bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite Element Modeling and Blister Test to Investigate the Adhesive Strength of Diamond Thin Film
Authors: Xiang Dao Hui , Chen Ming , Sun Fang Hong
Published: March 2009

Large advancements have been achieved in understanding nucleation and growth of CVD
diamond, but adhesion of diamond film to substrates is poor and there is no good methods about
how to quantitative evaluation of the adhesive strength. The blister test is a method appropriate for
measuring the adhesion of CVD diamond. In this test a pressure difference is applied across a thin
film and the pressure when the film separates from substrate is measured, and the adhesive strength
of diamond thin film was calculated using analytical model. Using the finite element model, the
deflection at the center of a free-standing window sample of diamond thin films is calculated as a
function of applied pressure and the adhesive strength is obtained using the FEM. The result
indicates that finite element method-based prediction of the total energy release rate is in good
agreement with that obtained from analytical expressions and experimentally observed values.
Effects of Octacalcium Phosphate on the Development of Bone Marrow Derived Stromal Cells: Comparison of Osteogenic Medium/OCP Induced Osteocalcin Expression
Authors: Liu Y. , Barralet J.E. , Cooper P. , Shelton R.M.
Published: March 2009

According to the gene repertoire, distinct morphology and the organisation of
extracellular matrix, osteoblast development was identified as a series of stages, proliferation,
differentiation, matrix deposition, matrix maturation and mineralization. Each of these stages
required tightly regulated and functionally coupled expression of genes related to the transcription
factors and bone matrix. In this paper, we identify the effects of OCP to the differentiation of
osteoblasts from the point of view of differentiation sequence development. Osteogenic medium
(Ost MEM) mainly regulated the osteocalcin (OC) mRNA expression in the first week of culture.
As culture continued to 24 days, OCP crystal assemblies became the main regulator. This shift in
the role that OCP and Ost MEM played in regulation may reflect different biological functions of
OC in Ost MEM induced regulation and OCP crystals induced regulation. The up-regulated OC
mRNA expression by OCP crystal assemblies may function as a signal to coordinate the activities of
osteoblasts and osteoclasts instead of inducing mineralisation at the end of the differentiation
sequence of osteoblasts. By comparing the modified expression pattern observed on the OCP crystal
particles with the patterns of differentiation sequences, it was found that BMSCs colonising OCP
crystal assemblies from day 7 to day 24 matched the process of differentiation in the early stages of
matrix deposition. The gene expressions of BMSC cultured in the osteogenic medium (positive
control) corresponded with the process from matrix deposition to mineralisation. Hence, the
differentiation process of BMSCs on OCP crystal assemblies was different from that found on the
positive control. BMSCs could differentiate to osteoblasts that would function as a regulator for
osteoclast activities.
Osteoblastic Cell Differentiation on BMP-2 Pre-Adsorbed Octacalcium Phosphate and Hydroxyapatite
Authors: Kumagai Takashi , Anada Takahisa , Honda Yoshitomo , Takami Masamichi , Kamijyo Ryutaro , Shimauchi Hidetoshi , Suzuki Osamu
Published: March 2009

The present study was designed to investigate whether bone morphogenetic protein-2
(BMP-2) adsorbed onto octacalcium phosphate (OCP) and hydroxyapatite (HA) surfaces influences
osteoblastic cell differentiation. Osteoblastic cell line, UAMS32, were cultured on plastic plate that
was coated of synthetic OCP and HA. BMP-2 was pre-adsorbed on these calcium phosphates at 4°C
or room temperature for 24h. The cells more proliferated on the BMP-2 pre-adsorbed OCP and HA
than that of the controls (OCP and HA coating without BMP-2). ALP activities were higher on HA
than on OCP when BMP-2 were pre-adsorbed at 4°C than at room temperature. The results suggest
that pre-adsorption of BMP-2 in different temperature affects osteoblastic cell differentiation, most
probably through different adsorption state of BMP-2 on this calcium phosphate.
Comparison of Gene-Expression of MC3T3-E1 Osteoblastic Cell Cultured on Machined Titanium Surface and Resorbable Blast Material Titanium Surface
Authors: Park S.H. , Kim H.H. , Lee H.S. , Choi Y.S. , Pae A.R. , Kim M.R.
Published: March 2009

Because of its high biocompatibility, hydroxyapatite(HA) has been considered as a good
blasting material. DNA microarray is a new molecular technology that enables the analysis of gene
expression in parallel on a very large number of genes, spanning a significant fraction of the human
genome. It is a qualitive analysis (e.g. it can differentiate each single gene) and quantitative, since it
has the sensitivity to detect a change of expression level in the investigated cells when compared to
normal samples. The aim of this study is to define the cell attachment and the genetic effect of
machined surface implant and RBM (resorbable blast media) surface implant on the osteoblastic
cell (MC3T3-E1 osteoblastic cell line) by cDNA microarray slide containing 21575 genes.
Cells were cultured on machined grade 4 titanium disks(Group 1, machined surface) and disks of
RBM (Group 2) and the samples were moved to new dishes and media were added and the plated
disks were cultured for 24 hours. Total RNA extraction was performed with Qiagen mini kit
(Qiagen, Chatsworth, CA, USA) for microarray assay. Microarray assay after culturing the cells on
the machined surface and RBM surface revealed that osteoinductive molecules appeared more
prominent on the RBM surface, whereas the adhesion molecules on the biomaterial were higher on
the machined surface than RBM surface.
Montmorillonite-Added Calcium Phosphate Bioceramic Foams
Authors: Hesaraki Saeed , Zamani A. , Hafezi M.
Published: March 2009

