Abstract: Soft-nanotechnologies are based upon the synthesis technologies of nanomaterials and
construction technologies of nanostructures by life forms. They are expected as new preparation
methods for biomaterials that could be recognized as regular extracellular matrices (ECM) in our
body by cells. We applied the soft-nanotechnology to synthesis of artificial bones made of HAp and
collagen with bone-like nanostructure and examined their physical and biological properties. The
nanocomposite obtained indicates bone-like nanostructure. Computer simulation and FT-IR
suggested that the self-organization of HAp and collagen is based on chemical interaction between
calcium ions on HAp surface and carboxy groups on collagen. After implantation in rats and dogs,
the nanocomposites are resorbed by osteoclasts followed by osteogenesis; therefore, the
nanocomposites are recognized as bone in the living body. Resorption rate can be controlled by
crosslinkage. We also prepared sponge-like elastic porous body by gel-lyophilization technique
using additional small amount of collagen solution. Bone tissue reactions of it are the same as the
nanocomposites as prepared. The nanocomposites are now in clinical research in Japan to be
commercialized in near future by Pentax Co.
Abstract: The development of calcium phosphate ceramics and other related biomaterials for bone graft
involved a better control of the process of biomaterials resorption and bone substitution. The
biphasic calcium phosphate ceramics (BCP) concept is determined by an optimum balance of
the more stable phase of HA and more soluble TCP. The material is soluble and gradually
dissolves in the body, seeding new bone formation as it releases calcium and phosphate ions
into the biological medium
The main attractive feature of BCP ceramic is their ability to form a direct bond with the host
bone resulting in a strong interface. The formation of this dynamic interface is the result of a
sequence of events involving interaction with cells; formation of carbonate hydroxyapatite
CHA (similar to bone mineral) by dissolution/precipitation processes. At the present time,
BCP is commercially available in blocks, particulates, customized design. The need of
material for Minimal Invasive Surgery (MIS) induced the development of a concept of
granules combination with polymer or calcium phosphate cement for injectable/mouldable
bone substitutes. Four types of injectable/mouldable bone substitutes have been developed by
INSERM Nantes University.
Abstract: Clinical applications of Calcium phosphate compounds are done in most cases with powders of
Calcium-tri-phosphate and/or Hydroxylapatite to enhance the surgery of orthopaedic repair.
The application of microspheres of these compounds has big advantages to faster surgery and higher
strength of the bone structure.
The special processes to produce microspheres of narrow size distribution and high sphericity out
Calcium-tri-phosphate and Hydroxylapatite are described.
Properties and composition of these microspheres as calcined and as sintered are given.
Abstract: This study deals with the microstructure and property profile of biomaterials within the
Ca-aluminate system (CA). Hydrated CA materials are stable in bone tissue, and thus not resorbable
as the Ca-phosphate materials are. Identified possible applications for CA-based materials are
within vertebroplasty and odontology. CA with ZrO2 particles as well as CA with glass particles
were examined with regard to mechanical properties, biocompatibility and bioactivity. The
hydrates formed - examined by HRTEM - are in the size range of 20-50 nm. With the studied
systems it is possible to obtain a combination of high and early strength, shape stability including
low expansion pressure, and in vivo bioactivity.
Abstract: Apatites can accommodate a large number of vacancies and afford multiple ionic
substitutions determining their reactivity and biological properties. Unlike other biominerals they
offer a unique adaptability to various biological functions. The diversity of apatites is essentially
related to their structure and to their mode of formation. Special charge compensation mechanisms
allow molecular insertions and ion substitutions and determine to some extent their solubility
behaviour. Apatite formation at physiological pH involves a structured surface hydrated layer
nourishing the development of apatite domains. This surface layer contains relatively mobile and
exchangeable ions, and is mainly responsible for the surface properties of apatite crystals from a
chemical (dissolution properties, ion exchange ability, ion insertions, molecule adsorption and
insertions) and a physical (surface charge, interfacial energy) point of view. These characteristics
are used by living organisms and can also be exploited in material science.
Abstract: Hydroxyapatite (HAp) has unique properties for biomaterials such as
hard-tissue-compatible material for bone and tooth and also soft-tissue-compatible
materials for skin tissue. However, the hard and brittle nature of HAp limits spreading
many medical devices. Recently, a unique composite of sintered HAp nano-crystals --
ceramics -- covalently coupled to polymer substrates was developed -- Nano-Ceramic
Coating --. The development was depended on the two original technologies: (1)
control of size/morphology of high-dispersed sintered nano-HAp, (2) donation of
covalent bonding between nano-HAp and substrates to coat strongly on the surface.
The nano-composite material holds not only the mechanical properties of the substrate
but also biological properties of the ceramics coated on the surface. In this report, the
method of synthesis of high-dispersed nano-HAp, the preparation of the nano-composite,
the biological properties with cells or animal tissue, and especially, the development of
medical devices, such as percutaneous device or blood vessel and so on, made of the
composite will be presented.
Abstract: Calcium phosphates (Ca-P) are major constituents of calcified tissues, and are also
extensively used for the elaboration of biomaterials. However, the usual high-temperature sintering
processes generally lead to strong alterations of their chemical, physical and biological properties.
Spark plasma sintering (SPS) is a non-conventional sintering technique based on the use of pulsed
current, enabling fast heating and cooling rates, and lower sintering temperatures are often
observed. The sintering of several orthophosphates (DCPD, amorphous TCP, beta-TCP, OCP, HA
and biomimetic nanocrystalline apatites) by SPS was investigated in order to track potential
advantages of this technique over usual Ca-P sintering methods. Special attention was given to the
SPS consolidation of highly bioactive nanocrystalline apatites.
Abstract: In this study the hydroxyapatite powder was sintered together with magnetite
nanopowder, which due to its low reactivity is commonly used in medicine, eg. in magnetic
resonance. Two types of sintered materials, containing equal content 6 mol% of biogenic
hydroxyapatite (BGHAp), reinforced with 50 wt% of different glass phases, were tested. The same
technological conditions comprising two-stage sintering with T1 (1100°C) and T2 (780°C) were used
for both types of materials. For selected specimens 2 wt% of 9 nm powder of Fe3O4 was added. The
microhardness of the specimens varies within quite wide range from 150 to 508 HV0.025.
Compressive splitting strength of the specimens (measured along the sample diameter) is within a
range of 3.61 – 4.99 MPa. Young’s modulus, modulus of rigidity and Poisson’s ratio are in the
ranges of: 20.81 – 24.86 GPa, 7.89 – 9.71 GPa and 0.252 – 0.307, respectively. Indentation fracture
toughness KIC is within a range of 0.6-1.0 MPa m1/2. The hysteresis loops were determined in order
to asses the possibility of application of this material as affecting the drug delivery carriers. The
specimens exhibit magnetization of the order of 1.5 emu/g.