Search

Background Polymeric sponge technique is recommended for developing the desired porosity of Biphasic calcium phosphate (BCP) which may favor bone regeneration. Purpose To investigate the healing of BCP with ratio of HA30/β‐TCP70 (HA30) and HA70/β‐TCP30 (HA70) polymeric sponge preparation, compare to commercial BCP (MBCP+TM). Materials and Methods Materials were tested X‐ray diffraction (XRD) pattern and scanning electron microscope (SEM) analysis. In eight male pigs, six calvarial defects were created in each subject. The defects were the filled with 1 cc of autogenous bone, MBCP+TM (MBCP), HA30, HA70, and left empty (negative group). The new bone formations, residual material particles and bone‐to‐graft contacts were analyzed at 4, 8, 12 and 16 weeks. Results Fabricated BCP showed well‐distributed porosity. At 16 weeks, new bone formations were 45.26% (autogenous), 33.52% (MBCP), 24.34% (HA30), 19.43% (HA70) and 3.37% (negative). Residual material particles were 1.88% (autogenous), 17.58% (MBCP), 26.74% (HA30) and 37.03% (HA70). These values were not significant differences (Bonferroni correction

BACKGROUND Polycaprolactone (PCL)-biphasic calcium phosphate (BCP) scaffolds fabricated using Melt-Stretching and Compression Molding (MSCM) can release calcium and phosphate ions, which are essential for bone formation. OBJECTIVE Responses of the osteoblasts seeded on three groups of scaffolds including group A; PCL-20% BCP (%wt), group B; PCL-30% BCP and group C (control); pure PCL (100% PCL) were evaluated. METHODS The cell-scaffold constructs were made by seeding osteoblast cell lines at 1×105 cells/scaffold. The constructs of each group were divided for culturing in proliferation medium (PR) and osteogenic induction medium (OS) for 30 days. RESULTS The cells attached and grew on the scaffolds of all groups. The cell number and the differentiation markers of groups A and B were remarkably higher than those of group C over the observation periods. Slow proliferation of the cells of group A and B in the PR medium in the first 7 days corresponded to the maximum increases in alkaline phosphatase activities (ALP). The maximum levels of ALP of those groups in the OS medium were not detected until day 14. The levels of osteocalcin of those groups were not statistically different when cultured in both mediums. CONCLUSIONS The MSCM scaffolds are suitable for supporting attachment and growth of the osteoblasts. Additional BCP into the PCL-based scaffolds accelerate early differentiation of the cells in the constructs even without osteogenic-inductive condition.

Background Biocompatibility and degradation of poly e-caprolactone (PCL)-Biphasic Calcium Phosphate (BCP) scaffolds fabricated by the "Melt Stretching and Compression Molding (MSCM)" technique were evaluated in rat models. Objectives Degradation behaviors and histological biocompatibility of the PCL-20% BCP MSCM scaffolds and compare with those of PCL-20% β-tricalcium phosphate (TCP) scaffolds commercially fabricated by Fused Deposition Modeling (FDM) were evaluated. Methods The study groups included Group A: PCL-20% BCP MSCM scaffolds and Group B: PCL-20% TCP FDM scaffolds, which were implanted subcutaneously in twelve male Wistar rats. On day 14, 30, 60 and 90, dimensional changes of the scaffolds and their surrounding histological features were assessed using Micro-Computed Tomography (μ-CT) and histological analysis. Changes of their molecular weight were assessed using Gel Permeation Chromatography (GPC). Results Formation of collagen and new blood vessels throughout the scaffolds of both groups increased with time with low degrees of inflammation. The μ-CT and GPC analysis demonstrated that the scaffolds of both groups degraded with time, but, their molecular weight slightly changed over the observation periods. All results of both groups were not significantly different. Conclusions The PCL-20% BCP MSCM scaffolds were biocompatible and biodegradable in vivo. Their properties were comparable to those of the commercial PCL-20% TCP scaffolds.

A composite of 70/30 poly(lactic acid)/hydroxyapatite was systematically prepared using various amounts of glycidyl methacrylate as reactive compatibilizer or Joncryl ADR®-4368 containing nine glycidyl methacrylate functions as a chain extension/branching agent to improve the mechanical and biological properties for suitable usage as internal bone fixation devices. The effect of glycidyl methacrylate/Joncryl on mechanical properties of poly(lactic acid)/hydroxyapatite was investigated through flexural strength. Cell proliferation and differentiation of osteoblast-like MC3T3-E1 cells cultured on the composite samples were determined by Alamar Blue assay and alkaline phosphatase expression, respectively. Result shows that flexural strength tends to decrease, as glycidyl methacrylate content increases except for 1 wt.% glycidyl methacrylate. With an addition of dicumyl peroxide, the flexural strength shows an improvement than that of without dicumyl peroxide probably due to the chemical bonding of the hydroxyapatite and poly(lactic acid) as revealed by FTIR and NMR, whereas the composite with 5 wt.% Joncryl shows the best result, as the flexural strength increases getting close to pure poly(lactic acid). The significant morphology change could be seen in composite with Joncryl where the uniform agglomeration of hydroxyapatite particles oriented in poly(lactic acid) matrix. Addition of the epoxy functional compatibilizers at suitable percentages could also have benefits to cellular attachment, proliferation, differentiation and mineralization. So that, this poly(lactic acid)/hydroxyapatite composite could be a promising material to be used as internal bone fixation devices such as screws, pins and plates.

