Bio-Medical Materials and Engineering - Volume 24, issue 1

Authors: Miao, Feng-qin | An, Yan-li | Yang, Rui | Tang, Qiu-sha | Zhang, Jian-qiong

Article Type: Research Article

Abstract: This paper aimed to investigate the preparation of doxorubicin-loaded bovine serum albumin nanoparticles (DOX/BSANP) and their effect on killing liver cancer cells in vitro and in vivo. DOX/BSANP was prepared using a desolvation-chemical crosslinking method. Their morphology and particle size were observed using transmission electron microscopy (TEM). The envelopment, drug-loading rates and slow-release characteristics were determined spectrophotometrically. Their ability to kill liver cancer cells in vitro was determined using the methyl thiazolyl tetrazolium (MTT) assay and flow cytometry (FCM). The tumor-suppressing effect of the nanoparticles in experimental animals in vivo was also evaluated. Under TEM, DOX/BSANP appeared spherical and was …distributed uniformly, with a diameter of about 120 nm and hydrated particle size of 170 nm determined by dynamic light diffraction. The envelopment rate was 82% and the drug-loading rate was 11.2%. The in vitro drug-release experiment showed that about 50% of the drug in drug-loaded nanoparticles was released continuously and slowly for 7 days. The MTT assay showed that DOX/BSANP significantly inhibited cell proliferation, while FCM showed that it induced tumor cell apoptosis. The in vivo tumor suppression test showed that the therapeutic effect of drug-loaded nanoparticles was superior to that of DOX alone. Show more

Keywords: DOX, albumin nanoparticles, desolvation-chemical crosslinking, liver cancer

DOI: 10.3233/BME-130847

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 599-607, 2014

Authors: Dlugosz, Tomasz

Article Type: Research Article

Abstract: The aim of this paper is to focus attention of experimenters on several sources of error that are not taken into account in the majority of bioelectromagnetics experiments, and which may lead to complete falsification of the results of the experiments.

Keywords: Electromagnetic field measurements, exposure systems, bioelectromagnetics studies, biomedical engineering

DOI: 10.3233/BME-130848

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 609-617, 2014

Authors: Li, Jia | Zheng, Wei | Pan, Ping | Sun, Xiaojun | Zhang, Yanfei

Article Type: Research Article

Abstract: In this paper, citric acid, 1,8-octanediol and 1,2-propanediol were used as reactive monomers to synthesize poly(1,2-propanediol-co-1,8-octanediol-co-citrate) (PPOC) elastomers by melt polycondensation. The PPOC elastomers were characterized by FTIR, 1H-NMR, thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), hydrophilic test and mechanical test. The results indicated that citric acid had reacted with 1,8-octanediol and 1,2-propanediol, respectively. The sol content, swelling degree and hydrophilicity of PPOC elastomers increased with the higher content of 1,2-propanediol, while the tensile strength and the thermal degradation temperature decreased. The results indicate the addition of 1,2-propanediol reduces the crosslinking density and the flexibility of PPOC elastomers.

Keywords: Poly(1,2-propanediol-co-1,8-octanediol-co-citrate), 1,2-propanediol, elastomer

DOI: 10.3233/BME-130849

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 619-624, 2014

Authors: Wang, Xian-Kang | Ye, Jin-Duo | Gu, Fu-Shun | Wang, Ai-guo | Zhang, Chun-Qiu | Tian, Qian-Qian | Li, Xue | Dong, Li-Min

Article Type: Research Article

Abstract: In this paper, the single arm external fixation of intertrochanteric fracture healing process after surgery was simulated to obtain a postoperative fracture healing and stress distribution in the external fixator. Firstly CT images of intertrochanteric fracture are reconstructed into the femur solid model. Then based, the external fixator is installed on the model, which lastly formed a finite element model of unilateral external fixation for intertrochanteric fracture. The calculated results show: during the beginning of the fracture healing, there is much higher stress in both screws and femur in the model with solid screws than that in the model with …hollow screw. The stress of the femur in the model with hollow screw is more evenly. During the middle time of Fracture healing, stress in the femoral head significantly decreases. And the stress at fracture site gradually increased with the healing occurrence. According to the results, the authors designed hollow screws to use external fixation surgery. Surgery confirmed that the use of hollow screws in fractures treatment can satisfy the strength requirements, and can effectively reduce operative time, less patient suffering. The research for external fixation can provide a reference, and promote the use of external fixation hollow screws. Show more

Keywords: single arm external fixation, the femoral intertrochanteric fracture, stress distribution, numerical simulation, surgery scheme

DOI: 10.3233/BME-130850

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 625-632, 2014

Authors: Zhao, Peng | Deng, Cuijun | Xu, Hongzhen | Tang, Xing | He, Hailong | Lin, Chao | Su, Jiansheng

