Bio-Medical Materials and Engineering - Volume 28, issue 6

Authors: Nemavhola, Fulufhelo

Article Type: Research Article

Abstract: The effect of myocardial infarction on the global functioning of the heart is well known. Less is understood regarding the effect of LV fibrotic infarction on the cardiac mechanics of the septal wall. To determine this unknown, the stress and strain of septal wall on the healthy and infarcted rat heart model is measured by using finite element models of rat heart geometries. The main objective of this study was to utilized computational methods to study the effect of LV free wall fibrotic infarction on the healthy septal wall. Three-dimensional biventricular rat heart geometries were developed from cardiac magnetic resonance …images of a healthy heart and a heart with left ventricular (LV) fibrotic infarction after infarct induction. From these geometries, FE models were established. Three-dimensional biventricular rat heart geometries developed from cardiac magnetic resonance images were used in creating FE models of healthy and infarcted rat hearts. The average radial strain percentage change of the healthy septal wall on the epicardium, mid-wall and endocardium was 61%, 52% and 14% higher than the infarcted septal wall, respectively. It was concluded that the fibrotic infarction has a potential cause the malfunction of the heart due to high myocardial stress and strain that the septal wall experiences Show more

Keywords: Finite element modeling, bi-ventricular heart model, computational mechanics, myocardial stress, myocardial strain

DOI: 10.3233/BME-171698

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 579-599, 2017

Authors: Pockevicius, Vytautas | Cepenas, Mindaugas | Miklusis, Donatas | Markevicius, Vytautas | Zabuliene, Lina | Navikas, Dangirutis | Valinevicius, Algimantas | Andriukaitis, Darius

Article Type: Research Article

Abstract: This article explores a non-invasive method to determine interstitial fluid level and pressure in tissue. Interdigital electrodes were chosen by simulated results in software “Comsol multiphysis 4.3a”. Environment model similar to human body was created. Measurements were carried out at different situations which can occur during preoperative and afterwards surgery. Non-invasive method decreases possibility of infection and will improve recovery process in postoperative period.

Keywords: Impedance, conductivity, interstitial fluid, fluid therapy, non-invasive, stretch sensor

DOI: 10.3233/BME-171699

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 601-612, 2017

Authors: Amini, Yousef | Amel Jamehdar, Saeid | Sadri, Keyvan | Zare, Sirwan | Musavi, Danial | Tafaghodi, Mohsen

Article Type: Research Article

Abstract: Background: Effective encapsulation of drugs into the delivery systems could increase the efficiency of nanoparticles in prevention and treatment of diseases. Objective: The purpose of this study was to compare the different methods for determination of encapsulation efficiency of a model protein in the PLGA nanoparticles. Methods: The various direct methods include dichloromethane, acetonitrile, modified acetonitrile and NaOH based extraction and radioactive methods were used to directly calculate the encapsulation efficiency of the loaded protein in the PLGA nanoparticles. Furthermore, indirect methods include BCA, Fluorescent and radioactive methods were compared. Results: The encapsulation efficiencies …determined by indirect methods include dichloromethane, acetonitrile, modified acetonitrile, NaOH based extraction and radioactive methods were 12.62% ± 1.97, 17.43% ± 2.51, 64.69% ± 4.31, 86.36% ± 2.25 and 90.15% ± 1.78, respectively. Moreover, the encapsulation efficiencies determined by indirect methods include BCA, fluorescent and radioactive methods were 81.46% ± 1.92, 88.23% ± 1.15 and 89.6% ± 1.9, respectively. Conclusions: Among the results obtained by indirect methods, radioactive and fluorescent methods showed more reliable. Moreover, NaOH and radioactive methods were the most reliable methods among the direct methods. Show more

Keywords: Encapsulation efficiency, direct methods, indirect methods, PLGA, nanoparticles

DOI: 10.3233/BME-171705

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 613-620, 2017

Authors: Tabatabaei, Fahimeh Sadat | Samadi, Ramin | Tatari, Saeed

Article Type: Research Article

Abstract: Background: Reconstruction of bone defects is often performed using bone autografts. However, limitations associated with the use of autografts led to the use of bone substitute materials. Objectives: The purpose of this study was to compare the surface characteristics of three commercially available grafts namely allografts, xenografts and alloplasts. Methods: This in vitro study was conducted on beta-tricalcium phosphate (β -TCP) alloplast, a mixture of demineralized bone matrix and mineralized bone allograft (DBM&MBA) and natural bovine bone mineral (NBBM) xenograft. Presence of apatite groups on the surface of samples was assessed by X-ray diffraction (XRD) while …the presence of functional groups was evaluated using Fourier transform infrared spectroscopy (FTIR). Also, dental pulp stem cells (DPSCs) were cultured on the surface of samples and their adhesion was evaluated under a scanning electron microscope (SEM). Results: The FTIR showed a relatively similar pattern for NBBM and TCP samples and a different pattern in DBM&MBA. The results of XRD analysis also showed similarities between NBBM and TCP with sharper peaks than the DBM&MBA sample. The SEM micrographs showed that at 24 hours, no cell was detectable on the surface of NBBM sample; whereas, elongated cells were noted on the surface of TCP and DBM&MBA samples. Conclusions: The patterns of β -TCP and NBBM samples in XRD and FTIR spectroscopy showed high resemblance but they had different behaviors with respect to cell adhesion. Show more

