Bio-Medical Materials and Engineering - Volume 24, issue 6

Authors: Han, Zikai | Feng, Pei | Gao, Chengde | Shen, Yang | Shuai, Cijun | Peng, Shuping

Article Type: Research Article

Abstract: Akermanite had attracted great attention due to the favourable mechanical properties and excellent biological performance. In this research, the microstructure and mechanical properties of akermanite scaffolds fabricated via laser sintering under different process conditions were studied and characterized. The results showed that the akermanite particles gradually mixed together, grew up and reached complete densification with the scanning speed decreasing from 450 to 150mm/min, while micro defects such as air holes occurred at 50mm/min. simultaneously, the compressive strength of the scaffolds went up and then descended, and the optimum value was 5.92±0.41 MPa. The Vickers hardness and fracture toughness increased consistently …and then tended to stabilize. X-ray diffraction (XRD) results indicated no new phase appeared under all process conditions. MG-63 cell culture revealed that cell adhesion and proliferation occurred, indicating excellent cytocompatibility of the scaffolds. Moreover, in vitro bioactivity tests showed that the apatite layer formed on the scaffolds and became dense and thick with the increase of soaking time in simulated body fluid (SBF), and this fact was further confirmed by energy-dispersive spectroscopy (EDS). Show more

Keywords: Akermanite, laser sintering, mechanical properties, scaffold

DOI: 10.3233/BME-141017

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2073-2080, 2014

Authors: Chang, Ching-Hsien | Liu, Hsia-Wei | Huang, Ching-Cheng

Article Type: Research Article

Abstract: A series of designed drug-release systems were prepared and established for clear moisture healing. These systems were designed to have an interpenetrating polymer network (IPN) structure, which contained a breathable polyurethane film, hydrocolloidlayer, and polyacrylate adhesive layer. Breathable polyurethane film (2000 g/m2 /24 hr) with high moisture permeability was employed as a base for new drug-release systems or wound dressings. All drug-release systems having a polyurethane film-backed hydrocolloid acrylated adhesive layer showed an increase of water uptakes with increasing time. After 114 hours, high water uptakes of drug-release systems with 20% hydrocolloid components were observed in the values of 160, …1100, and 1870% for different additional hydrocolloid components of carboxymethylcellulose, sodium alginate, and carbomer U10, respectively. New drug-release systems of polyurethane film-backed hydrocolloid/adhesive layers could be designed and established for wound care managements. Show more

Keywords: Hydrocolloid, drug-release systems, breathable, carbomer

DOI: 10.3233/BME-141018

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2081-2088, 2014

Authors: Chen, Jia-jun | Jin, Mei-xiang | Zhu, Shu-lai | Li, Fei | Xing, Ying

Article Type: Research Article

Abstract: This study aimed to establish a novel non-viral liposome vector delivering brain derived neurotrophic factor (BDNF) through the blood brain barrier. For this purpose, different water-oil ratios were tested to create liposomes for packaging the prophase synthesized plasmids encoding the BDNF proteins. In order to increase the targeted and peripheral circulation time, we connected the liposomes with transferrin (Tf) and a polyethylene glycol (PEG) long chain. The non-isotope method was used to measure the liposome envelopment ratio and ligand-binding ratio, and also to detect molecular biological features, such as particle size and stability. Tf-conjugated liposomes could be synthesized satisfactorily under …the following conditions: the ratio of phospholipid to cholesterol was 1:1; the ratio of enter to plasmid was 100:1; oil phase was dichloromethane; the oil to water ratio was 4:1; the rotary evaporation temperature was 30°C; the ultrasonic temperature was 10°C; the ultrasonic time was 10min; and 10% trehalose was in the presence. Generated liposomes had a uniform circular shape and particle size distribution. In this experiment, we successfully established a new type of Tf-conjugated liposomes carrying the gene of BDNF and the study provides an experimental basis for the future. Show more

Keywords: Brain derived neurotrophic factor, Tf-conjuaged, non-viral vector, liposome, transferrin

DOI: 10.3233/BME-141019

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2089-2099, 2014

Authors: Stout, David A. | Raimondo, Emilia | Marostica, Giuliano | Webster, Thomas J.

