the organic matrix influenced the crystallization of calcium phosphates and the mechanical properties of the composite hydrogels. In vitro biological tests showed that mineralized hydrogels support the proliferation of MG-63 osteoblast-like cells to a greater extent compared to pristine hydrogels.

Hydroxyapatite Double Substituted with Zinc and Silicate Ions: Possibility of Mechanochemical Synthesis and In Vitro Properties

In this study, the mechanochemical synthesis of substituted hydroxyapatite (HA) containing zinc and silicon ions having a chemical formula of Ca10-xZnx(PO4)6-x(SiO4)x(OH)2-x, where x = 0.2, 0.6, 1.0, 1.5, and 2.0, was carried out. The synthesized materials were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and inductively coupled plasma spectroscopy. We found that HA co-substituted with zinc and silicate formed up to x = 1.0. At higher concentrations of the substituents, the formation of large amounts of an amorphous phase was observed. The cytotoxicity and biocompatibility of the co-substituted HA was studied in vitro on Hek293 and MG-63 cell lines. The HA co-substituted with zinc and silicate demonstrated high biocompatibility; the lowest cytotoxicity was observed at x = 0.2. For this composition, good proliferation of MG-63 osteoblast-like cells and an increased solubility compared with that of HA were detected. These properties allow us to recommend the synthesized material for medical applications, namely, for the restoration of bone tissue and manufacture of biodegradable implants.

Analysis of the Calcium Phosphate-Based Hybrid Layer Formed on a Ti-6Al-7Nb Alloy to Enhance the Ossseointegration Process.

This paper reports on hybrid, bioactive ceramic Ca-P-based coating formation on a Ti-6Al-7Nb alloy substrate to enhance the osseointegration process. The Ti alloy was anodized in a Ca3(PO4)2 suspension and then the additional layer was formed by the sol-gel technique to obtain a mixture of the calcium phosphate compounds. The oxide layer was porous and additional ceramic particles were formed after sol-gel treatment (scanning electron microscopy analysis coupled with energy-dispersive x-ray spectroscopy). The ceramic particles were formed on some parts of the oxide layer and did not completely fill the pores. The layer thickness of the anodized Ti alloy was comprised between 3.01 and 5.03 µm and increased to 7.52–12.30 µm after the formation of an additional layer. Post-treatment of the anodized Ti alloys caused a decrease in surface roughness, and the layer became strongly hydrophilic. Crystalline phase analysis (X-ray diffraction, XRD) showed that the hybrid layer was composed of TiO2 (anatase), Ca3(PO4)2, Ca10(PO4)6(OH)2 and a partially amorphous phase; thus, the layer was also analyzed by Raman spectroscopy. The hybrid layer showed worse adhesion to the substrate than the anodized layer only; however, the coating was not brittle, and the first delamination of the layer was determined at 1.84 ± 0.11 N during scratch-test measurement. The hybrid coating was favorable for collagen type I and lactoferrin adsorption, strongly influencing the proliferation of osteoblast-like MG-63 cells. The coatings were cytocompatible and may find applications in formation of the functional layers on long-term implants’ surface after.

Fabrication of bioactive corrosion-resistant polyaniline/TiO2 nanotubes nanocomposite and their application in orthopedics

The long-term permanence of titanium implant was improved by incorporation of polyaniline on TiO2 nanotubes. The polyaniline incorporated TiO2 nanotubes (PANI-2/TNTA) has enhanced the bioactivity and corrosion resistance. Highly ordered nanotubes were formed on the titanium metal with an average tube diameter of ~ 85 nm which was confirmed by HR-SEM. The presence of anatase and rutile mixed phases was identified by XRD analysis. The formation of interfacial bonding between PANI and TNTA was confirmed by Raman and XPS analysis. The lower corrosion current density and higher polarization resistance (Rp) obtained for PANI-2/TNTA nanocomposite revealed the enhanced corrosion resistance behavior in physiological conditions. To ensure the durability of PANI-2/TNTA, the corrosion behavior was analyzed at different applied potentials using dynamic electrochemical impedance spectroscopy (DEIS). Up to 1 V, the higher impedance value was observed in Hanks’ solution. The bioactivity of the PANI-2/TNTA nanocomposite was confirmed by the more-notable cell adhesion and proliferation of MG-63 osteoblast-like cells. PANI-2/TNTA has the ability to reduce implant-associated infections. The existence of the amine group is responsible for better biostability and antimicrobial activity.

