U.S. patent application number 14/490680 was filed with the patent office on 2015-11-12 for composite thread and manufacture process thereof.
This patent application is currently assigned to BIO-LINE MEDICAL TECH CO., LTD. The applicant listed for this patent is Jui-Yu Lin. Invention is credited to Jui-Yu Lin.
Application Number | 20150322596 14/490680 |
Document ID | / |
Family ID | 54367317 |
Filed Date | 2015-11-12 |
United States Patent
Application |
20150322596 |
Kind Code |
A1 |
Lin; Jui-Yu |
November 12, 2015 |
COMPOSITE THREAD AND MANUFACTURE PROCESS THEREOF
Abstract
A composite thread including a core thread and at least one
wrapping film is provided. The wrapping film wraps the core thread
uniformly. The composite thread is mainly formed by the
biodegradable material, and has improved biocompatibility which is
suitable to be used in the surgery. A manufacture process thereof
is also provided.
Inventors: |
Lin; Jui-Yu; (Changhua
County, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lin; Jui-Yu |
Changhua County |
|
TW |
|
|
Assignee: |
BIO-LINE MEDICAL TECH CO.,
LTD
Taipei City
TW
|
Family ID: |
54367317 |
Appl. No.: |
14/490680 |
Filed: |
September 19, 2014 |
Current U.S.
Class: |
57/230 ; 57/210;
57/7 |
Current CPC
Class: |
A61L 2420/08 20130101;
A61L 17/10 20130101; D02G 3/045 20130101; D02G 3/449 20130101; A61L
17/12 20130101; D02G 3/448 20130101; D02G 3/36 20130101 |
International
Class: |
D02G 3/44 20060101
D02G003/44; D02G 3/36 20060101 D02G003/36; D02G 3/04 20060101
D02G003/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 9, 2014 |
TW |
103116544 |
Claims
1. A composite thread, comprising: a core thread; and at least one
wrapping film, wrapping a surface of the core thread.
2. The composite thread as claimed in claim 1, wherein the
composite thread is formed of a biodegradable polymer.
3. The composite thread as claimed in claim 2, wherein the
biodegradable polymer is selected from a group consisting of
polyester, polysaccharide, polyaminoacid, the copolymers thereof,
the blends thereof, and the mixtures thereof.
4. The composite thread as claimed in claim 2, wherein the
biodegradable polymer is selected from a group consisting of
poly-glutamic acid, polylysine, polyorthoester, polycaprolactone,
polylactide, polyglycolic acid, polysebacic polyanhydride,
polydioxanone, chitin, fucoidan, the copolymers thereof, the blends
thereof, and the mixtures thereof.
5. The composite thread as claimed in claim 1, wherein at least one
of the at least one wrapping film has a bioactive component.
6. The composite thread as claimed in claim 5, wherein the
bioactive component is selected from a group consisting of
anti-inflammatory agents, analgesic agents, anesthetic agents,
antihistamines, steroids, skin-lightening medicaments, diabetes
medicaments, cell growth factors, natural moisture-retaining
factors, nucleic acids, peptides, proteins, vitamins, antilipidemic
medicaments, anti-cholesterol medicaments, growth hormones,
hormones, antioxidizing medicaments, cell growth inhibitors, and
differentiation inhibitors.
7. The composite thread as claimed in claim 5, wherein the at least
one wrapping film is a plurality of layers of wrapping films, and
one of the wrapping film has a slowly biodegradable component.
8. The composite thread as claimed in claim 7, wherein the slowly
biodegradable component is selected from a group consisting of
poly-glutamic acid, polylysine, polyorthoester, polycaprolactone,
polylactide, polyglycolic acid, polysebacic polyanhydride,
polydioxanone, chitin, fucoidan, the copolymers thereof, the blends
thereof, and the mixtures thereof.
