Effect of High Magnesium and Astragaloside IV on Vascular Endothelial Cells.

Percutaneous coronary intervention (PCI) is the main treatment for patients with severe coronary vascular stenosis. However, In-stent neo-atherosclerosis (ISNA) is an important clinical complication in patients after PCI, which is mainly caused by a persistent inflammatory response and endothelial insufficiency. In the cardiovascular field, magnesium-based scaffolds stand out due to their properties. Magnesium plays a key role in regulating cardiovascular physiology. Magnesium deficiency can promote endothelial cell dysfunction, which contributes to the formation of atherosclerosis. Since astragaloside IV (AS­IV) has been proven to have potent cardioprotective effects, we asked whether high levels of magnesium cooperate with AS­IV might have effects on endothelial function and ISNA. We performed in vitro experiments on endothelial cells. Being treated with different concentrations of magnesium or/and AS-IV, the cell growth and migration were detected by CCK-8 and wound healing assay, respectively. The pro-inflammatory factors tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), adhesion molecule vascular cell adhesion molecule-1 (VCAM-1), and NF-kB were determined by qRT-PCR, ELISA kits or western blot. Results showed that high magnesium and AS-IV improved endothelial function, including promoting cell migration and decreasing the content of TNF-α, IL-6, VCAM-1, and NF-kB. With the supplement of AS-IV, additive magnesium maintains cell proliferation, migration, and function of endothelial cells. In conclusion, these findings suggest that high magnesium and AS­IV could improve vascular endothelial dysfunction. Early detection and treatment for neo-atherosclerosis may be of great clinical significance for improving stent implantation efficacy and long-term prognosis.

Robot Navigation System Assisted PFNA Fixation of Femoral Intertrochanteric Fractures in the Elderly: A Retrospective Clinical Study.

Objective: The incidence of hip fracture in the elderly is increasing. Robot navigation technology has the advantages of minimally invasive and accurate. To explore the difference between the clinical effects of proximal femoral anti-rotation intramedullary nail (PFNA) assisted by robot navigation in the treatment of femoral intertrochanteric fracture and traditional PFNA in the treatment of femoral intertrochanteric fracture in the elderly; analyze the advantages and feasibility of PFNA assisted by robot navigation in the treatment of femoral intertrochanteric fracture in the elderly. Patients and Methods: From February 2021 to October 2022, the elderly (>65 years old) with femoral intertrochanteric fracture underwent surgery in our center. Divided the patients included in the study into 2 groups based on the surgical method. The surgical method of robot group was PFNA fixation assisted by robot navigation, while the surgical method of traditional group was classic PFNA fixation, Baseline data (general condition, Evans classification, time from injury to operation, preoperative hemoglobin) and observation indicators (intraoperative bleeding, operation time, the length of incision for mail nail insertion, postoperative hemoglobin drop, blood transfusion rate and the Harris score of hip joint 1 year after operation) of the two groups were collected to compare whether there were differences between the two groups. Results: There was no statistical difference in baseline data between the two groups (P>0.05). The intraoperative bleeding in the robot group was 68.17±10.66 mL, the intraoperative bleeding in the traditional group was 174±8.11mL (P<0.001). The operation time in the robot group was 68.81 ± 6.89 min, in the traditional group, the operation time was 76.94 ± 8.18 min (P<0.001). The length of incision for mail nail insertion in the robot group was 3.53 ± 0.63 cm, the length of the incision for mail nail insertion in the traditional group was 4.23 ± 0.71 cm (P<0.001). 5 patients (13.9%) in the robot group received blood transfusion treatment, and 13 patients (36.1%) in the traditional group received blood transfusion treatment (P=0.029). The hemoglobin in the robot group decreased by 14.81 ± 3.27 g/l after operation compared with that before operation, while that in the traditional group decreased by 16.69 ± 3.32 g/l (P=0.018). The Harris score of the hip joint of the affected limb in the robot group was excellent in 25 cases, good in 8 cases and poor in 3 cases one year after the operation; In the traditional group, Harris scores were excellent in 18 cases, good in 11 cases and poor in 7 cases (P=0.021). Conclusion: PFNA fixation of femoral intertrochanteric fracture with robot navigation assistance has the advantages of minimally invasive and accurate, shorter operation time, less bleeding and lower blood transfusion rate than traditional surgical methods, and has certain advantages in reducing postoperative complications of elderly patients.

