Bio-Medical Materials and Engineering - Volume 24, issue 2

Authors: Mallick, Biswajit

Article Type: Research Article

Abstract: The aim of this work was to investigate the effect of 2.4 MeV proton irradiation on the dielectric property of polyethylene terephthalate (PET) microfibre nondestructively. The dielectric constant εd of single-microfibre has been measured as-such applying laser diffraction technique. Applying this methodology εd is found out to be slightly increases with proton fluence except at the fluence 1013 p/cm2 where material shows maximum crosslinking. The variations of the biological interaction with εd of PET material are correlated. Proton beam modified PET microfibre is therefore accepted to have further potential applications in radiation processing tissue response …microfibre, fabrication of medical devices etc. Show more

Keywords: PET microfiber, ion beam irradiation, dielectric constant, biological activity, fluence

DOI: 10.3233/BME-130947

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1425-1432, 2014

Authors: Zhang, Ying | Ng, Soon Seng | He, Tao | Fang, Ning | Neoh, K.G. | Kang, E.T. | Chen, Wei Ning | Chan, Vincent

Article Type: Research Article

Abstract: Thermo-responsive poly(N-isopropylacrylamide) (PIPAAm) with a particular lower critical solution temperature (LCST) have been applied for the non-invasive harvesting of confluent cell layer. Until now, the effect of adhesive ligand on the biophysical responses of cells during cell layer harvesting from PIPAAm has not been elucidated. In this study, the deadhesion kinetics of smooth muscle cells (SMC) on various adhesive ligands immobilized on PIPAAm were investigated. Firstly, the formation of elastin (EL), laminin (LA), hyaluronic acid (HA) and collagen (CL) coating on PIPAAm surfaces were validated with XPS, microBCA assay and AFM. It was shown that EL was most effective in …driving cell retraction on PIPAAm surface. Moreover, the highest rate of initial SMC deadhesion on EL-PIPAAm was driven by the formation of stress fibers. Interestingly, HA was most effective in preventing initial SMC detachment from PIPAAm surface in comparison with EL, LA and CL. Also, the adhesion energy of SMC on HA-PIPAAm remained constant, which was two times and six times higher than that on CL-PIPAAm and EL-PIPAAm, respectively from 20 min onward. Overall, the results reported herein pave the way for the engineering of the invasive regeneration/recovery of cells/tissue with adhesive ligand. Show more

Keywords: Thermosensitive polymer, cell adhesion, adhesive ligand, deadhesion

DOI: 10.3233/BME-130948

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1433-1445, 2014

Authors: Ozeki, K. | Goto, T. | Aoki, H. | Masuzawa, T.

Article Type: Research Article

Abstract: Sr-substituted hydroxyapatite thin films were prepared by sputtering technique from mixture targets of hydroxyapatite (HA) and strontium apatite (SrAp). The HA and SrAp powders were mixed at 0–100% Sr/(Sr+Ca) target ratios. The coated films were recrystallized by a hydrothermal treatment to reduce film dissolution. The films were then characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and inductively coupled plasma atomic emission spectrometry (ICP). The osteocompatiblity of the films was also evaluated by the size of the bone formation area in osteoblast cells. In the XRD patterns, peaks shifted to lower 2θ values with increasing Sr/(Sr+Ca) target ratios, …which indicated Sr incorporation into the HA lattice. In the SEM observation of the hydrothermally treated films, the surface was covered with globular particles, and the size of the globular particles increased from Sr0 to Sr40, and then the size decreased from Sr60 to Sr100. The ICP analysis showed that the Sr/(Sr+Ca) film ratios were almost the same as the target ratios. In the cell culture, the bone formation area on the Sr-substituted HA films increased with increasing Sr concentration, and saturated at Sr60. Show more

Keywords: Sputtering, hydroxyapatite, strontium, osteoblast cell

DOI: 10.3233/BME-130949

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1447-1456, 2014

Authors: Macheiner, Tanja | Kuess, Anna | Dye, Julian | Saxena, Amulya K.

