U.S. patent application number 12/591258 was filed with the patent office on 2010-05-13 for guided bone regeneration membrane and manufacturing method thereof.
This patent application is currently assigned to NATIONAL UNIVERSITY CORPORATION NAGOYA INSTITUTE OF TECHNOLOGY. Invention is credited to Toshihiro Kasuga, Yoshio Ota, Takashi Wakita.
Application Number | 20100119564 12/591258 |
Document ID | / |
Family ID | 40556262 |
Filed Date | 2010-05-13 |
United States Patent
Application |
20100119564 |
Kind Code |
A1 |
Kasuga; Toshihiro ; et
al. |
May 13, 2010 |
Guided bone regeneration membrane and manufacturing method
thereof
Abstract
Disclosed is a guided bone regeneration membrane including a
novel mechanism that effectively induces a bone reconstruction
ability. The mechanism is provided by forming a bi-layered
structure of a first nonwoven fabric layer containing a
silicon-releasable calcium carbonate and a poly(lactic acid) as
principal components and a second nonwoven fabric layer containing
a poly(lactic acid) as a principal component; and coating the first
nonwoven fabric layer with an apatite. The guided bone regeneration
membrane is available by using a nonwoven fabric manufacturing
technique through electrospinning and a simulated body fluid
soaking technique.
Inventors: |
Kasuga; Toshihiro; (Kiyosu,
JP) ; Ota; Yoshio; (Ogaki, JP) ; Wakita;
Takashi; (Gamagori, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
NATIONAL UNIVERSITY CORPORATION
NAGOYA INSTITUTE OF TECHNOLOGY
Nagoya-shi
JP
YABASHI INDUSTRIES CO., LTD.
Oagaki-shi
JP
YAMAHACHI DENTAL MFG., CO.
Gamagori-city
JP
|
Family ID: |
40556262 |
Appl. No.: |
12/591258 |
Filed: |
November 13, 2009 |
Current U.S.
Class: |
424/402 ;
264/465; 424/687 |
Current CPC
Class: |
A61L 31/06 20130101;
A61L 31/128 20130101; A61L 31/148 20130101; A61K 33/00 20130101;
C08L 67/04 20130101; A61L 2430/02 20130101; A61K 47/02 20130101;
A61P 19/08 20180101; A61L 31/06 20130101; C08L 67/04 20130101; A61L
31/128 20130101; C08L 67/04 20130101 |
Class at
Publication: |
424/402 ;
424/687; 264/465 |
International
Class: |
A61K 9/70 20060101
A61K009/70; A61K 33/10 20060101 A61K033/10; A61P 19/08 20060101
A61P019/08; B29C 47/00 20060101 B29C047/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 6, 2007 |
JP |
2007-231621 |
Claims
1. A guided bone regeneration membrane comprising a bi-layered
structure including a first nonwoven fabric layer and a second
nonwoven fabric layer, the first nonwoven fabric layer containing a
silicon-releasable calcium carbonate and a biodegradable resin as
principal components, and the second nonwoven fabric layer
containing a biodegradable resin as a principal component.
2. The guided bone regeneration membrane according to claim 1,
wherein the surface of the first nonwoven fabric layer containing a
silicon-releasable calcium carbonate and a biodegradable resin as
principal components is coated with an apatite, the apatite having
been deposited through soaking in a simulated body fluid.
3. The guided bone regeneration membrane according to claim 2,
wherein the biodegradable resin is a poly(lactic acid).
4. The guided bone regeneration membrane according to claim 2,
wherein the biodegradable resin is a poly(lactic acid).
5. The guided bone regeneration membrane according to claim 1,
wherein the silicon-releasable calcium carbonate is of vaterite
phase.
6. The guided bone regeneration membrane according to claim 2,
wherein the silicon-releasable calcium carbonate is of vaterite
phase.