MicroRNA-specific therapeutic targets and biomarkers of apoptosis following myocardial ischemia-reperfusion injury.

MicroRNAs are single-stranded non-coding RNAs that participate in post-transcriptional regulation of gene expression, it is involved in the regulation of apoptosis after myocardial ischemia-reperfusion injury. For example, the alteration of mitochondrial structure is facilitated by MicroRNA-1 through the regulation of apoptosis-related proteins, such as Bax and Bcl-2, thereby mitigating cardiomyocyte apoptosis. MicroRNA-21 not only modulates the expression of NF-κB to suppress inflammatory signals but also activates the PI3K/AKT pathway to mitigate ischemia-reperfusion injury. Overexpression of MicroRNA-133 attenuates reactive oxygen species (ROS) production and suppressed the oxidative stress response, thereby mitigating cellular apoptosis. MicroRNA-139 modulates the extrinsic death signal of Fas, while MicroRNA-145 regulates endoplasmic reticulum calcium overload, both of which exert regulatory effects on cardiomyocyte apoptosis. Therefore, the article categorizes the molecular mechanisms based on the three classical pathways and multiple signaling pathways of apoptosis. It summarizes the targets and pathways of MicroRNA therapy for ischemia-reperfusion injury and analyzes future research directions.

Treatment of proximal patellar tendon rupture with custom-made anchor-like plate and suture: cases report and literature review.

We reported 2 cases of patellar tendon rupture at the lower pole of the patella. For patellar tendon rupture, simple suture fixation has been proved to be inadequate in strength. Our center uses custom-made anchor-like plate and suture to treat proximal patellar fracture. The fixation strength is reliable, no additional bone tunnel is required, and the fixation of the lower patellar fracture can be achieved at the same time. After the operation, the patient starts functional exercise of the knee joint at an early stage, The function of the knee joint of the patient recovered well after 1 year, without other complications.

One quick and simple fixation method: posterior malleolus fractures in spiral tibial fractures.

OBJECTIVE: Spiral fracture of tibia combined with posterior malleolar fracture (PMF) is a special and regular injury. There is no uniform fixation method for PMF in this kind of injury. Intramedullary nail is the first choice for the treatment of tibial spiral fracture. We proposed a minimally invasive percutaneous screw combined with intramedullary nail technology to fix the PMF in the tibial spiral fracture. This study aims to explore the effectiveness and advantages of this technology. MATERIALS AND METHODS: From January 2017 to February 2020, 116 cases of spiral fracture of tibia combined with PMF who were operated in our hospital were divided into Fixation Group (FG) and No Fixation Group (NG) according to whether PMF was fixed. After minimally invasive percutaneous screw fixation of ankle fracture in FG patients, the tibial intramedullary nail was inserted to fix the fracture. Collected the operation and postoperative recovery of the two groups of patients, including the operation time, intraoperative blood loss, AOFAS score, VAS score and dorsiflexion restriction of ankle joint at the last follow-up, and compared whether there is any difference between the two groups of patients. RESULTS: The fracture of both groups healed.2 patients in NG had secondary displacement of PMF during operation, and the fracture finally healed after fixation. There were statistical differences between the two groups in terms of operation time, AOFAS score and weight bearing time. The operation time of FG was 67.9±11.2 min, and that of NG was 60.8±9.4 min; The weight bearing time of FG was 57.35±34.72 days, and that of NG was 69.17±21.43 days; The AOFAS score of FG was 92.50±3.46, and that of NG was 91.00±4.16. There were no significant difference in blood loss, VAS and dorsiflexion restriction of ankle joint between the two groups. The blood loss of FG was 66.8±12.3 ml, the blood loss of NG was 65.6±11.7 ml, the VAS score of FG was 1.37±0.47, the VAS score of NG was 1.43±0.51, the dorsiflexion restriction of FG was 5.8±4.1; the NG was 6.1±5.7. CONCLUSION: For the injury of tibial spiral fracture combined with PMF, our fixation technology can achieve minimally invasive fixation of PMF with percutaneous screws on the basis of intramedullary nail fixation of tibial fracture, promoting early functional exercise of ankle joint and early weight bearing of patients. This fixation technology is also characterized by simple and fast operation.