The production of the biomimetic scaffolds with well-designed porosity parameters is a critical and challenging factor in biomaterials processing. The porosity parameters (i.e., pore size, pore shape, and distribution pattern) impact scaffold permeability, proteins/cells infiltration, and angiogenesis. This study introduced a new approach for the production of gradient porous nanocomposite scaffolds with controllable porosity and permeability using basic biomaterials of collagen and nanobiphasic calcium phosphate (nBCP) powder consisting of nano HA/β-TCP. A modified freeze-drying method (i.e., variables; collagen/nBCP ratio and quenching rates) was integrated for the first time with the chemical foaming method with the use of vitamin E as a potential surfactant and porogen. Vitamin E successfully increased the range of pore size, pore interconnection, and scaffold permeability. Further control of collagen/nBCP ratios and quenching rates allowed modulation of the pore morphology, total porosity, and the surface roughness of the scaffold. Scaffolds produced using vitamin E with collagen/nBCP ratio of 92/8% at -80°C quenching rate displayed a multimodal heterogeneous pore network with a wide range of pore sizes of mostly round/oval and polygonal pore morphology. Furthermore, these scaffolds revealed a more consistent gradient porous network with peripheral large pores-that gradually become smaller toward scaffold central-that produced a significantly higher permeability and better support of initial cellular performances. Accordingly, considering the various potentials of vitamin E, this study would provide promising insight into the production of smart and customized scaffolds for regenerative and therapeutic applications.

The bone scaffold for tissue engineering should be biomimetic, particularly in simulating the porosity features of natural bony tissue including pore size, pore shape, pore distribution pattern, and porosity percentage. Control of these can impact the scaffold hydrophilicity and permeability, which in turn influence the protein adsorption, cellular functions, and vascularization process. Various methods have been investigated for control of porosity parameters; however, the field still suffers from major challenges, that is, inadequate control of porosity and hydrophilicity at different levels. In this study, we developed an integrated approach for generation and control of porosity within nanocomposite collagen/nanobiphasic calcium phosphate (collagen/nBCP) scaffold. A modified freeze-drying procedure was applied alongside a chemical foaming method exploring the ability of "Tween 20" as a potent biocompatible porogen. Several processing variables were also examined including; quenching rate (-18 and -80°C), collagen/nBCP ratio (92/8% and 85/15%), and Tween ratio (10%, 20%, and 30%). Detailed physicochemical and porosimetry analysis confirmed the ability of Tween to actively modify the scaffold permeability and pore size by increasing the range of pore size while quenching rate mostly influenced the pore shape, and collagen/nBCP ratio affected total porosity and roughness. The collagen/nBCP ratio of 92/8% treated with low Tween ratios (10% and 20%) and exposed to -80°C quenching rate displayed more favorable physicochemical behavior, significantly higher permeability, a gradient porosity, and better in vitro performances. The proposed technique in this study provides an insight into the production of customized scaffolds for various tissue engineering applications.

The aim of this study was to prepare experimental resin-modified glass ionomer cements (RMGICs) containing low levels of hydroxyethyl methacrylate (HEMA) for pulp protection. Liquid and powder phases of the experimental RMGICs were polyacid functionalized with methacrylate groups and spherical pre-reacted glass fillers (SPG). Two types of liquid phase containing 0 wt. % HEMA (CM liquid) or 5 wt. % HEMA (CMH liquid) were formulated. The experimental RMGICs were prepared by mixing SPG fillers with CM liquid (F1) or CMH liquid (F2). Rheological properties were examined using a strain-controlled rheometer (n = 5). The Vickers microhardness (n = 5) and dentin shear bond strength (SBS) (n = 10) of the materials were tested. Commercial pulp protection materials (Vitrebond and TheraCal LC) were used as comparisons. The viscosity and surface microhardness of F1 (22 m Pa·s, 18 VHN) and F2 (18 m Pa·s, 16 VHN) were significantly higher than those of Vitrebond (6 mPa·s, 6 VHN) and TheraCal (0.1 mPa·s, 7 VHN). The SBS of F1 (10.7 MPa) and F2 (11.9 MPa) was comparable to that of Vitrebond (15.4 MPa) but higher than that of TheraCal LC (5.6 MPa). The addition of 5 wt. % HEMA showed no significant effect on viscosity, surface microhardness, or SBS of the experimental RMGICs. The experimental materials showed higher viscosity and microhardness but similar SBS when compared with the commercial RMGIC.