Keywords: Bone graft, cell adhesion, FTIR, stem cells, XRD

DOI: 10.3233/BME-171700

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 621-631, 2017

Authors: Maitirouzi, Julaiti | Yanna, Li | Abulizi, Adinaer | Aihemaitiniyazi, Aizezi | Kuerban, Shataer | Shaojun, Huang

Article Type: Research Article

Abstract: Objective: To investigate the effects of Uygur sand therapy on the mechanical properties of the femur bone of osteoarthritic rabbits. Methods: Sixteen rabbits were injected with papain in the right posterior femoral articular cavity on the first, fourth and seventh day to establish the osteoarthritis (OA) rabbit model. Animals were divided into the experimental group and control group (8 rabbits each). The experimental group was treated with sand therapy, and the control group received no sand therapy treatment. Computed tomography (CT) scanning was used to collect the data of the femur before modeling, after modeling and 14 and …28 days after sand treatment. A 3D model of the femur was generated with the MIMIC software the bone layer was divided according to the different gray values and the change of the bone volume was analyzed. The body mesh is divided, and the material properties are given, then the three-point bending simulation is performed in Ansys. Additionally, the three-point bending test was performed on all the rabbits’ femur to obtain the deflection and maximum stress values. And the effects of the sand treatment on the volume and mechanical properties of the bone were analyzed. Finally, the simulation results are compared with the experimental results, and the effects of sand treatment on the volume and mechanical properties of the bone are analyzed. Results: (1) there is a tendency in the control group to convert the hard bone into dense bone and soft bone, while in the experimental group, the soft bone is converted into dense bone and hard bone obviously; (2) the morphological parameters of the experimental group are lower than those of the control group, whereas the maximum load, maximum normal stress, maximum shear stress of the experimental group are higher than those of the control group. (3) The mechanical test of three-point bending test was carried out using the three dimensional finite element model of rabbit femur. Conclusion: The sand therapy has positive effects on the volume distribution of bone layer and the mechanical properties of the femur of adult osteoarthritic rabbits. Show more

Keywords: Uyghur sand therapy, osteoarthritis, MIMICS, three-point bending test, finite element analysis

DOI: 10.3233/BME-171701

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 633-642, 2017

Authors: Kumar, M. | Mishra, S.K.

Article Type: Research Article

Abstract: Background: The clinical magnetic resonance imaging (MRI) images may get corrupted due to the presence of the mixture of different types of noises such as Rician, Gaussian, impulse, etc. Most of the available filtering algorithms are noise specific, linear, and non-adaptive. Objective: There is a need to develop a nonlinear adaptive filter that adapts itself according to the requirement and effectively applied for suppression of mixed noise from different MRI images. Methods: In view of this, a novel nonlinear neural network based adaptive filter i.e. functional link artificial neural network (FLANN) whose weights are trained by …a recently developed derivative free meta-heuristic technique i.e. teaching learning based optimization (TLBO) is proposed and implemented. Results: The performance of the proposed filter is compared with five other adaptive filters and analyzed by considering quantitative metrics and evaluating the nonparametric statistical test. The convergence curve and computational time are also included for investigating the efficiency of the proposed as well as competitive filters. Conclusion: The simulation outcomes of proposed filter outperform the other adaptive filters. The proposed filter can be hybridized with other evolutionary technique and utilized for removing different noise and artifacts from others medical images more competently. Show more

Keywords: MRI, adaptive filter, functional link artificial neural network, teaching learning optimization

DOI: 10.3233/BME-171702

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 643-654, 2017

Authors: Ghasemi, Abbas | Hashemi, Babak

Article Type: Research Article

Abstract: The purpose of this study is to analyze the co-existence effect of 30 wt.% TCP-BG phases on degradation and precipitation behaviors of PLLA based composite scaffold in biological media. First, phase separation method was used to synthesize of the pure PLLA and the trinary composite scaffolds, and second they were immersed in SBF solution for 45 days. Subsequently, the degradation and precipitation characteristic were investigated by analyzing of pH value and weight changes of the immersed samples, the ability of biological products formation and the change of relative molecular weight of PLLA matrix as function of the degradation time. Finally, …the experimental data of relative molecular weight change were verified by Han and Pan model and comparisons were made between them. Results have represented precipitation of huge amount of carbonate apatite on surface of the composite scaffold, and also the acidity of SBF media changes moderately which is prove better bioactivity properties compare to the pure PLLA scaffold. The results of comparison with the model point to quiet good agreement between them in early stage of degradation. So, the consequences suggest that the TCP-BG/PLLA composite scaffold have great potential to be applied in bone replacements or repairs. Show more

Keywords: Trinary composite scaffold, bio-degradation, modelling, carbonate apatite, tricalcium phosphate, bioactive glass

DOI: 10.3233/BME-171707

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 655-669, 2017

Authors: Bhuiyan, Didarul B. | Middleton, John C. | Tannenbaum, Rina | Wick, Timothy M.