Relationship between neutrophil/lymphocyte ratio and postoperative delirium in elderly patients with proximal femoral nail anti-rotation for intertrochanteric fractures.

OBJECTIVE: Delirium is a common postoperative complication in elderly patients with intertrochanteric femur fracture. This study aimed at analyzing risk factors for postoperative delirium (POD) in patients after proximal femoral nail anti-rotation (PFNA). METHODS: From February 2017 to February 2021, we included elderly patients with intertrochanteric fractures who underwent PFNA. The predictive ability and cut-off value of neutrophil/lymphocyte ratio (NLR) for POD were evaluated using receiver operating characteristic (ROC) curve. Univariate and multivariate analyses were used to investigate the association between NLR and POD. RESULTS: We enrolled 315 patients. The ROC curve suggested that NLR ≥ 4.85 was the optimal cut-off value for POD. The POD and non-POD groups differed significantly in age, diabetes, time from injury to operation, preoperative albumin level, neutrophil count, and NLR (P < 0.05). Logistic regression indicated that NLR ≥ 4.85 (odds ratio [OR] = 3.491; 95% confidence interval [CI]: 1.731-5.982; P < 0.001), old age (OR = 1.921; 95% CI: 1.267-4.125; P < 0.001), time from injury to operation ≥ 48 h (OR = 1.733; 95% CI: 1.212-3.542; P = 0.007), and preoperative albumin level ≤ 35 g/L (OR = 2.274; 95% CI: 1.662-4.846; P = 0.001) increased the risk of POD. CONCLUSION: Old age, time from injury to operation ≥ 48 h, preoperative albumin level ≤ 35 g/L, and NLR ≥ 4.85 were independent risk factors for POD. Thus, NLR may predict POD in elderly patients with intertrochanteric femur fractures after PFNA.

Comparison of clinical outcomes of three internal fixation techniques in the treatment of olecranon fracture: a retrospective clinical study.

OBJECTIVE: The application of double plating in olecranon fractures is becoming increasingly widespread. There is no research comparing this technique with traditional tension band wiring (TBW) and the single plate technique. The purpose of this study was to compare the efficacy of three fixation techniques in olecranon fractures. MATERIALS AND METHODS: From March 2016 to May 2020, we collected the clinical data of 95 patients with olecranon fractures who underwent surgical treatment. Thirty-five patients received TBW surgery (TBW Group), 32 patients received a 3.5 mm locking compression plate (LCP, 3.5 mm LCP Group), and 28 patients received double mini-locking plate treatment (DP Group). The operation time, fracture union time, time of return to work, range of motion (ROM), soft tissue stimulation to remove internal fixation, and patient-related functional results (the Weseley score, Mayo Elbow Performance Score [MEPS], and Disabilities of Arm, Shoulder and Hand Score [DASH]) were recorded. The clinical results and complications of the three internal fixation techniques were compared. RESULTS: The average follow-up time was 15.011.82 months (12-18 months). All patients' fractures healed by first intention. There were no statistically significant differences in the operation time, fracture union time, ROM, Weseley score, MEPS or DASH scores of the three groups of patients. The postoperative return time for patients in the TBW group was 10.002.15 weeks, the 3.5 mm LCP group was 9.561.93 weeks, and the DP group was 8.432.38 weeks (P = 0.014); 12 patients in the TBW group required removal of plant due to soft tissue stimulation, the 3.5 mm LCP group had 8 cases, and the DP group had 2 cases (P = 0.038). CONCLUSION: The postoperative clinical results and elbow joint function of patients with olecranon fractures fixed by tension band wiring, 3.5 mm LCP and double mini-locking plate are similar, which indicates that double-plate technology can be used as an alternative to the two groups of traditional techniques. In addition, double-plate technology also helps patients return to work earlier and has a lower incidence of soft tissue stimulation.