Article Type: Research Article

Abstract: During a heart attack, the heart's oxygen supply is cut off, and cardiomyocytes perish. Unfortunately, once these tissues are lost, they cannot be replaced and results in cardiovascular disease–the leading cause of deaths worldwide. Advancements in medical research have been targeted to understand and combat the death of these cardiomyocytes. For example, new research (in vitro) has demonstrated that one can expand cardiomyocyte adhesion and proliferation using polylactic-co-glycolic acid (PLGA) (50:50 (weight percent)) supplemented with carbon nanofibers (CNFs) to create a cardiovascular patch. However, the examination of other cardiovascular cell types has not been investigated. Therefore, the purpose of this …present in vitro study was to determine cell growth characteristics of three different important cardiovascular cell types (aortic endothelial, fibroblast and cardiomyocyte) onto the substrate. Cells were seeded onto different PLGA:CNF ratio composites to determine if CNF density has an effect on cell growth, both in static and electrically stimulated environments. During continuous electrical stimulation (rectangle, 2 nm, 5 V/cm, 1 Hz), cardiomyocyte cell density increased in comparison to its static counterparts after 24, 72 and 120 hours. A minor rise in Troponin I excretion in electrical stimulation compared to static conditions indicated nominal cardiomyocyte cell function during cell experiments. Endothelial and fibroblast cell growth experiments indicated the material hindered or stalled proliferation during both static and electrical stimulation experiments, thus supporting the growth of cardiomyocytes onto the dead tissue zone. Furthermore, the results specified that CNF density did have an effect on PLGA:CNF composite cytocompatibility properties with the best results coming from the 50:50 [PLGA:CNF (weight percent:weight percent)] composite. Therefore, this study provides further evidence that a conductive scaffold using nanotechnology should be further research for various cardiovascular applications. Show more

Keywords: Nanomaterials, cardiomyocyte, fibroblast, cardiovascular patch, carbon nanofiber

DOI: 10.3233/BME-141020

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2101-2107, 2014

Authors: Zhang, Yanli | Sun, Ting | Liu, Ruoyu | Feng, Xiaoli | Chen, Aijie | Shao, Longquan

Article Type: Research Article

Abstract: The effect of zirconia surface treatment by mesoporous zirconia coating on the microtensile bond strength (MTBS) between zirconia and resin cement was investigated in this work. 160 zirconia specimens were prepared and divided into four groups according to surface treatments: (1) airborne-particle-abrasion treatment (APA); (2) glass infiltration and hydrofluoric acid treatment (GI+HF); (3) mesoporous zirconia coating (MZ); and (4) no treatment (C). The as-prepared zirconia specimens were bonded using Panavia F2.0 and RelyX Unicem. The MTBS values were tested using a universal testing machine, and data were analyzed using ANOVA and SNK methods (a=0.05). The MTBS values obtained after GI+HF …and MZ treatments were significantly higher than those obtained after APA and C treatments (P<0.05), especially for samples cemented with Panavia F2.0. The results reveal that zirconia surface treatments using GI+HF and MZ yield higher bond strength than those using APA or C, regardless of the resin cements. Show more

Keywords: Mesoporous zirconia coating, microtensile bond strength, surface treatment, resin cement

DOI: 10.3233/BME-141021

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2109-2116, 2014

Authors: Li, Rui | Sun, Ying Chun | Wang, Chen | Gao, Ping

Article Type: Research Article

Abstract: The repair of a fractured porcelain surface with a resin composite was investigated. The effects of applying an opaque resin to porcelain surfaces, which were silanated by a ceramic primer from a repair kit or by an experimental silane coupling agent, were studied. The porcelain surfaces were silanated for 10 sec and 60 min. Three types of adherents were evaluated: opaque resin with light irradiation (OWL), opaque resin without light irradiation (ONL), and no opaque resin (NAO). The shear bond strengths of the resins to the porcelain surfaces were measured before and after thermocycling. The maximum shear bond strength (6.7 …MPa) after thermocycling was observed when the silanating period of the ceramic primer was 60 min. The opaque resin had no effect on the bond strength. Moreover, the bond strength obtained with the experimental silane coupling agent was found to be reduced by only 2 MPa, even after thermocycling. Show more

Keywords: Opaque resin, silane, porcelain, bond strength

DOI: 10.3233/BME-141022

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2117-2125, 2014

Authors: Wang, Fujun | Mohammed, Abedalwafa | Li, Chaojing | Ge, Peng | Wang, Lu | King, Martin W.

Article Type: Research Article

Abstract: Various tissue-engineered vascular grafts have been studied in order to overcome the clinical disadvantages associated with conventional prostheses. However, previous tissue-engineered vascular grafts have possessed insufficient mechanical properties and thus have generally required either preoperative cellular manipulation or the use of bioreactors to improve their performance. In this study, we focused on the concept of in situ cellularization and developed a tissue-engineered vascular graft with degradable/non-degradable polymer composites for arterial reconstruction that would facilitate the renewal of autologous tissue without any pretreatment. Additionally, these composites are designed to improve the mechanical performance of a small-diameter vascular prosthesis scaffold that is …made from a flexible membrane of poly(e-caprolactone) (PCL). The PCL scaffold was reinforced by embedding a tubular fabric that was knitted from polyethylene terephthalate (PET) yarns within the freeze-dried composite structure. Adding this knitted fabric component significantly improved the mechanical properties of the composite scaffold, such as its tensile strength and initial modulus, radial compliance, compression recovery, and suture retention force. Finally, this reinforced composite structure is a promising candidate for use as a tissue-engineered scaffold for a future small diameter vascular prosthesis. Show more

Keywords: Vascular prosthesis, knitted fabric, poly (e-caprolactone), composite structure, mechanical properties, reinforcement