The present work was performed to improve the mechanical strength of porous calcium phosphate blocks by adding a little amount of montmorillonite mineral to the calcium phosphate composition. 3.5 wt % of the montmorillonite mineral was added to the slurry of precipitated hydroxyapatite and the porosity was produced by infiltration of a polymer template. After the firing process (1200 oC), the compressive strength, phase composition, morphology and dissolution behavior of the porous bodies were evaluated by appropriate techniques. It was found that the additive improved the mechanical strength but decreased the dissolution rate of the porous calcium phosphate body. Also the final composition of the porous block (i.e. hydroxyapatite, HA, and β- tricalcium phosphate, β-TCP) was not influenced through the presence of the additive. It is suggested that the montmorillonite mineral can improve the sintering performance of the HA and β- TCP.
Protein Adsorption on Hydroxyapatite Nano-Crystals with Quartz Crystal Microbalance Technique
Authors: Yoshioka Tomohiko , Ikoma Toshiyuki , Monkawa Akira , Tonegawa Toru , Chakarov Dinko , Kasemo B. , Hanagata Nobutaka , Tanaka M.
Published: March 2009

Real time adsorption behaviors of six proteins with different isoelectric points on
hydroxyapatite (HAp) nanocrystal surfaces have been investigated by using HAp sensors for quartz
crystal microbalance with dissipation technique (QCM-D). The dissipation (D)–frequency (f) plots
clearly showed that the different types of protein adsorption behaviors; the D-f plots of acidic proteins
lie on one straight line with a constant slope under all initial protein concentrations, while those of
neutral and basic proteins lie on two straight lines with different slopes. The acidic proteins formed a
monolayer, while the neutral and basic proteins could cause conformational changes with the
adsorbed amount of proteins. The QCM-D technique with novel HAp nanocrystal sensor is useful for
the liquid phase changes of proteins on the surface.
Behavior of Cellularized-Hydroxyapatite Implants Coated with Cyclo-DfKRG Peptides in Spongious Bone: Quantitative Comparison of Micro-Tomodensitometry and Histomorphometry
Authors: Malinvaud Jack , Catros Sylvain , Pothuaud L. , Bareille Reiner , Amédée Joelle , Fricain Jean Christophe
Published: March 2009

In order to develop bone substitute with osteogenic properties, a novel strategy of
grafting cyclo-DfKRG peptides to enhance cells adhesion and osteointegration of hydroxyapatite
(HA) implants was developed. Objectives of the study were (1) to evaluate the osteogenic
properties of HA implants grafted with RGD peptides and (2) to compare histomorphometry and
micro-computed tomography ((CT) with bone quantification. Pure HA grafted or not with cyclo-
DfKRG peptides and autologous stromal cells was implanted in femoral condyle on 2 groups (2 and
4 weeks) of 6 New Zealand rabbits. Measurements concerning bone reconstruction and material
structure were obtained with a (CT and the results were compared to those obtained after
histomorphometry. Finally, it appears that grafting cyclo-DfKRG on HA implants enhances nonsignificantly
the rate of bone formation, and a high correlation of the results was found comparing
histomorphometry and (CT analysis.
In Vivo Demonstration of 2 Types of Microporosity on the Kinetic of Bone Ingrowth and Biphasic Calcium Phosphate Bioceramics Resorption
Authors: Malard Oliver , Gautier Helene , Daculsi G.
Published: March 2009

Microporosity and granules size are important parameters for the development of
suspension, composites and injectable bone substitutes. In this experimental study performed in a
rat bone model of critical size defects, were have determined the kinetics of bioceramic resorption
and bone ingrowth. Two kinds of granules (1mm in diameter) of Biphasic Calcium Phosphate BCP
(60/40 HA/TCP ratio) with 20% and 40% microporosity of less of 5 microns in size, were used.
Higher bone ingrowth was observed for low porosity (LP) at 3 weeks versus high porosity (HP); the
contrary was measured after 6 weeks. About the kinetics of BCP resorption, significant difference
between the 2 porosities was noticed, the higher for high microporosity. High porosity on time,
promotes more bone ingrowth at the expense of the bioceramic than lower microporosity.
Repairing Segmental Defect with a Composite Associating Collagen Membrane and MBCP® Combined with Total Bone Marrow Graft in Irradiated Bone Defect: an Experimental Study in Rabbit
Authors: Jegoux Franck , Aguado Eric , Cognet Ronan , Malard Oliver , Moreau Françoise , Daculsi G. , Goyenvalle Eric
Published: March 2009

The aim of this study was to study bone marrow quality from various location and
species for reconstruction of segmental critical size defect in irradiated weigh bearing bone.
Sample of bone marrow aspirates from rabbits and Beagle dog were analyzed. Rabbits were
implanted with a composite associating resorbable collagen membrane plus micro
macroporous biphasic calcium phosphate (MBCP®) and autologous bone marrow (BM)
injected after irradiation. Bone marrow samples were found to be significantly less rich in
tibia than in humerus and ilium in Dog and less rich in Dog than in Rabbit (p<0,05).
Successful osseous colonization bridging of the defect were obtain at 16 weeks in all animals.
Identical repartition of bone ingrowth and residual ceramic at the different levels of the
implant suggest an osteoinduction role of the bone marrow graft in the center of the defect.
This model succeeded in reconstruct a large segmental defect in weight bearing and
irradiated bone in rabbit.
Bone Regenerative Property of Octacalcium Phosphate in Mouse Critical Sized Calvarial Defects
Authors: Honda Yoshitomo , Kamakura Shinji , Kumagai Takashi , Suzuki Osamu
Published: March 2009