7. The guided bone regeneration membrane according to claim 3,
wherein the silicon-releasable calcium carbonate is of vaterite
phase.
8. The guided bone regeneration membrane according to claim 4,
wherein the silicon-releasable calcium carbonate is of vaterite
phase.
9. A method for manufacturing a guided bone regeneration membrane,
the method comprising the steps of: forming a first nonwoven fabric
through electrospinning, the first nonwoven fabric containing a
silicon-releasable calcium carbonate and a biodegradable resin as
principal components; and forming a second nonwoven fabric through
electrospinning, the second nonwoven fabric containing a
biodegradable resin as a principal component.
10. The method for manufacturing a guided bone regeneration
membrane, according to claim 9, wherein the biodegradable resin is
a polylactic acid).
11. The method for manufacturing a guided bone regeneration
membrane, according to claim 9, wherein the silicon-releasable
calcium carbonate is of a vaterite phase.
12. The method for manufacturing a guided bone regeneration
membrane, according to claim 10, wherein the silicon-releasable
calcium carbonate is of a vaterite phase.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a guided bone regeneration
membrane and a manufacturing method thereof. The guided bone
regeneration membrane is used in a guided bone regeneration (GBR)
technique which is one of techniques for repairing bone defects and
which is widely used in the field of oral surgery and maxillofacial
surgery.
RELATED ART OF THE INVENTION
[0002] Guided bone regeneration membranes are masking membranes
that cover bone defect areas so as to prevent invasion of
non-osteogenesis-contributed cells and tissues into the bone defect
areas and to allow the bone to reconstruct by taking full advantage
of self-regenerative power thereof. Guided bone regeneration
techniques using these membranes cure bone defects by using a
healing potential which the living body inherently has. The
techniques are not complicated in their operative procedures and
have given many satisfactory outcomes in oral surgery.
[0003] The guided bone regeneration membranes are broadly grouped
under non-bioresorbable membranes and bioresorbable membranes. A
polytetrafluoroethylene (expanded polytetrafluoroethylene; ePTEF)
has been practically used as a material for a non-bioresorbable
membrane, from which good clinical data have been obtained. This
material, however, places a not-so light burden on a patient,
because it is not bioresorbable and thereby needs a secondary
operation for the removal of the membrane after the target bone
defect area is repaired. In addition, it is difficult to adopt this
material to a large defect area, because the material is bioinert
(non-bioresorbable). In contrast, use of guided bone regeneration
membranes that are bioresorbable can avoid the surgical stress
caused by the secondary operation. Exemplary materials for such
bioresorbable guided bone regeneration membranes include
poly(lactic acid)s as bioresorbable synthetic polyesters; and
copoly(lactic acid/glycolic acid)s; and collagens and fasciae each
of biological origin. Such bioresorbable guided bone regeneration
membranes have been recently investigated and developed heavily,
and some of them have already been commercialized. Typically, there
have been proposed a wide variety of guided bone regeneration
membranes and manufacturing methods thereof; such as a bone
regeneration membrane including a composite of a bioresorbable
polymer with tricalcium phosphate or hydroxyapatite and having
micropores (Japanese Unexamined Patent Application Publication
(JP-A) No. H06 (1994)-319794); a protective membrane including a
felt made from a bioresorbable material (Japanese Unexamined Patent
Application Publication (JP-A) No. H07 (1995)-265337; and Japanese
Unexamined Patent Application Publication (JP-A) No. 2004-105754);
a multilayer membrane including a sponge-like collagen matrix layer
and a relatively impermeable barrier layer (Japanese Unexamined
Patent Application Publication (Translation of PCT Application)
(JP-A) No. 2001-519210); a bioresorbable tissue regeneration
membrane for dental use, which has a porous sheet-like structure
including a polymer blend containing two or more different
bioresorbable polymers (Japanese Unexamined Patent Application
Publication (JP-A) No. 2002-85547); a resorbable flexible implant
in the form of a continuous micro-porous sheet (Japanese Unexamined
Patent Application Publication (Translation of PCT Application)
(JP-A) No. 2003-517326); and a biocompatible membrane prepared by
three-dimensional powder sinter molding through application of
laser light to a biodegradable resin powder (Japanese Unexamined
Patent Application Publication (JP-A) No. 2006-187303).