DOI: 10.3233/BME-141023

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2127-2133, 2014

Authors: Du, Li | Wu, Shaoling | Li, Yanhui | Zhao, Xindong | Ju, Xiaoyan | Wang, Yuzhen

Article Type: Research Article

Abstract: Graphene oxide (GO) is a hotspot, especially in the field of biomedical. However, the clinical application of GO is still faces a lot of challenges. In order to improve the solubility and biocompatibility of GO, polyethylene glycol (PEG) was grafted on the surface of graphene oxide by amide reaction. PEGylated graphene oxide (PEG-GO) was characterized using Fourier transform infrared spectroscopy (FTIR). The stability of PEG-GO detected in different solutions. Raji cell was selected as a lymphoma cell model to study the cytotoxicity of PEG-GO. Cell viability was detected using the Cell Counting Kit-8 assay. Cells were treated with different concentrations …(10–100 μg/mL) of PEG-GO at different time points (6, 12, and 24 h). The FTIR spectrum of PEG-GO indicated that polyethylene glycol was successfully grafted onto GO. PEG-GO had excellent stability in all solutions. Cells treated with PEG-GO (10–100 μg/mL) for 24 hours had survival rates were over 80%. These results demonstrate that PEG-GO had an excellent dispersion in biological solutions and the toxicity of PEG-GO to lymphoma cells was low. The paper may provide cytological evidence for the application of PEG-GO in medicine. Show more

Keywords: PEGylated graphene oxide, lymphoma cells, cytotoxicity, CCK-8

DOI: 10.3233/BME-141024

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2135-2141, 2014

Authors: Xia, Dandan | Lin, Hong | Yuan, Shenpo | Bai, Wei | Zheng, Gang

Article Type: Research Article

Abstract: Implant-abutment assemblies are usually subject to long-term cyclic loading. To evaluate the dynamic fatigue performance of implant-abutment assemblies with different tightening torque values, thirty implant-abutment assemblies (Zimmer Dental, Carlsbad, CA, USA) were randomly assigned to three tightening groups (24 Ncm; 30 Ncm; 36 Ncm), each consisted of 10 implants. Five specimens from each group were unscrewed, and their reverse torque values recorded. The remaining specimens were subjected to a load between 30N~300N at a loading frequency of 15 Hz for 5×106 cycles. After fatigue tests, residual reverse torque values were recorded if available. In the 24 Ncm tightening group, all …the implants fractured at the first outer thread of the implant after fatigue loading, with fatigue crack propagation at the fractured surface showed by SEM observation. For the 30 Ncm and 36 Ncm tightening groups, a statistical significant difference (p<0.05) between the unloaded and loaded groups was revealed. Compared with the unloaded specimens, the specimens went through fatigue loading had decreased reverse torque values. It was demonstrated that insufficient torque will lead to poor fatigue performance of dental implant-abutment assemblies and abutment screws should be tightened to the torque recommended by the manufacturer. It was also concluded that fatigue loading would lead to preload loss. Show more

Keywords: Dental implants, fatigue testing, reverse torque value, preload

DOI: 10.3233/BME-141025

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2143-2149, 2014

Authors: Zhang, Hong-Yu | Zhu, Yu-Jiao | Hu, Xiang-Yu | Sun, Yan-Fang | Sun, Yu-Long | Han, Jian-Min | Yan, Yu | Zhou, Ming

Article Type: Research Article

Abstract: Surface grafting of polyelectrolyte brush, such as 3-sulfopropyl methacrylate potassium salt (SPMK), on hip implant materials has been reported to reduce the wear of the orthopaedic bearing surface. However, the biotribocorrosion behaviour of the SPMK brush has not been taken into consideration in previous research. In the present study, SPMK was grafted on Co28Cr6Mo alloy through photo-induced polymerization, and the biotribocorrosion behaviour was investigated by a series of frictional-electrochemical tests using a universal materials tester combined with an electrochemical measurement (three-electrode) system. Co28Cr6Mo disk and polyethylene (PE) pin were used as the contact pair, and the lubricants were 0.9% saline …solution (NaCl) and 0.9% saline solution coupled with 25% bovine serum albumin (BSA). The results showed that SPMK was successfully grafted on Co28Cr6Mo alloy, which was confirmed by the comparison of Raman spectroscopy and static contact angle of the samples before and after surface modification. The greatly reduced electrochemical parameters such as corrosion current and pitting potential indicated that the corrosion rate of Co28Cr6Mo alloy was significantly reduced following SPMK grafting. Additionally, the frictional-electrochemical coupled measurement performed under reciprocating sliding demonstrated that the lowest corrosion current was obtained for the SPMK-grafted Co28Cr6Mo disk, with 0.9% NaCl coupled with 25% BSA as the electrolyte. It is indicated from the present study that SPMK polyelectrolyte brush can greatly improve the anti-biotribocorrosion properties of Co28Cr6Mo alloy, and thus has potential application on surface modification of hip implant materials. Show more

Keywords: Biotribocorrosion, biotribology, surface grafting, hip implant, polyelectrolyte brush

DOI: 10.3233/BME-141026

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2151-2159, 2014