Papers by Keyword: Biodegradable Polymer

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Authors: Q. Qiu, Paul Ducheyne, P.S. Ayyaswamy
Authors: Masahiro Okada, Shoji Takeda, Tsutomu Furuzono
Abstract: HAp-nanoparticle-coated biodegradable polymer microspheres loaded with magnetic Fe3O4 particles can be successfully prepared by evaporating volatile oil (dichloromethane) from HAp-nanoparticle-stabilized oil droplets containing biodegradable polymer and Fe3O4 particles without any molecular surfactants or polymeric stabilizers. In this study it was found that the hydrophobic surface modification for the Fe3O4 particles was a key factor to prepare stable HAp-nanoparticle-stabilized oil droplets (and HAp-nanoparticle-coated polymer microspheres) loaded with magnetic Fe3O4 particles.
Authors: Rui Xia Yu, Xiang Yang Zhou, Zeng Zhao
Abstract: The research work reported in this paper design a novel biodegradable multichamber microstructure for implantable drug controlled release by introducing the approach of topology optimization. It is therefore highly desirable to overcome these restrictions that pre-defined topology of the device result in difficulty to obtain a linear or pulsed drug release profile. The designed biodegradable multichamber microstructure is fabricated using UV-LIGA microfabrication and Micro-molding technique. The simulation results show that the multichamber microstructure exhibits a preferable linear drug release profile.
Authors: Yi Zhi Chen, Arthur F.T. Mak, Min Wang
Abstract: Using an acellular simulated body fluid (SBF), bone-like apatite can be formed on a variety of biomaterials, bioactive or bioinert, after these materials have undergone appropriate treatment(s). This biomimetic apatite-forming process is now applied to tissue engineering scaffolds in an attempt to make the scaffolds osteoconductive. In the current investigation, to form bone-like apatite on polymers such as poly(L-lactic acid) (PLLA) and poly(glycolic acid) (PGA) which degrade fast in aqueous environment, a solution (5SBF) of five times the ion concentrations of SBF was used so that an accelerated apatite formation could be achieved on PLLA and PGA. It was shown that indeed apatite could be formed on PLLA and PGA in 5SBF within 24 hours and that the apatite formed in 5SBF was similar in morphology and composition to that formed in the classical biomimetic process employing SBF or 2SBF. Results obtained in this investigation are very useful for producing osteoconductive scaffolds for bone tissue engineering.
Authors: Guang Ying Liu, Huan Zhen Zhang, Wei Li, Xin Zhang
Abstract: Carbon source used as electron donors is critical to heterotrophic denitrification. Addition of external carbon source is necessary when internal organics are deficient. A review was conducted on the use of external carbon source in denitrification. Traditional carbon sources such as methanol and ethanol, alternative carbon sources such as cellulose-rich materials, biodegradable polymers and primary sludge are included in external carbon sources. Present situation and problems of its biodegradability and effects in denitrification are summarized. Focus in external carbon source includes further study on the biodegradation mechanism of the media, slow release performance and nitrate removal rate of available carbon source and continuous research on new kinds of substrates. Recommendations on further study of carbon source are put forward.
Authors: H. Niiranen, T. Pyhältö, P. Rokkanen, T. Paatola, Pertti Törmälä
Authors: Tetsuya Tateishi, Guo Ping Chen
Abstract: A new method for the preparation of biodegradable porous scaffolds has been developed by using preprepared ice particulates as porogen material. A novel kind of hybrid biodegradable porous scaffold has been developed by forming collagen microsponges in the pores or interstices of a synthetic polymer sponge or mesh. A hybrid sponge of synthetic polymer, collagen and hydroxyapatite has been developed for hard tissue engineering. Bovine articular cartilage-like tissue has been engineered by culturing chondrocytes in the PLGA-collagen scaffolds.
Authors: A.L. Oliveira, M.I. Santos, A.A. Pedro, Rui L. Reis
Abstract: In the present study sodium clodronate, a well known therapeutic agent from the family of bisphosphonates (BP) was incorporated in an apatite coating, previously formed on the surface of a starch based biomaterial by a sodium silicate methodology, as a strategy to develop a site-specific drug delivery system for bone tissue regeneration. The effects on the resulting apatite coatings were evaluated in terms of morphology, chemistry and structure. As a preliminary approach, this first study aimed at evaluating also the effects of this BP on the viability, growth and function of a human osteoblast cell line, since there is still little information available on the interaction between BPs and this type of cells.
Authors: Masanori Kikuchi, M. Tanaka
Abstract: Biomaterials Center is composed of five groups and collaborate each other to examine interdisciplinary fields of biomaterials. In the ceramics-based biomaterials research, we have been developing three novel bone regeneration materials, i.e., high-porosity hydroxyapatite (HAp) ceramics with high-strength, guided bone regeneration (GBR) membranes and bone-like nanocomposite composed of HAp and collagen. The GBR membrane composed of β-tricalcium phosphate and biodegradable copolymer of lactide, glycolide and ε-caprolactone has thermoplastic, pH auto-adjustment and enough mechanical property to protect an invasion of surrounding tissues. With the membrane, bone defect up to 20 × 10 × 10 mm3 in length in mandibles and segmental bone defect up to 20 mm in length in tibiae of beagles are regenerated without any additional bone fillers or cell transplantations. The bone-like nanocomposite is synthesized by a co-precipitation of HAp and collagen via their self-organization. The dense composite has a half to quarter mechanical strength (40 MPa) to cortical bone and the porous one demonstrates sponge-like viscoelasticity. The composites implanted into bone are incorporated into bone remodeling metabolism like as autogenous bone graft, i.e., they are resorbed by osteolasts followed by osteogenesis by osteoblasts.
Authors: Manuela E. Gomes, Rui L. Reis, Antonious G. Mikos
Abstract: This study aims to investigate the effect of culturing conditions (static and flow perfusion) on the proliferation and osteogenic differentiation of rat bone marrow (RBM) stromal cells seeded on two starch based three-dimensional scaffolds exhibiting distinct porous structures. For this purpose, it was selected: i) a scaffold based on SEVA-C (a blend of starch with ethylene vinyl alcohol) obtained by extrusion with a blowing agent and ii) a scaffold based on SPCL (a blend of starch with polycaprolactone) obtained by a fiber bonding process. The obtained results suggest that flow perfusion culture enhances the osteogenic differentiation of RBM cells and improves their distribution in 3-D starch-based scaffolds, by improving nutrients delivery in the interior of the scaffolds and simultaneously by stimulating the seeded cells by exposing them to fluid shear forces. They also indicate that scaffold architecture and pore interconnectivity affect the homogeneity of the formed tissue.
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