Bone regeneration by calcium phosphates has been known to be intricately dependent on
material properties or implanted milieu of host animals, such as site and species. Critical sized
calvarial defects of mouse were recently used as the model for investigating bone regeneration ability
and the mechanisms. The purpose of the present study is to investigate whether the critical sized
mouse calvarial defects can be utilized to examine bone regeneration with synthetic octacalcium
phosphate (OCP). OCP , prepared by wet synthesis methods, was sieved 0.3 ~ 0.5 mm in diameter and
used for the animal experiment. At 14 days after surgery, histological examination showed that
implantation of OCP grafted defects significantly enhanced bone formation compared with the
control defect. OCP tended to convert to hydroxyapatite with time. The tartrate-resistant acid
phosphatase (TRAP) positive osteoclastic cells were observed around the OCP particles. The results
suggest that the mouse critical sized calvarial bone defects are useful model to investigate the bone
formation by the OCP implantation.
Hybrid Chitosan Membranes Tested in Sheep for Guided Tissue Regeneration
Authors: Cortez P.P. , Shirosaki Yuki , Botelho C.M. , Simões M.J. , Gartner F. , da Costa R.M. Gil , Tsuru Kanji , Hayakawa Satoshi , Osaka Akiyoshi , Lopes M.A. , Santos José D. , Maurício Ana Colette
Published: March 2009

Previous in vitro studies confirmed an improved cytocompatibility of chitosan-silicate
hybrid membranes over chitosan membranes. The main goal of this study was to assess the in vivo
histocompatibility of both membranes through subcutaneous implantations at different time periods,
1 week, 1, 2 and 3 months, using a sheep model. Chitosan membranes elicited an exuberant
inflammatory response and were consequently rejected. The hybrid chitosan membranes were not
rejected and the degree of inflammatory response decreased gradually until the third month of
implantation. Histological evaluation also showed that these membranes can be resorbed in vivo.
This study demonstrates that the incorporation of silicate into the chitosan solution improves its
histocompatibility, indicating that the hybrid chitosan-silicate membranes are suitable candidates to
be used in clinical applications.
Stimulatory Effect on Osseous Repair of Zinc-Substituted Hydroxyapatite: Histological Study in Rabbit’s Tibia
Authors: Calasans-Maia Monica , Rossi Antonella M. , Dias Eliane Pedra , Santos Silvia R. A. , Áscoli Fabio , Granjeiro José Mauro
Published: March 2009

The study was carried out aiming the evaluation of the effect of hydroxyapatite (HA) and
zinc-substituted hydroxyapatite (ZnHA) on osseous repair of rabbit’s tibia. For the study, 15 adult
animals, weighing around 2.5 and 3.0 Kg, sourced by the Fluminense Federal University Animal
Lab were acquired. Two perforations were created in each tibia and filled with cylinders (2x6 mm)
of HA (group 1, right) or ZnHA (group 2, left). The animals were killed after 7, 14, and 28 days for
evaluating the histological aspects of the interface site and bone repair. No sign of inflammatory
reaction surrounding the cylinders area were observed, neither giant cells. Osteogenesis was
evidently accelerated in all healing periods for the ZnHA group in regards to the HA group.
Randomly dispersed areas of neoformed bone among wide areas of fibrous connective tissue was
observed in the HA group. We conclude that both biomaterials are biocompatible, but zinc-containg
HA enhanced and accelerated the osteogenesis in relation to HA.
BSA Adsorption on Hydroxyapatite after Thermal Treatment
Authors: Mavropoulos Elena , da Rocha Nilce C.C. , Rocha-Leão Maria Helena M. , Rossi Antonella M.
Published: March 2009

Adsorption experiments of bovine serum albumin on hydroxyapatite previously annealed at temperatures up to 1100°C was performed at 37°C and phosphate buffer, pH 6.0. Kinetic process was very efficient and irreversible for low phosphate buffer concentration. Thermal treatment contributed to the decrease of bovine serum albumin immobilization indicating that sorption process depended on HA specific surface area and the number of surface active sites. However, it was verified that particle size was also an important parameter for bovine serum albumin immobilization.
Circulating Cytokines as Biological Indicators for PE and Ceramics Articulations
Authors: Fiorito Silvana , Magrini Laura , Streicher Robert
Published: March 2009

We studied the role of cytokines (TNF-α, IL-6,IL-1β, TGF-β) as markers of osteolysis in patients
who underwent to a hip prosthesis implantation subdivided in two groups: group A with an ultrahigh
molecular weight polyethylene (UHMWPE) insert articulating against a metal ball head , and
group B with an all alumina ceramic combination.
Profibrogenic (TGF-β) and pro-inflammatory cytokines (TNF-α, IL-6,IL-1β) are secreted by the
periprosthetic synovial-like fibrous membrane in hip artificial implants. They are secreted by
inflammatory activated cells and trigger the cascade of biochemical events leading to the activation
of osteoclasts and bone resorption.
A statistically significant increase of TGF-β serum levels was observed between TGF-β values in
implanted patients as compared to normal subjects and between TGF-β values after versus before
implantation in Group A.
A progressive decrease in TNF-α and IL-6 serum levels has been observed in both Groups, when
compared with the initial values before the implantation. IL-1β levels decreased up to 60 months
after the implantation
Our data suggest that monitoring circulating cytokines could be a good indicator for the
proliferation and activity of the periprosthetic synovial-like membrane and potential osteolysis. This
could allow for an adequate early treatment.
In Vitro Assessment of New Niobium Phosphate Glasses and Glass Ceramics
Authors: Prado da Silva Marcelo Henrique , Ramirez C. Moura , Granjeiro José Mauro , Rossi Antonella M.
Published: March 2009