Effect of calcium glucoheptonate on proliferation and osteogenesis of osteoblast-like cells in vitro.

Calcium is the key macromineral having a role in skeletal structure and function, muscle contraction, and neurotransmission. Bone remodeling is maintained through a constant balance between calcium resorption and deposition. Calcium deficiency is resolved through calcium supplementation, and among the supplements, water-soluble organic molecules attracted great pharmaceutical interest. Calcium glucoheptonate is a highly water-soluble organic calcium salt having clinical use; however, detailed investigations on its biological effects are limited. We assessed the effects of calcium glucoheptonate on cell viability and proliferation of osteoblast-like MG-63 cells. Calcium uptake and mineralization were evaluated using Alizarin red staining of osteoblast-like MG-63 cells treated with calcium glucoheptonate. Expression of osteogenic markers were monitored by western blotting, immunofluorescence, and qRT-PCR assays. Increased proliferation and calcium uptake were observed in the MG-63 cells treated with calcium glucoheptonate. The treatment also increased the expression of osteopontin and osteogenic genes such as collagen-1, secreted protein acidic and cysteine rich (SPARC), and osteocalcin. Calcium glucoheptonate treatment did not exert any cytotoxicity on colorectal and renal epithelial cells, indicating the safety of the treatment. This is the first report with evidence for its beneficial effect for pharmaceutical use in addressing calcium deficiency conditions.

Cucurbita pepo leaf extract induced synthesis of zinc oxide nanoparticles, characterization for the treatment of femoral fracture

The present work showed the green, eco-friendly synthesis of zinc oxide nanoparticles (ZnO NPs) using leaf extract of Cucurbita pepo. The prepared ZnO NPs were studied using different characterization techniques such as Fourier transform infrared (FTIR), X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis) and Transmission electron microscopy (TEM). TEM images confirmed the formation of NPs with average size of 8 nm. XRD showed the crystalline nature of prepared ZnO NPs. This shows that the ZnO NPs induced cytotoxicity that affected the proliferation of MG63 osteoblast-like cells in a concentration dependent manner. Further, the ZnO NPs induced reduction in cell proliferation was confirmed by Fluorescein diacetate hydrolysis (FDA) staining. FDA staining results showed a reduction in fluorescence intensity with an increase in the concentration of ZnO NPs. The untreated control which was unaffected showed the highest fluorescence compared to ZnO NPs treated samples. A significantly diminished fluorescence was observed in samples incubated with 80 ppm ZnO NPs. In conclusion, these cell experimental results confirmed that the fabricated ZnO NPs are an important substitute for osteoporotic and bone tissue formation.

Preparation and characterization of highly porous ceramic-based nanocomposite scaffolds with improved mechanical properties using the liquid phase-assisted sintering method

Recent advances in the field of biomaterials have led to the development of ceramic–matrix nanocomposites with enhanced mechanical properties, which is essential for hard tissue scaffolds. In this study, the improvement in mechanical and biological properties of β-tricalcium phosphate reinforced with 45S5 bioactive glass under different sintering conditions was studied. In order to improve the thermal stability and biological responses, β-tricalcium phosphate was doped with 5 mol% strontium ions. Highly porous nanocomposites, with different weight ratios of Sr-tricalcium phosphate/bioactive glass (75/25, 50/50, 25/75), were fabricated through the foam replication method by sintering samples under various thermal conditions (1200–1250 ℃/0–1 h). The effects of bioactive glass content and sintering parameters on microstructure and mechanical behaviors of the nanocomposites were assessed. The obtained results showed that increasing 45S5 bioactive glass content, sintering temperature, and dwelling time gradually improved the mechanical properties of final products which were ascribed to the improved ceramic densification. The composites with the optimal compressive strength were selected to apply in further characterization and cell culture experiments. The selected scaffolds showed excellent bioactivity since a continuous layer of minerals covered the entire surface of composites after immersion in simulated body fluid solution for two weeks. Moreover, the cell culture studies demonstrated that the composite scaffolds could well support the attachment and proliferation of MG-63 osteoblast-like cells. This investigation clearly concluded that the appropriate incorporation of 45S5 bioactive glass into the β-tricalcium phosphate matrix can effectively promote the mechanical behavior, bioactivity, and biocompatibility of the resultant composite scaffolds.