[0004] In particular, oral or maxillary bone defects should be
desirably cured as soon as possible, because it is very important
to maintain and ensure mastication for the health maintenance in a
super-graying society. To improve osteogenic ability, there have
been attempts to incorporate to a bioresorbable membrane a factor
such as an osteogenesis inducer (Japanese Unexamined Patent
Application Publication (JP-A) No. H06 (1994)-319794), a growth
factor or a bone morphogenic protein (Japanese Unexamined Patent
Application Publication (Translation of PCT Application) (JP-A) No.
2001-519210; and Japanese Unexamined Patent Application Publication
(JP-A) No. 2006-187303). However, it is difficult to handle these
factors. Accordingly, demands have been made to develop a
bioresorbable guided bone regeneration membrane having superior
bone reconstruction ability to allow the bone to self-regenerate
more reliably and more rapidly.
[0005] In view of recent trends of researches and technologies for
bio-related materials, the main stream of researches has been
shifted from a materials design for the bonding of a material with
the bone to a materials design for the regeneration of a real bone;
in these researches, the role of silicon in osteogenesis has been
received attention; and there have been designed a variety of
materials containing silicon (TSURU Kanji, OGAWA Tetsuro, and
OGUSHI Hajime, "Recent Trends of Bioceramics Research, Technology
and Standardization", Ceramics Japan, 41, 549-553 (2006)). For
example, there has been reported that the controlled release of
silicon genetically acts on cells to promote osteogenesis (H.
Maeda, T. Kasuga, and L. L. Hench, "Preparation of Poly(L-lactic
acid)-Polysiloxane-Calcium Carbonate Hybrid Membranes for Guided
Bone Regeneration", Biomaterials, 27, 1216-1222 (2006)).
Independently, when composites of a poly(lactic acid) with one of
three calcium carbonates (calcite, aragonite, and vaterite) are
soaked in a simulated body fluid (SBF), the composite of a
poly(lactic acid) with vaterite forms a bone-like apatite within a
shortest time among the three composites (H. Maeda, T. Kasuga, M.
Nogami, and Y Ota, "Preparation of Calcium Carbonate Composite and
Their Apatite-Forming Ability in Simulated Body Fluid", J. Ceram.
Soc. Japan, 112, S804-808 (2004)). These findings demonstrate that
the use of vaterite which gradually releases silicon is believed to
be a key to provide a guided bone regeneration membrane that gives
rapid bone reconstruction.
SUMMARY OF THE INVENTION
[0006] An object of the present invention is to provide a
bioresorbable guided bone regeneration membrane that includes a
novel mechanism effectively inducing a bone reconstruction ability.
Another object of the present invention is to provide a method for
manufacturing a guided bone regeneration membrane of high
performance (achieving rapid bone reconstruction) in an inexpensive
and industrially advantageous manner.
[0007] The present invention provides, in an embodiment, a guided
bone regeneration membrane which has a bi-layered structure
including a first nonwoven fabric layer and a second nonwoven
fabric layer. The first nonwoven fabric layer contains a
silicon-releasable calcium carbonate (Si--CaCO.sub.3) and a
biodegradable resin, represented by a poly(lactic acid) (PLA), as
principal components (hereinafter referred to as
"Si--CaCO.sub.3/PLA layer"). The second nonwoven fabric layer
contains biodegradable resin, representedbya PLA, as a principal
component (hereinafter referred to as "PLA layer"). In the guided
bone regeneration membrane, the Si--CaCO.sub.3/PLA layer may be
further coated with an apatite.
