Small Extracellular Vesicles Released from Bioglass/Hydrogel Scaffold Promote Vascularized Bone Regeneration by Transferring miR-23a-3p.

Background: The treatment of critical-size bone defect is a great difficulty in orthopedics. Osteogenesis and angiogenesis are critical issue during the process of bone repair and remodeling. Mesenchymal stem cells (MSCs)-derived exosomes have the same therapeutic effect to MSCs-based therapies. The effect of human umbilical cord MSCs-derived sEVs (hUC-MSCs-sEVs) on vascularized bone regeneration and the potential mechanism remains to be investigated. Herein, we aimed to explore the therapeutic effect and the mechanism of hUC-MSCs-sEVs on critical-size bone defect. Methods: To investigate the potential osteogenesis and angiogenesis effects of sEVs in vitro, we extracted sEVs from hUC-MSCs, and then sEVs were co-incubated with BMSCs and HUVECs. We next investigated the effect and potential mechanism of sEVs on the effects of osteogenesis and angiogenesis. We fabricated 3D-printed bioglass scaffold with Gelma/nanoclay hydrogel coatings to load sEVs (BG-gel-sEVs) to ensure in vivo sustained efficacy of sEVs. Finally, the skull defect model was used to evaluate the capacity of vascularized bone regeneration of the composited scaffolds. Results: hUC-MSCs-sEVs facilitated calcium deposition and the endothelial network formation, inducing osteogenic differentiation and angiogenesis by delivering miR-23a-3p to activate PTEN/AKT signaling pathway. Additionally, the BG-gel-sEVs composited scaffold achieved vascularized bone regeneration in vivo. Conclusion: This finding illuminated that hUC-MSCs-sEVs promoted osteogenesis and angiogenesis by delivering miR-23a-3p to activate PTEN/AKT signaling pathway, achieving vascularized bone regeneration.

Facile extrusion 3D printing of gelatine methacrylate/Laponite nanocomposite hydrogel with high concentration nanoclay for bone tissue regeneration.

The extrusion 3D printing of hydrogels has evolved as a promising approach that can be applied for specific tissue repair. However, the printing process of hydrogel scaffolds with high shape fidelity is inseparable from the complex crosslinking strategy, which significantly increases the difficulty and complexity of printing. The aim of this study was to develop a printable hydrogel that can extrude at room temperature and print scaffolds with high shape fidelity without any auxiliary crosslinking during the printing process. To this end, a novel formulation consisting of a Laponite suspension with a high solid concentration and a gelatine methacrylate (GelMA) nanocomposite hydrogel was developed. A homogeneously dispersed high-concentration (up to 20% w/v) Laponite suspension was obtained by stirring at 0 °C. The addition of Laponite with high concentration improved the rheological properties, the degradation stability, and the mechanical strength of the hydrogel. The formulation of 15% (w/v) GelMA and 8% (w/v) Laponite nanocomposite hydrogel exhibited desirable printability and biocompatibility. The GelMA/Laponite hydrogels significantly promoted bone marrow mesenchymal stem cell (BMSC) proliferation and osteogenic differentiation. Both desirable printability under mild conditions and cyto-compatibility enable composite hydrogel a potential candidate as biomaterial inks to be applied for bone tissue regeneration.

3D printing of an integrated triphasic MBG-alginate scaffold with enhanced interface bonding for hard tissue applications.

Osteochondral defects affect both of cartilage and subchondral areas, thus it poses a significant challenge to simultaneously regenerate two parts in orthopedics. Tissue engineering strategy is currently regarded as the most promising way to repair osteochondral defects. This study focuses on developing a multilayered scaffold with enhanced interface bonding through 3D printing. One-shot printing process enables control over material composition, pore structure, and size in each region of the scaffold, while realizes seamlessly integrated construct as well. The scaffold was designed to be triphasic: a porous bone layer composed of alginate sodium (SA) and mesoporous bioactive glasses (MBG), an intermediate dense layer also composed of SA and MBG and a cartilaginous layer composed of SA. The mechanical strength including the interface adhesion strength between layers were characterized. The results indicated that SA crosslinking after 3D printing anchored different materials together and integrated all regions. Additional scaffold soaking in simulated body fluid (SBF) and cell culture medium induced apatite deposition and had weakened the compressive and tensile strengths, while no layer dislocation or delamination occurred.

miR-23a-3p-abundant small extracellular vesicles released from Gelma/nanoclay hydrogel for cartilage regeneration.