Niobo-phosphate glasses were produced in order to assess the citotoxicity of samples with different compositions. Different P2O5/Ca ratios were studied in an attempt to correlate the biological behavior of new niobo-phosphate bioactive glasses with conventional bioactive calcium phosphate glasses. The most biocompatible glass composition was chosen to produce glassreinforced hydroxyapatite composites.
Modifying Brushite Cement Degradation Using Calcium Alginate Beads
Authors: Grover Liam M. , Patel Sarika , Hu Y. , Gbureck Uwe , Barralet J.E.
Published: March 2009

The hydrolysis of brushite in calcium phosphate cements to form hydroxyapatite is
known to result in the long term stability of the material in the body. It has previously been
established that this hydrolysis reaction can be influenced by implant volume, media refreshment
rate and media composition. In this study, the effect of macroporosity on the rate of degradation of
the material is investigated. Macroporosity was incorporated into the material using calcium
alginate beads mixed into the cement paste. The inclusion of the calcium alginate beads did not
influence the degree of conversion of the material and allowed the incorporation of porosity at up to
maximum of 57%. The macroporosity weakened the cement matrix (from 46.5 to 3.2 MPa). When
aged the brushite in the macroporous cement dissolved completely from the matrix resulting in a
weight loss of 60wt% in a period of 28 days. This suggests that the controlled incorporation of
calcium alginate beads into brushite cements in vivo can be used to control implant degradation rate.
Development of Alkali Containing Calcium Phosphate Cements
Authors: Gildenhaar Renate , Berger Georg , Lehmann E. , Knabe Christine
Published: March 2009

Commercially available calcium phosphate cements set by precipitation of nanoapatite or brushite. The goal of this study was to elucidate the most suitable conditions for forming cements from calcium potassium sodium phosphate. Furthermore, the behaviour of these cements after immersion in SBF and/or TRIS solution was investigated. Using varying additives resulted in differences in solubility kinetics. The XRD spectra of all investigated cement compositions displayed Ca2KNa(PO4)2 after setting. However, the various cement compositions differed with respect to apatite formation when immersed in TRIS buffer in and/or SBF solution. Therefore, when investigating calcium phosphate cements we consider it necessary to clearly differentiate between the phases which form after completion of the final setting time when these materials set in air, and the phases which form in a time dependant manner after immersion in different biological fluids.
Biological Evaluation of Chelate-Setting Apatite Cement Using Inositol Phosphate
Authors: Kida K. , Horiguchi Y. , Oribe Kazuya , Morisue H. , Matsumoto Morio , Toyama Y. , Aizawa Mamoru
Published: March 2009

We have successfully developed novel “chelate-setting apatite cement” using
hydroxyapatite (HAp) particles surface-modified with inositol phosphate (IP6) . The HAp particles
surface-modified with IP6 were mixed with water (HAp/water ratio = 1.00/0.50[w/w]) to fabricate
apatite cements. We have examined the biocompatibility of the apatite cement using the culture
system of MC3T3-E1 cells and the rabbit model. The cell-culture test using MC3T3-E1 cells has
shown that the apatite cement has noncytotoxicity. This cement has been implanted into tibiae of
rabbits. When tissue response was examined histologically up to 24 weeks, new bone formation
was observed around the surface of the cement. The present work demonstrates that this apatite
cement is useful as a material for artificial bone grafting.
Development of Injectable Calcium Phosphate Cement Adding with ZrO2
Authors: Gong J.Y. , Qu Shu Xin , Cui Q. , Weng Jie
Published: March 2009

In the present study, ZrO2 was added into the injectable calcium phosphate cements (CPCs) to improve their mechanical strength. Different mass fractions of ZrO2 (5 %, 10 %, 15 %, 20%) were mixed with the powder components consisted of tricalcium phosphate (α-TCP) and hydroxyapatite (HA). Then formed the paste via adding the liquid component consisted of citric acid. The compressive strength, the injectability, the initial setting time and finial time of CPC were measured, respectively. X-ray diffraction (XRD) was employed to analyse the phase of as-prepared CPC. Scanning Electron Microscope (SEM) and Energy dispersive spertrum (EDS) were used to observe the morphology and indicate the element components of CPC. The compressive strength of ZrO2-CPC was higher than that of CPC without added ZrO2. The compressive strength got the maximal when the mass fraction of ZrO2 was 15%. It had no effect on the injectability with adding ZrO2, which were 89 % to 92 %. It had a slight down-regulation of the initial and final setting time with adding ZrO2. SEM showed that there was amounts needle-like substance in CPC, which might be related to the improvement of compressive strength of CPC. XRD showed that there were HA, a few of α-TCP and ZrO2 diffraction peaks in CPCs. The present results indicate that it is feasible to improve the compressive strength of injectable CPC via adding ZrO2.
Sedimentation Study of Biphasic Calcium Phosphate Particles
Authors: Fatimi Ahmed , Tassin Jean Francois , Axelos Monique Aselo V. , Weiss Pierre
Published: March 2009

Injectable calcium phosphate (CaP) biomaterial is considered as an injectable bone
substitute (IBS). It was developed to minimize invasive surgery in various applications in
orthopedic and dental surgery. The IBS considered of a polymer solution mixed with biphasic
calcium phosphate (BCP) ceramic particles. Two particle sizes of BCP (40-80 and 80-200μm) were
used and the weight ratio was 40%. This study investigated the influence of polymer solution on the
BCP particles stability. Effects of particles size and limiting viscosity of polymer on the
sedimentation were studied. The polymer concentration and particles size can be adapted to provide
the best stability and storage of IBS.
Organic/Inorganic Hybrid Calcium Phosphate Biomaterials
Authors: Cave M.R. , Farrar David , Wright Adrian J.
Published: March 2009