[0008] The PLA layer has the function of preventing the invasion of
soft tissues, and the apatite-coated Si--CaCO.sub.3/PLA layer has
the function of improving cellular affinity and/or osteogenic
ability. In another embodiment, a technique of manufacturing a
nonwoven fabric through electrospinning is adopted to the
manufacturing of such a guided bone regeneration membrane. This
provides an easy manufacturing of a membrane that has continuous
pores for supplying nutrients to cells and shows improved fitting
ability to an affected area. Such a bioresorbable apatite that
improves cellular initial adhesion can be easily applied to the
Si--CaCO.sub.3/PLA layer by soaking the layer in a simulated body
fluid (SEF).
[0009] The guided bone regeneration membrane according to the
present invention shows high cellular growth ability in cellular
affinity tests using osteoblastic cells (MC3T3-E1 cells) and is
expected as a bioresorbable guided bone regeneration membrane that
excels in bone reconstruction ability. The method according to the
present invention can easily and efficiently manufacture a guided
bone regeneration membrane having the above possibility.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Other objects, features and advantages of the present
invention will be understood more fully from the following detailed
description made with reference to the accompanying drawings. In
the drawings:
[0011] FIG. 1 is a scanning electron micrograph (SEM photograph) of
a PLA layer surface of a guided bone regeneration membrane prepared
in Example 1;
[0012] FIG. 2 is a scanning electron micrograph of a
Si--CaCO.sub.3/PLA layer surface of the guided bone regeneration
membrane prepared in Example 1;
[0013] FIG. 3 is a scanning electron micrograph of a surface of a
PLA layer prepared in Example 2;
[0014] FIG. 4 is a scanning electron micrograph of a surface of a
Si--CaCO.sub.3/PLA layer prepared in Example 2;
[0015] FIG. 5 is a scanning electron micrograph of fibers
configuring the Si--CaCO.sub.3/PLA layer prepared in Example 2;
[0016] FIG. 6 is a scanning electron micrograph of fibers
configuring the Si--CaCO.sub.3/PLA layer after soaking a composite
membrane prepared in Example 2 in 1.5 SBF;
[0017] FIG. 7 depicts X-ray diffraction patterns of the composite
membrane prepared in Example 2, before and after soaking in 1.5SBF;
and
[0018] FIG. 8 is a graph for the evaluation of the cellular
affinity of the Si--CaCO.sub.3/PLA layer and PLA layer prepared in
Example 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The present invention will be described further with
reference to various embodiments in the drawings.
First Embodiment
[0020] According to a preferred embodiment of the present
invention, such a guided bone regeneration membrane can be
manufactured through the steps of electrospinning and soaking in a
simulated body fluid (SBF). In the electrospinning step, a positive
high voltage is applied to a polymer solution, and the resulting
polymer solution is sprayed as fibers to a negatively charged
collector.