9. A manufacturing process of a composite thread, comprising:
providing a core thread formed of a plurality of line segments
connected in series; continuously immersing the core thread into a
first wrapping film solution and removing the core thread from the
first wrapping film solution, wherein each of the line segments of
the core thread is removed from the first wrapping film solution
after the next line segment is immersed into the first wrapping
film solution; obtaining the core thread wrapped by a first
wrapping film by performing a first drying step; continuously
immersing the core thread wrapped by the first wrapping film into a
second wrapping film solution and removing the core thread wrapped
by the first wrapping film from the second wrapping film solution,
wherein each of the line segments of the core thread is removed
from the second wrapping film solution after the next line segment
is immersed into the second wrapping film solution; and obtaining a
composite thread wrapped by a second wrapping film by performing a
second drying step.
10. The manufacturing process of the composite thread as claimed in
claim 9, wherein the method of continuously immersing the core
thread into the first wrapping film solution and removing the core
thread from the first wrapping film solution comprises: disposing a
first rotation shaft in the first wrapping film solution, and
continuously rolling the core thread into the first wrapping film
solution by using the first rotation shaft; and disposing a second
rotation shaft outside the first wrapping film solution, and
continuously removing the core thread from the first wrapping film
solution by using the second rotation shaft.
11. The manufacturing process of the composite thread as claimed in
claim 9, wherein the method of continuously immersing the core
thread wrapped by the first wrapping film into the second wrapping
film solution and removing the core thread wrapped by the first
wrapping film from the second wrapping film solution comprises:
disposing a third rotation shaft in the second wrapping film
solution, and continuously rolling the core thread wrapped by the
first wrapping film into the second wrapping film solution by using
the third rotation shaft; and disposing a fourth rotation shaft
outside the second wrapping film solution, and continuously
removing the core thread from the second wrapping film solution by
using the fourth rotation shaft.
12. The manufacturing process of the composite thread as claimed in
claim 9, wherein the first drying step or the second drying step
comprises a heating step.
13. A composite thread, manufactured by manufacturing steps as
follows: providing a core thread formed of a plurality of line
segments connected in series; continuously immersing the core
thread into a first wrapping film solution and removing the core
thread from the first wrapping film solution, wherein each of the
line segments of the core thread is removed from the first wrapping
film solution after the next line segment is immersed into the
first wrapping film solution; obtaining the core thread wrapped by
a first wrapping film by performing a first drying step;
continuously immersing the core thread wrapped by the first
wrapping film into a second wrapping film solution and removing the
core thread wrapped by the first wrapping film from the second
wrapping film solution, wherein each of the line segments of the
core thread is removed from the second wrapping film solution after
the next line segment is immersed into the second wrapping film
solution; and obtaining a composite thread wrapped by a second
wrapping film by performing a second drying step.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 103116544, filed on May 9, 2014. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of this
specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a thread and a manufacturing
process thereof, and particularly relates to a biodegradable
composite thread and a manufacturing process thereof.
[0004] 2. Description of Related Art
[0005] Generally speaking, threads are commonly used in surgeries
to sew organs such as blood vessels, viscera, and skin, etc. Since
the materials and characteristics of threads influence how the
threads are treated after surgeries, the development on the
materials of threads becomes an important issue. Based on the
structures of the materials, the threads may be divided into
single-strand threads and multi-strand threads. Based on the
sources of the materials, the threads may be divided into natural
threads and synthetic threads. In addition, based on the
absorbability of the threads, the threads may be divided into
absorbable threads and unabsorbable threads.
[0006] The unabsorbable threads are not degradable, so the threads
need to be removed after being used. On the contrary, the
absorbable threads are degradable. When used to sew a cut, the
absorbable threads may be absorbed by the human body after a period
of time, and is thus not necessary to be removed. Accordingly, the
absorbable threads are nowadays commonly used in surgeries that
require sewing. The absorbable threads have a preferable
biocompatibility and appropriate tensile strength, which improve
the safety as well as convenience in the surgery. Besides, it is
preferred that the threads has a preferable surface sliding
characteristics, so that after the threads pass through the organs
or are knotted, the friction force generated when fixing the
tissues is reduced as much as possible.