Calcium alkyl phosphates and their strontium and magnesium analogues were synthesised by the reaction of aqueous metal salts with a range of alkyl phosphates of varying chain length and were characterised by X-ray diffraction, thermogravimetric and FTIR analyses. These hybrid structures are based on alternating organic/metal phosphate regions and were found to exhibit a linear increase in interlayer separation upon increasing the length of the alkyl chain. Our analysis suggests a general formula for these phases of M(ROPO3).nH2O (where M = Ca, Sr, Mg and R = alkyl group), containing alkyl bilayers reminiscent of phospholipid bilayers found in biological membranes.
Improvement of the Mechanical Properties of Calcium Phosphate Bone Substitutes by Polycaprolactone Infiltration
Authors: Quiquerez Marion , Peroglio Marianna , Gremillard Laurent , Chevalier Jérôme , Chazeau Laurent , Gauthier Catherine , Hamaide Thierry , Bignon Aurélien
Published: March 2009

In this study we show that mechanical properties of bioceramic scaffolds can be
significantly improved by repeated infiltration with a low-viscosity polycaprolactone solution.
Biphasic calcium phosphate (BCP: 70% hydroxyapatite, 30% β-tricalcium phosphate) scaffolds
characterized by a bimodal pore size distribution and a global porosity of 70% have been chosen as
starting materials. Polymer content in the ceramic scaffold was varied so that an inorganic/organic
ratio close to that of bone may be achieved. Work of fracture at maximum stress was 36 J/m2 for the
ceramic scaffold alone and reached 127 J/m2 for the 8-times infiltrated samples. These results are
superior to the ones previously obtained with polycaprolactone infiltrated alumina due to higher
micropore content. We show that during bending tests, polycaprolactone phase formed fibrils while
the crack propagated. Crack bridging by polycaprolactone ensured the integrity of the composite
once the ceramic scaffold was broken and directly involved in the composite toughening. Because
of its composition, microstructure and mechanical behavior of this kind composite can be an
interesting candidate for bone substitution.
Mechanical Behaviour of Interpenetrating Co-Continuous β-TCP-PDLLA Composites
Authors: Ehrenfried Lisa M. , Farrar David , Morsley David , Cameron Ruth
Published: March 2009

Co-continuous degradable polymer-ceramic composites were produced via in-situ polymerization of (D,L-lactic)acid monomer within a porous β-tricalcium phosphate matrix. The mechanical properties of both the composite and the unfilled porous ceramic were investigated with compressive testing. The average stress to failure increased from 1.3±0.1 MPa for the unfilled ceramic matrix to 82±2 MPa for the composite. The Young’s modulus increased from approximately 20 MPa to 700±42 MPa. A combination of X-ray micro-tomography and mechanical testing provided insight into the failure mechanisms of the composite. Stress may be deflected by crack bridging around the polymer phase leading to debonding of the polymer along the crack lines.
Calcium Phosphate Mineralized GBR Membranes: Preparation and Properties
Authors: Chou A.H.K. , LeGeros Racquel Z. , Mijares Dindo Q. , Frondoza C. , LeGeros John P.
Published: March 2009

The osteoconductive property of calcium phosphate (CaP) biomaterials allow attachment,
proliferation, migration, and phenotypic expression of bone cells leading to formation of new bone. The
purpose of research is to develop new method of mineralizing commercial GBR membranes with calcium
phosphate (CaP) and determine cell response. Resolut Adapt LT (Gore-tex) composed of co-polymer
PGA/TMC and Biomend Extend (Zimmer) composed of bovine collagen were used. Membranes
were mineralized with CaP using precipitation and new microwave methods. The mineralized and
non-mineralized membranes were characterized using SEM, EDS, XRD, FT-IR, and TGA. Cell
response to mineralized and non-mineralized membranes was determined using human osteoblastlike
cells (MG-63). Microwave method was more efficient in terms of amount of minerals
incorporated with membranes and time required. SEM, EDS, and FT-IR identified carbonate apatite
in the mineralized membranes. No significant difference in cell proliferation was observed
between mineralized and non-mineralized membranes. Greater production of type 1 collagen was
observed with CaP mineralized membranes.
Formation of an FGF-2-Apatite Composite Layer on Ethylene-Vinyl Alcohol Copolymer
Authors: Sasaki Kenkichi , Oyane Ayako , Hyodo Koji , Ito Atsuo , Sogo Yu , Kamitakahara Masanobu , Ioku Koji
Published: March 2009

A composite layer of fibroblast growth factor-2 (FGF-2) and low-crystalline apatite was
formed on an ethylene-vinyl alcohol copolymer specimen using two types of aqueous calcium
phosphate solutions supplemented with 10 !g·mL-1 FGF-2; one is a CP solution that is prepared by
dissolving chemical reagents into ultrapure water and the other is an RKB solution that can be
prepared by mixing clinically approved infusion fluids. In both solutions, a sufficient amount of
FGF-2 for new skin tissue formation (1 !g·cm-2) was immobilized on the specimen surface.
Ternary Bio-Nanostructured Systems Prepared under High Pressure Conditions
Authors: Piticescu Roxana M. , Trandafir Viorica , Danciu V. , Vuluga Z. , Vasile Eugeniu , Iordachescu D.
Published: March 2009