Cell attachment and proliferation of osteoblast-like MG63 cells on silk fibroin membrane for guided bone regeneration.

BackgroundThe aim of this study is to verify the feasibility of using silk fibroin (SF) as a potential membrane for guided bone regeneration (GBR).MethodsVarious cellular responses (i.e., cell attachment, viability, and proliferation) of osteoblast-like MG63 cells cultured on an SF membrane were quantified. After culturing on an SF membrane for 1, 5, and 7 days, the attachment and surface morphology of MG63 cells were examined by optical and scanning electron microscopy (SEM), cell viability was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell proliferation was quantified using 4′,6-diamidino-2-phenylindole (DAPI) fluorescence staining.ResultsOptical microscopy revealed that MG63 cells cultured on the SF membrane proliferated over the 7-day observation period. The viability of cells cultured on SF membranes (SF group) and on control surfaces (control group) increased over time (P < 0.05); however, at respective time points, cell viability was not significantly different between the two groups (P > 0.05). In contrast, cell proliferation was significantly higher in the SF membrane group than in the control group at 7 days (P < 0.05).ConclusionsThese results suggest that silk fibroin is a biocompatible material that could be used as a suitable alternative barrier membrane for GBR.

Effect of Clodronate on Antigenic Profile, Growth, and Differentiation of Osteoblast-Like Cells

To evaluate the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ) by studying the effects of different concentrations of clodronate, a non-nitrogen-containing bisphosphonate, on osteoblast growth, differentiation, and antigenic profile. Osteoblast-like cells (MG63) were incubated in culture medium with different doses of clodronate. Their proliferative capacity was determined with a spectrophotometric technique (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium assay). Flow cytometry was used to study the antigenic profile. Cell differentiation was evaluated by nodule formation and alkaline phosphatase (ALP) activity was measured by spectrophotometric assay. Clodronate had a significant stimulatory effect on osteoblast-like cell (MG63) proliferation (P<.05). A significant decrease in the expression of CD54, CD80, CD86, and HLA-DR membrane antigens versus controls was observed after 24hours of treatment with the different clodronate doses assayed (P<.05). A significant decrease (P= .004) in ALP activity was found after 24hours of treatment with the lowest dose (10(-9)mol/L), and a significant decrease in calcium deposition was found after 15 and 21days of treatment (P < .05). Clodronate increases the proliferation of MG63 osteoblast-like cells and decreases their differentiation capacity, generally at low doses, and modulates the expression of costimulatory molecules associated with immune function. Clodronate exerts its effect on osteoblasts by altering their physiology and impairing their repair capacity, which could be related to the development of BRONJ. However, further research is warranted to elucidate fully the mechanisms by which bisphosphonates can produce this disease.

The effects of 6-gingerol on proliferation, differentiation, and maturation of osteoblast-like MG-63 cells.

We investigated whether 6-gingerol affects the maturation and proliferation of osteoblast-like MG63 cells in vitro. Osteoblast-like MG63 cells were treated with 6-gingerol under control conditions, and experimental inflammation was induced by tumor necrosis factor-α (TNF-α). Expression of different osteogenic markers and cytokines was analyzed by real-time PCR, Western blotting, and enzyme-linked immunosorbent assay. In addition, alkaline phosphatase (ALP) enzyme activity and biomineralization as markers for differentiation were measured. Treatment with 6-gingerol resulted in insignificant effects on the proliferation rate. 6-Gingerol induced the differentiation of osteoblast-like cells with increased transcription levels of osteogenic markers, upregulated ALP enzyme activity, and enhanced mineralized nodule formation. Stimulation with TNF-α led to enhanced interleukin-6 and nuclear factor-κB expression and downregulated markers of osteoblastic differentiation. 6-Gingerol reduced the degree of inflammation in TNF-α-treated MG-63 cells. In conclusion, 6-gingerol stimulated osteoblast differentiation in normal physiological and inflammatory settings, and therefore, 6-gingerol represents a promising agent for treating osteoporosis or bone inflammation.

Direct covalent coupling of proteins to nanostructured plasma polymers: a route to tunable cell adhesion

Flat and nanostructured thin films were fabricated by deposition of ultra-thin (<2nm) layer of hydrocarbon plasma polymer over polished silicon and over a pattern of 8nm-thick poly(ethylene) islands on silicon. Linker-free radical-based covalent binding of bovine serum albumin and tropoelastin was confirmed for both types of films. The binding capability of albumin was found to be stable over many days of ambient air storage time. Tropoelastin-mediated flat plasma polymers favored adhesion and proliferation of osteoblast-like MG-63 cells. Nanostructured plasma polymers were multi-affine and their hierarchical surface represented an additional barrier for cell attachment.

