Bio-Medical Materials and Engineering - Volume 30, issue 2

Authors: Yu, Zhang | Lili, Jiang | Tiezheng, Zheng | Li, Sha | Jianzhuang, Wang | Haichao, Dong | Kedong, Song | Tianqing, Liu

Article Type: Research Article

Abstract: BACKGROUND: Meniscus tissue engineering has provided a great potential treatment for meniscal injuries. However, few scaffolds in meniscus tissue engineering have matched the mechanical properties of native meniscus. OBJECTIVE: In this study, we developed a composite scaffold using decellularized meniscus extracellular matrix (DMECM) and gelatin/chitosan (G/C) to explore a preferable ratio to enhance the elastic modulus and cytotoxicity properties of scaffolds. METHODS: The microstructure, porosity, cytotoxicity, and strength of the composite scaffolds were evaluated. The micro-architectures of the samples were evaluated using scanning electron microscope (SEM). Fourier Transform Infrared analysis (FTIR) was used to confirm the …chemical structure with different type composite scaffolds. The compressive elastic modulus of all the scaffolds were measured by the universal tensile testing machine DNS300. Calcein-AM (fluorescent green) and propidium iodide (fluorescent red) were used to stain live cells and dead cells. Morphology and spatial distribution of cells within scaffolds were observed by confocal laser scanning microscopy FV 1000. RESULTS: SEM showed that the composite scaffolds had suitable porous structure. CCK-8 and live/dead staining demonstrated that the composite scaffolds had no cytotoxicity and could promote bone marrow mesenchymal stem cells (BMSCs) proliferation. The FTIR results demonstrated the successful mixing of these two elements, and the addition of DMECM improved the elastic modulus and cytotoxicity of G/C composite scaffolds. CONCLUSIONS: This study developed a composite scaffold using DMECM and G/C, and demonstrated that it might be suitable for meniscal tissue engineering application. Show more

Keywords: Meniscus extracellular matrix, gelatin/chitosan scaffolds, meniscal tissue engineering, compressive elastic modulus, cytotoxicity

DOI: 10.3233/BME-191038

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 125-132, 2019

Authors: Kang, Kyoung-Tak | Park, Joon-Hee | Koh, Yong-Gon | Shin, Jaewon | Park, Kwan Kyu

Article Type: Research Article

Abstract: BACKGROUND: The effects of the posterior slope of the tibial prosthesis on unicompartmental knee arthroplasty have not been fully evaluated and controversies still exist. OBJECTIVE: This study evaluates the effects of the posterior slope of the tibia on contact stresses in polyethylene inserts and articular cartilage using finite element analysis. METHODS: We generated a computational model followed by the development of a posterior tibial slope (PTS) from −1° to 15° cases with increments of 2° PTS models. Using a validated finite element (FE) model, we investigated the influence of the changes in PTS on the …contact stress in the medial polyethylene insert and lateral cartilage. The FE model’s loading condition is level walking, a normal daily activity. RESULTS: The contact stress increased on the lateral articular cartilage as the PTS increased. The contact stress on the polyethylene insert differed from the contact stress on the lateral articular cartilage, and it generally increased as the PTS decreased. However, in the initial stance phase when an axial force was exerted, it increased as the PTS increased. CONCLUSIONS: Our results show that an offset of ±2° from the initial anatomical tibial slope does not biomechanically affect the outcome. Show more

Keywords: Unicompartmental knee arthroplasty, posterior tibial slope, finite element analysis

DOI: 10.3233/BME-191039

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 133-144, 2019

Authors: Karteva, Ekaterina | Manchorova, Neshka | Petrova, Nadia | Damyanov, Zhelyazko | Vladimirov, Stoyan

