Bio-Medical Materials and Engineering - Volume 27, issue 2-3

Authors: Linsheng, Li | Guoxiang, Lin | Lihui, Li

Article Type: Research Article

Abstract: In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60 V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF …solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity. Show more

Keywords: Magnesiunm alloys, electrophoretic deposition, coating, biological composite material, biocompatibility, bioactivity

DOI: 10.3233/BME-161582

Citation: Bio-Medical Materials and Engineering, vol. 27, no. 2-3, pp. 251-258, 2016

Authors: Ueno, Fabio Roberto | Kido, Hueliton Wilian | Granito, Renata Neves | Gabbai-Armelin, Paulo Roberto | Magri, Angela Maria Paiva | Fernandes, Kelly Rosseti | da Silva, Antonio Carlos | Braga, Francisco José Correa | Renno, Ana Claudia Muniz

Article Type: Research Article

Abstract: The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder – CaPp, CaP powder with collagen – CaPp/Col, CaP fibers – CaPf and CaP fibers with collagen – CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor …crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair. Show more

Keywords: Composite, calcium phosphate, collagen, fibers, bone repair

DOI: 10.3233/BME-161581

Citation: Bio-Medical Materials and Engineering, vol. 27, no. 2-3, pp. 259-273, 2016

Authors: Houshyarifar, Vahid | Chehel Amirani, Mehdi

Article Type: Research Article

Abstract: In this paper we present a method to predict Sudden Cardiac Arrest (SCA) with higher order spectral (HOS) and linear (Time) features extracted from heart rate variability (HRV) signal. Predicting the occurrence of SCA is important in order to avoid the probability of Sudden Cardiac Death (SCD). This work is a challenge to predict five minutes before SCA onset. The method consists of four steps: pre-processing, feature extraction, feature reduction, and classification. In the first step, the QRS complexes are detected from the electrocardiogram (ECG) signal and then the HRV signal is extracted. In second step, bispectrum features of HRV …signal and time-domain features are obtained. Six features are extracted from bispectrum and two features from time-domain. In the next step, these features are reduced to one feature by the linear discriminant analysis (LDA) technique. Finally, KNN and support vector machine-based classifiers are used to classify the HRV signals. We used two database named, MIT/BIH Sudden Cardiac Death (SCD) Database and Physiobank Normal Sinus Rhythm (NSR). In this work we achieved prediction of SCD occurrence for six minutes before the SCA with the accuracy over 91%. Show more

Keywords: Sudden cardiac arrest, heart rate variability, support vector machine, k nearest-neighbour, bispectrum, SDNN, RMSSD

DOI: 10.3233/BME-161583

Citation: Bio-Medical Materials and Engineering, vol. 27, no. 2-3, pp. 275-285, 2016

Authors: Assadian, Mahtab | Jafari, Hassan | Ghaffari Shahri, Seyed Morteza | Idris, Mohd Hasbullah | Almasi, Davood

Article Type: Research Article

Abstract: In this study, different types of calcium-phosphate phases were coated on NaOH pre-treated pure magnesium. The coating was applied by electrodeposition method in order to provide higher corrosion resistance and improve biocompatibility for magnesium. Thickness, surface morphology and topography of the coatings were analyzed using optical, scanning electron and atomic-force microscopies, respectively. Composition and chemical bonding, crystalline structures and wettability of the coatings were characterized using energy-dispersive and attenuated total reflectance–Fourier transform infrared spectroscopies, grazing incidence X-ray diffraction and contact angle measurement, respectively. Degradation behavior of the coated specimens was also investigated by potentiodynamic polarization and immersion tests. The experiments …proved the presence of a porous coating dominated by dicalcium-phosphate dehydrate on the specimens. It was also verified that the developed hydroxyapatite was crystallized by alkali post-treatment. Addition of supplemental fluoride to the coating electrolyte resulted in stable and highly crystallized structures of fluoridated hydroxyapatite. The coatings were found effective to improve biocompatibility combined with corrosion resistance of the specimens. Noticeably, the fluoride supplemented layer was efficient in lowering corrosion rate and increasing surface roughness of the specimens compared to hydroxyapatite and dicalcium-phosphate dehydrates layers. Show more

Keywords: Magnesium, biodegradable implant, fluoridated hydroxyapatite, electrodeposition, corrosion

DOI: 10.3233/BME-161585

Citation: Bio-Medical Materials and Engineering, vol. 27, no. 2-3, pp. 287-303, 2016

Authors: Kohata, Kazuhiro | Itoh, Soichiro | Horiuchi, Naohiro | Yoshioka, Taro | Yamashita, Kimihiro

Article Type: Research Article

Abstract: Background: The electrical potential, which is generated in bone by collagen displacement, has been well documented. However, the role of mineral crystals in bone piezoelectricity has not yet been elucidated. Objective: We examined the mechanism that the composite structure of organic and inorganic constituents and their collaborative functions play an important role in the electrical properties of human bone. Methods: The electrical potential and bone structure were evaluated using thermally stimulated depolarized current (TSDC) and micro computed tomography, respectively. After electrical polarization of bone specimens, the stored electrical charge was calculated using TSDC measurements. The CO3 …/PO4 peak ratio was calculated using attenuated total reflection to compare the content of carbonate ion in the bone specimens. Results: The TSDC curve contained 3 peaks at 100, 300 and 500°C, which were classified into 4 patterns. The CO3 /PO4 peak ratio positively correlated with the stored charges at approximately 300°C in the polarized bone. There was a positive correlation between the stored bone charge and the bone mineral density only. Conclusions: It is suggested that the peak at 300°C is attributed to carbonate apatite and the total bone mass of human bone, not the three-dimensional structure, affects the stored charge. Show more

Keywords: Electrical property, human bone, electrical polarization, carbonate apatite, bone mineral density

DOI: 10.3233/BME-161587

Citation: Bio-Medical Materials and Engineering, vol. 27, no. 2-3, pp. 305-314, 2016