Outcomes for a custom-made anchor-like plate combined with cerclage in the treatment of inferior pole patellar fracture.

OBJECTIVE: An inferior pole fracture of the patella requires surgical treatment to restore the knee extension mechanism of the knee joint. Different from other types of patellar fractures, inferior pole fractures are usually comminuted, and other traditional fixation methods, such as tension band wiring, may not meet the fixation needs. We propose fixing inferior pole fractures of the patella with a custom-made anchor-like plate combined with cerclage and report the surgical outcomes. MATERIAL AND METHODS: This is a retrospective clinical study. From June 2018 to August 2020, 21 patients with inferior patella fracture treated at Hong Hui Hospital Affiliated to Xi'an Jiaotong University received a custom-made anchor-like plate combined with cerclage. Complications of the surgical fixation methods and final knee function were used as the main outcome measures. RESULTS: All fractures achieved good union, and the union time ranged from 8 to 12 weeks. No patients had serious complications, such as internal fixation failure or infection. The average duration of surgery of patients was 75.05 7.26 min, and the intraoperative blood loss was 60.099.49 ml. At the last follow-up, the range of motion of the knee was 120°-140°, with an average of 131.436.92°, the Bostman score was 27-30, and the Lysholm score ranged from 82 to 95. All patients showed good knee function one year after the operation. CONCLUSION: We used a modified T-shaped plate combined with cerclage technology to fix inferior fractures pole of the patella, providing reliable fixation, allowing early functional exercise of the knee joint, and providing patients with good knee joint function after surgery.

Open reduction and internal fixation of the tibial avulsion fracture of the posterior cruciate ligament: which is better, a hollow lag screw combined with a gasket or a homemade hook plate?

OBJECTIVE: To compare the clinical results of homemade hook plates and hollow lag screws combined with spacers in the treatment of posterior cruciate tibial ligament avulsion fractures. MATERIALS AND METHODS: This was a retrospective clinical cohort study that included 64 patients with PCL tibial avulsion fractures. Thirty-two of them were fixed with a homemade hook plate (hook plate group), and 32 were fixed with a hollow lag screen combined with a gasket (hollow lag screen group). By reviewing the medical record data and follow-up results, the operation time, postoperative drainage, fracture healing time, surgical complications, knee mobility, recovery of joint function, and whether postoperative gastrocnemius muscle strength changed in the two groups were compared. RESULTS: All patients had successful wound and fracture healing. No adverse events, such as bone nonunion, infection, wound haematoma, or joint stiffness, occurred in either group. There were no patients with decreased gastrocnemius muscle strength in either group. Internal fixation failure occurred in 2 cases in the hollow lag screen group but not in the hook plate group. There were no significant differences between the two groups in terms of operative time, postoperative drainage, fracture healing time, knee mobility at the last follow-up, or Lysholm score. CONCLUSION: It is safe and effective to use a homemade hook plate to fix PCL tibial avulsion fractures through an inverted L-shaped posterior medial approach. A homemade hook plate may have potential advantages over a hollow lag screen combined with gasket fixation.

Theoretical analysis of a 60 W solar-pumped single crystal fiber laser.

In order to improve the output power of solar-pumped single-crystal fiber (SCF) lasers, we propose a novel solar concentrating system, to the best of our knowledge, consisting of a parabolic mirror, a 3D compound parabolic concentrator, and a hollow-core reflector. By ray tracing with TracePro, the influence of the fiber's diameter and the hollow reflector's shape on the solar absorption efficiency is theoretically investigated. A typical Nd:YAG SCF with a core diameter of 1 mm, length of 150 mm, and doping concentration of 1 at.% is selected for a simulation of laser operation. The output characteristics of the laser are analyzed by solving the rate equation and power transmission equation; the maximum output power and solar-to-laser conversion efficiency are 60.62 W and 4.64%, respectively. The thermal effects of the laser are simulated by Comsol software. When the input solar power is 1307.4 W, the temperature decreases sharply first and then saturates along the SCF fiber, with the maximum value of 69.18°C at the input fiber end. This concentrating system can effectively overcome the limitation of end-launching solar power into SCFs and has great potential in improving the output power of solar fiber lasers.