Article Type: Research Article

Abstract: Photo-crosslinked chitosan-gelatin scaffolds were fabricated and applied for chondrocyte culture in vitro. Photocurable methacryloyl chitosan was synthesized and characterized by FTIR and 1H NMR, respectively. Microstructure and mechanical properties of the chitosan-gelatin scaffold treated with or without EDC as crosslinking agent were analyzed by scanning electronic microscopy (SEM), compression and viscoelastic measurement. It is demonstrated that EDC-treated chitosan-gelatin scaffold possesses better porous structure and improved mechanical properties. Photo-crosslinked chitosan-gelatin scaffold could be further integrated in sodium alginate hydrogel using calcium chloride to support proliferation of chondrocytes for over 21 days and maintain spherical phenotype, as evaluated by AlamarBlue assay and …SEM, respectively, implying that the chitosan-gelatin-hydrogel system exhibits great cyto-biocompatibility. Results of this study show that photo-crosslinked chitosan-gelatin scaffold in sodium alginate hydrogel is suited as a scaffold candidate for cartilage tissue engineering. Show more

Keywords: chitosan, gelatin, chondrocyte, hydrogel, cartilage tissue engineering

DOI: 10.3233/BME-130851

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 633-641, 2014

Authors: Wang, Min | Ning, Yingyuan | Zou, Haixiao | Chen, Si | Bai, Yi | Wang, Aihua | Xia, Haibin

Article Type: Research Article

Abstract: Ti6Al4V discs with a thickness of 2.5 mm and dimensions of 15 × 15 mm2 were fabricated. The titanium nitride (TiN) surface was formed via Nd:YAG laser-nitriding. A sandblast acid-etched (SA) surface was used as a control. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and surface roughness tests were conducted to study the surface and cross-section morphologies as well as the properties of TiN and SA surfaces. MC3T3-E1 osteoblast-like cells were cultured on the TiN and SA surfaces to evaluate the effect of TiN surface on cellular behaviors, including attachment, proliferation and differentiation. Morphological testing results revealed that …the cross-section of TiN exhibited dendritic crystallization without cracking. The proliferation and differentiation of MC3T3-E1 cells on the laser-nitriding TiN surface were significantly increased compared to those cultured on SA surface. These findings suggested that the TiN surface generated from Nd:YAG laser-nitriding were favorable for the proliferation and differentiation of MC3T3-E1 cells, which is significant for implant surface modification. Show more

Keywords: laser-nitriding, TiN surface, MC3T3-E1 cells, adhesion, differentiation

DOI: 10.3233/BME-130852

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 643-649, 2014

Authors: Wang, Haiyan | Lin, Derong | Wang, Di | Hu, Lijiang | Huang, Yudong | Liu, Li | Loy, Douglas A.

Article Type: Research Article

Abstract: Sunscreens that absorb UV light without photodegradation could reduce skin cancer. Polyvinyl silsesquioxanes are known to have greater thermal and photochemical stability than organic compounds, such as those in sunscreens. This paper evaluates the UV transparency of vinyl silsesquioxanes (VS) and its hybrids with SiO2(VSTE) and TiO2(VSTT) experimentally and computationally. Based on films of VS prepared by sol-gel polymerization, using benzoyl peroxide as an initiator, vinyltrimethoxysilane (VMS) formulated oligomer through thermal curing. Similarly, VSTE films were prepared from VMS and 5–25 wt-% tetraethoxysilane (TEOS) and VSTT films were prepared from VMS and 5–25 wt-% titanium tetrabutoxide (TTB). Experimental average transparencies …of the modified films were found to be about 9–14% between 280–320 nm, 67–73% between 320–350nm, and 86–89% between 350–400nm. Computation of the band gap was absorption edges for the hybrids in excellent agreement with experimental data. VS, VSTE and VSTT showed good absorption in UV-C and UV-B range, but absorbed virtually no UV-A. Addition of SiO2 or TiO2 does not improve UV-B absorption, but on the opposite increases transparency of thin films to UV. This increase was validated with molecular simulations. Results show computational design can predict better sunscreens and reduce the effort of creating sunscreens that are capable of absorbing more UV-B and UV-A. Show more

Keywords: Silsesquioxane, silica, titanium dioxide, hybrid films, ultraviolet region, sunscreen, computation of band gap

