Bio-Medical Materials and Engineering - Volume 29, issue 1
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Bio-Medical Materials and Engineering is to promote the welfare of humans and to help them keep healthy. This international journal is an interdisciplinary journal that publishes original research papers, review articles and brief notes on materials and engineering for biological and medical systems.
Articles in this peer-reviewed journal cover a wide range of topics, including, but not limited to: Engineering as applied to improving diagnosis, therapy, and prevention of disease and injury, and better substitutes for damaged or disabled human organs; Studies of biomaterial interactions with the human body, bio-compatibility, interfacial and interaction problems; Biomechanical behavior under biological and/or medical conditions; Mechanical and biological properties of membrane biomaterials; Cellular and tissue engineering, physiological, biophysical, biochemical bioengineering aspects; Implant failure fields and degradation of implants. Biomimetics engineering and materials including system analysis as supporter for aged people and as rehabilitation; Bioengineering and materials technology as applied to the decontamination against environmental problems; Biosensors, bioreactors, bioprocess instrumentation and control system; Application to food engineering; Standardization problems on biomaterials and related products; Assessment of reliability and safety of biomedical materials and man-machine systems; and Product liability of biomaterials and related products.
Abstract: Background: Since it can take an enormous amount of time and cost to discriminate counterfeit medicines by using conventional methods, counterfeit medicines has been spread in the world markets. Objective: The purpose of this study was to develop a rapid and simple analytical method to discriminate counterfeit drugs using near infrared (NIR) spectroscopy. Methods: Seven types of brand name tablet and generic tablets containing atorvastatin calcium sesquihydrate (AT) preparations were used as simulated counterfeit medicines. NIR spectra of 35 AT tablet products were measured using a diffuse reflection method. Results: The NIR spectral data…were analyzed by principal component analysis (PCA). The PCA results suggested that the model had sufficient accuracy to discriminate the 7 types for AT tablets. The NIR spectral data were also analyzed using a soft independent modeling of class analogy (SIMCA) method. Predicting the classification of the AT tablet samples was performed based on all the validated AT tablet data using the SIMCA model, and the probability of classification of 7 types was 100%. The discrimination power spectrum of the SIMCA model indicated significant patterns based on diluents. Conclusions: The PCA and SIMCA classification of the AT tablets were depended on the major excipient combinations.
Keywords: Counterfeit drugs, near infrared spectroscopy, atorvastatin calcium sesquihydrate, principal component analysis, soft independent modeling of class analogy, discrimination power spectrum
Abstract: Background: The periodontal ligament (PDL), which maintains homeostasis in the periodontium, is a group of specialized connective tissue fibers attached to both the cementum and alveolar bone. Regeneration of periodontium with PDL cells has been investigated, and the chemical and molecular structures of scaffolds control the adhesion and differentiation of cells. Therefore, the development of adequate materials for PDL-derived cells is essential to regenerate the periodontium. Objective: We evaluated the suitable passage time for PDL-derived cells and investigated the behaviors of PDL-derived cells grown on hydroxyapatite (HAp) scaffolds coated with type I and type III collagen.…Methods: PDL-derived cells were isolated with enzyme from the upper molars of male Wister rats. After characterization of HAp, type I collagen, and type III collagen, PDL-derived cells at passage 2 were seeded onto collagen-coated HAp. Cell adhesion, proliferative potential, and osteoconductivity were analyzed with immunostaining, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, Alizarin S staining, and real-time polymerase chain reaction. Results: Type I and III collagens were successfully coated on HAp. Gene expression analysis revealed that passage 2 was suitable for maintaining differentiation potential. Proliferative potential and cell adhesion were significantly higher on type III collagen than on HAp alone or type I collagen. In contrast, the osteoconductivity of type III collagen was significantly lower than those of HAp and type I collagen. Conclusion: PDL-derived cells on type I collagen differentiated into osteogenic cells and formed hard tissues. However, type III collagen enhanced the adhesion of PDL-derived cells and inhibited mineralization.
Abstract: Introduction: Burn injuries represent a high risk of morbidity and mortality. The wound healing process is complex and requires the participation of different types of cells. Therefore, new biomaterials, which innovate the wound healing process, are being investigated. Objective: The aim of this study was to investigate the use of bacterial cellulose both in its pure state and enriched with lidocaine in full-thickness burns in rats. Methods: Thirty rats (Wistar) (260 ± 20 gramas) divided into control group (CG), bacterial cellulose membrane group (MG) and bacterial cellulose membrane enriched with lidocaine group (MLG) were used. The burns were…induced using a 150°C heated soldering iron, held on the animal neck for 10 seconds. The biomaterial was applied immediately after injury and skin samples were collected on the tenth day of the treatment. The level of significance of p ⩽ 0.05 was used for the conclusion of the statistical analysis. Results: The groups treated with the biomaterials, a histological pattern compatible with a more advanced repair stage showing skin appendages, mild inflammatory infiltrate, better collagen fiber organization and mild immunostaining COX-2 and MMP-9 was observed, when compared to the control group that did not receive any type of treatment. Conclusion: Thus, was concluded that the bacterial cellulose-based biomaterial both in its pure state and enriched with lidocaine optimizing the full-thickness burn wound healing in rats.
