Abstract: Magnetite nanoparticles were used for their ability to be heated when they are put in an
oscillating magnetic field. When they are located inside tumors they can eradicate the tumor cells
by heating. We have developed a biomaterial constituted by a mineral degradable matrix containing
magnetite nanoparticles. This material can be injected into bone metastasis in which it sets and
releases magnetite particles uptaked inside the cancer cells. We have implanted this material inside
rabbit bone to check by histology the fate of the nanoparticles in bone. The implant matrix was
degraded within a few days releasing the nanoparticles. They were found inside monocytes and
fibroblasts having ingrown the material. The nanoparticles could form aggregates which then were
fragmented in micro/nanoparticles penetrating the surrounding cells. This study showed that the
nanoparticles are released from the mineral matrix within a few days and penetrate the cells in their
Abstract: Porous chitosan-silicate hybrids were prepared by freeze-drying the precursor sol
solutions synthesized from chitosan and 3-glycidoxypropyltrimethoxysilane (GPTMS).
Degradability of and the release of cytochrome C in to phosphate buffer saline solution (PBS) were
examined as a function of the GPTMS content. The hybrids were less degradable with larger
GPTMS contents, and the cytochrome C release profile was so controllable as to give either burst
release or slow one due to the GPTMS content. Thus, the present porous chitosan-silicate hybrids
were considered applicable to drug delivery systems.
Abstract: Nano-materials and technology increasingly come under emphasis on application in
biomedical treatment and pharmaceutical field. Drug particle with nano-size has better bioactivity
and absorptivity, which advance the efficiency of utilization. The nanoporous alumina membranes
fabricated by anodization are provided with orderd nanoporous structure, highly uniform pore size,
straight and parallel pore channels, moreover, this material possesses favorable biocompatibility.
Recently, application of nanoporous alumina membranes in medical science has becoming public
concerned in present biomedical material field. Our experiment aimed at fabricating nanoporous
alumina membranes with definite mechanical strength to cylindrical biofiltration capsules, which
can be used to encapsulate nanodrug to control drug delivery. The release characteristic was
examined by monitoring the diffusion of fluorescein isothocyanate (FITC) with molecular weight of
389.4Da as a function of time after encapsulation within the alumina tubes.
Abstract: Our previous studies showed that synthetic octacalcium phosphate (OCP) enhances bone
regeneration more than hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). Also, a synthetic
bone substitute constructed of synthetic octacalcium phosphate (OCP) and porcine atelocollagen
sponge (OCP/Col) showed stable bone regeneration. The present study was designed to investigate
the difference of bone regeneration by OCP/Col and other calcium phosphate-collagen composites.
OCP/Col, β-TCP$-collagen% composite (β-TCP/Col), or HA$-collagen% composite (HA/Col) sponge
was prepared from pepsin-digested atelocollagen isolated from the porcine dermis and OCP, β-TCP,
or HA granules, respectively. A standardized critical-sized defect was made in the rat calvarium, and
various calcium phosphate-collagen composites were implanted into the defect. The rats were fixed
at four weeks after implantation and radiographic and histological examinations were performed by
undecalcified cross sections of implants. Radiographic examination showed that uniform radiopaque
masses were observed in the created defects treated with OCP/Col, whereas granulous and foggy
radiopacity was observed in β-TCP/Col and HA/Col. Histological examination showed that newly
formed bone was observed in the reticulum of OCP/Col and around the implanted OCP. The
regenerated bone by β-TCP/Col or HA/Col seemed to be less than that by OCP/Col and would not to
be nucleated by the granules of β-TCP or HA. The present study indicated that bone regeneration by
OCP/Col was different from those of β-TCP/Col and HA/Col. Application of OCP/Col would be
expected for clinical use in the future.
Abstract: 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.
Abstract: Apatite/β−TCP particles exhibiting non-conventional urchin-like morphology were
prepared by hydrothermal synthesis. Their implantation in the rat calvarium was followed during 60
days. A total absence of osteoconduction was observed despite a favorable chemical composition,
stressing the fundamental role of particle morphology on bone regeneration. Results are discussed
in relation with other literature data. Possible explanations include the disfavored accumulation of
biological mediators due to the acicular shape of the particles and/or a limited accessibility for cells.
Abstract: 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.
Abstract: To clarify new bone tissues, radiography with a newly developed tunable wavelength and
highly parallel Parametric X-ray, PXR, was applied. Methods: PXR was generated by a LINAC at
LEBRA, Nihon University (Hayakawa et al., 2005). X-ray wavelength was tuned from 7 KeV, 0.177
nm, to 16 KeV, 0.0775 nm. Coated or grit-blasted Ti-alloy implants modified with coating or blasting
were implanted in surgically created defects in rabbit tibia. Undecalcified polished thin sections were
prepared from the implant/bone areas 1 and 4 weeks after implantation. Results: PXR radiography
showed a distinct difference between the newly formed bone and the compact bone. Color-mapping
of the images showed an increase in the total amount of bone formation with time. Conclusion:
Application of LEBRA-PXR, a high-powered, highly monochromatized and highly parallel oriented
X-ray allowed easy and accurate radiographic analysis of new bone formation around the implant.