A novel internal fixation technique for the treatment of olecranon avulsion fracture.

Objective: Tension band wiring and proximal ulnar plate fixation are commonly used fixation methods for olecranon fractures. However, they may not be suitable for repairing proximal olecranon avulsion fractures. In this study, we present a novel fixation technique for the treatment of proximal avulsion fractures, which is a T-shaped plate combined with a wire. Materials and methods: Between March 2016 and May 2020, surgery was performed on 16 patients with proximal olecranon avulsion fractures by using a T-shaped plate combined with a wire fixation at our hospital. The parameters followed were fracture healing time, elbow range of motion (ROM), related functional scores (the Mayo score and the DASH score), and complications related to internal fixation. Results: The average follow-up period was 17 (14-21) months and fractures had healed in all patients included in the study, with an average fracture union of 9.25 (8-12) weeks. No patient reported fixation failure, serious infection, or revision surgery. The average ROM of the elbow joint was 123° (120-135°). The Mayo score was excellent in 11 patients and good in 5. The average DASH score was 17.75 (12-24). Conclusion: Olecranon avulsion fractures were fixed with a T-shaped steel plate combined with a steel wire, which can be used for early functional exercise and for achieving good final functional results. This method can provide stable fixation, especially in elderly patients with osteoporosis.

Co-culture of BMSCs and HUVECs with simvastatin-loaded gelatin nanosphere/chitosan coating on Mg alloy for osteogenic differentiation and vasculogenesis.

Mg alloys are increasingly being investigated as a versatile and economical alternative for developing bone repair implants because of their high mechanical strength, wide availability, adjustable structure and properties. In this study, magnesium alloy WE43 is coated on both sides with gelatin nanosphere/chitosan (GNs/CTS), a coating enhanced by incorporating simvastatin (SIM). SIM-loaded GNs/CTS coated magnesium alloy can promote the osteogenic differentiation of bone mesenchymal stem cells (BMSCs). BMSCs and human umbilical vein endothelial cells (HUVECs) are co-cultured through transwell systems. The release of SIM from the coating is found to increase the secretion of chemokine and angiogenic factors from BMSCs, which promote the migration and tube formation of HUVECs, respectively. Bone morphogenetic protein secreted by HUVECs is seen to increase by the release of SIM from the coating, promoting the osteogenic differentiation of BMSCs. The secretion of chemokines from HUVECs promote the migration of BMSCs. The coated magnesium alloy substrate loaded with SIM is found to regulate the osteogenic differentiation of BMSCs. The study of the paracrine interaction between BMSCs and HUVECs proves that the applied coating promotes both osteogenic differentiation and vascularization, thus demonstrating a new approach for the design of bone repair materials based on magnesium alloys.

Electrophoretic Deposition of Bioadaptive Drug Delivery Coatings on Magnesium Alloy for Bone Repair.

Biodegradable polymer coatings on magnesium alloys are attractive, as they can provide corrosion resistance as well as additional functions for biomedical applications, e.g., drug delivery. A gelatin nanospheres/chitosan (GNs/CTS) composite coating on WE43 substrate was fabricated by electrophoretic deposition with simvastatin (SIM) loaded into the GNs. Apart from a sustained drug release over 28 days, an anticorrosion behavior of the coated WE43 substrates was confirmed by electrochemical tests. Both the degradation and corrosion rates of the coated substrate were significantly minimized in contrast to bare WE43. The cytocompatibility of the coated samples was analyzed  both quantitatively and qualitatively. Additionally, the osteogenic differentiation of MC3T3-E1 cells on SIM-containing coatings was assessed by measuring the expression of osteogenic genes and related proteins, alkaline phosphatase (ALP) activity, and extracellular matrix mineralization, showing that the SIM-loaded composite coating could upregulate the expression of osteogenic genes and related proteins, promote ALP activity, and enhance extracellular matrix mineralization. In summary, the SIM-loaded GNs/CTS composite coatings were able to enhance the corrosion resistance of the WE43 substrate and promote osteogenic activity, thus demonstrating a promising coating system for modifying the surface of magnesium alloys targeted for orthopedic applications.