DOI: 10.3233/BME-130853

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 651-657, 2014

Authors: Wu, Ming-Yue | Li, Quan-Li | Chen, Lian-Zi

Article Type: Research Article

Abstract: In this study, orthophosphoric acid (H3 PO4 ) in the treatment of porous titanium (Ti) is investigated and the ability of rat bone marrow stromal cells (BMSCs) is assessed to proliferate and differentiate on these modified surfaces in vitro. To improve the cytocompatibility of Ti surfaces, pure Ti was activated commercially by simple chemical pretreatment in H3 PO4 with different densities. Next, the phosphorylated specimens were soaked in simulated body fluid (SBF) to study the effect of biomineralization. The3-[4,5-dimethylthiazol-2-y1]-2, 5-diphenytetrazolium bromide (MTT) assay and the measurement of alkaline phosphatase (ALP) activity utilized to assess proliferation and differentiation of BMSCs …on exposure to modified Ti surfaces. Scanning electron microscopic (SEM) images showed that the surfaces of the pre-treated samples were characterized by a complex structure which consisted of a mesh-like morphological matrix and an uniform surface with different morphic crystals of titanium dihydrogen orthophosphate (Ti(H2 PO4 )3 ). These crystals contained hydroxyl with phosphate residues that resulted in biomineralization of cells. Therefore, BMSCs reveales a well-dispersed morphology on these modified and functionalized Ti surfaces. The viability and ALP activity of BMSCs on these altered biomimetic surfaces are found to be greater than those of the controls. It is concluded that the treatment of Ti by acid etching in orthophosphoric acid is a suitable method to enhance the in vitro proliferation and differentiation of BMSCs. Show more

Keywords: titanium implant, phosphorylation, cytocompatibility, stem cells, biomaterials, cellular engineering

DOI: 10.3233/BME-130854

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 659-671, 2014

Authors: Lin, Chao | Song, Yanyan | Lou, Bo | Zhao, Peng

Article Type: Research Article

Abstract: A dextranated, bioreducible cationic polyamide was designed and employed for non-viral gene delivery in vitro and in vivo. Initially, a new bioreducible cationic polyamide with p-nitrophenyl ester terminal group (denoted as SSBAP) was synthesized by polycondensation reaction of an excess amount of bis-(p-nitrophenyl)-3, 3'-dithiodipropanoate and 1, 4-bis(3-aminopropyl)piperazine. The SSBAP was then chemically conjugated with 5kDa amino-terminated dextran to yield dextran-SSBPA-dextran triblock copolymer (denoted as Dex-SSBAP-Dex). This copolymer was capable of binding genes to form nanoscale polyplexes with a near-neutral surface charge. Moreover, a sufficient gene release from the polyplexes in response to an intracellular reducing environment was observed. In vitro …transfection against MCF-7 and SKOV-3 cells showed that Dex-SSBAP-Dex copolymer effectively transfected the cells with comparable efficiency to that of 25kDa branched or linear polyethylenimine as positive controls. Besides, intravenous administration of the copolymer-based polyplexes in nude mice afforded detectable gene expression largely in the lung. Importantly, the copolymer revealed low cytotoxicity in vitro, as determined by AlamarBlue assay, and caused no death of the mice. Dextranated, bioreducible cationic polyamide holds high potential as a non-viral vector for gene delivery. Show more

Keywords: Dextran, disulfide, gene delivery, transfection, in vivo

DOI: 10.3233/BME-130855

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 673-682, 2014

Authors: Qu, Z.W. | Meng, Q.G. | Xiao, X. | Li, B.L. | Zhang, F.M.

Article Type: Research Article

Abstract: A high degree of cell adhesion to a scaffold at the initial stage of cell inoculation is essential to bone tissue engineering. In realising high cell adhesion rate on a scaffold within a few hours, a chitosan/hydroxyapatite (CS/HA) scaffold with a channel/sphere pore was prepared via in situ hybridisation in combination with lyophilisation, in which the HA nanoparticles were dispersed in the CS uniformly. The size of the channel pore and the sphere pore of the CS/HA scaffold was 150 μm to 650 μm and 3 μm to 15 μm, respectively. The compression strength and porosity of the CS/HA scaffold …were 3.54±0.32 MPa and 88.4%, respectively. The nitrogen content increased by 7.5% compared with the CS/HA scaffold without Arg-Gly-Asp (RGD) modification. More than 67% of the RGD in the PBS solution diffused into the CS/HA scaffold spontaneously. The effect of the RGD peptide on bone marrow mesenchymal stem cells (MSCs) on the CS/HA scaffold was investigated through cell adhesion rate, alkaline phosphatase (ALP) activity, and mineralised calcium nodules. The cell adhesion rates of the CS/HA scaffold with different RGD concentrations (50, 100 mg/L) were 71.6% and 80.7%, respectively, after 4 hours of culture; the rates were 30.9% and 47.5% higher than that of the CS/HA group (54.7%), respectively. The expressed ALP content of the CS/HA scaffold with RGD (191±6 U/g protein) was 107.7% higher than that (92±9U/g protein) of CS/HA (p<0.01). Furthermore, a higher amount of mineralised calcium nodules with red brown appeared in the CS/HA scaffold with RGD as opposed to that in the CS/HA group. The RGD peptide in the CS/HA scaffold not only achieved high cell adhesion in a short period of time, but also enhanced cell adhesion ability and promoted the MSCs to differentiate from osteoblasts. Show more

Keywords: RGD peptides, Chitosan, Hydroxyapatite, Bone Marrow Mesenchymal Cells, Tissue engineering

DOI: 10.3233/BME-130856

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 683-693, 2014