Article Type: Research Article

Abstract: We have developed a novel multicomponent nano-hydroxyapatite-poly(D,L-lactide-co-glycolide)-collagen biomaterial (nHAP-PLGA-collagen) with mechanical properties similar to human cancellous bone. To demonstrate the bone forming capacity of nHAP-PLGA-collagen prior to in vivo experiments, nHAP-PLGA-collagen films and 3D porous scaffolds were seeded with human mesenchymal stem cells (hMSCs) to characterize cell proliferation and osteogenic differentiation. Over 21 days hMSCs seeded on 2D nHAP-PLGA-collagen films proliferate, form nodules, deposit mineral and express high alkaline phosphatase activity (ALP) indicating commitment of hMSCs towards osteogenic lineage. When seeded in 3D scaffolds, hMSCs migrate throughout the connected porous network of the nHAP-PLGA-collagen scaffold and proliferate to fill …the scaffold voids. Over 35 days, cells express ALP, osteocalcin and deposit minerals with kinetics similar to osteogenesis in vivo . Adipogenic or chondrogenic differentiation is not detected in 3D constructs, indicating that in an osteogenic environment the presence of bone ECM specific molecules in nHAP-PLGA-collagen scaffolds support homogeneous bone tissue development. This ability of nHAP-PLGA-collagen matrices to provide biochemical stimulation to support osteogenesis from stem cells along with its high mechanical strength suggests that nHAP-PLGA-collagen is a suitable biomaterial for bone regeneration. This platform technology of covalently attaching ECM proteins and molecules with synthetic and natural polymers to adjust material properties and biochemical signaling has a potential for a wider range of applications in tissue engineering and regenerative medicine. Show more

Keywords: Bone tissue engineering, regenerative medicine, collagen, PLGA, hydroxyapatite, osteogenic differentiation

DOI: 10.3233/BME-171703

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 671-685, 2017

Authors: Aherwar, Amit | Bahraminasab, Marjan

Article Type: Research Article

Abstract: Biomaterials are continuously being developed to overcome the drawbacks of existing materials and provide improved function in artificial organs. Currently Co–Cr based alloys are used in many medical applications such as hip and knee implants which still require modification to better perform. In this article, therefore, the influence of tungsten allying element on electrochemical corrosion resistance and biocompatibility behaviour of a recently developed Co-30Cr-4Mo-1Ni alloy composition were investigated. The tungsten modified alloys were prepared by using a high temperature vertical vacuum casting technique at five different weight percentages (0–4wt.% tungsten). The electrochemical corrosion behaviour of all the samples under NaCl …solution was studied by using potentiodynamic scan method. The corrosion characteristics were investigated in terms of corrosion potential (E corr ) and corrosion current density (I corr ). From the results of the analysis, it was observed that out of all samples, an alloy with 2wt.% of tungsten in composition (i.e. Co-30Cr-4Mo-1Ni-2W) exhibited better corrosion resistance. Furthermore, histopathological evaluations in subcutaneous tissue were performed in rats according to the standard ISO 10993 to examine the biocompatibility of the prepared samples. The results showed no evidence of inflammatory cell migration, no epidermal necrosis, no vacuolar degeneration of basal cell, no adnexal atrophy and vesicle formation of any samples. The obtained findings indicate that Co-30Cr-4Mo-1Ni-2W can be used in biomedical applications including femoral component of hip and knee implants. Show more

Keywords: Co–Cr alloy, corrosion, biocompatibility, tungsten, femoral component material, animal model

DOI: 10.3233/BME-171706

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 687-701, 2017

Authors: Luo, Jingwan | Lin, Longxiang | Liao, Nina | Zhang, Keke | Liu, Chang | Sun, Yulong

Article Type: Research Article

Abstract: The bursting strength is a key parameter to assess hemostatic ability of tissue sealants. It is associated to mechanical property of the materials, the binding strength of the materials to the tissues as well as the applied conditions of the materials, such as temperature and wound size. Few works have systematically investigated the relationship of the hemostatic ability of hydrogels with the factors listed above. This study introduced a method to systematically investigate the effect of the thickness, covered area and components of hydrogels, and the applied conditions on the bursting strength of hydrogels. The gelatin hydrogel and fibrin glue …were used in this study. The method quantitatively investigated the effect of material properties and applied conditions on the bursting strength of materials. It also suggested a minimum dosage of tissue sealant used in both animal study and clinical practice. This study proved that the method we proposed is reliable to assess the bursting strength of materials for the hemostatic application. Show more

Keywords: Hemostatic ability, fibrin glue, evaluating method, in vitro

DOI: 10.3233/BME-171704

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 6, pp. 703-710, 2017