Amplification of Oxidative Stress in MCF-7 Cells by a Novel pH-Responsive Amphiphilic Micellar System Enhances Anticancer Therapy.

The excessive increase of intracellular reactive oxygen species (ROS) makes tumor cells usually in the state of oxidative stress. Although tumor cells can adapt to this state to a certain extent by upregulating antioxidant systems, the further ROS insults disrupt the transient intracellular redox balance, eventually leading to apoptosis and necrosis. Therefore, increasing the intracellular ROS level can effectively amplify the oxidative stress and induce apoptosis, which can be employed as a strategy for tumor treatment. Herein, a unique pH-responsive ROS inducing micellar system was reported in this study to specifically amplify the ROS signal in tumor cells. This micellar system was constructed by a new amphiphilic polymer, PIAThydCA, composed of poly(itaconic acid) (PIA) as the hydrophilic backbone, d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) as the hydrophobic side chain, and cinnamaldehyde (CA) as the ROS-generating agent, which were linked to PIA by the pH-sensitive hydrazone bond. PIAThydCA micelles could be degraded in the intracellular acidic environment through the hydrolysis of hydrazone bond and release CA. CA and TPGS could amplify oxidative stress cooperatively to kill MCF-7 human breast cells preferentially through the mitochondrial apoptosis pathway. Therefore, we anticipate that the PIAThydCA micelles could exert great potential in anticancer therapy.

Upregulation of circular RNA circ_0000502 predicts unfavorable prognosis in osteosarcoma and facilitates cell progression via sponging miR-1238.

Growing evidence suggests that circular RNAs (circRNAs) play a significant role in regulating cancer initiation and metastasis. Osteosarcoma (OS) is a sophisticated disease with various genes activated or silenced. In this study, we defined a novel cancer-related circRNA, circ_0000502 in OS progression. qRT-PCR was conducted to detect its expression level in OS tissue samples and cell lines. In addition, the clinical significance of circ_0000502 was investigated. Afterwards, gain-of-function and loss-of-function in vitro assays were performed to detect the cell growth, apoptosis, migration, and invasion altered by circ_0000502 by CCK-8, clone-forming, flow cytometry, and transwell experiments. Xenograft study was performed to validate the in vitro data. The luciferase reporter assay was used to explore the mechanism of circ_0000502. Circ_0000502 was identified upregulated in both OS tissue specimens and cells. In addition, its expression predicts clinical severity and unfavorable prognosis in the 63 recruited patients with OS. Circ_0000502 facilitated cell proliferation, migration, and invasion in OS cells and inhibited cell apoptosis. The animal study further confirmed the in vitro results. For mechanism exploration, circ_0000502 could directly sponge microRNA (miR)-1238, and the oncogenic functions of circ_0000502 is partially dependent on its regulation of miR-1238 proved by rescue assays. In summary, this study might help to develop rational predictive and therapeutic target for patients with OS.

A Facile Flow-Casting Production of Bioactive Glass Coatings on Porous Titanium for Bone Tissue Engineering.

Additive manufacturing enabled the fabrication of porous titanium (PT) with customized porosity and mechanical properties. However, functionalization of PT surfaces with bioactive coatings is being challenged due to sophisticated geometry and highly porous structure. In this study, a facile flow-casting technique was developed to produce homogeneous 45S5 bioactive glass (BG) coatings on the entire surface of PT. The coating weight as a function of BG concentration in a BG-PVA slurry was investigated to achieve controllable coating yield without blocking macropore structure. The annealing-treated BG coating not only exhibited compact adhesion confirmed by qualitative sonication treatment, but also enhanced the mechanical properties of PT scaffolds. Moreover, in-vitro assessments of BG-coated PT cultured with MC3T3-E1 cells was carried out having in mind their potential as bioactive bone implants. The experimental results in this study offer a simple and versatile approach for the bio-functionalization of PT and other porous biomedical devices.

Electrophoretic deposition of dexamethasone-loaded gelatin nanospheres/chitosan coating and its dual function in anti-inflammation and osteogenesis.

