In maxillofacial surgery, there is a significant need for the design and fabrication of porous scaffolds with customizable bionic structures and mechanical properties suitable for bone tissue engineering. In this paper, we characterize the porous Ti6Al4V implant, which is one of the most promising and attractive biomedical applications due to the similarity of its modulus to human bones. We describe the mechanical properties of this implant, which we suggest is capable of providing important biological functions for bone tissue regeneration. We characterize a novel bionic design and fabrication process for porous implants. A design concept of "reducing dimensions and designing layer by layer" was used to construct layered slice and rod-connected mesh structure (LSRCMS) implants. Porous LSRCMS implants with different parameters and porosities were fabricated by selective laser melting (SLM). Printed samples were evaluated by microstructure characterization, specific mechanical properties were analyzed by mechanical tests, and finite element analysis was used to digitally calculate the stress characteristics of the LSRCMS under loading forces. Our results show that the samples fabricated by SLM had good structure printing quality with reasonable pore sizes. The porosity, pore size, and strut thickness of manufactured samples ranged from (60.95± 0.27)% to (81.23±0.32)%, (480±28) to (685±31) μm, and (263±28) to (265±28) μm, respectively. The compression results show that the Young's modulus and the yield strength ranged from (2.23±0.03) to (6.36±0.06) GPa and (21.36±0.42) to (122.85±3.85) MPa, respectively. We also show that the Young's modulus and yield strength of the LSRCMS samples can be predicted by the Gibson-Ashby model. Further, we prove the structural stability of our novel design by finite element analysis. Our results illustrate that our novel SLM-fabricated porous Ti6Al4V scaffolds based on an LSRCMS are a promising material for bone implants, and are potentially applicable to the field of bone defect repair.
Alloys ; Bionics ; Bone Substitutes/chemistry* ; Bone and Bones/pathology* ; Compressive Strength ; Elastic Modulus ; Finite Element Analysis ; Humans ; Lasers ; Materials Testing ; Maxillofacial Prosthesis Implantation ; Porosity ; Pressure ; Printing, Three-Dimensional ; Prostheses and Implants ; Prosthesis Design ; Stress, Mechanical ; Surgery, Oral/instrumentation* ; Tissue Engineering/methods* ; Titanium/chemistry*

To produce bionic bone material that is consistent with human bone in chemical composition and molecular structure using rat tail tendon collagen type Ⅰ.The type Ⅰcollagen derived from rat tail was extracted by acetic acid to form collagen fibers. The reconstructed collagen fibers were placed in the mineralized solution to mimic bone mineralization for 2-6 days. Bone mineralization was observed by transmission electron microscopy and electron diffraction.Collagen fibers with characteristic D-Band structure were reconstructed by using rat tail tendon collagen type Ⅰ extracted with acid hydrolysis method. Transmission electron microscopy and electron diffraction showed that calcium hydroxyapatite precursor infiltrated into the collagen fibers, and the collagen fibers were partially mineralized after 2 days of mineralization; the collagen fibers were completely mineralized and bionic bone material of typeⅠ collagen/calcium hydroxyapatite was formed after 6 days of mineralization.The collagen type Ⅰ can be extracted from rat tail tendon by acid hydrolysis method, and can be reformed and mineralized to form the bionic bone material which mimics human bone in chemical composition and the molecular structure.
Animals ; Biocompatible Materials ; chemical synthesis ; Bone Matrix ; chemistry ; growth & development ; Bone Substitutes ; chemical synthesis ; Bone and Bones ; anatomy & histology ; chemistry ; Calcification, Physiologic ; Collagen Type I ; biosynthesis ; chemistry ; ultrastructure ; Humans ; Hydroxyapatites ; chemistry ; Rats ; Tail ; Tendons ; chemistry ; ultrastructure ; Tissue Engineering ; methods

OBJECTIVETo prepare a novel strontium-containing calcium sulfate and assess its and biocompatibility.

METHODSA novel strontium-containing α-calcium sulfate hemihydrate (Sr-caS) bone substitute as prepared with hydrothermal reaction and examined for X-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric differential scanning calorimetric (TG-DSC) patterns. The biocompatibility of the material was evaluated by in vitro cytotoxicity test in L-929 cells, hemolysis test of blood, and in vivo implantation test in SD rats.

RESULTSThe XRD spectra of the prepared Sr-CaS powder highlighted 3 strong characteristic peaks of α-CaSO4 at 14.63°, 25.72° and 29.80° with a strontium-specific peak at 24.78°. The FTIR patterns of Sr-CaS resembled those of CaS. TG-DSC results showed that the material contained a non-evaporable water content of 6.03%. In vitro cytotoxicity test in L-929 cells suggested that the material had a class 1 cytotoxicity, and the hemolysis rate of its aqueous extract was 4.3%. The material implanted in the muscular tissues of SD rats maintained a steady state in the surrounding tissues.