Many researchers have assumed that a combination of hydroxyl apatite (HAP) and
collagen (COL) may be the best solution for bone replacement and have prepared their composites
by several techniques [1]. However, such HAP/COL composite had no nanostructure similar to
bone, and consequently indicated no bone-like mechanical properties. These results demonstrate
that the chemical composition similar to bone only is insufficient for bone metabolism and
mechanical properties. Mechanical and biological performance of this type of materials could be
improved by adding TiO2 within the initial mixture of nanostructured composites [2].
Ternary nanostructured systems consisting of hydroxyl apatite, TiO2 aerogel and collagen were
prepared for the first time by hydrothermal procedure in high pressure conditions. Among many
advantages, the synthesis method proposed in this paper could lead to formation of chemically
bonded compounds as a consequence of high pressure conditions. The resulted material could find
applications in bone tissue regenerative medicine, either in powder form for bone defects treatment,
or in matrix form as osteoconductive coating for metal implants. Further studies are necessary to
evaluate the osteoconductive properties.
Effect of Increasing Polyvinyl Alcohol Content on the Porous Structure and Mechanical Properties of Sol-Gel Derived Hybrids Foams
Authors: de Oliveira Agda Aline Rocha , Oréfice R.L. , Mansur Herman S. , Pereira Marivalda
Published: March 2009

Bioactive glass/polymer hybrids are promising materials for biomedical applications
because they combine the bioactivity of these bioceramics with the flexibility of polymers. In
previous work hybrid foams with 80% bioactive glass and 20% polyvinyl alcohol (PVA) were
prepared by the sol-gel process for application as scaffold for bone tissue engineering. In this work
it was evaluated the effect of increasing the PVA content of the hybrids on structural characteristics
and mechanical properties of hybrid foams produced by this method. The hybrids were prepared
with inorganic phase composition of 70%SiO2-30%CaO and PVA fractions of 20 to 60% by the
sol-gel method. The structural and mechanical characterization of the obtained foams was done by
FTIR, SEM, Helium Picnometry, and compression tests. To reduce the acidic character of the
hybrids due to the catalysts added, different neutralization solutions were tested. The immersion of
hybrids in a calcium acetate solution was the most adequate neutralization method, avoiding
calcium loss while maintaining pH nearly 7,0 and low PVA loss. The foams presented porosity of
60-85% and pore diameters of 100-500μm with interconnected structure. The pore structure varied
with the polymer content in the hybrid. The compression tests showed that an increase of PVA
fraction in the hybrids improved their mechanical properties.
A Resorbable Surface Formed on Ti Alloy Material
Authors: Rohanová Dana , Helebrant Aleš , Haufová P. , Brázda Lukáš , Bezdička Petr
Published: March 2009

This paper performs a new way of a resorbable surface on Ti alloy preparation.
Precalcification of a chemically treated Ti or Ti alloy surface by a supersaturated calcification
solution - SCS2 (high content of Ca2+ as well as (PO4)3- ions) allows to short of an induction
period in SBF solution (practically immediate reaction stats a hydroxyapatite precipitation). Soluble
octacalcium phosphate (Ca8H2(PO4)6. 5H2O was detected by RTG on the surface after calcification.
Presumption is: a healing time of the calcified Ti alloy could be shortened.
Nano-Hydroxyapatite Coatings on Titanium Substrates. Finite Element Analysis of Process and Experimental Plasma Thermal Sprayed Coatings
Authors: Citterio-Bigot Helene , Jakani S. , Benmarouane Abdelilah , Millet Pierre , Lodini Alain
Published: March 2009

The aim of this study was to create a nano-structured coating using Plasma Thermal Spraying (PTS). This process consists in introducing pre-agglomerated nanosized particles in a high-temperature and high-velocity gas jet and projected them onto the substrate to form, layer by layer, a nanostructured coating. In order to retain nanometer grain sizes in the deposited coating through specific PTS technologies, a thermal field and velocity distribution in the plasma jet are analytically calculated. A finite element analysis is employed to calculate the thermal field evolution inside the agglomerated particles and the thermal induced internal stress distribution is determined. The parameters determined by the theoretical analysis are used for experimental coatings. The average crystallite size of nano-hydroxyapatite powder was 90nm. After deposit via Plasma Thermal Spraying (PTS) process and followed by a 2 hours heat treatment to reduce amorphous fraction, the experimental deposited coating shows that it retains the nanometer crystallite sizes. The substructure of nanocrystals was evaluated at about 120nm in size. Such a nanocoating may play the role of nucleation site to bone, allowing a faster stabilization of the implant.
Exchange Reactions at Calcium Phosphates Surface and Applications to Biomaterials
Authors: Barroug Allal , Legrouri Ahmed , Rey Christian
Published: March 2009

The interaction of calcium phosphates with biological molecules under controlled
conditions permits the formulation of meaningful conclusions concerning the driving forces. The
uptake and release at the material-solution interface is the result of the various interactions between
and within the system components which include the solid surface, the adsorbate, the solvent and
other solutes present. The understanding of adsorption and desorption mechanisms with respect to
active molecules can be exploited for the development of drug delivery applications.
Functional Behaviour of Human Periodontal Ligament Cells around Various Dental Implants
Authors: Luo Xiao Ting , Gao Zhen , Yan Shi Gui , Deng Wei , Zhang Wen Shu , Yan Wei Qi
Published: March 2009

In the present investigation, four titanium (Ti) surfaces of dental implants were compared
through in vitro systems. The surface roughness of Ti was measured by TR240 mobile surface
roughmeter. The Ti implants were seeded with human periodontal ligament cells (hPLDCs) and
maintained for a period of 0-7 days. The adhesion, proliferation, and differentiation of hPLDCs
were observed by using Cell morphology, cell counting and Osteocalcin (OC) immunofluorescent
staining. Results suggest that surface roughness of titanium favors hPDLCs behavior and improves
cell adhesion, proliferation, and differentiation.
Implant Surface Conditioning with Tetracycline-HCl: A SEM Study
Authors: Herr Y. , Woo J.A. , Kwon Y.H. , Park J.B. , Heo S.J. , Chung J.H.
Published: March 2009