Abstract: Background: The development of dermal scaffolds is of major interest in reconstructive surgery. Human Acellular Dermal Matrices (HADMs) provides biomechanical support and elicits new tissue formation. The use of allograft dermis is limited by its immunogenic characteristics. Our research group has focused on the use of human alloplastic glycerolized reticular dermis. Objective: The dermal grafts were subjected to two different decellularization protocols in parallel, in order to compare the efficacy in the elimination of residual DNA. Methods: It was compared the incubation of the dermis in NaOH (0.06 N) and in the standard culture medium “Dulbecco Modified…Eagle Medium” (DMEM). The samples were incubated in the specific medium for 8 weeks. The newly developed real-time TaqMan® MGB-PCR assay was applied for both the detection and absolute quantification of residual DNA. Results: It was observed that the level of residual DNA decreased until time T3 and remained constant until time T8. Moreover, there was no statistical difference between treatment with DMEM or NaOH 0.06 N as to the amount of residual DNA. Conclusions: Decellularization methods, DMEM or NaOH 0.06 N do not affect DNA recovery. The proposed approach offers an alternative method to quantify residual DNA in HADM samples.
Keywords: HADM, DMEM, NaOH, DNA extraction, Taqman PCR
Abstract: Background: WPS is a non-invasive method to investigate human health. During signal acquisition, noises are also recorded along with WPS. Objective: Clean WPS with high peak signal to noise ratio is a prerequisite before use in disease diagnosis. Wavelet Transform is a commonly used method in the filtration process. Apart from its extensive use, the appropriate factors for wavelet denoising algorithm is not yet clear in WPS application. The presented work gives an effective approach to select various factors for wavelet denoise algorithm. With the appropriate selection of wavelet and factors, it is possible to reduce noise in WPS. Methods:…In this work, all the factors of wavelet denoising are varied successively. Various evaluation parameters such as MSE, PSNR, PRD and Fit Coefficient are used to find out the performance of the wavelet denoised algorithm at every one step. Results: The results obtained from computerized WPS illustrates that the presented approach can successfully select the mother wavelet and other factors for wavelet denoise algorithm. The selection of db9 as mother wavelet with sure threshold function and single rescaling function using UWT has been a better option for our database. Conclusion: The empirical results proves that the methodology discussed here could be effective in denoising WPS of any morphological pattern.
Keywords: Wrist pulse signal, signal processing, wavelet denoising, PSNR
Abstract: Based on a kind of sintered hydroxyapatite (HA) with a good cytocompatibility, a series of polylactic acid (PLA) and PLA/HA with the various PLA:HA weight ratio (5:5, 4:6, 3:7, 2:8, 1:9) were fabricated by supercritical CO2 . The physical and chemical properties were evaluated by pH, degradation, water absorption, porosity, density, mechanical property, and cytotoxicity respectively. With the increase of HA content, the pH value and porosity increased gradually, while weight loss rate and the density showed a gradual downward trend. Existence of HA can drastically improve the hydroscopicity of PLA scaffolds. The compression strength values slightly increased (p >…0.05 ) from 39.96 MPa of PLA to 45.00 MPa of PLA/HA with the ratio of 7:3, subsequently, the values decreased (p < 0.05 ) from 43.29 MPa (8:2) to 19.00 MPa (9:1). While the modulus of elasticity decreased (p < 0.05 ) from 5.89 to 1.84 GPa with increasing HA content. The PLA/HA (8:2) promoted cell proliferation more significantly than any of other groups (p < 0.05 ). Based on the results, the overall properties of porous scaffolds are the optimal when the weight ratio of PLA/HA is 8:2. Its pH, porosity, density, compression strength, and elasticity modulus are 7.39, 83.0%, 0.60g/cm−3 , 34.1 MPa and 2.63 GPa, respectively. SEM observation presented a homogeneous distribution of HA in PLA matrix and a foam-like structure comprising interconnected pores.