Articular cartilage has limited self-regenerative capacity and the therapeutic methods for cartilage defects are still dissatisfactory in clinic. Recent studies showed that exosomes derived from mesenchymal stem cells promoted chondrogenesis by delivering bioactive substances to the recipient cells, indicating exosomes might be a novel method for repairing cartilage defect. Herein, we investigated the role and mechanism of human umbilical cord mesenchymal stem cells derived small extracellular vesicles (hUC-MSCs-sEVs) on cartilage regeneration. In vitro results showed that hUC-MSCs-sEVs promoted the migration, proliferation and differentiation of chondrocytes and human bone marrow mesenchymal stem cells (hBMSCs). MiRNA microarray showed that miR-23a-3p was the most highly expressed among the various miRNAs contained in hUC-MSCs-sEVs. Our data revealed that hUC-MSCs-sEVs promoted cartilage regeneration by transferring miR-23a-3p to suppress the level of PTEN and elevate expression of AKT. Moreover, we fabricated Gelatin methacrylate (Gelma)/nanoclay hydrogel (Gel-nano) for sustained release of sEVs, which was biocompatible and exhibited excellent mechanical property. In vivo results showed that hUC-MSCs-sEVs containing Gelma/nanoclay hydrogel (Gel-nano-sEVs) effectively promoted cartilage regeneration. These results indicated that Gel-nano-sEVs have a promising capacity to stimulate chondrogenesis and heal cartilage defects, and also provided valuable data for understanding the role and mechanism of hUC-MSCs-sEVs in cartilage regeneration.

Inhibition of CXCR4 inhibits the proliferation and osteogenic potential of fibroblasts from ankylosing spondylitis via the Wnt/ß­catenin pathway.

Ankylosing spondylitis (AS) is an autoimmune condition characterized by chronic inflammation and abnormal ossification as the primary features of the disease. The aim of the present study was to investigate the role of C­X­C chemokine receptor type 4 (CXCR4) in ossification from patients with AS. CXCR4 expression was assessed by western blot analysis and immunohistochemistry analysis of tissues obtained from patients with AS and controls. Fibroblasts were isolated, cultured and incubated with AMD 3100 and stromal cell­derived factor­1 to inhibit and promote CXCR4 levels, respectively. CXCR4 was upregulated in hip synovial tissues from patients with AS compared with that observed in controls. AS fibroblasts exhibited increased proliferation and growth rates. Inhibition of CXCR4 increased the phosphorylation of ß­catenin and downregulated the expression of ß­catenin, v­myc avian myelocytomatosis viral oncogene homolog, cyclin D1 and osteocalcin. Alizarin red staining demonstrated a decrease in biomineralization activity following the inhibition of CXCR4. These data support the hypothesis that inhibiting CXCR4 in patients with AS may suppress the ossification of fibroblasts.

An arthroscopic technique for full-thickness rotator cuff repair by transposition of the long head of biceps.

Arthroscopic rotator cuff (RC) repair is now considered as an effective treatment for patients with symptomatic rotator cuff tears. We reported a new method for repairing a full-thickness RC tear by using the double-row technique with transposition of the long head of biceps (LHB). The novelty of this technique is using the long head of the biceps as an augmentation. The indication of this technique consists of two aspects including LHB lesions and RC tears. Three patients were enrolled. An ideal reconstruction of the anatomic footprint of the tendon and stabilization of glenohumeral joint was achieved after the double-row technique with the transposition of the long head of biceps. At 6-month postoperation, the mean VAS score was 1.23±0.15 and the mean Constant score was 88.00±9.17. Transposition of the long head of biceps is a choice for full-thickness RC tear. LEVEL OF EVIDENCE: IV, case series.

Arthroscopic fixation of pediatric tibial eminence fractures using suture anchors: a mid-term follow-up.

PURPOSE: The aim of this study was to follow a group of skeletally immature patients who received arthroscopy-assisted fixation of the displaced tibial eminence fractures with suture anchors and evaluate the clinical results. METHODS: Twenty-one pediatric patients with displaced tibial eminence fractures were enrolled in this retrospectively study. They received arthroscopy-assisted reduction and fixation using suture anchors. All cases were followed up for 40-47 months with a mean of 43.4 months. Follow-up examinations included radiographic assessment, Lysholm score, Tegner score, International Knee Documentation Committee (IKDC) rating scale and KT-1000 test. RESULT: Twenty patients were available for our final evaluations. They improved significantly at the final follow-up compared with preoperative examinational results with respect to the results of radiographic assessment, Lysholm score, Tegner score, IKDC rating scale and KT-1000 test. CONCLUSION: Arthroscopy-assisted reduction and fixation of the displaced tibial eminence fractures using suture anchors is a simple and reliable technique and is suitable for skeletally immature patients.