High doses of bisphosphonates reduce osteoblast-like cell proliferation by arresting the cell cycle and inducing apoptosis

ObjectivesThe study objective was to evaluate the effect on osteoblast growth of high concentrations of three nitrogen-containing bisphosphonates (pamidronate, alendronate, and ibandronate) and one non-nitrogen-containing bisphosphonate (clodronate), using the MG-63 cell line as an osteoblast model, in order to determine the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ). Materials and methodsOsteoblasts were incubated in culture medium with different doses of pamidronate, alendronate, ibandronate or clodronate. The proliferative capacity of the osteoblasts was determined by spectrophotometry (MTT-based) at 24 h of culture. Flow cytometry was used to determine the percentage of cells in each cell cycle phase (G0/G1, G2/M, and S) and to discriminate apoptotic cell death from necrotic cell death in the cell cycle at 24 h of treatment. ResultsAll the bisphosphonates assayed produced a significant and dose-dependent reduction in MG-63 proliferation at the high doses assayed (10−4 and 5 × 10−5 M) in comparison with controls (p <0.001). Cell cycle study revealed that all assayed bisphosphonates significantly arrested the cell cycle in phase G0/G1 at doses of 10−4 and 5 × 10−5 M, increasing the percentage of cells in this phase (p <0.05). Apoptosis/necrosis studies showed significant changes compared with control cells, with an increased percentage of cells in apoptosis after treatment with 10−4 or 5 × 10−5 M of pamidronate, alendronate, ibandronate, or clodronate (p <0.05). ConclusionsHigh doses of nitrogen-containing or non-nitrogen-containing bisphosphonates can reduce the proliferation of MG-63 osteoblast-like cells by arresting the cell cycle and inducing apoptosis/necrosis.

Nitrogen-containing bisphosphonates modulate the antigenic profile and inhibit the maturation and biomineralization potential of osteoblast-like cells.

The aim was to evaluate the effect of three nitrogen-containing bisphosphonates at different concentrations on osteoblast growth, differentiation, and antigenic profile, using the MG-63 cell line as osteoblast model, in order to determine the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ). Osteoblasts were incubated in culture medium with 10(-5), 10(-7), or 10(-9)M of pamidronate, alendronate, or ibandronate. Proliferative capacity of the osteoblasts was determined by spectrophotometry (MTT) at 24 and 48h of culture. Flow cytometry was used to study antigenic profile (CD54, CD80, CD86, HLA-DR) and phagocytic activity. Cell differentiation was evaluated at 7, 15, and 21days by the study of nodule formation and alkaline phosphatase activity (ALP) at 24h by spectrophotometric assay. Pamidronate, alendronate, and ibandronate each exerted a significant stimulatory effect on MG63 proliferation that depended on the dose and treatment duration (p < 0.05). In general, a significantly decreased expression of CD54, CD80, and HLA-DR membrane antigens was observed after 24h of treatment with each nitrogen-containing bisphosphonate (p < 0.05), but there was no significant difference in phagocytic activity versus controls. A decrease in ALP activity was observed after 24h of treatment and a decrease in calcium deposition after 15 and 21days (p < 0.05). Nitrogen-containing bisphosphonates can increase the proliferation of MG-63 osteoblast-like cells, modulate their expression of co-stimulatory molecules associated with immune function, and decrease their differentiation capacity, generally at low doses. These findings suggest that low doses of nitrogen-containing bisphosphonates exert their effect on osteoblasts by altering their physiology, which would explain the disruption of their repair capacity and may be directly related to the development of BRONJ.

