Bio-Medical Materials and Engineering - Volume 28, issue 3

Authors: Han, Bensong | Xue, Feng | Fan, Cunyi | Mo, Xiumei

Article Type: Research Article

Abstract: Objectives: This study aims to investigate the small intestinal submucosal (SIS) surface after heparinization with the hypothermia plasma technique, to improve the blood compatibility of SIS, and to explore the possibility of construction of small-caliber vascular grafts with modified SIS scaffolds in vivo. Methods: SIS films prepared from jejunums of pigs were processed for surface treatment at different time periods with the argon plasma initiation technique under vacuum, and were then immediately immersed in 4% (m/v) heparin sodium solution for 24-h heparinization. The surface morphologies of heparinized SIS were observed under a scanning electron microscope (SEM). The antithrombogenicity …of the modified SIS films was tested by measuring the water contact angle, blood coagulation time, activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and observation of platelet adherence by SEM. Heparinized SIS films were sewn into a small caliber (3-mm) tube and implanted into the defect of a canine femur by anastomosis as a vascular graft. The efficiency of the SIS graft was evaluated according to the patency for the circulation of blood with Doppler color ultrasonography and hematoxylin-eosin staining. Results: Heparinized SIS showed a significantly different surface morphology compared with that of untreated SIS. The SIS surface resembles wrinkled film, but the heparinized SIS surface is uniformly coated with microdots, and appears to have a layer of heparin adhesion. Conclusion: Heparin was attached to the SIS surface after hypothermia plasma treatment. Hydrophilicity and antithrombogenicity of heparinized SIS were clearly increased. The heparinized SIS vascular graft showed great potential for replacement of defective small-caliber vessels. Show more

Keywords: Thrombogenesis, SIS, argon plasma, heparin, small-caliber vessels

DOI: 10.3233/BME-171668

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 213-222, 2017

Authors: Tu, Ying | Chen, Chen | Li, Yubao | Hou, Yi | Huang, Min | Zhang, Li

Article Type: Research Article

Abstract: The development of guided bone regeneration (GBR) technique brings a promising alternative for bone defects and fracture healing. In this study, an asymmetric nano-hydroxyapatite/chitosan (n-HA/CS) composite GBR membrane was fabricated by means of solution-blending and solvent-evaporating in vacuum. The membranes were characterized using SEM, XPS and contact angle. It was found that the composite membrane displayed an asymmetric structure, in which the upper surface was CS and the under surface was a complex of n-HA and CS, and some interactions between n-HA and CS were also confirmed to exist. The contact angle testing showed that the under surface was more …hydrophilic than the upper surface. The in vivo experiments demonstrated that the asymmetric composite membrane had the ability to make osteoblasts mineralize and promote loose bone calcified, and then accelerate the bone regeneration. Compared with CS membrane, the asymmetric composite membrane displays a better bone regeneration ability and is suitable for GBR membrane. Show more

Keywords: GBR technique, nano-hydroxyapatite, chitosan, degradation, asymmetric membrane

DOI: 10.3233/BME-171669

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 223-233, 2017

Authors: Zygmuntowicz, Justyna | Zima, Aneta | Czechowska, Joanna | Szlazak, Karol | Ślosarczyk, Anna | Konopka, Katarzyna