[0021] A spinning solution for the formation of the PLA layer (PLA
spinning solution) is prepared by dissolving a poly(lactic acid) in
chloroform (CHCl.sub.3) or dichloromethane (DCM). The PLA spinning
solution preferably has a poly (lactic acid) concentration of from
4 to 12 percent by weight for easy spinning. In this connection,
the poly(lactic acid) generally has a molecular weight of from
about 20.times.10.sup.4 to about 30.times.10.sup.4. For maintaining
conditions for satisfactory spinning, the PLA spinning solution may
further contain dimethylformamide (DMF) and/or methanol
(CH.sub.3OH) in an amount up to about 50 percent by weight relative
to the amount of CHCl.sub.3 or DCM. Another spinning solution for
the formation of the Si--CaCO.sub.3/PLA layer (Si--CaCO.sub.3/PLA
spinning solution) is prepared by adding Si--CaCO.sub.3 to the PLA
spinning solution. The Si--CaCO.sub.3 is preferably added to the
solution so that the Si--CaCO.sub.3/PLA layer has a Si--CaCO.sub.3
content of from 40 to 60 percent by weight. This allows an apatite
to deposit efficiently on Si--CaCO.sub.3/PLA fibers in the SBF
soaking step. Alternatively, a Si--CaCO.sub.3/PLA spinning solution
can be prepared by kneading a poly (lactic acid) and Si--CaCO.sub.3
in predetermined proportions using a heating kneader to give a
composite, and dissolving the composite in a solvent. The
Si--CaCO.sub.3 may be prepared, for example, by the method
described in Japanese Patent Application No. 2006-285429
(corresponding to Japanese Unexamined Patent Application
Publication (JP-A) No. 2008-100878). The PLA layer preferably
contains a poly(lactic acid) (PLA) alone or a copolymer between a
poly (lactic acid) and a poly(glycolic acid) (PGA) (copoly(lactic
acid/glycolic acid)) Exemplary other biodegradable resins usable
herein include synthetic polymers such as polyethylene glycols
(PEGS), polycaprolactones (PCLs), as well as copolymers among
lactic acid, glycolic acid, ethylene glycol, and/or caprolactone;
and natural polymers such as fibrin, collagens, alginic acids,
hyaluronic acids, chitins, and chitosans. Each of these can be used
instead of the PLA component in the Si--CaCO.sub.3/PLA layer. The
Si--CaCO.sub.3/PLA layer and the PLA layer may further contain
inorganic substances that are usable without biological problems.
Examples of such inorganic substances include tricalcium phosphate,
calcium sulfate, sodium phosphate, sodium hydrogenphosphate,
calcium hydrogenphosphate, octacalcium phosphate, tetracalcium
phosphate, calcium pyrophosphate, and calcium chloride.
[0022] Using an electrospinning apparatus, each of the PLA layer
spinning solution and the Si--CaCO.sub.3/PLA spinning solution is
charged and sprayed from a nozzle, converted into fibers in an
electric field while evaporating the solvent, the charged fibers
are jetted toward a collector on a negative electrode and form a
thin layer of fibers on the collector. A desired guided bone
regeneration membrane can be prepared by changing spinning
conditions such as the concentration, solvent type, and supply
speed (feed rate) of the spinning solution; spinning time; applied
voltage; and distance between the nozzle and the collector. The
prepared nonwoven fabrics may be pressed so as to be compacted or
to have a desired thickness. A guided bone regeneration membrane
having a bi-layered structure is configured by spraying the PLA
spinning solution to form a PLA layer, and thereafter spraying the
Si--CaCO.sub.3/PLA spinning solution to form a Si--CaCO.sub.3/PLA
layer on the PLA layer; or by preparing a PLA nonwoven fabric and a
Si--CaCO.sub.3/PLA nonwoven fabric independently, and combining the
two nonwoven fabrics. The guided bone regeneration membrane having
a bi-layered structure is cut to a desired size and soaked in a
simulated body fluid (SBF) or a solution with 1.5 times higher
concentration of inorganic ions compared to SBF (1.5SBF) at about
37.degree. C. for a predetermined time to precipitate an apatite on
the Si--CaCO.sub.3/PLA layer. This gives a bioresorbable guided
bone regeneration membrane including a novel mechanism that
effectively induces the bone reconstruction ability. The SBF
soaking can be performed even after the combining (or laminating)
the two layers. Even in this case, the apatite deposits
substantially not on the PLA layer but selectively on the
Si--CaCO.sub.3/PLA layer. This is because silicon contained in the
Si--CaCO.sub.3/PLA layer induces nucleation of apatite, and the
calcium component dissolves out to abruptly increase the degree of
supersaturation of apatite, and the apatite selectively deposits on
the surface of the Si--CaCO.sub.3/PLA layer; but the surface of the
PLA layer is hydrophobic to avoid the deposition of apatite
substantially.