Article Type: Research Article

Abstract: BACKGROUND: Human dentin is a highly calcified tissue of mesenchymal origin with a heterogeneous structure. Its morphology is constantly remodelled throughout the life span of the tooth, as well as under the influence of external stimuli. OBJECTIVE: The aim of the present study was to obtain information about the thermal changes in the crown and root dentin specimens of vital and devitalized teeth. METHODS: The investigated samples were divided into 6 groups, depending on the patients’ age and dentin location (crown, root). An additional group of endodontically treated teeth was created. The methods of choice were …were combined thermal analysis (DTA-TG(DTG)-MS and gas chromatography-mass spectrometry. RESULTS: After heating up to 1200 °C, endo- and exothermal effects were observed. The effects’ dynamic was the same for all samples. The differences were in the samples’ weight after the experiment, with root dentin showing the greatest mass loss percentage. CONCLUSIONS: The observed mass loss differences could be attributed to the presence of impurities in the dentin, as well as alterations in the collagen matrix. Ageing and endodontic treatment could catalyse the accumulation of such changes and affect the microstructure of the mineralized tissue. Show more

Keywords: Differential thermal analysis, mass loss, transparent dentin, endodontically treated teeth

DOI: 10.3233/BME-191040

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 145-156, 2019

Authors: Kang, Kyoung-Tak | Koh, Yong-Gon | Park, Kyoung-Mi | Lee, Jun-Sang | Kwon, Sae Kwang

Article Type: Research Article

Abstract: BACKGROUND: The conservation of the joint anatomy is an important factor in total knee arthroplasty (TKA). The restoration of the femoral posterior condylar offset (PCO) has been well known to influence the clinical outcome after TKA. OBJECTIVE: The purpose of this study was to determine the mechanism of PCO in finite element models with conservation of subject anatomy and different PCO of ±1, ±2, ±3 mm in posterior direction using posterior cruciate ligament-retaining TKA. METHODS: Using a computational simulation, we investigated the influence of the changes in PCO on the contact stress in the polyethylene (PE) insert …and patellar button, on the forces on the collateral and posterior cruciate ligament, and on the quadriceps muscle and patellar tendon forces. The computational simulation loading condition was deep knee bend. RESULTS: The contact stresses on the PE insert increased, whereas those on the patellar button decreased as posterior condylar offset translated to the posterior direction. The forces exerted on the posterior cruciate ligament and collateral ligaments increased as PCO translated to the posterior direction. The translation of PCO in the anterior direction, in an equivalent flexion angle, required a greater quadriceps muscle force. CONCLUSIONS: Translations of the PCO in the posterior and anterior directions resulted in negative effects in the PE insert and ligament, and the quadriceps muscle force, respectively. Our findings suggest that orthopaedic surgeons should be careful with regard to the intraoperative conservation of PCO, because an excessive change in PCO may lead to quadriceps weakness and an increase in posterior cruciate ligament tension. Show more

Keywords: Posterior condylar offset, total knee arthroplasty, finite element analysis

DOI: 10.3233/BME-191041

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 157-169, 2019

Authors: Park, Kwan Kyu | Koh, Yong-Gon | Park, Kyoung-Mi | Park, Joon-Hee | Kang, Kyoung-Tak

Article Type: Research Article

Abstract: BACKGROUND: Component malalignment in unicompartmental knee arthroplasty (UKA) has been related to the concentration in tibiofemoral joint of contact stress and to poor post-operative outcomes. Few studies investigated a biomechanical effect of femur component position in sagittal plane. The purpose of this study was to evaluate the biomechanical effect of the femoral components on the sagittal alignment under flexion and extension conditions using computational simulations. METHODS: The flexion and extension conditions of the femoral component were analyzed from 10° extension to 10° flexion in 1° increments. We considered the contact stresses in the polyethylene (PE) inserts and articular …cartilage, and the force on the collateral ligament, under gait cycle conditions. RESULTS: The contact stress on the PE insert increased as flexion of the femoral component increased, but there was not a remarkable difference in the amount of increased contact stress upon extension. There was no difference in the contact stress on the articular cartilage upon extension of the femoral component, but it increased in flexion during stance and double support periods. The forces on the medial collateral ligaments increased with the extension and decreased with the flexion of the femoral component, whereas the forces on the lateral collateral ligaments showed opposite trends. CONCLUSIONS: Surgeons should be concerned with femoral component position on UKA not only in frontal plane but also in the sagittal plane, because flexion or extension of the femoral component may impact the PE or opposite compartment along with the surrounding ligaments around knee joint. Show more

Keywords: Unicompartmental knee arthroplasty, malalignment, finite element analysis