SUMMARY OF THE INVENTION
[0007] The invention provides a composite thread and a
manufacturing method thereof. The composite thread has
biodegradability and is suitable to be implanted into an organism
and capable of generating a specific effect.
[0008] A composite thread of the invention includes a core thread
and at least one wrapping film. In addition, the wrapping film
wraps a surface of the core thread.
[0009] A manufacturing method of a composite thread of the
invention includes manufacturing steps as follows: providing a core
thread formed of a plurality of line segments connected in series;
continuously immersing the core thread into a first wrapping film
solution and removing the core thread from the first wrapping film
solution, wherein each of the line segments of the core thread is
removed from the first wrapping film solution after the next line
segment is immersed into the first wrapping film solution;
obtaining the core thread wrapped by a first wrapping film by
performing a first drying step; continuously immersing the core
thread wrapped by the first wrapping film into a second wrapping
film solution and removing the core thread wrapped by the first
wrapping film from the second wrapping film solution, wherein each
of the line segments of the core thread is removed from the second
wrapping film solution after the next line segment is immersed into
the second wrapping film solution; and obtaining a composite thread
wrapped by a second wrapping film by performing a second drying
step.
[0010] A composite thread of the invention is manufactured by
manufacturing steps as follows: providing a core thread formed of a
plurality of line segments connected in series; continuously
immersing the core thread into a first wrapping film solution and
removing the core thread from the first wrapping film solution,
wherein each of the line segments of the core thread is removed
from the first wrapping film solution after the next line segment
is immersed into the first wrapping film solution; obtaining the
core thread wrapped by a first wrapping film by performing a first
drying step; continuously immersing the core thread wrapped by the
first wrapping film into a second wrapping film solution and
removing the core thread wrapped by the first wrapping film from
the second wrapping film solution, wherein each of the line
segments of the core thread is removed from the second wrapping
film solution after the next line segment is immersed into the
second wrapping film solution; and obtaining a composite thread
wrapped by a second wrapping film by performing a second drying
step.
[0011] Based on the above, the composite thread of the invention is
formed of a biodegradable material, and may thus be absorbed by an
organism. Therefore, the composite thread has a preferable
biocompatibility and is suitable to be partially or completely
implanted into an organism. When the composite thread is used in a
surgery, the composite thread may have the function of sewing and
repairing organs such as skin, blood vessels and viscera, etc. In
addition, the component in the wrapping film on the composite
thread may be spread to the surrounding tissues to achieve an
additional assisting function.
[0012] To make the above features and advantages of the invention
more comprehensible, embodiments accompanied with drawings are
described in detail as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0014] FIG. 1 is a block diagram illustrating a manufacturing
process of a composite thread according to an embodiment of the
invention.
[0015] FIG. 2 is a flow chart illustrating a manufacturing process
of a composite thread according to an embodiment of the
invention.
[0016] FIG. 3 is a cross-sectional schematic view of a composite
thread according to an embodiment of the invention.
[0017] FIG. 4 is a schematic view illustrating a coating machine
according to an embodiment of the invention.
[0018] FIG. 5A is a view of a polydioxanone (PDO) thread under an
electron microscope.
[0019] FIG. 5B is a view of a composite thread wrapped with a first
wrapping film under an electron microscope.
[0020] FIG. 5C is a view of a composite thread wrapped with a
second wrapping film under an electron microscope.
[0021] FIG. 5D is a view illustrating degradation of a composite
thread after 28 days of in vitro test.
[0022] FIG. 6 illustrates a relation between weight loss rates and
a degradation time of the composite threads in Examples 1-4.
[0023] FIG. 7 illustrates a relation between pH values and a
degradation time in the in vitro degradation test of the composite
threads in Examples 1-4.
[0024] FIG. 8 illustrates a test outcome of a cell survival rate of
each test sample.