EXAMPLES
[0023] Manufacturing methods of guided bone regeneration membranes
according to embodiments of the present invention will be
illustrated with reference to several examples below. It should be
noted, however, that these examples are included merely to aid in
the understanding of the present invention and are not to be
construed to limit the scope of the present invention.
[0024] Raw materials used in the examples are as follows.
[0025] Silicon-releasable calcium carbonate (Si--CaCO.sub.3):
Vaterite having a silicon content of 2.9 percent by weight and
prepared by using slaked lime (Microstar T; purity 96% or more;
Yabashi Industries Co., Ltd., Japan), methanol (analytical grade
reagent; purity 99.8% or more; Kishida Chemical Co., Ltd., Japan),
.gamma.-aminopropyltriethoxysilane (TSL 8331; purity 98% or more;
GE Toshiba Silicones Co., Ltd., Japan), and carbon dioxide gas
(high-purity liquefied carbon dioxide gas; purity 99.9%; Taiyo
Kagaku Kogyo K.K.)
[0026] Poly(lactic acid) (PLA): PURASORB PL Poly(L-lactide),
molecular weight of 20.times.10.sup.4 to 30.times.10.sup.4, PURAC
Biochem
[0027] Chloroform (CHCl.sub.3): Analytical grade reagent, purity
99.0% or more, Kishida Chemical Co., Ltd., Japan
[0028] N,N-Dimethylformamide (DMF): Analytical grade reagent,
purity 99.5% or more, Kishida Chemical Co., Ltd., Japan Example
1
[0029] A PLA spinning solution having a PLA concentration of 6.8
percent by weight was prepared by blending 10 g of PLA, 110 g of
CHCl.sub.3, and 27.5 g of DMF. Independently, a Si--CaCO.sub.3/PLA
spinning solution having a Si--CaCO.sub.3 concentration of 7.5
percent by weight and a PLA concentration of 5.0 percent by weight
was prepared by blending 15 g of Si--CaCO.sub.3, 10 g of PLA, 140 g
of CHCl.sub.3, and 35 g of DMF. Using the prepared spinning
solutions, a guided bone regeneration membrane having a bi-layered
structure of nonwoven fabrics was manufactured through
electrospinning.
[0030] [PLA Layer Preparation Conditions]
[0031] Spinning solution feed rate: about 0.1 ml/min., applied
voltage: 15 kV, distance between the nozzle and collector: 10 cm,
nozzle: laterally moves in a width of 3 to 4 cm at a rate of 15
cm/min, conveyor-type collector (conveyor speed: 5 to 6 m/min),
spinning time: about 170 minutes
[0032] [Si--CaCO.sub.3/PLA Layer Preparation Conditions]
[0033] Spinning solution feed rate: about 0.16 ml/min, applied
voltage: 20 kV, distance between the nozzle and collector: 10 cm,
nozzle: laterally moves in a width of 3 to 4 cm at a rate of 15
cm/min, conveyor-type collector (conveyor speed: 5 to 6 m/min),
spinning time: about 130 minutes
[0034] The microstructure of the prepared PLA layer (side for
preventing soft tissue invasion) is shown in the scanning electron
microscope (SEM) photograph of FIG. 1. The microstructure of the
Si--CaCO.sub.3/PLA layer (bone regeneration side) is shown in the
scanning electronmicrograph of FIG. 2, demonstrating that
Si--CaCO.sub.3 particles are attached to PLA fibers.
Example 2
[0035] A spinning solution having a PLA concentration of 9.0
percent by weight was prepared by blending 9 g of PLA and 91 g of
CHCl.sub.3, and using this spinning solution, a PLA layer was
prepared through electrospinning.