DOI: 10.3233/BME-191042

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 171-182, 2019

Authors: Zaczyk, Marcin

Article Type: Research Article

Abstract: BACKGROUND/OBJECTIVE: We present a description of an experiment in which the parameters describing the quality of the mandrel embedding an implant into a bone were determined. A method was developed that allows, from outside a living organism, the strength of the mandrel of the implant in the bone tissue to be determined. Using the proposed technique, we investigated how the mechanical properties of the bone affect the quality of the implant mandrel embedding in the bone tissue. MATERIALS AND METHODS: As part of the research work, we conducted 15 compression tests on previously prepared samples that reflected an …uncemented endoprosthesis embedding in the proximal base of a femur bone. RESULTS: The results of the research showed that the load applied is dispersed between the mandrel and the bone tissue. The mechanical stability of the embedding affects the mechanical properties of the bone. The experiment revealed the nature of the mechanical stability of the embedding in relation to the increasing contact surface area. CONCLUSIONS: We observed a non-linear nature of dependences of bone density as the main parameter describing the properties of bone relative to the extent of loosening expressed in the form of the slip surface of the mandrel relative to the bone. The mechanical stability of the embedding is crucial in the initial phase of the implant healing because it eliminates the loosening of the mandrel embedding. It provides a guarantee that the specific geometry of the treated motion apparatus part will be preserved and lowers the risk of inflammatory conditions during the treatment process. Show more

Keywords: Hip arthroplasty, bone-implant mounting, static load in the hip joint, density of hip bone, contact bone-implant, model bone-implant

DOI: 10.3233/BME-191043

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 183-190, 2019

Authors: Cheng, Jin | Wang, Cong | Gu, Yongquan

Article Type: Research Article

Abstract: BACKGROUND: A tissue engineering technique based on use of the extracellular matrix (ECM) as a scaffold shows great potential for preparing small-caliber vascular grafts. Decellularization protocols are still not standardized for bioengineering. The effects of freeze-thaw cycles used for decellularization are unknown. OBJECTIVE: To evaluate the effects of freeze-thaw cycles on porcine carotid arteries during decellularization and to develop a promising protocol for preparing ECM scaffolds. METHODS: Porcine carotid arteries were decellularized with freeze-thaw cycles followed by three different chemical protocols. Histological analysis, scanning electron microscopy, mechanical tests and pore size measurement were performed to assess …their effects on the ECM. RESULTS: The composition, structure, and mechanical properties were not significantly changed after freeze-thaw cycles, with the exception of endothelial cells loss. Freeze-thaw led to a porous structure within arteries. The use of Triton X-100 followed by sodium dodecyl sulfate (SDS) resulted in ECM scaffolds with well-preserved composition, structure, and mechanical properties, as well as with adequate porosity. CONCLUSIONS: As the initial step for decellularization, freeze-thaw had little impact on arteries. Decellularized porcine carotid arteries, prepared using freeze-thaw cycles followed by treatment with Triton X-100 and SDS, may serve as a promising biological scaffold as a tissue-engineered vascular graft. Show more

Keywords: Tissue engineering, decellularization, extracellular matrix, vascular grafts, freeze-thaw

DOI: 10.3233/BME-191044

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 191-205, 2019

Authors: Su, Tzu-Rong | Chu, Ying-Hung | Yang, Hui-Wen | Huang, Yu-Feng | Ding, Shinn-Jyh

Article Type: Research Article

Abstract: BACKGROUND: Surface modification of metallic implants is critical for improving the clinical performance of the dental and orthopedic devices. Bioactive glasses exhibit different levels of cellular function and physicochemical behavior; however, there have been few previous studies on the effect of constituents of the bioactive glasses on the in vitro osteogenic activity and corrosion resistance of apatite-based coatings. OBJECTIVE: The objective of this work was to investigate the effect of SiO2 , CaO, Na2 O, and P2 O5 on plasma-sprayed apatite coatings on Ti alloy substrates for tailoring the properties of implants making them suitable for clinical …applications. METHODS: The corrosion potential and corrosion current of various coatings in simulated body fluid (SBF) were examined. MG63 cell proliferation, differentiation, and mineralization of plasma-sprayed apatite-matrix coatings were evaluated. RESULTS: The SiO2 and CaO-containing HA (HSC) coating had a higher corrosion potential than the other three coatings, while SiO2 -containing HA (HS) coating displayed the highest corrosion current among all coatings. The effect of the oxides on cell functions followed the order SiO2 > CaO > P2 O5 > Na2 O in terms of cell attachment, proliferation, differentiation, and mineralization. CONCLUSIONS: The flexibility in oxide doping may allow for the tunable biological properties and corrosion-resistant ability of the apatite coatings. Show more