[0025] FIG. 9 illustrates a test outcome of a cell survival rate of
each test sample.
DESCRIPTION OF THE EMBODIMENTS
[0026] Reference will now be made in detail to the present
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers are used in the drawings and the description
to refer to the same or like parts.
[0027] FIG. 1 is a block diagram illustrating a manufacturing
process of a composite thread according to an embodiment of the
invention. FIG. 2 is a flow chart illustrating the manufacturing
process of the composite thread according to the embodiment.
Referring to FIGS. 1 and 2, Step S10 is firstly performed. A core
thread 102 formed of a plurality of line segments connected in
series is provided. In other words, the core thread 102 is a
continuous thread formed by connecting the plurality of line
segments.
[0028] The core thread 102 may be formed of a biodegradable polymer
selected from a group consisting of polyester, polysaccharide,
polyamino acid, the copolymers thereof, the blends thereof, and the
mixtures thereof, for example. More specifically, the core thread
102 is selected from a group consisting of poly-glutamic acid,
polylysine, polyorthoester, polycaprolactone, polylactide,
polyglycolic acid, poly(sebacic acid) polyanhydride, polydioxanone,
chitin, fucoidan, the copolymers thereof, the blends thereof, and
the mixtures thereof, for example. A biodegradable polymer may be
gradually degraded by being absorbed by an organism. Therefore, the
biodegradable polymer may be present in the organism for a specific
period of time.
[0029] Then, Step S20 is performed. The core thread 102 is
continuously immersed into a first wrapping film solution 204a and
removed from the first wrapping film solution 204a. In addition,
each of the line segments of the core thread 102 is removed from
the first wrapping film solution 204a after the next line segment
is immersed into the first wrapping film solution 204a.
[0030] The first wrapping film solution 204a is a solution having a
bioactive component, for example. The bioactive component is
selected from a group consisting of anti-inflammatory agents,
analgesic agents, anesthetic agents, antihistamines, steroids,
skin-lightening medicaments, diabetes medicaments, cell growth
factors, natural moisture-retaining factors, nucleic acids,
peptides, proteins, vitamins, antilipidemic medicaments,
anti-cholesterol medicaments, growth hormones, hormones,
antioxidizing medicaments, cell growth inhibitors, and
differentiation inhibitors, for example.
[0031] Specifically, the core thread 102 may be wound on a feeding
thread shaft 202A, for example. The core thread 102 may be
sequentially disposed on a plurality of rotation shafts and
transported by using the rotation shafts. For example, a first
rotation shaft 202a may be disposed in the first wrapping film
solution 204a, and a second rotation shaft 202b may be disposed
outside the first wrapping film solution 204a. By rotating the
first rotation shaft 202a, the core thread 102 may be continuously
rolled into the first wrapping film solution 204a. In this way, the
first wrapping film solution 204a is coated on a surface of the
core thread 102. The second rotation shaft 202b may then
continuously pull the core thread 102 out of the first wrapping
film solution 204a. The first rotation shaft 202a and the second
rotation shaft 202b may have the same rotating speed. A thickness
of the first wrapping film solution 204a on the core thread 102 may
be determined by adjusting the rotating speed. In addition, when
transporting the core thread 102, the core thread 102 may have a
tensile force due to pulling of the first rotation shaft 202a and
the second rotation shaft 202b. In this way, the first wrapping
film solution 204a may adhere to the core thread 102 more
uniformly, and the usage of the first wrapping film solution 204a
may be reduced.
[0032] Then, Step S30 is performed. The core thread 102 coated with
a first wrapping film 104 is obtained by performing a first drying
step. Specifically, by using the second rotation shaft 202b, the
core thread 102 coated with the first wrapping film solution 204a
is transported to a heating tube H1 for a heating step, so as to
remove a solvent in the first wrapping film solution 204a and
obtain the first wrapping film 104 that is approximately cured. The
first wrapping film 104 wraps a surface of the core thread 102. A
temperature in the heating step is approximately between 55.degree.
