Bio-Medical Materials and Engineering - Volume 22, issue 6

Authors: Bayraktaroglu, Esra | Gulsoy, H. Ozkan | Gulsoy, Nagihan | Er, Ozay | Kilic, Hasan

Article Type: Research Article

Abstract: The research was investigated the effect of boron additions on sintering characteristics, mechanical, corrosion properties and biocompatibility of injection molded austenitic grade 316L stainless steel. Addition of boron is promoted to get high density of sintered 316L stainless steels. The amount of boron plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders have been used with the elemental NiB powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperature. The …debinded samples were sintered at different temperature for 60 min. Mechanical property, microstructural characterization and electrochemical property of the sintered samples were performed using tensile testing, hardness, optical, scanning electron microscopy and electrochemical corrosion experiments. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. Results of study showed that sintered 316L and 316L with NiB addition samples exhibited high mechanical and corrosion properties in a physiological environment. Especially, 316L with NiB addition can be used in some bioapplications. Show more

Keywords: Powder injection molding, sintering, biomaterials, in vitro, bioactivity simulated body fluid

DOI: 10.3233/BME-2012-0723

Citation: Bio-Medical Materials and Engineering, vol. 22, no. 6, pp. 333-349, 2012

Authors: Hu, Chang-Lin | Lin, Zhan-Sheng | Chen, Yen-Yu | Lin, Yuan-Hsiang | Lai, Mei-Feng | Li, Meng-Lin

Article Type: Research Article

Abstract: The laser Doppler flowmeter has become an effective tool for the clinical study of microcirculation with non-invasive measurements and excellent velocity resolution. Microcirculation flow measurements cannot be used as reference criteria for circulation function. Thus, the relative change in fingertip microcirculation was measured through inflation and deflation of an automatic sphygmomanometer wrapped around the arm, and the blood pressure and functional parameters of circulation, such as biological zero (BZ), peak flow (PF) and time to peak flow (tp ), were determined. For 50 healthy participants, the correlation coefficients for the laser Doppler flowmeter and oscillometric results were 0.950 and 0.838 …for systolic and diastolic pressure, respectively. The mean and standard errors for both methods fell within the range specified in the Association for the Advancement of Medical Instrumentation standards. The BZ of an edema patient was about 5 times higher than normal. For patients with peripheral arterial occlusive disease (PAOD), the PF could not be determined, and the tp was about twice the normal value. The accuracy of blood pressure measurements using the laser Doppler flowmeter was comparable to that of the commonly used oscillometric sphygmomanometer, and the physiological circulation functional parameters were useful in identifying signs of edema and PAOD. Show more

Keywords: Laser Doppler, flowmeter, microcirculation, blood pressure, peripheral arterial occlusive disease, edema

DOI: 10.3233/BME-2012-0724

Citation: Bio-Medical Materials and Engineering, vol. 22, no. 6, pp. 351-359, 2012

Authors: Chlebowski, Arthur L. | Chow, Eric Y. | Ellison, Casey | Irazoqui, Pedro P.

Article Type: Research Article

Abstract: As implantable devices gain more widespread use, medical device manufacturers are constantly looking for novel materials that increase and improve capability and functionality. The packaging needs to be biocompatible, but it is also highly desirable for it to be radio transparent to facilitate wireless telemetry and remote powering. Low temperature co-fired ceramics (LTCC) provide a viable solution that meets these desired specifications while also having characteristics that support ease of manufacturing such as the ability for molding, shaping, and even embedding components within the material. In this work, inductor coils used for wireless telemetry and powering are integrated into the …walls of the LTCC-based package to maximize the size of the passive component while optimizing the miniaturization of the implant. The package designed and fabricated in this work consisted of inductors approximating 20 mH with a quality factor of 7.8 at 2 MHz. When compared to similar devices in the literature the LTCC inductor out performed these devices when a power-link figure of merit is used for comparison. Show more

Keywords: Inductor, integrated, low temperature co-fired ceramic, packaging, implantable

DOI: 10.3233/BME-2012-0725

Citation: Bio-Medical Materials and Engineering, vol. 22, no. 6, pp. 361-372, 2012

Authors: Chang, Chih Hao | Tsao, Ching Ting | Chang, Ken Yu | Chen, Szu Hsien | Han, Jin Lin | Hsieh, Kuo Huang

Article Type: Research Article

Abstract: Segmented polyurethane (SPU) materials based on different soft-segment component (PPG, PTMO and PBA) and various length of soft-segment (molecular weight of PBA: 500, 700 and 1000) were synthesized in this research. The soft-segment components were synthesized from polyether-polyols (PPG and PTMO) or from polyester-polyol (PBA). The physical properties and structure characterization of the synthesized SPUs were fully investigated using differential scanning calorimetry (DSC) analysis, and stress–strain measurements. Blood compatibility was evaluated with the platelet adhesion ratio (PAR) and the morphological observation for adhering platelets. Our results showed that the physical properties and blood compatibility of SPUs were closely related to …its composition, which was controlled by (1) the types of the soft-segment component employed and (2) the length of soft segments. Polyether-polyol-based SPUs exhibited greater phase separations, poorer tensile strengths, and better blood compatibility, compared with polyester-polyol-based SPUs. SPUs with shorter soft-segment component exhibited greater phase mixing, higher tensile strength, but lower blood compatibility of SPUs, as compared with its counterparts with longer soft-segment component. Show more

Keywords: Segmented polyurethane (SPU), polyol, blood compatibility, phase separation

DOI: 10.3233/BME-2012-0726

Citation: Bio-Medical Materials and Engineering, vol. 22, no. 6, pp. 373-382, 2012

Authors: Bhargava, Srilatha | Doi, Hisashi | Kondo, Ryota | Aoki, Hideki | Hanawa, Takao | Kasugai, Shohei

Article Type: Research Article

Abstract: Surface modification techniques affect phase transformation which in turn influences strength of zirconia biomaterial. The study aimed at evaluating the tetragonal to monoclinic (t–m) phase transition of zirconia occurring after sandblasting three different ceramic abrasive materials and its subsequent effect on the strength. Zirconia bars (n=24) were sandblasted using silicon carbide (SiC), alumina (Al2 O3 ) and zirconia (ZrO2 ) particles. After surface characterization by a scanning electron microscope (SEM) and a laser profilometer, the relative amount of transformed monoclinic (m) phase was analyzed by X-ray diffractometry (XRD) and its corresponding effect on the flexural strength and fatigue strength were …determined. Data were analyzed using one-way analysis of variance ANOVA (p<0.05). Furthermore, Weibull statistics was used to analyze the variability of flexural strength. The highest amount of monoclinic content was found after sandblasting with SiC consequently resulting in an increased flexural strength and fracture resistance under cyclic load conditions. Weibull modulus was reduced in all the groups with SiC blasting showing the least degradation of m values. The strengthening mechanism that is attributed to sandblasting procedure is influenced by the abrasive material used. Show more

Keywords: Zirconia, sandblasting, phase transformation, flexural strength, Weibull modulus

DOI: 10.3233/BME-2012-0727

Citation: Bio-Medical Materials and Engineering, vol. 22, no. 6, pp. 383-398, 2012

Article Type: Other

Citation: Bio-Medical Materials and Engineering, vol. 22, no. 6, pp. 399-405, 2012

Article Type: Other

Citation: Bio-Medical Materials and Engineering, vol. 22, no. 6, pp. 407-408, 2012