Gentamicin coating of nanotubular anodized titanium implant reduces implant-related osteomyelitis and enhances bone biocompatibility in rabbits.

Titanium and titanium alloy are widely used as orthopedic implants for their favorable mechanical properties and satisfactory biocompatibility. The aim of the present study was to investigate the antibacterial effect and bone cell biocompatibility of a novel implant made with nanotubular anodized titanium coated with gentamicin (NTATi-G) through in vivo study in rabbits. The animals were divided into four groups, each receiving different kinds of implants, that is, NTATi-G, titanium coated with gentamicin (Ti-G), nanotubular anodized titanium uncoated with gentamicin (NTATi) and titanium uncoated with gentamicin (Ti). The results showed that NTATi-G implant prevented implant-related osteomyelitis and enhanced bone biocompatibility in vivo. Moreover, the body temperature of rabbits in NTATi-G and Ti-G groups was lower than those in Ti groups, while the weight of rabbits in NTATi-G and Ti-G groups was heavier than those in NTATi and Ti groups, respectively. White blood cell counts in NTATi-G group were lower than NTATi and Ti groups. Features of myelitis were observed by X-ray films in the NTATi and Ti groups, but not in the NTATi-G and Ti-G groups. The radiographic scores, which assessed pathology and histopathology in bone tissues, were significantly lower in the NTATi-G and Ti-G groups than those in the NTATi and Ti groups, respectively (P<0.05). Meanwhile, explants and bone tissue culture demonstrated significantly less bacterial growth in the NTATi-G and Ti-G groups than in the NTATi and Ti groups, respectively (P<0.01). The bone volume in NTATi-G group was greater than Ti-G group, and little bone formation was seen in NTATi and Ti groups.

Efficacy of intra-articular magnesium for postoperative analgesia in total hip arthroplasty.

The aim of the present study was to compare the efficacy of intra-articular magnesium sulphate and a saline placebo for postoperative pain control following total hip arthroplasty (THA). Sixty patients underwent THA and were randomly allocated into two groups to receive intra-articular injections of either 10 ml magnesium sulphate (100 mg/ml; magnesium group, n=30) or 10 ml normal saline solution (control group, n=30). Postoperative analgesia was maintained by intravenous morphine injection. The outcome measurements were visual analogue score (VAS), morphine consumption and Harris hip score (HHS). The two groups were well matched. The outcome of VAS at rest was significantly lower at postoperative hours 6 and 12 in the magnesium group as compared with the control group, although the difference was insignificant preoperatively and at postoperative hours 2, 4, 24 and 48, and days 3, 7 and 14. This indicator during activity was also lower in the magnesium group at postoperative hour 24 than that of the control group, although the difference was insignificant preoperatively and at hour 48, and days 7 and 14. The consumption of morphine (the total quantity) at 0-6, 6-12 and 0-48 h in the magnesium group was significantly lower than in the control group, although no significant differences were observed at 12-24 and 24-48 h between the groups. The improvements of HHS from preoperative to postoperative scores were statistically significant, however, no significant differences were identified between groups. Thus, the findings indicate that intra-articular magnesium sulphate injections provided improved pain control and reduced the need for morphine when compared with a saline placebo following THA.

The Value of Radionuclide Bone Imaging in Defining Fresh Fractures Among Osteoporotic Vertebral Compression Fractures.

Vertebral fractures are the most common osteoporotic fractures. To perform percutaneous vertebral body cement augmentation, it is essential to accurately identify the affected vertebrae. The study evaluated the role of radionuclide bone imaging in identifying fresh osteoporotic vertebral compression fractures. A prospective study of 39 patients with acute osteoporotic vertebral compression fractures was carried out. All patients underwent magnetic resonance imaging (MRI) and radionuclide bone imaging to determine if the fractures were fresh, followed by percutaneous kyphoplasty for the fresh fractures. The positive rate on radionuclide bone imaging was 92.1% (82/89), and the positive rate on MRI was 93.3% (83/89), with no statistically significant difference (P > 0.05). Eighty-one vertebrae had the same positive identification by both radionuclide bone imaging and MRI, and 5 of the same vertebrae were diagnosed negative by both techniques. One patient with positive radionuclide bone imaging was negative according to MRI, and 2 patients were entirely positive by MRI but negative by radionuclide bone imaging. A kappa test showed good consistency between the 2 methods for detecting the affected vertebrae (Kappa = 0.751, P < 0.01). Radionuclide bone imaging is as sensitive as MRI in the diagnosis of fresh osteoporotic vertebral compression fracture, making it an effective method for detecting affected vertebrae for percutaneous vertebroplasty.

