Bio-Medical Materials and Engineering - Volume 21, issue 2

Authors: Porrini, Roberto | Rocchetti, Vincenzo | Vercellino, Vittorio | Cannas, Mario | Sabbatini, Maurizio

Article Type: Review Article

Abstract: Tooth extraction usually involves alveolar bone loss and reduction in height and width of the remaining alveolar socket, owing to the physiological bone resorption. This occurrence may perform an inadequate bone profile, that make difficult orthodontic applications, compromising the functional and aesthetic restoration of dental implants. The present review will provide an update on the biological and clinical profile of materials currently in use and those under investigation, in the recovering of bone margins of edentulous sockets.

Keywords: Occlusive membrane, graft materials, osteoconductivity, osteoinductivity

DOI: 10.3233/BME-2011-0659

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 2, pp. 63-74, 2011

Authors: Zhang, Wei | Wang, Huaiyu | Oyane, Ayako | Tsurushima, Hideo | Chu, Paul K.

Article Type: Research Article

Abstract: Plasma technology is widely employed to tailor the surface chemistry of polymeric biomaterials. In this work, nitrogen-containing functional groups were generated on a polymer surface by N2 plasma immersion ion implantation (PIII). We evaluated the abilities of the resulting surface to inhibit bacterial growth and to enhance osteoblast differentiation from the perspective of bone tissue engineering. Our results demonstrate that the N2 PIII-treated polymer surface exhibits antibacterial properties against Escherichia coli. Moreover, the N2 PIII-treated polymer surface has the ability to enhance differentiation of osteoblasts. N2 PIII-treated polymer surface may therefore be useful in bone tissue engineering.

Keywords: Bone tissue engineering, differentiation, disinfection, osteoblasts, plasma, polymer

DOI: 10.3233/BME-2011-0657

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 2, pp. 75-82, 2011

Authors: Niina, Onnela | Hirotaka, Takeshita | Yoshiuki, Kaiho | Toshiya, Kojima | Risato, Kobayashi | Tetsu, Tanaka | Jari, Hyttinen

Article Type: Research Article

Abstract: Retinal implants may provide vision for people suffering from photoreceptor degeneration caused by different eye diseases. Electrode size in retinal implant should be decreased in order to increase the resolution provided by the implant. We defined electric properties of five different electrode materials (Au, Ir-b, Ti, TiN, Pt-b) widely used in retinal prostheses. The comparison of different electrode materials requires that the electrical properties of different materials are defined using exactly the same measurement conditions and devices. Existing studies about electrode material properties are often made using slightly different measurement parameters or electrode processing conditions making the comparison between different …materials difficult. Here, the electrochemical characterization included cyclic voltammetry and electrochemical impedance spectroscopy. Ir-b and Pt-b had greater charge injection capacity than other materials. The fabricated material samples showed that in this experiment the electrode diameter larger than 200 μm should be used to suppress irreversible reaction of stimulus electrodes with the needed stimulus currents. Thus, either we have to find novel electrode materials or surface treatment methods to decrease the electrode area providing increased electrode and pixel number of the prosthesis or we have to show that stimulus currents smaller than 40 μA are enough to induce phosphenes. Show more

Keywords: Retina prosthesis, cyclic voltammetry, electrical impedance spectroscopy, electrical properties of electrodes

DOI: 10.3233/BME-2011-0658

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 2, pp. 83-97, 2011

Authors: Jafari, Javad | Emami, Shahriar Hojjati | Samadikuchaksaraei, Ali | Bahar, Mohammad Ali | Gorjipour, Fazel