Keywords: Poly(lactic acid), hydroxyapatite, composite biomaterial, supercritical CO2, bone repair
Abstract: BACKGROUND: Braided stents, such as Pipeline Embolization Device (PED; ev3 Neurovascular, Irvine, CA, USA), are commonly used to treat cerebral aneurysms. However, little information is available on the compression and bending characteristics of such stents. OBJECTIVE: This paper investigates how geometrical parameters of braided stents influence their radial compression and bending characteristics. METHODS: Six groups of braided stent models with different braiding angles, numbers of wires and wire diameters are constructed. Parametric analyses of these models are conducted using Abaqus/Explicit software. The numerical results of a finite element analysis are validated by comparison with data of…theoretical analysis. RESULTS: The results show that the radial stiffness is not uniform along the longitudinal direction of the stent. When the braiding angle increases from 30° to 75°, the minimum radial deformation decreases from 0.85 mm to 0.0325 mm (at a pressure of 500 Pa, for 24 braided wires). When the wire diameter increases from 0.026 mm to 0.052 mm, the minimum radial deformation decreases from 0.65 mm to 0.055 mm (at a pressure of 500 Pa and a braiding angle of 60°, for 24 braided wires). Frictions don’t affect stent diameter and its axial length when braided stent is crimping, but the friction must be considered when it is related to the radial pressure required for compression the braided stent. CONCLUSIONS: Compared with commonly used intracranial stents, a braided stent with geometrical parameters close to PED stent has a smaller radial stiffness but a considerably greater longitudinal flexibility. The results of this analysis of braided stents can help in the design and selection of flow diverter stents for clinical treatment of cerebral aneurysms.
Abstract: Accumulation of cholesterol and other atherogenic lipids such as low-density lipoprotein (LDL) in artery wall causes reduction of vessel diameter and artery stenosis. The study of the mass transfer of these large molecules in the wall with considering effective factors on lumen flow and different physiological factors is the subject considered nowadays. In this paper, results of two dimensional and axi-symmetric simulations of three different models of the artery with 60% stenosis under pulsatile blood flow are presented. Filtration velocity of LDL mass transport in the permeable artery wall and shear stress of blood flow are investigated using ADINA software…Three different flow models are considered. In the first and second models, the filtration velocity considered as a given parameter and constant in arterial wall boundary, while in third model arterial wall considered as porous wall, the filtration velocity is calculated from pressure difference as an input parameter of the model. The results show that filtration velocity is strongly depend on geometry and it is not constant along the wall, contrary to simplified models. The results of concentration variations in lumen and wall illustrate the increase in near wall LDL concentration or concentration polarization.
Abstract: Although titanium (Ti) is clinically used for hard tissue reconstruction, it has low bone-bonding ability, i.e. bioactivity. Materials able to deposit apatite on their surfaces within the body is considered to exhibit bioactivity. Effects of the metallographic structure and machining process of Ti on its apatite-forming ability remains unclear. In this study, Ti substrates subjected to various preheating and machining processes were then subjected to NaOH and heat treatments. The apatite-forming abilities of resulting Ti were examined in simulated body fluid (SBF). Preheating of the Ti decreased its reactivity with NaOH solution. When quenched or annealed Ti was subjected to…NaOH and heat treatments, the induction period for apatite formation in SBF slightly increased. This was attributed to a decrease in sodium titanate and increase in rutile on the Ti surface after the treatments. Substrates subjected to wire-electrical-discharge machining did not form apatite. This was attributed to the inhibition of PO4 3− adsorption on their surfaces following Ca2+ adsorption, which is an essential process for apatite nucleation. Contamination of Ti surface by components of the brass wire used in the machining contributed to the inhibition. The bioactivity of surface-modified Ti was therefore significantly affected by its thermal treatment and machining process.
Abstract: In this study, highly porous Mg–Ca–Zn–Co alloy scaffolds for tissue engineering applications were prepared by powder metallurgy based space holder method. Mg–Ca–Zn–Co alloy foam can be used as a scaffold material for hard tissue generation. Mechanical properties of the porous specimens are close to cancellous bone. Increasing Zn content in the alloy decreased the Mg grain size and enhanced the mechanical properties. Increasing Zn content of the alloy from 1.0 to 8.0 wt.% increased the Young’s modulus from 12 GPa to 23 GPa. Ca addition prevented the oxidation of the specimens during sintering. Electrochemical corrosion behaviour of the specimens was…examined in the simulated body fluid. Corrosion rate was decreased with Zn addition up to 3.0 wt.% and then increased. Increasing Co content increased the corrosion rate. Weight loss/gain and Mg ion release values were increased with increasing immersion time. Weight loss of the specimen was initially decreased with Zn addition up to about 3% and then increased.
Keywords: Mg–Ca–Zn–Co, scaffold, space holder, metal foam, corrosion, tissue engineering