Treatment of comminuted patellar fracture with the nitinol patellar concentrator.

AIM: To evaluate the clinical effect of the nitinol (NiTi)-patellar concentrator (NT-PC) for the treatment of comminuted patellar fractures. MATERIAL AND METHODS: A total of 32 patients with acute comminuted patellar fracture accepted open reduction and internal fixation with the NT-PC, and the curative effects were evaluated using the Böstman clinical grading scale. RESULTS: All fractures were anatomically reduced by surgery and all cases were followed-up for six to 18 months. The mean score of patients according to the Böstman clinical grading scale was 25.6, with 29 of 32 (90.7%) patients achieving excellent or good results. Two patients had traumatic arthritis, one had slippage of the NT-PC, and all patients received pharmacotherapy. CONCLUSIONS: The application of the NT-PC is a satisfactory approach to the treatment of comminuted patellar fractures.

Comparison of therapeutic effects between drainage blood reinfusion and temporary clamping drainage after total knee arthroplasty in patients with rheumatoid arthritis.

OBJECTIVE: To compare the therapeutic effects between drainage blood reinfusion and temporary clamping drainage after total knee arthroplasty in patients with rheumatoid arthritis to provide a basis for clinical practice. METHODS: Data from 83 patients with rheumatoid arthritis undergoing total knee arthroplasty were retrospectively analyzed. The 83 patients were divided into a drainage blood reinfusion group (DR group, n = 45) and a temporary clamping drainage group (CD group, n = 38). In the DR group, postoperative drainage blood was used for autotransfusion. In the CD group, closed drainage was adopted, and the drainage tube was clamped for 2 h postoperatively followed by patency. The postoperative drainage amount, hemoglobin level, rate and average volume of allogeneic blood transfusion, swelling and ecchymosis of the affected knee joint, time to straight-leg raising and range of active knee flexion were compared between the two groups. RESULTS: The total drainage volume was higher in the DR group than in the CD group (P = 0.000). The average volume of postoperative allogeneic blood transfusion (P = 0.000) and the decrease in the hemoglobin level 24 h after total knee arthroplasty (P = 0.012) were lower in the DR group than in the CD group. Swelling and ecchymosis of the affected knee joint, time to straight-leg raising and the range of active knee flexion were improved in the DR group compared with the CD group (all P<0.05). CONCLUSION: Compared with temporary clamping drainage, drainage blood reinfusion after total knee arthroplasty can reduce the allogeneic blood transfusion volume and is conducive to early rehabilitation in patients with rheumatoid arthritis.

Effect of irrigation fluid temperature on core body temperature and inflammatory response during arthroscopic shoulder surgery.

PURPOSE: This study was designed to evaluate the influence of irrigation fluid on the patients' physiological response to arthroscopic shoulder surgery. METHODS: Patients who were scheduled for arthroscopic shoulder surgery were prospectively included in this study. They were randomly assigned to receive warm arthroscopic irrigation fluid (Group W, n = 33) or room temperature irrigation fluid (Group RT, n = 33) intraoperatively. Core body temperature was measured at regular intervals. The proinflammatory cytokines TNF-α, IL-1, IL-6, and IL-10 were measured in drainage fluid and serum. RESULTS: The changes of core body temperatures in Group RT were similar with those in Group W within 15 min after induction of anesthesia, but the decreases in Group RT were significantly greater after then. The lowest temperature was 35.1 ± 0.4 °C in Group RT and 35.9 ± 0.3 °C in Group W, the difference was statistically different (P < 0.05). Hypothermia occurred in 31 out of 33 subjects in Group RT (31/33; 94 %), but was significantly lower in Group W (9/24; 27 %; P < 0.05). Serum TNF-α changes were undetectable postoperatively. No statistical significant differences in serum IL-1 and serum IL-10 levels were observed between groups. Serum IL-6 levels were significantly lower in Group W (P < 0.05). The levels of the above cytokines in drainage fluid were all significantly lower in Group W after surgery (P < 0.05). CONCLUSION: Hypothermia occurs more often in arthroscopic shoulder surgery by using room temperature irrigation fluid compared with warm irrigation fluid. And local inflammatory response is significantly reduced by using warm irrigation fluid. It seems that warm irrigation fluid is more recommendable for arthroscopic shoulder surgery.