Keywords: Hydroxyapatite, bioactive glass, component effect, osteogenesis, corrosion

DOI: 10.3233/BME-191045

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 207-218, 2019

Authors: Wadugodapitiya, Surangika | Sakamoto, Makoto | Sugita, Kaito | Morise, Yusuke | Tanaka, Masaei | Kobayashi, Koichi

Article Type: Research Article

Abstract: BACKGROUND: In vivo evaluation of the elastic properties of the knee joint capsule has not been adequately performed. OBJECTIVES: To establish a methodology to assess the stiffness of the normal knee joint capsule over a range of knee flexion angles using ultrasound elastography. METHODS: Ultrasound elastography with an acoustic coupler was used to assess the stiffness of the anteromedial capsule of the knee joints of 10 male (mean age 22.63 ± 1.02 years) and 10 female (mean age 21.6 ± 0.8 years) subjects at static knee flexion angles of 0°, 45°, 90°, and 120°. Relative …stiffness of the capsule was obtained using the strain ratio (SR ), defined as the ratio of the strain in the capsule to that in the acoustic coupler. RESULTS: The intraclass correlation coefficient (1, 3) ranged from 0.95 to 0.96, and the correlation coefficient between examiners (2, 3) was 0.94. SR values decreased significantly as the flexion angle increased (P < 0.01). At 90° and 120°, it was significantly higher in female than in male subjects (P < 0.01). CONCLUSIONS: This study established a feasible and reproducible method to obtain the stiffness characteristics of the anteromedial knee joint capsule using ultrasound elastography with an acoustic coupler. Show more

Keywords: Knee joint capsule, ultrasound elastography, relative stiffness, strain ratio, knee flexion, sex-specific

DOI: 10.3233/BME-191046

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 219-230, 2019

Authors: Hayatsu, Yukihiro | Watanabe, Koyu | Sasaki, Konosuke | Masaki, Naoki | Katahira, Shintaro | Kumagai, Kiichiro | Kawamoto, Shunsuke | Ohmi, Toshihito | Yokobori Jr., A. Toshimitsu | Saiki, Yoshikatsu

Article Type: Research Article

Abstract: OBJECTIVE: We aimed to develop a novel ultrasound system and examine its feasibility for noninvasively detecting thoracic aortic aneurysm (TAA) in clinical settings. METHODS: We developed a novel ultrasound system consisting of a modified console and data analysis algorithm. The exploratory study included 100 patients hospitalized for elective cardiovascular surgery. After admission, the arterial pulse waveform at the left carotid artery was acquired using the novel system. Based on these data, we inferred the presence of TAA based on arterial viscoelasticity and instability, which are reflected into the time-averaged trajectory of deformation of the blood vessel wall caused …by disturbance of blood flow. Meanwhile, all patients underwent computed tomography as preoperative screening to confirm the presence of TAA. The sensitivity and specificity of TAA detection using the novel ultrasound system were calculated. RESULTS: The datasets from 37 patients were not suitable for analysis and were thus discarded. Based on computed tomography findings, 40 patients were categorized into the aneurysm group while 23 were judged not to have and aortic aneurysm. On the other hand, 44 patients were diagnosed as having TAA based on ultrasound findings obtained using the novel system. The overall sensitivity and specificity of the ultrasound system were 0.83 and 0.52, respectively. CONCLUSION: We successfully developed a novel system for noninvasive, ultrasound-based evaluation of the left carotid artery to detect TAA. Although improvements to the probe and diagnostic algorithm are warranted, this device has potential utility for mass screening to detect asymptomatic TAA as part of community-level healthcare programs. Show more

Keywords: Thoracic aortic aneurysm, ultrasound, non-invasive detection, peripheral artery

DOI: 10.3233/BME-191047

Citation: Bio-Medical Materials and Engineering, vol. 30, no. 2, pp. 231-241, 2019