C. to 65.degree. C.
[0033] Then, Step S40 is performed. The core thread 102 wrapped by
the first wrapping film 104 is continuously immersed into a second
wrapping film solution 204b and removed from the second wrapping
film solution 204b. In addition, each of the line segments of the
core thread 102 is removed from the second wrapping film solution
204b after the next line segment is immersed into the second
wrapping film solution 204b.
[0034] The second wrapping film solution 204a is a solution having
a slowly biodegradable component, for example. The slowly
biodegradable component is selected from a group consisting of
poly-glutamic acid, polylysine, polyorthoester, polycaprolactone,
polylactide, polyglycolic acid, polysebacic polyanhydride,
polydioxanone, chitin, fucoidan, the copolymers thereof, the blends
thereof, and the mixtures thereof, for example.
[0035] For example, a third rotation shaft 202c may be disposed in
the second wrapping film solution 204b, and a fourth rotation shaft
202d may be disposed outside the second wrapping film solution
204b. By rotating the third rotation shaft 202c, the core thread
102 may be continuously immersed into the second wrapping film
solution 204b. In this way, the second wrapping film solution 204b
is coated on the surface of the core thread 102. The fourth
rotation shaft 202d may then continuously pull the core thread 102
out of the second wrapping film solution 204b. The third rotation
shaft 202c and the fourth rotation shaft 202d may have the same
rotating speed. A thickness of the second wrapping film solution
204b on the core thread 102 may be determined by adjusting the
rotating speed. In addition, an additional rotation shaft may be
disposed between the rotation shafts, so as to determine a
transporting direction and allow the manufacturing process to
proceed smoothly. The invention is not limited thereto. When
transporting the core thread 102, the core thread 102 may have a
tensile force due to pulling of the third rotation shaft 202c and
the fourth rotation shaft 202d. In this way, the second wrapping
film solution 204b may adhere to the core thread 102 more
uniformly, and the usage of the second wrapping film solution 204b
may be reduced.
[0036] Then, Step S50 is performed. The core thread 102 coated with
a second wrapping film 106 is obtained by performing a second
drying step. Specifically, by using the fourth rotation shaft 202d,
the core thread 102 coated with the second wrapping film solution
204b is transported to a heating tube H2 for a heating step, so as
to remove a solvent in the second wrapping film solution 204b and
obtain the second wrapping film 106 that is approximately cured.
The second wrapping film 106 covers a surface of the first wrapping
film 104. A temperature in the heating step is approximately
between 45.degree. C. to 55.degree. C. After the manufacturing
process above, the composite thread 100 is approximately completed.
For an illustrative purpose, the composite thread 100 of this
embodiment is described as having a plurality of layers (e.g. two
layers) of wrapping films, for example. However, the invention is
not limited thereto. In other embodiments, the composite thread 100
may include only one layer of wrapping film, such as the first
wrapping film 104 having a bioactive component.
[0037] FIG. 3 is a cross-sectional schematic view of a composite
thread according to an embodiment of the invention. Referring to
FIGS. 2 and 3, the composite thread 100 includes the core thread
102, the first wrapping film 104, and the second wrapping film 106.
The first wrapping film 104 wraps the surface of the core thread
102. The second wrapping film 106 wraps the surface of the first
wrapping film 104, and the first wrapping film 104 is located
between the core thread 102 and the second wrapping film 106.
[0038] Specifically, the composite thread 100 is biodegradable.
Therefore, the composite thread 100 is suitable to be used as a
surgical thread in a surgery. In addition, it is not necessary to
remove the stitches when using the composite thread 100. Besides,
the diameter of the composite thread 100 of the invention may be
designed in a range between 0.05-0.7 mm. The size of the composite
thread 100 is small and suitable to be implanted into an organism
to facilitate the organism to activate a self-repairing process.