The increased surface roughness of dental implants has shown enhanced integration of
bone tissues to implant surfaces, but may be predisposed to an increased risk of pathogenic bacterial
infection and contamination with bacterial products. Tetracycline-HCl (Tc) treatment has been
regarded as a practical and effective chemical modality for decontamination and detoxification of
contaminated implant surfaces. The purpose of this study was to examine if Tc treatment alters the
microstructures of the modified surface of dental implants. For this purpose, dental implants with
pure titanium machined surface (MS), sandblasted, large grit, acid-etched surface (SLAS), or
anodized surface (AS) were used. The surface of dental implants was rubbed for 30, 60, 90, 120, or
150 sec with sponge pellets soaked in Tc solution (50mg/ml) and in distilled water for 0 and 150 sec
as the control group. The specimens were then routinely processed for scanning electron
microscopy. The results show that Tc treatment did not change the surface of MS, SLAS, and AS.
Development of a Hydroxyapatite Bone Tissue Engineering Scaffold with a Trimodal Pore Structure
Authors: Buckley Conor T. , O’Kelly K.U.
Published: March 2009

Tissue-engineering scaffold-based strategies have suffered from limited cell depth
viability when cultured in vitro, with viable cells existing within the outer 250-500μm from the
fluid-scaffold interface. This is primarily believed to be due to the lack of nutrient delivery into and
waste removal from the inner regions of the scaffold construct. Other issues associated with porous
scaffolds involve poor seeding efficiencies and limited cell penetration resulting in heterogeneous
cellular distributions. This work focuses on the development a novel hydroxyapatite multi-domain
porous scaffold architecture (i.e. a scaffold providing a discrete domain for cell occupancy and a
separate domain for nutrient delivery) with the specific objectives of embodying in one scaffold the
structures required to optimise cell seeding, cell proliferation and migration and potentially to
facilitate vascularisation once implanted in vivo. This paper presents the development of the multidomain
architecture and preliminary results on cell viability which show a significant improvement
in cell viability in the scaffold interiors.
Three Dimensional Macroporous Calcium Phosphate Scaffolds for Bone Tissue Engineering
Authors: Teixeira S. , Oliveira S.M. , Ferraz M.P. , Monteiro F.J.
Published: March 2009

Calcium phosphate ceramics are widely used as bone substitutes since they are
biocompatible and bioactive. Having a chemical composition close to natural bone, calcium
phosphate ceramics are promising bone substitute materials in orthopaedics, maxillofacial surgery
and dentistry. Hydroxyapatite (HA) and tricalcium phosphate (TCP) are the most commonly used
calcium phosphates, because their calcium/phosphorus (Ca/P) ratios are close to that of natural bone
and they are relatively stable in physiological environment. HA is a major constituent of bone
materials and is resorbed after a long time of residence in the body.
In this work, highly porous hydroxyapatite scaffolds were produced by polymer replication method
and their properties evaluated by Scanning Electron Microscopy (SEM) and micro computerized
tomography ()-CT).
Synthesis and Characterization of Silica-Chitosan Porous Hybrids for Tissue Engineering
Authors: Reis Emmerson M. , Vasconcelos Wander L. , Mansur Herman S. , Pereira Marivalda
Published: March 2009

A variety of types of organic polymers have been employed in the synthesis of hybrids with silica. In this work the sol-gel method was used for preparation of macroporous 3D hybrid scaffolds based on silica and chitosan in various compositions (10, 20 and 30% wt). The hybrids were analyzed by Scanning Electron Microscopy (SEM), X-ray Diffraction (DRX) and Infra-red Spectroscopy (FTIR) and the effect of addition of the polymer was evaluated. The foams obtained by sol-gel process were appropriate to produce hybrids based on chitosan-silica and showed large pore size distribution and porosity, except for hybrids with higher polymer content. The FTIR spectroscopy showed a band relative to Si-O-C bond that was also found to increase with the increasing the amounts of chitosan in the hybrid. This fact can suggest an interaction between the organic-inorganic phases in the material and provide new insights on the advantages of chitosansilica hybrid materials produced via sol-gel methodology.
The Structure and Properties of Electroceramics for Bone Graft Substitution
Authors: Baxter F.R. , Turner I.G. , Bowen Chris R. , Gittings J.P. , Chaudhuri J.B. , Lewis R.W.C.
Published: March 2009

Hydroxyapatite (HA) and barium titanate (BT) powders were mixed and sintered to form
hydroxyapatite – barium titanate (HABT) ceramics. These materials were then poled and their
piezoelectric properties were measured. The microstructure of unpoled samples was examined
using scanning electron microscopy (SEM).The piezoelectric constants (d33 and d31) of the ceramics
were found to be dependent on the proportion of BT in the ceramic In materials containing less
than 70% BT, no piezoelectric effect was found. Above this value, the piezoelectric constant
increased with the addition of BT up to a value of 108pCN-1 for pure BT. Values of d33 for
ceramics containing more than 80% BT are above values previously shown to have a positive
influence on bone growth in vivo. SEM analysis indicated that the grain size within the materials
decreased as the proportion of BT in the material was reduced. Examination of the microstructure
of the ceramics indicated the presence of electrical domains in the 100% BT and 95% BT ceramics.
Domains were not visible below 95% BT. The reduction in grain size may influence the reduction
in piezoelectric activity within the materials but cannot be considered to be the only cause.
Comparative Study of MRI and Photoacoustic Imaging on Brain Blood Perfusion Function of Rat/Mouse
Authors: Zhou Quan , Yang Shi Hua , Chen Wen Li , Dong Yang , Huang Li
Published: March 2009