Article Type: Research Article

Abstract: Background: Material properties of the scaffolds as well as their microstructure are vital in determining in vivo cellular response. Three-dimensional (3D), highly porous scaffolds are used in tissue engineering to provide a suitable microenvironment and to support regeneration of bone. Both pore sizes and their architecture, in particular interconnection density, impact functionality of scaffold during its biomedical applications. Objective: In this paper a comparative study of the microstructure of highly porous hydroxyapatite scaffolds produced via gelcasting of foamed slurries and replication of polyurethane sponge were carried out. Methods: Quantitative stereological analysis of the microstructure was conducted …using transmission X-ray computed microtomography (μ CT) and scanning electron microscopy (SEM). Application of the X-ray microtomography allowed obtaining the 2D cross-sectional images of examined samples, and then the 3D reflection of individual samples. Results: In our studies we proved that the distribution of pores in HAp bioceramics can be controlled by selection of the manufacturing method. In the case of material produced by the gelcasting method, the porosity of the samples was about ∼ 78   vol.% , while for the method of replication of the porous organic matrix it was higher ∼ 84   vol.% . Application of gelcasting method resulted in bioceramics with the macropores ranging from 95 μ m to 158 μ m (the modal value of 120 μ m). Furthermore, micropores of size 34 μ m–60 μ m – so called “windows”, were observed on spherical macropores surfaces. In the case of replication of polyurethane sponge only macropores from 295 μ m to 337 μ m (the modal value of 300 μ m) were obtained. Application of μ CT and SEM give more information than classical mercury intrusion porosimetry in studies of porous bioceramics. Developed materials met the criteria for porous bone substitutes. Conclusions: The results of quantitative description of microstructure allowed determining the differences between porous hydroxyapatite bioceramics obtained via replication of porous organic matrix and gelcasting of foamed slurry. The stereological analysis demonstrated, that bioceramics prepared via gelling of foamed slurry has a lower pore size and grains (1.1–1.9 μ m) than the material obtained by the method of replication of polyurethane sponge (2.1–2.3 μ m). Based on morphological analysis the porosity of tested materials was determined. In the case of material produce by the gelcasting, porosity of the samples was about ∼ 78   vol.% , while for method of replication of the porous organic matrix the porosity was higher and constituted ∼ 84   vol.% . Furthermore, evaluated materials varied in porosity and the pore size distribution. It was stated that the method of gelcasting resulted in hydroxyapatite bioceramics with the macropores diameter (95–158 μ m), micropores so called “windows” (34–60 μ m) – observed on spherical macropores walls and micropores of size 0.6 μ m–1.3 μ m, which were visible in sintered areas. When the method of replication of polyurethane sponge was applied only macropores from 295 μ m to 337 μ m were obtained. The comparable values of shape factors such as elongation, curvature of pours boundary and convexity, confirmed that macropores in both studied series had similar shape. Show more

Keywords: Porous HAp bioceramics, stereological analysis, computed tomography

DOI: 10.3233/BME-171670

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 235-246, 2017

Authors: Thote, Abhishek M. | Sharma, Krishna | Uddanwadiker, Rashmi V. | Shrivastava, Sunita

Article Type: Research Article

Abstract: Background: Approximately 50% patients with a deep bite possess anatomically extruded mandibular canines. Objective: The objective of this study was to specify an optimum toe (Θ) of the vertical segment of a cantilever from the distal aspect to achieve pure intrusion of a mandibular canine with the segmented arch in lingual orthodontics (LiO). Methods: The geometrical model of a mandibular canine was developed to compute the required values of Θ (positive values – toe-in, negative values – toe-out). Different positions of the cantilever attachment on the lingual bracket top (occlusal) surface were considered according to different …heights (h ) from the cusp of a canine i.e. 2, 3, 4 and 5 mm in each case of horizontal distance (x ) from canine surface i.e. 2 and 3 mm. In x = 2 mm case, the required values of Θ at h = 2 , 3 , 4   and  5 mm were − 5 °, 0°, + 6 ° and + 11 ° respectively. While, in x = 3 mm case, the required values of Θ at h = 2 , 3 , 4   and  5 mm were 0°, + 5 °, + 12 ° and + 17 ° respectively. Results: In finite element analysis (FEA), the computed values of Θ were verified by displaying the results of a mandibular canine movement in the form of vectors of nodal displacements along with undeformed and deformed models. Conclusions: In the cases of x = 2 mm   and  3 mm , no toe angles were required at heights h = 3 mm   and  2 mm respectively. Hence, these can be considered as better positions of the cantilever attachment than others. Show more

Keywords: Mandibular canine, pure intrusion, segmented arch, LiO, geometrical model, FEA

DOI: 10.3233/BME-171671

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 247-256, 2017

Authors: Kamangar, Sarfaraz | Badruddin, Irfan Anjum | Ameer Ahamad, N. | Soudagar, Manzoor Elahi M. | Govindaraju, Kalimuthu | Nik-Ghazali, N. | Salman Ahmed, N.J. | Yunus Khan, T.M.