Article Type: Research Article

Abstract: PURPOSE: The yield of a critical number of basal epithelial cells with high mitotic rates from native tissue is a challenge in the field of tissue engineering. There are many protocols that use enzymatic methods for isolation of epithelial cells with unsatisfactory results for tissue engineering. This study aimed to develop a protocol for isolating a sufficient number of epithelial cells with a high Proliferating Index from ovine esophagus for tissue engineering applications. METHODS: Esophageal mucosa was pretreated with dispase–collagenase solution and plated on collagen-coated culture dishes. Distinction of the various types of epithelial cells and developmental stages was …done with specific primary antibodies to Cytokeratins and to Proliferating Cell Nuclear Antigen (PCNA). RESULTS: Up to approximately 8100 epithelial cells/mm2 of mucosa tissue were found after one week of migration. Cytokeratin 14 (CK 14) was positive identified in cells even after 83 days. At the same time the Proliferating Index was 71%. CONCLUSION: Our protocol for isolation of basal epithelial cells was successful to yield sufficient numbers of cells predominantly with proliferative character and without noteworthy negative enzymatic affection. The results at this study offer the possibility of generation critical cell numbers for tissue engineering applications. Show more

Keywords: Isolation of epithelial cells, ovine esophagus, cytokeratins, explant culture, collagenase–dispase solution

DOI: 10.3233/BME-130950

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1457-1468, 2014

Authors: Tang, C.Y. | Tsui, C.P. | Tang, Y.M. | Wei, L. | Wong, C.T. | Lam, K.W. | Ip, W.Y. | Lu, W.W.J. | Pang, M.Y.C.

Article Type: Research Article

Abstract: With the development of micro-computed tomography (micro-CT) technology, it is possible to construct three-dimensional (3D) models of human bone without destruction of samples and predict mechanical behavior of bone using finite element analysis (FEA). However, due to large number of elements required for constructing the FE models of entire bone, this demands a substantial computational effort and the analysis usually needs a high level of computer. In this article, a voxel-based approach for generation of FE models of entire bone with microscopic architecture from micro-CT image data is proposed. To enable the FE analyses of entire bone to be run …even on a general personal computer, grayscale intensity thresholds were adopted to reduce the amount of elements. Human metacarpal bone (MCP) bone was used as an example for demonstrating the applicability of the proposed method. The micro-CT images of the MCP bone were combined and converted into 3D array of pixels. Dual grayscale intensity threshold parameters were used to distinguish the pixels of bone tissues from those of surrounding soft tissues and improve predictive accuracy for the FE analyses with different sizes of elements. The method of selecting an appropriate value of the second grayscale intensity threshold was also suggested to minimize the area error for the reconstructed cross-sections of a FE structure. Experimental results showed that the entire FE MCP bone with microscopic architecture could be modeled and analyzed on a personal computer with reasonable accuracy. Show more

Keywords: Voxel-based, finite element model, micro-computed tomography (micro-CT), microscopic architecture, human metacarpal bone, grayscale intensity threshold

DOI: 10.3233/BME-130951

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1469-1484, 2014

Authors: Kohorst, Philipp | Tegtmeyer, Sven | Biskup, Christian | Bach, Friedrich-Wilhelm | Stiesch, Meike

Article Type: Research Article

Abstract: The aim of this experimental in-vitro study was to investigate the machining of human dentin using an abrasive water jet and to evaluate the influence of different abrasives and water pressures on the removal rate. Seventy-two human teeth had been collected after extraction and randomly divided into six homogeneous groups (n=12). The teeth were processed in the area of root dentin with an industrial water jet device. Different abrasives (saccharose, sorbitol, xylitol) and water pressures (15 or 25 MPa) were used in each group. Dimensions of dentin removal were analysed using a stripe projection microscope and both drilling depth as …well as volume of abrasion were recorded. Morphological analyses of the dentin cavities were performed using scanning electron microscopy (SEM). Both drilling depth and volume of abrasion were significantly influenced by the abrasive and the water pressure. Depending on these parameters, the drilling depth averaged between 142 and 378 μm; the volume of abrasion averaged between 0.07 and 0.15 mm3 . Microscopic images revealed that all cavities are spherical and with clearly defined margins. Slight differences between the abrasives were found with respect to the microroughness of the surface of the cavities. The results indicate that abrasive water jet machining is a promising technique for processing human dentin. Show more

Keywords: Water jet, abrasive, dentin, machining, removal rate, scanning electron microscopy

