Bio-Medical Materials and Engineering - Volume 24, issue 6
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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: The 3rd International Conference on Biomedical Engineering and Biotechnology (iCBEB 2014), held in Beijing from the 25th to the 28th of September 2014, is an annual conference that intends to provide an opportunity for researchers and practitioners around the world to present the most recent advances and future challenges in the fields of biomedical engineering, biomaterials, bioinformatics and computational biology, biomedical imaging and signal processing, biomechanical engineering and biotechnology, amongst others. The papers published in this issue are selected from this conference, which witnesses the advances in biomedical engineering and biotechnology during 2013–2014.
Keywords: Advances in biomedical engineering, iCBEB
Abstract: In this work, bioengineering methods that can be used to quantitatively analyze videocapsule endoscopy images that have been acquired from celiac patients versus controls are described. For videocapsule endoscopic analysis, each patient swallows a capsule which contains an imaging device and light source. In celiac and control patients, images are acquired and analyzed at the level of the small intestine. The data used for videocapsule analysis consisted of high resolution images of dimension 576 × 576 pixels, acquired twice per second. The goal of the quantitative analysis is to detect abnormality in celiac patient images as compared with controls. Several…types of abnormality can exist at the level of the small intestine in celiac patients. In untreated patients, and often even after treatment with a gluten-free diet, there can be villous atrophy, as well as presence of fissures and a mottled appearance. To detect and discern these abnormalities, several methods of statistical and structural feature extraction and selection are described. It was found that there is a significantly greater variation in image texture and average brightness level in celiac patients as compared with controls (p < 0.05). Celiac patients have a longer dominant period as compared with controls, averaging 6.4 ± 2.6 seconds versus 4.7 ± 1.6 seconds in controls (p = 0.001). This suggests that overall motility is slower in the celiac patients. Furthermore, the mean number of villous protrusions per image was found to be 402.2±15.0 in celiac patients versus 420.8±24.0 in control patients (p < 0.001). The average protrusion width was 14.66±1.04 pixels in celiacs versus 13.91±1.47 pixels in controls (p = 0.01). The mean protrusion height was 3.10±0.26 grayscale levels for celiacs versus 2.70±0.43 grayscale levels for controls (p < 0.001). Thus celiac patients tended to have fewer protrusions, and these were more varied in shape, tending to be blunted, as compared with controls, which more often had fine, uniform protrusions. A variety of computerized methods are now available to quantitate videocapsule images for comparison of celiac versus control patients. Since these methods are based on computer algorithms, they can be automated and there is no variation in the results due to observer bias. These methods readily lend themselves to automation, so that it may be possible to map the entire small intestine for presence of abnormality in real-time. It is also possible to develop an automated, quantitative clinical score which can be displayed with real-time update during the procedure. This would be useful to determine progress in celiac patients on a gluten-free diet, and to better understand the properties of the healing process in these patients.
Keywords: Celiac disease, endoscopy, imaging, small intestine, videocapsule
Abstract: Celiac disease commonly occurs in approximately 1% of populations, but it can be difficult to diagnose. The standard method to diagnose celiac disease includes analysis of endoscopy images of the small intestinal mucosa to detect presence of villous atrophy, which can be subtle. We have devised a means to improve the image-based detection of villous atrophy and other abnormality in videocapsule endoscopy by means of incorporating basis images. Basis images were extracted from a series of 200 consecutive image frames acquired over 100 seconds at the level of the duodenal bulb in 13 celiac patients and in 13 controls. They…were converted from color to 256 grayscale levels (gsl; 0 = black, 255 = white). Eight basis images were used for analysis. A histogram was constructed for each basis image, and the mean and standard deviation of the histogram values were tabulated. The significance of the difference in histogram mean level for celiacs versus controls was determined. Then the histogram mean was plotted versus the standard deviation, separately for all eight basis images, and also averaged for all bases combined. The mean histogram level for celiacs was 127.59+6.05 gsl versus 129.25+5.53 gsl for controls (p< 0.05). Thus celiac basis images tended to be darker and also more variable as compared with controls. For nonlinear classification, using the average of combined basis images, the sensitivity was 84.6% while the specificity was 92.3%. Using the single most important basis image for nonlinear classification, the sensitivity was 84.6% while the specificity was 76.9%. Construction of basis images can be useful to condense videocapsule image series into salient information, for detection of differences in grayscale level mean and variation in celiac versus control image series, and for classification of celiac versus control videoclips with nonlinear discriminant functions.
Keywords: Basis images, celiac disease, classification, histogram, nonlinear discriminant function
Abstract: The appropriate location and release of target gene is necessary for gene therapy. In our previous paper, a gene vector named P123-PEI-R13 has been successfully synthesized, and the physical characteristics and cellular trafficking of nanoparticle P123-PEI-R13/DNA has been explored explicitly, but little was known about its disassembly within cells. In order to investigate its intracellular disassembly, P123-PEI-R13/DNA complex was exposed to the different competitors (RNA, DNA, proteins) or different conditions of pH and osmolarity, DNA release was determined by gel electrophoresis. Meanwhile, confocal laser technology was used to locate the complex in cells. The results revealed that DNA, RNA and…osmolarity could affect the stability of the complex obviously, especially RNA which exist in nucleus. In addition, the speed of DNA release decreased as the weight ratio of polymer increased. Images got by a confocal fluorescence microscope confirmed that after cell uptake, P123-PEI-R13 could translocate DNA into nucleus.