CONCLUSIONThis strontium-containing calcium sulfate material we prepared shows an excellent biocompatibility for potential use as a novel artificial bone material.

Animals ; Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Calcium Sulfate ; chemistry ; Cell Line ; Mice ; Microscopy, Electron, Scanning ; Prostheses and Implants ; Rats ; Rats, Sprague-Dawley ; Spectroscopy, Fourier Transform Infrared ; Strontium ; chemistry ; X-Ray Diffraction

OBJECTIVETo investigate the growth activity of osteoblast on a novel strontium incorporated calcium sulfate and make comparison with normal calcium sulfate material.

METHODSOsteoblast was inoculated on samples and cell proliferation was measured on the 1st, 3rd, 5th days, and the activities of ALP and osteocalcin were observed on the 5th day. And microcosmic morphology of osteoblast was observed by scanning electron microscopy(SEM).

RESULTSOsteoblast grows robustly on tested material. Cell quantity on the surface of novel material was obviously higher than normal calcium sulfate material (P < 0.05). The activity of ALP and osteocalcin on novel material was 57.8% and 40.2% higher than on normal calcium sulfate material respectively (P < 0.05). On strontium incorporated surface, osteoblast spread well. Cells were polygonal with abundant cytoplasm and the morphology was active.

CONCLUSIONStrontium incorporated calcium sulfate can sustain robust growth activity of osteoblast, which is promising to be used for bone substitute materials.

3T3 Cells ; Alkaline Phosphatase ; metabolism ; Animals ; Bone Substitutes ; chemistry ; pharmacology ; Calcium Sulfate ; chemistry ; pharmacology ; Cell Proliferation ; drug effects ; Mice ; Osteoblasts ; cytology ; drug effects ; metabolism ; Osteocalcin ; metabolism ; Strontium ; chemistry

The compressive strength of the original bone tissue was tested, based on the raw human thigh bone, bovine bone, pig bone and goat bone. The four different bone-like apatites were prepared by calcining the raw bones at 800 degrees C for 8 hours to remove organic components. The comparison of composition and structure of bone-like apatite from different bone sources was carried out with a composition and structure test. The results indicated that the compressive strength of goat bone was similar to that of human thigh bone, reached (135.00 +/- 7.84) MPa; Infrared spectrum (IR), X-ray diffraction (XRD) analysis results showed that the bone-like apatite from goat bone was much closer to the structure and phase composition of bone-like apatite of human bones. Inductively Coupled Plasma (ICP) test results showed that the content of trace elements of bone-like apatite from goat bone was closer to that of apatite of human bone. Energy Dispersive Spectrometer (EDS) results showed that the Ca/P value of bone-like apatite from goat bone was also close to that of human bone, ranged to 1.73 +/- 0.033. Scanning electron microscopy (SEM) patterns indicated that the macrographs of the apatite from human bone and that of goat bone were much similar to each other. Considering all the results above, it could be concluded that the goat bone-like apatite is much similar to that of human bone. It can be used as a potential natural bioceramic material in terms of material properties.
Animals ; Apatites ; chemistry ; Biomechanical Phenomena ; Bone Substitutes ; chemistry ; Bone and Bones ; physiology ; Cattle ; Compressive Strength ; Goats ; Humans ; Microscopy, Electron, Scanning ; Swine ; X-Ray Diffraction

BACKGROUNDBone grafting is commonly used to repair bone defects. As the porosity of the graft scaffold increases, bone formation increases, but the strength decreases. Early attempts to engineer materials were not able to resolve this problem. In recent years, nanomaterials have demonstrated the unique ability to improve the material strength and toughness while stimulating new bone formation. In our previous studies, we synthesized a nano-scale material by reinforcing a porous β-tricalcium phosphate (β-TCP) ceramic scaffold with Na2O-MgO-P2O5-CaO bioglass (β-TCP/BG). However, the in vivo effects of the β-TCP/BG scaffold on bone repair remain unknown.

METHODSWe investigated the efficacy of β-TCP/BG scaffolds compared to autografts in a canine tibiofibula defect model. The tibiofibula defects were created in the right legs of 12 dogs, which were randomly assigned to either the scaffold group or the autograft group (six dogs per group). Radiographic evaluation was performed at 0, 4, 8, and 12 weeks post-surgery. The involved tibias were extracted at 12 weeks and were tested to failure via a three-point bending. After the biomechanical analysis, specimens were subsequently processed for scanning electron microscopy analysis and histological evaluations.