DOI: 10.3233/BME-130952

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1485-1495, 2014

Authors: Iwama, Akira | Yamada, Chie | Uchida, Kentaro | Ujihira, Masanobu

Article Type: Research Article

Abstract: Reduction of cellular damage in densely cultured cell monolayers after cryopreservation by pre-incubation with hyaluronan (HA) was investigated. Monolayers of human dermal fibroblasts were cultured for 24 h at a density of 0.5×104 or 5×104 cells/cm2 . The following two experimental conditions were compared: cells incubated with or without 0.5% w/w HA solution for 6 h. Samples were frozen from 4 to −80°C at 0.3 or 3°C/min in a cryoprotectant solution containing 10% w/w dimethyl sulfoxide, cooled down below −185°C, and then thawed. Post-thaw cell viability was evaluated by the fluorescent double-staining technique using a fluorescence microscope, and …cellular uptake of the fluorescein–isothiocyanate-labeled HA after pre-incubation was also observed. Cell viability decreased with increasing cell density at both cooling rates without preliminary HA incubation. However, cell viability did not decrease at either cooling rate with preliminary HA incubation. Cellular HA uptake was observed. Pre-incubation with HA reduces cellular damage in densely cultured cell monolayers. Show more

Keywords: Cryopreservation, cell viability, densely cultured cell monolayers, human dermal fibroblast, hyaluronan, preliminary incubation

DOI: 10.3233/BME-130953

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1497-1506, 2014

Authors: Morawska-Chochół, Anna | Chłopek, Jan | Domalik-Pyzik, Patrycja | Szaraniec, Barbara | Grzyśka, Ewa

Article Type: Research Article

Abstract: A promising group of biomaterials assigned for the production of intramedullary nails are composites with a polylactide (PLA) matrix, reinforced with wires made of magnesium alloys and carbon fibres. The paper describes the effect of the composition of magnesium alloy wires, their number and orientation in the composite, as well as their connection with differently directed long carbon fibres, on the mechanical properties and the degradation rate of the obtained intramedullary nails. Among the tested implant prototypes, the best mechanical characteristics and a gradual and uniform course of magnesium alloy wires were exhibited by the PLA+CF1D+MgI composite nails (with a …unidirectional orientation of carbon fibres and an axially oriented single Mg alloy wire). The strength of these nails became gradually decreased with the incubation time, which should allow for a gradual loading of the bone. In the case of the PLA with only magnesium alloy wires (without carbon fibres), the increase of the number of wires, on the one hand, stimulates the improvement of the nails' strength, yet on the other hand, a higher content of magnesium alloys in the PLA matrix affects the nails' faster resorption. Show more

Keywords: Intramedullary nails, magnesium alloys, polylactide, carbon fibres, degradation, composite

DOI: 10.3233/BME-130954

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1507-1515, 2014

Authors: Babamir, Seyed Morteza | Dehkordi, Mehdi Borhani

Article Type: Research Article

Abstract: Continuous Infusion Insulin Pump (CIIP) system is responsible for monitoring diabetic blood sugar. In this paper, we aim to specify and simulate the CIIP software behavior. To this end, we first: (1) presented a model consisting of the CIIP system behavior in response to its environment (diabetic) behavior and (2) we formally defined the safety requirements of the system environment (diabetic) in the Z formal modeling language. Such requirements should be satisfied by the CIIP software. Finally, we programmed the model and requirements.

Keywords: Insulin pump, formal modeling, simulation, safety requirement, verification

DOI: 10.3233/BME-130955

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1517-1526, 2014

Authors: Coşkun, Gökçe | Karaca, Esra | Ozyurtlu, Mustafa | Özbek, Serhat | Yermezler, Aysun | Çavuşoğlu, İlkin

Article Type: Research Article

Abstract: Poly(vinyl alcohol)/sodium alginate nanofibrous mats were produced by electrospinning method at optimum process parameters. Evaluation of alginate-based electrospun nanofibrous mats as a wound dressing material and their comparison to commercially available wound dressings produced with conventional methods were carried out in vivo. Tissue specimens were examined histopathologically on 4th, 6th, 15th, 21st postoperative days. In contrast to other dressings it was observed that nanofibrous mat could survive on the wound crust in early stages of healing. In terms of epithelization, epidermis characteristics, vascularization and formation of hair follicles, nanofibrous mat showed the best healing performance. This could be explained with …presence of nanofibrous mat acting as an artificial skin on the wound region until new tissue regenerated. Show more

Keywords: Electrospinning, nanofiber, alginate, wound dressing, histological evaluation, in vivo

DOI: 10.3233/BME-130956

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1527-1536, 2014

Article Type: Correction

DOI: 10.3233/BME-140957

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 2, pp. 1537-1537, 2014