For example, when the composite thread 100 is implanted into a
lower layer of dermis at a plurality of points in a plurality of
direction through stitches, a three-dimensional mesh structure may
be formed to provide more support the skin. In addition, the wound
of stitches and the composite thread 100 together trigger minor
acute reaction and prompt the repairing mechanism of the skin,
which release a plurality of growth factors and stimulates the
generation of collagen to facilitate the metabolism of the skin and
improve the skin quality.
[0039] More specifically, the first wrapping film 104 of the
composite thread 100 contains a bioactive component that may be
released to the organism to achieve an additional assisting effect
such as skin-lightening and anti-oxidizing, etc. The second
wrapping film 106 contains a slowly biodegradable component having
the effect of slowing down spreading, such as slowing down the
speed that the bioactive component is spread in the organism, so as
to elongate the overall release time of the bioactive component and
achieve the function of controlling the release accordingly. In
this embodiment, the core thread 102 and the second wrapping film
106 are biodegradable, for example. In addition, the degradation
time of the core thread 102 may be longer than the degradation time
of the second wrapping film 106. In this way, the second wrapping
film 106 may be completely degraded before degradation of the core
thread 102 is completed, so as to release the bioactive component
in the first wrapping film 104 as much as possible. It should be
noted that the composite thread 100 of the invention is described
as having two layers of wrapping films for an illustrative purpose.
However, the invention is not limited thereto. In other
embodiments, a similar coating process or other processes may be
performed to manufacture two or more layers of wrapping films, such
that the composite thread 100 may have a more variety of composite
effects.
[0040] FIG. 4 is a schematic view illustrating a coating machine
according to an embodiment of the invention. Referring to FIG. 4, a
coating machine 200 includes the feeding thread shaft 202A, a
receiving thread shaft 202B, a plurality of rotation shafts 202, a
plurality of heating tubes H, and a plurality of lifting tables
206. The core thread 102 is wound on the feeding thread shaft 202A,
and the core thread 102 may be disposed on the plurality of
rotation shafts 202. A transporting path of the core thread 102 may
be designed by disposing the rotation shafts. A coating solution
204 may be disposed on the lifting tables 206. The lifting tables
206 may adjust the height of the coating solution 204. In this way,
the transporting path of the core thread 102 may pass through the
coating solution 204. In addition, the transporting path of the
core thread 102 passes through the heating tube H, so as to obtain
a coating layer by removing a solvent in the coating solution 204.
After coating at least two coating layers, the composite thread
that is manufactured may be wound on the receiving thread shaft
202B. Here, the method described herein is to form a wrapping film
on the core thread 102 by coating. However, the invention is not
limited thereto.
[0041] Examples 1 and 2 are described below to illustrate the
invention. However, the invention is not limited thereto.
[0042] The core thread is a biodegradable material, which may be
absorbed after being embedded into an organism for a period of
time. The core thread itself and the product after the core thread
is degraded are compatible with cells, and unlikely to induce
negative reactions such as an irritative reaction, a foreign body
reaction, or an oncogenic reaction, etc.
[0043] In Example 1, the core thread was formed of polydioxanone
(PDO), for example. When a PDO thread is embedded into the skin,
the thread is capable of promoting microcirculation in local
tissues, activating reparative processes of cells, and stimulating
collagen production.
[0044] In Example 1, the bioactive component is vitamin C having a
skin lightening effect, for example. A preparation method of the
first wrapping film solution is provided below. First of all, 10 g
of Polyvinylpyrrolidone (PVP) and 50 g of vitamin C were mixed and
placed into a beaker having a capacity of 250 ml. Then, 100 ml of
deionized water was added. Then, the solution was heated at
37.degree. C. on a heating board and stirred until all solid bodies
were completely dissolved. The vitamin C solution as the first
wrapping film solution was thus prepared. The concentration of the
vitamin C solution is between 25 wt % and 35 wt %.