Wound dressings composed of copper-doped borate bioactive glass microfibers stimulate angiogenesis and heal full-thickness skin defects in a rodent model.

There is a need for better wound dressings that possess the requisite angiogenic capacity for rapid in situ healing of full-thickness skin wounds. Borate bioactive glass microfibers are showing a remarkable ability to heal soft tissue wounds but little is known about the process and mechanisms of healing. In the present study, wound dressings composed of borate bioactive glass microfibers (diameter = 0.4-1.2 µm; composition 6Na2O, 8K2O, 8MgO, 22CaO, 54B2O3, 2P2O5; mol%) doped with 0-3.0 wt.% CuO were created and evaluated in vitro and in vivo. When immersed in simulated body fluid, the fibers degraded and converted to hydroxyapatite within ∼7 days, releasing ions such as Ca, B and Cu into the medium. In vitro cell culture showed that the ionic dissolution product of the fibers was not toxic to human umbilical vein endothelial cells (HUVECs) and fibroblasts, promoted HUVEC migration, tubule formation and secretion of vascular endothelial growth factor (VEGF), and stimulated the expression of angiogenic-related genes of the fibroblasts. When used to treat full-thickness skin defects in rodents, the Cu-doped fibers (3.0 wt.% CuO) showed a significantly better capacity to stimulate angiogenesis than the undoped fibers and the untreated defects (control) at 7 and 14 days post-surgery. The defects treated with the Cu-doped and undoped fibers showed improved collagen deposition, maturity and orientation when compared to the untreated defects, the improvement shown by the Cu-doped fibers was not markedly better than the undoped fibers at 14 days post-surgery. These results indicate that the Cu-doped borate glass microfibers have a promising capacity to stimulate angiogenesis and heal full-thickness skin defects. They also provide valuable data for understanding the role of the microfibers in healing soft tissue wounds.

Comparison of therapeutic effects between drainage blood reinfusion and temporary clamping drainage after total knee arthroplasty in patients with rheumatoid arthritis

OBJECTIVE: To compare the therapeutic effects between drainage blood reinfusion and temporary clamping drainage after total knee arthroplasty in patients with rheumatoid arthritis to provide a basis for clinical practice. METHODS: Data from 83 patients with rheumatoid arthritis undergoing total knee arthroplasty were retrospectively analyzed. The 83 patients were divided into a drainage blood reinfusion group (DR group, n = 45) and a temporary clamping drainage group (CD group, n = 38). In the DR group, postoperative drainage blood was used for autotransfusion. In the CD group, closed drainage was adopted, and the drainage tube was clamped for 2 h postoperatively followed by patency. The postoperative drainage amount, hemoglobin level, rate and average volume of allogeneic blood transfusion, swelling and ecchymosis of the affected knee joint, time to straight-leg raising and range of active knee flexion were compared between the two groups. RESULTS: The total drainage volume was higher in the DR group than in the CD group (P = 0.000). The average volume of postoperative allogeneic blood transfusion (P = 0.000) and the decrease in the hemoglobin level 24 h after total knee arthroplasty (P = 0.012) were lower in the DR group than in the CD group. Swelling and ecchymosis of the affected knee joint, time to straight-leg raising and the range of active knee flexion were improved in the DR group compared with the CD group (all P<0.05). CONCLUSION: Compared with temporary clamping drainage, drainage blood reinfusion after total knee arthroplasty can reduce the allogeneic blood transfusion volume and is conducive to early rehabilitation in patients with rheumatoid arthritis. .

Fabrication of hydroxyapatite on pure titanium by micro-arc oxidation coupled with microwave-hydrothermal treatment.

Porous hydroxyapatite (HA)-containing composite films were prepared by a novel method consisting of micro-arc oxidation (MAO) combined with microwave-hydrothermal (M-H) treatment. The morphology, composition and phase composition of the bioactive films were investigated with scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction. MTT assay was carried out to investigate the in vitro effects of the different surfaces on bone integration properties. The prepared MAO films consisted mainly of anatase, rutile and tricalcium phosphate along with amorphous calcium (Ca) and phosphorus (P) phases. The M-H-treated composite films were composed primarily of anatase, rutile and HA. As the time and temperature of the M-H treatment increased, the number of HA crystals gradually increased. Using the M-H method, HA was obtained at a lower temperature and in a shorter period of time compared to the conventional hydrothermal method. The results suggest that the M-H method significantly decreases the hydrothermal reaction temperature and also greatly shortens the reaction time. Due to the nanocrystallinity and porosity of the prepared composite films, the method presented here shows promise for the formation of bioactive materials for medical applications.