Article Type: Research Article

Abstract: The current study investigates the effect of multi stenosis on the hemodynamic parameters such as wall pressure, velocity and wall shear stress in the realistic left coronary artery. Patients CT scan image data of normal and diseased left coronary artery was chosen for the reconstruction of 3D coronary artery models. The diseased 3D model of left coronary artery shows a narrowing of more than 70% and 80% of area stenosis (AS) at the left main stem (LMS) and left circumflex (LCX) respectively. The results show that the decrease in pressure was found downstream to the stenosis as compared to the …coronary artery without stenosis. The maximum pressure drop was noted across the 80% AS at the left circumflex branch. The recirculation zone was also observed immediate to the stenosis and highest wall shear stress was found across the 80% area stenosis. Our analysis provides an insight into the distribution of wall shear stress and pressure drop, thus improving our understanding on the hemodynamics in realistic coronary artery. Show more

Keywords: Coronary artery, non-Newtonian flow, stenosis, CFD, computer tomography

DOI: 10.3233/BME-171672

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 257-266, 2017

Authors: Sano, Hirotaka | Tokunaga, Masako | Noguchi, Moriyuki | Inawashiro, Takashi | Irie, Taichi | Abe, Hiroo | Yokobori Jr, A. Toshimitsu

Article Type: Research Article

Abstract: Background: Retearing mechanism after transosseous equivalent (TOE) rotator cuff repair has not been fully clarified yet. Objective: The purposes of this study were to compare the stress distribution pattern in the tendon stump between knotted and knotless TOE repair and to investigate the role of suture tension applied during medial knot tying using a 3-dimensional finite element (3D-FE) method. Methods: Both knotted and knotless TOE repairs were simulated on the 3D-FE human rotator cuff tear model. Elastic analysis was performed to compare the stress distribution pattern inside the tendon between the two models. The amount of …compressive load applied to the medial-row sutures was then changed as 0, 20, 40, 60, 80, and 100 N in the knotted model. Results: Knotted model demonstrated more distinct stress concentration inside the tendon around medial-row sutures than the knotless model. Mean von Mises equivalent stress in this area in the 0, 20, 40, 60, 80, and 100 N models was 0.26, 0.35, 0.50, 0.70, 1.11, and 1.14 MPa, respectively. Conclusions: In the knotted TOE repair, tight medial knot tying might cause a high stress concentration around medial knots, which may constitute one of the pathogenetic factors of postoperative retearing at this site. Show more

Keywords: Rotator cuff tear, transosseous equivalent repair, medial knot tying, retearing, stress concentration, finite element method

DOI: 10.3233/BME-171673

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 267-277, 2017

Authors: Luo, Yunhua | Liang, Zhaoyang

Article Type: Research Article

Abstract: Understanding how a helmet protects the head, especially the soft brain tissues, is the prerequisite for improving helmet design. Intracranial pressure and stresses/strains in the brain tissues are the direct indicators of traumatic brain injury and they can be used to measure helmet performance. In this study, the effects of helmet design parameters such as the helmet shell stiffness, liner compliance and thickness on the brain injury indicators were investigated by virtual impact tests. A finite element head model (FEHM) was first constructed from medical images; a personally-fitted helmet made of composite material and foam was virtually prototyped using geometric …information extracted from the FEHM; a helmet-head finite element model was then assembled. Virtual impact tests were conducted using the resulting helmet-head model. The obtained results suggested that, if the helmet shell already has adequate strength to resist excessive deformation and fracture, further increasing shell stiffness and strength would not considerably reduce intracranial pressure and brain strains; to reach the maximum protection with the available materials, the key is to effectively use the second stage in the stress-strain history of the liner foam material. Show more

Keywords: Closed-head injury, sport helmet, image-based finite element model, composite materials, liner foam, virtual impact test

DOI: 10.3233/BME-171674

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 279-291, 2017

Authors: Fujioka-Kobayashi, Masako | Schaller, Benoit | Zhang, Yufeng | Pippenger, Benjamin E. | Miron, Richard J.