[0045] The slowly biodegradable component was
poly(lactide-co-glycolide) acid (PLGA) copolymer, for example. In
addition, a ratio between lactide (LA) and glycolide (GA) was
75:25. A preparation method of the second first wrapping film
solution is provided below. First of all, 11 g of the PLGA
copolymer having an inherent value (I.V.) at 0.4 was placed into a
beaker having a capacity of 250 ml. Then, 100 ml of dichloromethane
was added. The solution was then stirred until all solid bodies
were completely dissolved. The PLGA copolymer solution, as the
second wrapping film solution, is thus prepared. The concentration
of the PLGA copolymer solution is about 10 wt %.
[0046] The first heating tube of the coating machine was heated to
60.degree. C. in advance. The second heating tube was heated to
50.degree. C. in advance. The first coating film solution was
placed below the first heating tube, and the second coating film
solution was placed below the second heating tube. Afterwards, the
speed of the receiving thread shaft was set at 0.3 rpm, and the
receiving thread shaft started to rotate. At this time, the PDO
thread passed through the first wrapping film solution and then the
solvent was baked dry by the first heating tube to form the first
wrapping film. Then, the PDO thread passed through the second
wrapping film solution, and then the solvent was baked dry by the
second heating tube to form the second wrapping film. Finally, the
receiving thread shaft collected the composite thread that was
manufactured. The time duration that the PDO thread is absorbed by
the human body is approximately 180 to 240 days. The time duration
that the PLGA copolymer wrapping film is absorbed by the human body
is about 28 days.
[0047] The manufacturing process described in Example 2 is similar
to that described in Example 1, but the bioactive component in
Example 2 is different from that in Example 1. In Example 2, the
bioactive component was vitamin E having an anti-oxidizing effect,
for example. A preparation method of the first wrapping film
solution is provided below. First of all, 10 g of
Polyvinylpyrrolidone (PVP) and 50 g of vitamin E were mixed and
placed into a beaker having a capacity of 250 ml. Then, 100 ml of
methylene chloride was added. Then, the solution was stirred until
all solid bodies were completely dissolved. The vitamin E solution
as the first wrapping film solution was thus prepared. The
concentration of the vitamin E solution is between 25 wt % and 35
wt %.
[0048] The composite thread of Example 3 is similar to that of
Example 1. The bioactive components in Examples 1 and 3 were
Vitamin C. However, Example 3 differs from Example 1 in that the
inherent value of the PLGA copolymer in Example 3 was 0.8. The
composite thread of Example 4 is similar to that of Example 2. The
bioactive components in Examples 2 and 4 were Vitamin E. However,
Example 4 differs from Example 2 in that the inherent value of the
PLGA copolymer in Example 4 was 0.8.
[0049] FIG. 5A is a view of a polydioxanone (PDO) thread under an
electron microscope. FIG. 5B is a view of a composite thread
wrapped with a first wrapping film under an electron microscope.
FIG. 5C is a view of a composite thread wrapped with a second
wrapping film under an electron microscope. FIG. 5D is a view
illustrating degradation of a composite thread after 28 days of the
in vitro test. Referring to FIG. 5A, before coating of the active
component (i.e. without the first wrapping film), there were a
plurality of strip-like cracks on a lateral surface of the thread.
Referring to FIG. 5B, after the first wrapping film was formed, the
lateral surface of the composite thread became more complete.
Referring to FIG. 5C, after the second wrapping film was formed, a
plurality of pores were formed on the lateral surface of the
composite thread. The pores were formed when the solvent (e.g.
dichloromethane) in the PLGA copolymer wrapping film solution
having a viscosity to a certain degree (e.g. I.V. at 0.4) was
evaporated when the solution was heated. Referring to FIG. 5D, it
is shown that after 28 days of the in vitro test, the second
wrapping film was degraded, and the biodegradability of the second
wrapping film is thus shown. Since the second wrapping film is
slowly degraded within a period of time, the component of the first
wrapping film may be slowly released to the body of an organism, so
as to control the bioactive component to be slowly released.