Evaluation of injectable strontium-containing borate bioactive glass cement with enhanced osteogenic capacity in a critical-sized rabbit femoral condyle defect model.

The development of a new generation of injectable bone cements that are bioactive and have enhanced osteogenic capacity for rapid osseointegration is receiving considerable interest. In this study, a novel injectable cement (designated Sr-BBG) composed of strontium-doped borate bioactive glass particles and a chitosan-based bonding phase was prepared and evaluated in vitro and in vivo. The bioactive glass provided the benefits of bioactivity, conversion to hydroxyapatite, and the ability to stimulate osteogenesis, while the chitosan provided a cohesive biocompatible and biodegradable bonding phase. The Sr-BBG cement showed the ability to set in situ (initial setting time = 11.6 ± 1.2 min) and a compressive strength of 19 ± 1 MPa. The Sr-BBG cement enhanced the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells in vitro when compared to a similar cement (BBG) composed of chitosan-bonded borate bioactive glass particles without Sr. Microcomputed tomography and histology of critical-sized rabbit femoral condyle defects implanted with the cements showed the osteogenic capacity of the Sr-BBG cement. New bone was observed at different distances from the Sr-BBG implants within eight weeks. The bone-implant contact index was significantly higher for the Sr-BBG implant than it was for the BBG implant. Together, the results indicate that this Sr-BBG cement is a promising implant for healing irregularly shaped bone defects using minimally invasive surgery.

Effects of functional groups on the structure, physicochemical and biological properties of mesoporous bioactive glass scaffolds.

Functionalization of biomaterials with specific functional groups is one of the most straightforward strategies to induce specific cell responses to biomaterials. In this study, thiol (SH) and amino (NH2) functional groups have been successfully modified on the surfaces of mesoporous bioactive glass (MBG) scaffolds to form thiol-functionalized MBG (SH-MBG) and amino-functionalized MBG (NH2-MBG) scaffolds by a post-grafting technique. The effects of the functional groups on the structure, physicochemical and biological properties of MBG scaffolds were systematically investigated. The results showed that the functionalization of MBG scaffolds did not change their structures, and the SH-MBG and NH2-MBG scaffolds still had hierarchical pore architecture (macropores of 300-500 µm and mesopores of 3.5-4 nm) and high porosity (84-86%), similar to the MBG scaffolds. Furthermore, the SH-MBG and NH2-MBG scaffolds possessed similar apatite mineralization ability and biocompatibility compared to the MBG scaffolds. Importantly, the SH-MBG and NH2-MBG scaffolds significantly stimulated adhesion, proliferation and differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs). Therefore, functionalization of MBG scaffolds with SH and NH2 functional groups would be a viable way to tailor the surface characteristics for stimulating biological responses of hBMSCs, and the functionalized MBG scaffolds would be a promising bioactive material for bone tissue engineering applications.

Three-dimensional printed strontium-containing mesoporous bioactive glass scaffolds for repairing rat critical-sized calvarial defects.

The development of a new generation of biomaterials with high osteogenic ability for fast osseointegration with host bone is being intensively investigated. In this study, we have fabricated three-dimensional (3-D) strontium-containing mesoporous bioactive glass (Sr-MBG) scaffolds by a 3-D printing technique. Sr-MBG scaffolds showed uniform interconnected macropores (∼400µm), high porosity (∼70%) and enhanced compressive strength (8.67±1.74MPa). Using MBG scaffolds as a control, the biological properties of Sr-MBG scaffolds were evaluated by apatite-forming ability, adhesion, proliferation, alkaline phosphatase activity and osteogenic gene expression of osteoblast-like cells MC3T3-E1. Furthermore, Sr-MBG scaffolds were used to repair critical-sized rat calvarial defects. The results showed that Sr-MBG scaffolds possessed good apatite-forming ability and stimulated MC3T3-E1 cell proliferation and differentiation. Importantly, the in vivo results revealed that Sr-MBG scaffolds had good osteogenic capability and stimulated new blood vessel formation in critical-sized rat calvarial defects within 8 weeks. Therefore, 3-D printed Sr-MBG scaffolds with favorable pore structure and high osteogenic ability have more potential applications in bone regeneration.