The aim of this work is to assess the cerebrovascular reserve capacity (CVRC) by MR
PWI and photoacoustic brain imaging with “ACZ” tolerance test in mouse and rat, and to compare
their role in evaluating the CVRC. Experimental animals included 2 groups: Wistar-Kyoto rats
(WKY) (12-week-old, 235~265g) were assessed by MRI and BALB/c mice (4-week-old, 25~35g
body weight) were assessed by our photoacoustic imaging system. On photoacoustic imaging, the
diameter of the vascular in the superficial layer of the mouse cortex were measured and compared
between the resting and acetazolamide (Acz)-activated mice, which reflected cerebral blood flow
(CBF) without blood sampling. MR PWI was performed respectively before and after
acetazolamide administrated orally on a clinical 1.5 Tesla GE Signa MR fx/i whole-body MR
system. The region of interest (ROI) was chosen in the bilateral frontal lobe to measure the value of
rCBV, rCBF and MTT. The results show that there was statistical difference between the resting
and acetazolamide (Acz)-activated animals in the values of the diameter of the vascular in the
superficial layer of the mouse cortex by photoacoustic imaging and in the values of rCBV and
rCBF（P＞0.05）of the rat by MRI. It was concluded that the method of PWI and photoacoustic
imaging combined with the “ACZ stress test” can be used to evaluate the CVRC by measuring
values of rCBV and rCBF and diameter of the vascular, respectively.
Scanning Photoacoustic Tomography of Biological Tissues with a Piezoelectricity Double-Ring Sensor
Authors: Wang Hui , Xiang Liang Zhong
Published: March 2009

Scanning photoacoustic tomography with a piezoelectric double-ring sensor was
explored to image biological tissues, and short laser pulses irradiated tissues to generate acoustic
waves by thermoelastic expansion. The laser-induced photoacoustic waves were detected by a
piezoelectric double-ring sensor. This double-ring sensor has the advantage that it is more sensitive
in the forward direction compared with other conventional sensors. An optical fiber for illumination
of the sample was integrated with the sensor, which enabled reflection-mode detection of ultrasonic
waves. Consequently, two-dimension photoacoustic tomography of biological tissues could be
obtained in a manner analogous to the ultrasound B-scan mode by a linear scan over the tissue
surfaces. To reach a large depth, 1064nm laser light was used in our experiments. The experimental
results showed that the reconstructed photoacoustic images agree well with the structures of the
samples. It demonstrated that this sensor has potential to monitoring tumor angiogenesis, and
antiangiogenic therapy in vivo.
Fast Photoacoustic System Based on an Acoustic Lens and the Peak Detection Technology
Authors: Zhang Han Chao , Tang Zhi Lie , He Yong Heng , Guo Li Na
Published: March 2009

A fast photo-acoustic (PA) imaging system was developed and tested on phantom
sample, which consists of an acoustic lens，a multi-element linear transducer array, and the peak
detection circuit. The multi-element linear transducer array consists of 64 elements. By utilizing an
acoustic lens, the PA signals generated from the sample are imaged and detected by a multi-element
linear transducer array, which directly changes the PA signals into the homologous electronic
signals. Thus we can map the image more rapidly, with the peak detection circuit, which was
designed specially. Compared to other exiting technology and algorithm, the PA imaging system
based on an acoustic lens and the peak detection technology was characterized with speediness and
real-time. The images reconstructed in this experiment have high definition and resolution，and
may have potential for developing an appliance for clinical diagnosis.
Aspheric Mirror Testing with Phase Retrieval Method
Authors: Hu Xiao Jun , Zheng Zi Wen , Dai Yi Fan , Li Sheng Yi
Published: March 2009

A novel algorithm and experiment using phase retrieval to test aspheric mirror without
auxiliary optical elements has been developed. To test aspheric mirror without auxiliary optical
elements, a new algorithm has been invented to overcome the calculation difficulty due to the
significant departure of aspheric surface from a sphere. In this algorithm, the aspheric surface is
fitted into several annular ellipse sub-apertures, and each sub-aperture aberration can be retrieved
the same as ball mirror testing. The whole aspheric surface can be retrieved by stitching all the subapertures
together. An experiment has been carried out to test the validity of this algorithm.
An Investigation of Form Errors Predicted Model for Injection Moulded Aspheric VCD Lens
Authors: To Suet , Jiang Bing Yan , Weng Can , Lee Wing Bun
Published: March 2009

The aspheric VCD lens is hard to fabricate by injection moulding due to its small volume
and high precision requirement. The processing conditions have critical effects on the quality of the
moulded lenses. An optic lens needs precisely controlled surface contours, so determination of the
processing conditions for lens moulding becomes very complicated. This study’s purpose is to
investigate experimentally some effects of the moulding conditions on the form errors of injection
moulded lens. An aspheric VCD lens was moulded using polymethyl methacrylate. Different
combinations of moulding conditions were used focusing on moulding process parameters of the
ram speed, the mould temperature, the melt temperature and the packing pressure, The predicted
model of form errors was formulated by orthogonal and regression analysis. Finally, the predicted
model is proven to be valid based on the residual diagnostic plots.
A HDRI Camera Based on SLM
Authors: Chen Zhe Bo , Xu Jin , Lin Bin , Ni Xu Xiang , Lu Zu Kang
Published: March 2009

A high dynamic range image camera (HDRI) is a kind of camera which captures the
HDRI image. HDRI means the image with high dynamic range, it can record the gray information
of the object with much wider dynamic range. HDR image has great applications in many fields.
The existing HDRI camera needs either the special image sensor or can capture the still object only.
In this paper, a new kind of camera is proposed. In this camera, a space light modulator (SLM) is
used to acquire images with different exposure, then a HDRI is made with these images. This
camera can acquire dynamic image and it is cheap and easy to extend.