Surface modification of metallic implants with bioactive and biodegradable coatings could be a promising approach for bone regeneration. The objective of this study was to prepare chitosan/gelatin nanospheres (GNs) composite coating for the delivery of dexamethasone (DEX). GNs with narrow size distribution and negative surface charge were firstly prepared by a two-step desolvation method. Homogeneous and stable gelatin nanospheres/chitosan (GNs/CTS) composite coatings were formed by electrophoretic deposition (EPD). Drug loading, encapsulation efficiency and in vitro release of DEX were estimated using high performance liquid chromatography (HPLC). The anti-inflammatory effect of DEX-loaded coatings on macrophage RAW 264.7 cells was assessed by the secretion of tumour necrosis factor (TNF) and inducible nitric oxide synthase (iNOS). Osteogenic differentiation of MC3T3-E1 osteoblasts on DEX-loaded coatings was investigated by osteogenic gene expression and mineralization. The DEX in GNs/CTS composite coating showed a two-stage release pattern could not only suppress inflammation during the burst release period, but also promote osteogenic differentiation in the sustained release period. This study might offer a feasible method for modifying the surface of metallic implants in bone regeneration.

Electric Field-Assisted Orientation of Short Phosphate Glass Fibers on Stainless Steel for Biomedical Applications.

Structural and compositional modifications of metallic implant surfaces are being actively investigated to achieve improved bone-to-implant bonding. In this study, a strategy to modify bulk metallic surfaces by electrophoretic deposition (EPD) of short phosphate glass fibers (sPGF) is presented. Random and aligned orientation of sPGF embedded in a poly(acrylic acid) matrix is achieved by vertical and horizontal EPD, respectively. The influence of EPD parameters on the degree of alignment is investigated to pave the way for the fabrication of highly aligned sPGF structures in large areas. Importantly, the oriented sPGF structure in the coating, owing to the synergistic effects of bioactive composition and fiber orientation, plays an important role in directional cell migration and enhanced proliferation. Moreover, gene expression of MC3T3-E1 cells cultured with different concentrations of sPGF is thoroughly assessed to elucidate the potential stimulating effect of sPGF on osteogenic differentiation. This study represents an innovative exploitation of EPD to develop textured surfaces by orientation of fibers in the macroscale, which shows great potential for directional functionalization of metallic implants.

Bioactivity assessment of PLLA/PCL/HAP electrospun nanofibrous scaffolds for bone tissue engineering.

AIMS: The purpose of this paper was to fabricate PLLA/PCL nanofibrous scaffolds containing HAP to mimic the native bone extracellular matrix for potential applications as bone tissue engineering scaffolds materials and ultimately to help the repairing of bone defects. MATERIALS AND METHODS: PLLA (MW 200kDa), PCL (MW 80kDa), HAP, dichloromethane, N,N-dimethylformamide; α-MEM, FBS, trypsin-EDTA, penicillin G, streptomycin, ß-sodium glycerophosphate, l-ascorbic acid, dexamethasone; CCK-8, Alkaline Phosphatase Assay Kit, Mouse Osteocalcin ELISA Kit, MC3T3-E1 cells. PLLA, PCL and HAP were dissolved in the solution of DCM and DMF to fabricate nanofibrous scaffolds through electrospinning. The morphology of the scaffolds was investigated with SEM, while the diameter of the fibers, pore size and water uptake of the scaffolds were tested, respectively. TGA was carried out to verify the percentage of HAP in the composite scaffolds fabricated with different HAP concentrations. Cell count kit-8 assay, alkaline phosphatase (ALP) assay, and osteocalcin assay were applied to observe the MC3T3-E1 cells proliferation, differentiation on the composite scaffolds. KEY FINDINGS: MC3T3-E1 cells were found to grow actively on the composite scaffolds based on the results of CCK-8 assay. The level of MC3T3-E1 differentiation was evaluated through the ALP activity and osteocalcin concentration, which showed higher value with HAP containing (PLLA/PCL/HAP) than that ones without (PLLA/PCL). SIGNIFICANCE: The results demonstrated that the biocomposite PLLA/PCL/HAP nanofibrous scaffold should be a promising candidate for proliferation, differentiation and mineralization of osteoblasts, and potentially can be used for bone tissue regeneration.