Fabrication of Porous Hydroxyapatite Scaffolds as Artificial Bone Preform and its Biocompatibility Evaluation

In this study, a novel porous hydroxyapatite scaffold was designed and fabricated to imitate natural bone through a multipass extrusion process. The conceptual design manifested unidirectional microchannels at the exterior part of the scaffold to facilitate rapid biomineralization and a central canal that houses the bone marrow. External and internal fissures were minimized during microwave sintering at 1,100°C. No deformation was noted, and a mechanically stable scaffold was fabricated. Detailed microstructure of the fabricated artificial bone was examined by scanning electron microscope and X-ray diffractometer, and material properties like compressive strength were evaluated. The initial biocompatibility was examined by the cell proliferation of MG-63 osteoblast-like cells using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Preliminary in vivo investigation in a rabbit model after 4 weeks and 8 weeks of implantation showed full osteointegration of the scaffold with the native tissue, and formation of bone tissue within the pore network, as examined by microcomputed tomography analyses and histological staining. Osteon-like bone microarchitecture was observed along the unidirectional channel with microblood vessels. These confirm a biomimetic regeneration model in the implanted bone scaffold, which can be used as an artificial alternative for damaged bone.

Cellular Response of Calcium Phosphate Bone Substitute Containing Hydroxyapatite and Tricalcium Phosphate

This study developed calcium phosphate bone substitutes and their microstucture and in vitro cell response were evaluated in comparison with commercial hydroxyapatite (HA). HA powder was ball-milled and then sintered to transfer into the calcium phosphate bulks (CPB). The density, hardness, and microstructure of the CPB were investigated. The viability and proliferation of MG63 osteoblast-like cells on the commercial HA and the CPB were evaluated. The x-ray diffraction confirmed that the CPB consisted of α-tricalcium phosphate (α-TCP), CaO, and HA. The hardness, density, and α-TCP-to-HA ratio of the CPB decreased when increasing the sintering duration. Cell tests demonstrated that the CPB exhibited an earlier cell-spread response than the commercial HA. This study demonstrated that a phase transformation of HA into α-TCP and CaO was achieved by sintering. The cell tests indicated that the CPB has favorable in vitro cellular performance, which implied that it presented potential as bone substitute.

Effects of Er:YAG laser on bacteria associated with titanium surfaces and cellular response in vitro

This in vitro study examined (a) the anti-bacterial efficacy of a pulsed erbium-doped yttrium aluminum garnet (Er:YAG) laser applied to Streptococcus sanguinis or Porphyromonas gingivalis adhered to either polished or microstructured titanium implant surfaces, (b) the response of osteoblast-like cells and (c) adhesion of oral bacteria to titanium surfaces after laser irradiation. Thereto, (a) bacteria adhered to titanium disks were irradiated with a pulsed Er:YAG laser (λ = 2,940 nm) at two different power settings: a lower mode (12.74 J/cm(2) calculated energy density) and a higher mode (63.69 J/cm(2)). (b) After laser irradiation with both settings of sterile titanium, disks were seeded with 10(4) MG-63 cells/cm(2). Adhesion and proliferation were determined after 1, 4, and 24 h by fluorescence microscopy and scanning electron microscopy. (c) Bacterial adhesion was also studied on irradiated (test) and non-irradiated (control) surfaces. Adhered P. gingivalis were effectively killed, even at the lower laser setting, independent of the material's surface. S. sanguinis cells adhered were effectively killed only at the higher setting of 63.69 J/cm(2). Laser irradiation of titanium surfaces had no significant effects on (b) adhesion or proliferation of osteoblast-like MG-63 cells or (c) adhesion of both oral bacterial species in comparison to untreated surfaces. An effective decontamination of polished and rough titanium implant surfaces with a Er:YAG laser could only be achieved with a fluence of 63.69 J/cm(2). Even though this setting may lead to certain surface alterations, no significant adverse effect on subsequent colonization and proliferation of MG-63 cells or increased bacterial adhesion was found in comparison to untreated control surfaces.

Single-step electrochemical deposition of antimicrobial orthopaedic coatings based on a bioactive glass/chitosan/nano-silver composite system

Composite orthopaedic coatings with antibacterial capability containing chitosan, Bioglass® particles (9.8μm) and silver nanoparticles (Ag-np) were fabricated using a single-step electrophoretic deposition (EPD) technique, and their structural and preliminary in vitro bactericidal and cellular properties were investigated. Stainless steel 316 was used as a standard metallic orthopaedic substrate. The coatings were compared with EPD coatings of chitosan and chitosan/Bioglass®. The ability of chitosan as both a complexing and stabilizing agent was utilized to form uniformly deposited Ag-np. Due to the presence of Bioglass® particles, the coatings were bioactive in terms of forming carbonated hydroxyapatite in simulated body fluid (SBF). Less than 7wt.% of the incorporated silver was released over the course of 28days in SBF and the possibility of manipulating the release rate by varying the deposition order of coating layers was shown. The low released concentration of Ag ions (<2.5ppm) was efficiently antibacterial against Staphyloccocus aureus up to 10days. Although chitosan and chitosan/Bioglass® coating supported proliferation of MG-63 osteoblast-like cells up to 7days of culture, chitosan/Bioglass®/Ag-np coatings containing 342 μg of Ag-np showed cytotoxic effects. This was attributed to the relatively high concentration of Ag-np incorporated in the coatings.