RESULTSRadiographic evaluation at 12 weeks post-operation revealed many newly formed osseous calluses and bony unions in both groups. Both the maximum force and break force in the scaffold group (n = 6) were comparable to those in the autograft group (n = 6, P > 0.05), suggesting that the tissue-engineered bone repair achieved similar biomechanical properties to autograft bone repair. At 12 weeks post-operation, obvious new bone and blood vessel formations were observed in the artificial bone of the experimental group.

CONCLUSIONSThe results demonstrated that new bone formation and high bone strength were achieved in the β-TCP/BG scaffold group, and suggested that the β-TCP/BG scaffold could be used as a synthetic alternative to autografts for the repair of bone defects.

Animals ; Autografts ; Bone Substitutes ; chemistry ; Ceramics ; Dogs ; Female ; Fibula ; injuries ; surgery ; Hydroxyapatites ; chemistry ; Tibia ; injuries ; surgery ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry

To evaluate the biological safety of collagen-based bone repairing material, we implanted the sample or reference substance into rats, and observed relative signs, including the specific inspection targets in animals, blood examination, analysis of immune organ, the pathological examination of organs and tissues, NK cell killing activity assay, lymphocyte group analysis, serum IL-1, IL-6, TNF-alpha detection, detection of immune globulin. Meanwhile, we set control group, sham group, and immunosuppression group. The final results showed that there was no abnormal mental state before and after the experiment. Compared with the control group, the tested group indicated no significant difference in blood test, immune organ analysis, the pathological examination of organs and tissues, NK cell killing activity assay, lymphocyte subset analysis serum IL-1, IL-6, TNF-alphadetection, and detection of immune globulin. Collagen-based bone repairing material produced a slight and transient stimulation on the rats, but created no significant inflammatory responses.
Absorbable Implants ; Animals ; Bone Matrix ; physiology ; transplantation ; Bone Regeneration ; Bone Substitutes ; Collagen ; chemistry ; Implants, Experimental ; Materials Testing ; Prostheses and Implants ; Rats

The present paper is aimed to study the preparation and application of individual artificial bone of carbon/carbon composites. Using computer tomography images (CT), we acquired a three-dimensional image. Firstly, we described bone contour line outlined with manual and automatic method by the binary volume data. Secondly, we created 3D object surface information by marching cubes. Finally, we converted this information to non-uniform rational B-spine (NURBS) by using geomagic software. Individual artificial bone with carbon/carbon composite was prepared through the CNC Machining Center. We replaced the humeral head of the tested rabbit, and then observed the effects of implantation in neuroimaging and pathological section. Using this method, we found that the bone shape processed and bone shape replaced was consistent. After implantation, the implant and the surrounding bone tissue bound closely, and bone tissue grew well on the surface of the implant. It has laid a sound foundation of the preparation using this method for individual artificial bone of carbon/carbon composite material.
Animals ; Bone Substitutes ; chemistry ; Carbon ; chemistry ; Imaging, Three-Dimensional ; Rabbits ; Software ; Tomography, X-Ray Computed

We examined the biocompatibility and the safety of a-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites for bone reconstruction application. The biocompatibility of the CSH/MWCNT composites was evaluated by the measures which taking L929 fibroblast cells cultured in the extracted liquid of the composite soaking solution and putting bone marrow stromal cells planted on the composite pellets in vitro, respectively. The cell proliferation was evaluated by MTT test and further observed using an inverted optical microscope and a scanning electric microscope. The toxicity of the composites was evaluated by acute and subacute systemic toxicity test. Long-term muscle and bone implantation in vivo tests were also conducted. L929 fibroblast cells grew well in the extracted liquid, as well as bone marrow stromal cells that could adhere on the surface of sample pellets and proliferated rapidly. MTT test showed that there were no significant differences between the experimental and control groups (P > 0.05). In vivo test manifested that the composites were no toxicity, no irritation to skin and good for bone defect reconstruction. It was proved that a-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites exhibited excellent biocompatibility for the potential application in bone tissue engineering.
Animals ; Biocompatible Materials ; chemistry ; Bone Marrow Cells ; cytology ; Bone Substitutes ; chemical synthesis ; chemistry ; Calcium Sulfate ; chemistry ; Cell Line ; Cell Proliferation ; Fibroblasts ; cytology ; Materials Testing ; Nanotubes, Carbon ; chemistry ; Rabbits ; Stromal Cells ; cytology ; Tissue Engineering ; methods ; Toxicity Tests

Animals ; Bone Regeneration ; Bone Substitutes ; Computer-Aided Design ; Humans ; Lactic Acid ; chemistry ; Microsurgery ; Neovascularization, Physiologic ; Polyesters ; chemistry ; Polyglycolic Acid ; chemistry ; Starch ; chemistry ; Stem Cells ; cytology ; Tissue Engineering ; methods