Physical properties and biocompatibility of polycaprolactone (PCL)–biphasic calcium phosphate (BCP) scaffolds fabricated by the modified melt stretching and multilayer deposition (mMSMD) technique were evaluated in vitro. The PCL–BCP scaffold specimens included group A; PCL: BCP (wt%) = 80:20 and group B; 70:30. Mechanical properties of the scaffolds were assessed using a universal testing machine. Degradation behaviors of the scaffolds were assessed over 60 days. The amount of calcium and phosphate ions released from the scaffolds was detected over 30 days. Attachment and growth of osteoblasts on the scaffolds and indirect cytocompatibility to those cells were evaluated. The results showed that the scaffolds of both groups could withstand compressive forces on their superior aspect very well; however, their lateral aspect could only withstand light forces. Degradation of the scaffolds over 2 months was low (group A = 1.92 ± 0.47% and group B = 2.9 ± 1.3%, p > 0.05). The concentrations of calcium and phosphate ions released from the scaffolds of both groups significantly increased on day 7 ( p

Calcium phosphate bioceramics nanoparticles such as nano-hydroxyapatite (nHA) and nano-tricalcium phosphate (nTCP) are the main focus of basic and applied research for bone tissue regeneration. In particular, a combination of these two phases (nHA + nTCP) which refers to as "nano-biphasic calcium phosphates (nBCP)" is of interest due to the preferred biodegradation nature compared to single-phase bioceramics. However, the available synthesis processes are challenging and the biomaterials properties are yet to be optimized to mimic the physiochemical properties of the natural nanoscale bone apatite. In this study, a new approach was developed for the production of optimized bioceramic nanoparticles aiming to improve their biomimecity for better biological performances. Nanoparticles were synthesized through a carefully controlled and modified wet mechano-chemical method combined with a controlled solid-state synthesis. Different processing variables have been analyzed including; milling parameters, post-synthesis treatment, and calcination phase. Detailed physicochemical characterizations of nanoparticles revealed higher crystallinity (∼100%), lower crystallite/particle size (58 nm), higher homogeneity, reduced particle agglomeration size (6 μm), and a closer molar ratio (1.8) to biological apatite compared to control and standard samples. Furthermore, the study group was confirmed as calcium-deficient carbonate-substituted BCP nanoparticles (nHA/nβ-TCP: 92/8%). As such, the introduced method can afford an easier and accurate control over nanoparticle physiochemical properties including the composition phase which can be used for better customization of biomaterials for clinical applications. The findings of this article will also help researchers in the further advancement of production strategies of biomaterials. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1654-1666, 2019.

This study aimed to evaluate in vitro biocompatibility of a composite of nanoscale biphasic calcium phosphate (BCP) and collagen (C) compared to pure BCP (P) in different composition ratios of nanohydroxyapatite to nano-β-tricalcium phosphate (HA/β-TCP). Each study group comprised of three ratios of BCP (30/70, 40/60, and 50/50). For evaluation of cellular response toward each ratio, mouse osteoblast (MC3T3-E1) cell line was cultivated on the scaffolds for 19 days. Analysis of cell proliferation, cell viability, cell attachment and morphology, alkaline phosphatase (ALP) activity, and osteocalcin synthesis were done on culture days 1, 3, 7, 13, 15, and 19, appropriately. The scanning electron microscopy showed that the osteoblasts attached successfully to scaffolds surfaces in both BCP groups and in all different ratios by spreading their filopodia and expressing similar viability that was confirmed by confocal laser scanning electron microscope. BCP scaffold (P3070) showed remarkable ALP activity, whereas BCP (P5050) showed highest osteocalcin activity. Collagen coating supported high cell proliferation on culture day 1 and possessed limited benefit restricted to early phase of cell differentiation. In conclusion, the fabricated nanoscale BCP scaffolds offered high biocompatibility and supported well the cell proliferation and differentiation regardless the composition ratio. Furthermore, higher ratio of TCP supported the early phase of cell proliferation, whereas higher HA ratio influenced the later phase. Finally, BCP scaffolds P5050 and C4060 were suggested as candidates for clinical applications. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 52–61, 2014.

The biphasic calcium phosphate (BCP) concept was introduced to overcome disadvantages of single phase biomaterials. Different composition ratios of BCP bioceramics have been studied, yet controversies regarding the effects of ratio on biomaterial behavior still exist. In this study, BCP scaffolds were prepared from nano hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) that were synthesized via a solid state reaction. Three different composition ratios of pure BCP and collagen-based BCP scaffolds (%HA/%β-TCP; 30/70, 40/60, and 50/50) were produced using a polymeric sponge method. Physical and mechanical properties of all materials and scaffolds were investigated. SEM showed overall distribution of both macropores (80–200 μm) and micropores (0.5–2 μm) with high interconnected porosities. Total porosity of pure BCP (90% ± 3%) was found to be higher than collagen-based BCP (85% ± 2%). It was observed that following sintering process, dimensional shrinkage of large scaffolds (39% ± 4%) was lower than small ones (42% ± 5%) and scaffolds with high HA ratios (50%) experienced higher dimensional changes than those with higher β-TCP (70%) ratios (45% ± 3% and 36% ± 1%, respectively). Compressive strength of both groups was less than 0.1 MPa and collagen coating had almost no influence on mechanical behavior. Further studies may improve the physical properties of these scaffolds and investigate their exact biological behaviors. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A: 2260–2268, 2012.