[0036] [PLA Layer Preparation Conditions]
[0037] Spinning solution feed rate: 0.05 ml/min, applied voltage:
20 kV, distance between the nozzle and collector: 15 cm, nozzle:
fixed, plate collector: fixed, spinning time: 60 minutes
[0038] Independently, PLA and Si--CaCO.sub.3 were kneaded in a
heating kneader at 200.degree. C. for 15 minutes to give a
Si--CaCO.sub.3/PLA composite containing 60 percent by weight of
Si--CaCO.sub.3. A spinning solution having a Si--CaCO.sub.3
concentration of 13.0 percent by weight and a PLA concentration of
8.7 percent by weight was prepared by blending 25 g of the
Si--CaCO.sub.3/PLA composite and 90 g of CHCl.sub.3, and using this
spinning solution, a Si--CaCO.sub.3/PLA layer was prepared through
electrospinning.
[0039] [Si--CaCO.sub.3/PLA Layer Preparation Conditions]
[0040] Spinning solution feed rate: 0.05 ml/min, applied voltage:
is 20 kV, distance between the nozzle and collector: 15 cm, nozzle:
fixed, plate collector: fixed, spinning time: 30 minutes
[0041] The two nonwoven fabrics prepared by the above procedures
were each cut to a desired size and affixed or combined with each
other to give one membrane. Specifically, the PLA layer was laid
over the Si--CaCO.sub.3/PLA layer, and a stainless steel mesh
(40-mesh) was laid over the PLA layer. A plate heated at
150.degree. C. to 160.degree. C. was placed on the stainless steel
mesh and pressed under a suitable pressure for about 10 seconds to
give the combined membrane (composite membrane). The scanning
electron micrographs of the PLA layer surface and of the
Si--CaCO.sub.3/PLA layer surface are shown in FIG. 3 and FIG. 4,
respectively. The scanning electron micrograph of fibers
configuring the Si--CaCO.sub.3/PLA layer is shown in FIG. 5,
demonstrating that Si--CaCO.sub.3 particles are attached to PLA
fibers.
[0042] The Si--CaCO.sub.3/PLA layer surface of the resulting
composite membrane was brought into contact with 1.5SBF at
37.degree. C. for one day. The scanning electron micrograph of
fibers on the side in contact with 1.5SBF is shown in FIG. 6,
demonstrating that a substance quite different from Si--CaCO.sub.3
covers the surface of fibers, as compared to FIG. 5. The X-ray
diffraction patterns before and after soaking in 1.5SBF are shown
in FIG. 7, indicating that peaks of apatite appear after the
soaking. These results demonstrate that the Si--CaCO.sub.3/PLA
layer surface is coated with apatite.
[0043] FIG. 8 shows how cellular numbers (in terms of cellular
numbers per 1 cm.sup.2) vary after the inoculation of osteoblastic
cells on the apatite-coated Si--CaCO.sub.3/PLA layer surface
(Si-composite), on the PLA layer surface (PLA), and on a control
(Thermanox: plastic disc for cell culture which has been treated on
its surface). The data in FIG. 8 demonstrate that the layer
including PLA in combination with a novel mechanism gives higher
growth capability to osteoblasts, and the resulting guided bone
regeneration membrane is expected as a bioresorbable guided bone
regeneration membrane that excels in bone reconstruction
ability.
[0044] Experimental Conditions
[0045] Cultivation using 24-well plate
[0046] Cell type; murine osteoblastic cells (MC3T3-E1 cells: Riken
Institute of Physical and Chemical Research)
[0047] Cellular inoculation number: 1.times.10.sup.4 cells/well
[0048] Medium: .alpha.-MEM (containing 10% fetal bovine serum)
[0049] Medium exchange: on the day following the inoculation,
thereafter every other day
[0050] Cell counting method: The measurement was performed using
the Cell Counting Kit-8 (cellular growth/cellular toxicity
analytical reagent; Dojindo Laboratories) in accordance with the
protocol attached to the reagent.
[0051] While the above description is of the preferred embodiments
of the present invention, it should be appreciated that the
invention may be modified, altered, or varied without deviating
from the scope and fair meaning of the following claims.
* * * * *