Article Type: Research Article

Abstract: In this study, chitosan and gelatin solutions were blended at five different ratios. Samples were fed into electrospinning apparatus to produce non-woven nanofibrous mats. Scanning electron microscopy (SEM) showed that the low-viscosity sample with 30% chitosan and 70% gelatin (sample 30/70) formed the least amount of beads and droplets and yielded fibers with the highest morphological uniformity. To examine the effect of processing parameters on fibers morphology and nanofibers diameter, flow rate, voltage and distance between needle to the collector were changed in the sample 30/70. SEM revealed that high voltages (25 kV) and flow rates (1.5 ml · h−1 ) decrease …the uniformity of fibers and lead to bead and droplet formation. It has also shown that the distance between the tip and the collector have no significant effect on fibers' structure. The values of 15 kV (voltage), 0.2 ml · h−1 (flow rate) and the fixed distance of 15 cm were identified as the optimal electrospinning conditions, which produce fibers with a mean diameter of 180±20 nm. Fourier transform infrared (FTIR) experiment revealed an increase in N–H bending and decrease in C–O stretching vibration in both chitosan and gelatin at 1060 and 1148 cm−1 . The in vitro biocompatibility tests performed with human skin fibroblasts showed excellent cell proliferation (MTT assay) and attachment (SEM) on these scaffolds confirming its highly acceptable biological properties. Show more

Keywords: Chitosan, gelatin, electrospinning, nanofibers, scaffold

DOI: 10.3233/BME-2011-0660

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 2, pp. 99-112, 2011

Authors: Kataoka, Yu | Tamaki, Yukimichi | Miyazaki, Takashi

Article Type: Research Article

Abstract: Wire-type electric discharge machining has been applied to the manufacture of endosseous titanium implants as this computer associated technique allows extremely accurate complex sample shaping with an optimal micro textured surface during the processing. Since the titanium oxide layer is sensitively altered by each processing, the authors hypothesized that this technique also up-regulates biological responses through the synergistic effects of the superficial chemistry and micro topography. To evaluate the respective in vitro cellular responses on the superficial chemistry and micro topography of titanium surface processed by wire-type electric discharge, we used titanium-coated epoxy resin replica of the surface. An oxide …layer on the titanium surface processed by wire-type electric discharge activated the initial responses of osteoblastic cells through an integrin-mediated mechanism. Since the mRNA expression of ALP on those replicas was up-regulated compared to smooth titanium samples, the micro topography of a titanium surface processed by wire-type electric discharge promotes the osteogenic potential of cells. The synergistic response of the superficial chemistry and micro topography of titanium processed by wire-type electric discharge was demonstrated in this study. Show more

Keywords: Titanium, surface modification, cell

DOI: 10.3233/BME-2011-0661

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 2, pp. 113-121, 2011

Authors: Türkoğlu Şaşmazel, Hilal | Aday, Sezin | Manolache, Sorin | Gümüşderelioğlu, Menemşe

Article Type: Research Article

Abstract: In this study, low pressure water/O2 plasma treatment was performed in order to obtain COOH functionalities on the surface of poly-ε-caprolactone (PCL) membranes as well as non-woven polyester fabric (NWPF) discs. The plasma treatments were performed in a cylindrical, capacitively coupled RF-plasma-reactor and then following steps were performed: in situ (oxalyl chloride vapors) gas/solid reaction to convert –OH functionalities into –COCl groups; and hydrolysis under open laboratory conditions using air moisture for final–COOH functionalities. COOH and OH functionalities on modified surfaces were detected quantitatively by using fluorescent labeling technique and an UVX 300G sensor. Electron spectroscopy for chemical analysis …(ESCA) was used to evaluate the relative surface atomic compositions and the carbon and oxygen linkages located in non-equivalent atomic positions of untreated and modified surfaces. Atomic force microscope (AFM) analysis showed that nanoscale features of the PCL surfaces are dramatically changed during the surface treatments. Scanning electron microscopy (SEM) results indicated the changes in the relatively smooth appearance of the untreated NWPF discs after the plasma treatment. Periodontal ligament (PDL) fibroblasts were used in cell culture studies. Cell culture results showed that plasma treated PCL membranes and NWPF discs were favorable for the PDL cell spreading, growth and viability due to the presence of functional groups and/or nanotopographies on their surfaces. Show more

Keywords: Poly(ε-caprolactone), polyethylene terephthalate, low pressure plasma, periodontal ligament fibroblasts

DOI: 10.3233/BME-2011-0662

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 2, pp. 123-137, 2011