Article Type: Research Article

Abstract: Bone morphogenetic protein 9 (BMP9) has previously been characterized as the strongest osteoinductive growth factor among the BMP family. The aim of the present study was to evaluate the possibility of combining rhBMP9 with an injectable biphasic calcium phosphate (I-BCP, maxresorb inject® ), since I-BCP is an easy to handle biomaterial with ideal properties for bone augmentation procedures. The adsorption potential of rhBMP9 as well as the cell behavior of bone stromal ST2 cells were investigated on cell viability, adhesion, proliferation and osteogenic differentiation for I-BCP combined with/without rhBMP9 in vitro . I-BCP demonstrated excellent adsorption/retention potential of rhBMP9 with …a slow and steady release over a 10 day period by ELISA. Cell attachment at 8 hours and cell proliferation at 1, 3 and 5 days was decreased on I-BCP with/without rhBMP9 when compared to control tissue-culture plastic. While I-BCP had little influence on osteoblast differentiation, its combination with rhBMP9 significantly increased ALP activity at 7 days and mRNA levels of osteoblast differentiation markers including ALP and osteocalcin at 14 days. I-BCP served as an excellent carrier for rhBMP9 clearly demonstrating its osteoinductive potential. We therefore confirm the great potential of rhBMP9 to serve as a future regenerative growth factor for bone applications. Show more

Keywords: Bone morphogenetic proteins, BMP9, BCP, biphasic calcium phosphate, carrier system, bone regeneration, bone augmentation, osteogenesis

DOI: 10.3233/BME-171675

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 293-304, 2017

Authors: Yamamoto, Meguru | Kataoka, Yu | Manabe, Atsufumi

Article Type: Research Article

Abstract: Background: The use of dental computer-aided design/computer-aided manufacturing (CAD/CAM) restoration is rapidly increasing. Objective: This study was performed to evaluate the marginal and internal cement thickness and the adhesive gap of internal cavities comprising CAD/CAM materials using two digital impression acquisition methods and micro-computed tomography. Methods: Images obtained by a single-image acquisition system (Bluecam Ver. 4.0) and a full-color video acquisition system (Omnicam Ver. 4.2) were divided into the BL and OM groups, respectively. Silicone impressions were prepared from an ISO-standard metal mold, and CEREC Stone BC and New Fuji Rock IMP were used to create …working models (n = 20 ) in the BL and OM groups (n = 10 per group), respectively. Individual inlays were designed in a conventional manner using designated software, and all restorations were prepared using CEREC inLab MC XL. These were assembled with the corresponding working models used for measurement, and the level of fit was examined by three-dimensional analysis based on micro-computed tomography. Results: Significant differences in the marginal and internal cement thickness and adhesive gap spacing were found between the OM and BL groups. Conclusions: The full-color movie capture system appears to be a more optimal restoration system than the single-image capture system. Show more

Keywords: CAD/CAM, cement thickness, micro-CT

DOI: 10.3233/BME-171676

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 305-314, 2017

Authors: Takeuchi, Issei | Nobata, Sho | Oiri, Naoto | Tomoda, Keishiro | Makino, Kimiko

Article Type: Research Article

Abstract: Background: Inorganic gold nanoparticles (NPs) have a huge potential in targeted drug delivery. Simple preparation and surface modification procedure with their special physicochemical properties of gold NPs attract their use such as tumor targeting and the detection of cancerous cell. Objective: Various studies were reported, however, details of biodistribution profile of gold NPs were not enough evaluated. We have studied biodistribution profile of gold NPs having various particle sizes (20, 50 and 100 nm). Methods: Gold concentrations in brain, heart, lungs, liver, stomach, pancreas, spleen, kidneys, blood, urine, and feces were measured at 5 minutes, 0.25, …0.5, 1, 2, 3, 6, 12, 18 and 24 hours after administration of gold NPs using inductively coupled plasma atomic emission spectrometry. Results: In lungs and brain, especially 20-nm gold NPs were accumulated after 2-3 hours of dose administration, and they were kept for 24 hours, whereas they showed relatively low accumulation in heart, stomach and pancreas. After 12 hours, 3.3–14.4% of the injected gold were observed in fecal matter and urine. Conclusions: From this study, the application of gold NPs for targeted delivery to lungs and brain and the excretion route of the gold NPs from the body were suggested Show more

Keywords: Gold nanoparticles, biodistribution, intravenous, mice, excretion route

DOI: 10.3233/BME-171677

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 315-323, 2017