[0050] A degradation test on the composite threads of Examples 1-4
are described below. The test procedure is described as follows.
First of all, the composite threads that were weighted were placed
in test tubes. Then, 5 ml of normal saline (phosphate buffer
saline, PBS) having a pH value at 7.4 was added to the test tubes
where the samples are placed. Then, the test tubes were placed in a
thermostatic tank having a temperature set at 37.degree. C. After a
fixed period of time, the samples were taken out to be dried and
weighted. Then, pH values of the liquids in the test tubes were
measured.
[0051] FIG. 6 illustrates a relation between weight loss rates and
a degradation time of the composite threads in Examples 1-4. As
shown in FIG. 6, the longer the degradation duration time was, the
lower the weight of each of the composite threads became,
indicating that the first wrapping film and the second wrapping
film on the composite threads were gradually peeled off through
time.
[0052] FIG. 7 illustrates a relation between pH values and a
degradation time in the in vitro degradation test of the composite
threads in Examples 1-4. Referring to FIG. 7, as the second
wrapping film was gradually dissolved, the PLGA copolymer was
gradually released to the liquids in the test tubes. Therefore, the
pH values gradually dropped.
[0053] The in vitro test of cell survival rate on a plurality of
composite threads is described below. The test described herein was
conducted in accordance with the standard of ISO 10993-5. The test
samples included a PDO composite thread coated with a wrapping film
having 8 wt % of vitamin C, a PDO composite thread coated with a
wrapping film having 15 wt % of vitamin C, a PDO composite thread
coated with a wrapping film having 4 wt % of vitamin E, and a PDO
composite thread coated with a wrapping film having 8 wt % of
vitamin E. In addition, a blank control group (incubated with 5 ml
of the minimum essential medium (MEM) culture medium containing
bovine serum), a negative control group (a PE film, extracted at
37.degree. C. for 24 hours at the ratio of 6 cm.sup.2/mL), and a
positive control group (incubated with 0.2% of phenol) were also
included.
[0054] The used MEM extracts were prepared in accordance with the
standard of ISO 10993-12. The test samples were mixed with the MEM
extracts at the ratio of 6 cm.sup.2/mL. Then the MEM extracts were
used to extract the test samples at 37.degree. C. for 24 hours, so
as to obtain an extract of each of the test samples. Then, the
extract of each of the test samples was co-cultured with a mouse
fibroblast strain L929 (NCTC clone 929) for 72 hours under a
condition of 5% of CO.sub.2 at 37.degree. C. Then, a MTT assay, a
quantitative analysis, was performed to test the cell survival
rate. FIG. 8 illustrates a test outcome of the cell survival rate
of each test sample. As shown in FIG. 8, the composite thread of
the invention had a higher cell survival rate, indicating that the
composite thread of the invention has a higher
biocompatibility.
[0055] In addition, the same test was performed on different test
samples to test the in vitro cell survival rate. Here, the test
samples included a PDO thread coated with 31 wt % of the vitamin C
wrapping film and PLGA copolymer wrapping film and a PDO thread
coated with 31 wt % of the vitamin E wrapping film and PLGA
copolymer wrapping film. FIG. 9 illustrates a test outcome of the
cell survival rate of each test sample. From the experiments, for
the test samples using the composite thread of the invention, at
least 80 percent of cell viability was observed.
[0056] In view of the foregoing, the composite thread of the
invention is formed of a biodegradable material, and may thus be
absorbed by an organism. Therefore, the composite thread of the
invention has a preferable biocompatibility and is suitable to be
partially or completely implanted into an organism. When the
composite thread is used in a surgery, the composite thread may
have the function of sewing and repairing organs such as skin,
blood vessels, and viscera, etc. In addition, the component in the
wrapping film on the composite thread may be spread to the
surrounding tissues to achieve an additional assisting
function.
[0057] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
invention covers modifications and variations of this invention
provided they fall within the scope of the following claims and
their equivalents.
* * * * *