Abstract: To solve the contradiction between the cell toxicity and transfection efficiency of polyethylenimine (PEI) derivate in non-viral gene therapy, a novel gene vector, P123-PEI-R18 was synthesized by using biodegradable PEI derivate conjugated with trifunctional peptide RGD-TAT-NLS. The particle size of P123-PEI-R18/DNA was around 100–250nm. The gene vector could condense DNA at the weight ratio of 2 and protect plasmid DNA from being dissolved in the blood circulation. Importantly, the complexes exhibited lower cell toxicity and higher transfection efficiency contrasted with PEI 25 kDa in vitro. P123-PEI-R18 holds high potential as a safe and efficient gene vector.
Abstract: Age-related macular degeneration (ARMD) and intraocular neovascular diseases have been treated clinically by anti-VEGF antibody drug bevacizumab. However, the use of bevacizumab in the treatment of retinal neovascular diseases has been limited due to the short half-life and frequent injections. In this research, novel amphiphilic hydrophilic-hydrophobic block copolymers of methoxy-poly (ethylene glycol)-block-poly (lactic-co-glycolic acid) were synthesized with ring-opening polymerization, and cross-linked with 2,2-bis (2-oxazoline) (BOX). The aqueous solution of the block copolymers can reverse the sol-gel-sol phase transition. After 1 month of intravitreal injection, the histomorphology of a rabbit's retina was preserved, which indicated the mPEG-PLGA-BOX hydrogel had no cytotoxicity…in vivo. Released bevacizumab from the mPEG-PLGA-BOX hydrogel inhibited the RF/6A (Maraca mulatta retina epithelial cell) and HUVEC cell growth, and anti-angiogenesis in 3-D cultures, which showed the bioactivity of the anti-VEGF agent, were maintained in the hydrogel within the release process. In conclusion, the mPEG-PLGA-BOX hydrogel had a sol-gel behavior phase transition, and its intraocular biocompatibility and the characteristics of biodegradability and bioactivity appear to be a promising intravitreal injection carrier for bevacizumab delivery.
Keywords: Bevacizumab, thermo-responsive hydrogel, drug delivery system, angiogenesis
Abstract: This paper discusses the process technology to fabricate multilayer-Polydimethylsiloxane (PDMS) based microfluidic device for bio-particles concentration detection in Lab-on-chip system. The micro chamber and the fluidic channel were fabricated using standard photolithography and soft lithography process. Conventional method by pouring PDMS on a silicon wafer and peeling after curing in soft lithography produces unspecific layer thickness. In this work, a multilayer-PDMS method is proposed to produce a layer with specific and fixed thickness micron size after bonding that act as an optimum light path length for optimum light detection. This multilayer with precise thickness is required since the microfluidic is…integrated with optical transducer. Another significant advantage of this method is to provide excellent bonding between multilayer-PDMS layer and biocompatible microfluidic channel. The detail fabrication process were illustrated through scanning electron microscopy (SEM) and discussed in this work. The optical signal responses obtained from the multilayer-PDMS microfluidic channel with integrated optical transducer were compared with those obtained with the microfluidic channel from a conventional method. As a result, both optical signal responses did not show significant differences in terms of dispersion of light propagation for both media.
Abstract: The small intestinal submucosa (SIS) is an acellular collagen-based matrix, primarily composed of fibrillar collagens (types I, II, and V). They enhance healing due to a minimal immune response. A good degradation rate is the degradation of materials equal to the rate of remodeling in the host. The SIS should apply a good degradation rate and cytocompatibility. In this study, a series of SIS with different degradation rates is obtained by treatment with Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Morphology, composition, degradable ratio, mechanical properties and cytocompatibility of the SIS are evaluated. We determined a 20μm thickness and 60μm pore size of…the native SIS. The degradable ratio of the native SIS was approximately 90% in the presence of 0.25 mg/ml collagenase for 24 hours. The storage modulus of the native SIS was 388MPa. The degradable ratio of the SIS decreased to 6% and the storage modulus increased to 777 MPa after being treated with 30mM EDC for 24 hours. In cytocompatibility assay, cell numbers on the native SIS were similar as on the treated SIS due to the non-toxicity of the EDC treatment process. This SIS exhibited collagenase resistance, stronger mechanical strength and good cytocompatibility after the EDC treatment concluded. The cross-linked SIS could be utilized as a potential cell carrier for tissue engineering application.
Keywords: Carbodiimide cross-linked, small intestinal submucosa (SIS), biodegradation, cytocompatibility
Abstract: The WPI-NaCas-GLY antimicrobial film takes full advantage of the controlled release of active or antimicrobial agents as well as demonstrates a great potential for functioning as an alternative biodegradable polymer in practical applications. The moisture sorption kinetics of the film as an important carrier of active agents was investigated at various relative humidities (RH). The results indicated that the moisture sorption characterization and procedure of this film can be described well by the empirical Peleg model with higher confidence and concordance. The model could predict the film's moisture content at any time (Mt ), the time to reach any given…level of R (tR ), the equilibrium moisture at any RH condition (Me ), and isotherm trend based upon experimental data and modeled constants k1 , k2 , a, b, c, and d without giving consideration to their physical meaning. The water vapor transmission rate of the WPI-NaCas-GLY antimicrobial film increased exponentially with increasing RH due to its hydrophilicity, which was primarily caused by the presence of glycerol in a higher content. The results also suggested that aw predominately affects the film's Me values compared with the temperature factor by fixed nonlinear multiple regression analyses.