Human β‐defensins differently affect proliferation, differentiation, and mineralization of osteoblast‐like MG63 cells

Purpose of this study was to investigate whether human β-defensins (hBDs) affect maturation and proliferation of osteoblast-like MG63 cells in vitro. Osteoblast-like MG63 cells were stimulated with hBD-1, -2, and -3 under control conditions and with hBD-2 during experimental inflammation (induced by interleukin-1β, tumor necrosis factor-α, toll-like receptor-2 and -4 agonists). Expression of different osteogenic markers and hBDs were analyzed by real-time PCR, immunohistochemistry, and enzyme-linked immunosorbent assay. In addition, alkaline phosphatase (ALP) enzyme activity and biomineralization as markers for differentiation were monitored. All tested hBDs were expressed on mRNA and protein level in MG63 cells. Only stimulation with hBD-2 elevated the proliferation rate. hBD-2 and hBD-3 positively affected the differentiation of osteoblast-like cells provided by increased transcript levels of osteogenic markers, up-regulated ALP enzyme activity and enhanced mineralized nodule formation. All pro-inflammatory stimuli enhanced interleukin-6 and hBD-2 expression and down-regulated markers of osteoblastic differentiation. In accordance, inflammation increased transcript level of Notch-1 (an inhibitor of osteoblastic differentiation). hBD-2 was not able to revert effects of inflammation on differentiation. In bone cells human β-defensins exhibit further functions than antimicrobial peptide activity. These include stimulation of proliferation and differentiation. Differentiation arrest due to inflammation could not be overcome by hBD-2 alone.

Premixed, injectable PLA-modified calcium deficient apatite biocement (cd-AB) with washout resistance

By using a non-aqueous solution as the mixing liquid, the washout resistance of the calcium deficient apatite biocement (cd-AB) was significantly improved, over that of the conventional method of using cd-AB with water as the liquid phase. In this study, premixed and injectable cd-AB was prepared, which had the advantage of being stable in the syringe and hardens only after being delivered to the defect area. The cd-AB powder with a Ca/P ratio of 1.5 consists of a mixture of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA). A solution of polylactide (PLA) in N-methyl-2-pyrrolidone (NMP) was used as the liquid phase of the premixed cd-AB. The premixed cd-AB paste injected into an aqueous environment exhibited excellent washout resistance. The premixed cd-AB had longer setting time and lower compressive strength than conventional cd-AB. The hydration products of premixed cd-AB were a mixture of calcium deficient hydroxyapatite (cd-HA) and PLA. In vitro Tris–HCl immersion tests demonstrated that the premixed cd-AB could be degradable. The results revealed that the premixed cd-AB was cytocompatible and had no adverse effects on the attachment and proliferation of MG-63 osteoblast-like cells in vitro. The most distinct advantages of premixed and injectable PLA-modified cd-AB were its excellent washout resistance and in vitro degradability, suggesting that it may be a promising candidate for bone repair.

Influence of processing parameters on pore structure of 3D porous chitosan–alginate polyelectrolyte complex scaffolds

Fabrication of porous polymeric scaffolds with controlled structure can be challenging. In this study, we investigated the influence of key experimental parameters on the structures and mechanical properties of resultant porous chitosan-alginate (CA) polyelectrolyte complex (PEC) scaffolds, and on proliferation of MG-63 osteoblast-like cells, targeted at bone tissue engineering. We demonstrated that the porous structure is largely affected by the solution viscosity, which can be regulated by the acetic acid and alginate concentrations. We found that the CA PEC solutions with viscosity below 300 Pa.s yielded scaffolds of uniform pore structure and that more neutral pH promoted more complete complexation of chitosan and alginate, yielding stiffer scaffolds. CA PEC scaffolds produced from solutions with viscosities below 300 Pa.s also showed enhanced cell proliferation compared with other samples. By controlling the key experimental parameters identified in this study, CA PEC scaffolds of different structures can be made to suit various tissue engineering applications.