KR20140056422A

KR20140056422A - Tissue engineering scaffold improving bioactive activity and method for preparing the same

Info

Publication number: KR20140056422A
Application number: KR1020120118874A
Authority: KR
Inventors: 송호준; 박영준; 안지해; 홍성빈; 송요한
Original assignee: 전남대학교산학협력단
Priority date: 2012-10-25
Filing date: 2012-10-25
Publication date: 2014-05-12

Abstract

The present invention relates to a tissue engineering scaffold with improved bioactive activity and a preparing method of the same. A tissue engineering scaffold according to the present invention comprises: a biocompatibility polymer and a dielectric material treated by electrical polarization. More specifically, the dielectric material is an tissue engineering scaffold manufactured by electrical polarization-treating at least one among hydroxyapatite, titanium dioxide and calcium titanate and powdering.

Description

TECHNICAL FIELD The present invention relates to a scaffold for tissue engineering with increased bioactivity and a method for preparing the scaffold.

The present invention relates to a scaffold for tissue engineering with increased bioactivity and a method for producing the scaffold.

Recently, there have been a lot of researches on bone replacement and bone regeneration due to the increase of patients with bone diseases as they enter the aging society. The research for substitution and regeneration of injured hard tissue according to this social request is one of the most popular research subjects now.

Implant technology that directly replaces the teeth or femur using non-absorbable biomaterials such as titanium, metal, and ceramics as a replacement for damaged tissue has already been widely used in clinical practice. However, non-absorbable biomaterials have difficulties in directly replacing relatively localized bone damage, and there are inconveniences and risks that need to be removed through secondary surgery after recovery if necessary.

In order to overcome the disadvantages of metal or ceramic implants as described above, studies on artificial osteogenesis and operation using a biodegradable scaffold that induces regeneration of injured bone in vivo and replace it with a bone over time have been conducted ought.

Biodegradable polymers such as PLLA (poly-L-lactic acid), PGA (polyglutamic acid), PLGA (poly (lactide-co-glycolide)) and the like are commonly used as scaffold materials . However, since the biodegradable polymers have low bioactivity and significantly weaker mechanical properties than bone, development of scaffolds in which biodegradable polymers and bioactive ceramics are combined by various methods is required.

One of the easiest ways to increase the bioactivity of biopolymer materials is to prepare a porous scaffold containing bone conductive powder such as hydroxyapatite or bio-glass, which is a major mineral component of bone. However, such a method can not provide its own bioactivity to the exceeding mascafold. Therefore, a new technique for dramatically increasing the bioactivity of the biopolymer scaffold is required.

Accordingly, an object of the present invention is to provide a scaffold for tissue engineering with increased bioactivity and a method for producing the scaffold.

It is another object of the present invention to provide a scaffold for tissue engineering, which is formed into various three-dimensional structures and at the same time has increased biological activity, and a method for producing the scaffold.

This object is achieved according to the invention by a biocompatible polymer; And an electrically poled dielectric material. &Lt; RTI ID = 0.0 > [0002] < / RTI >

The dielectric material may include at least one of hydroxyapatite, titanium dioxide, and calcium titanate subjected to an electric polarization treatment followed by pulverization.

Wherein the dielectric material is formed by forming at least one of the hydroxyapatite, titanium dioxide, and calcium titanate into a bulk or thin film form, applying a voltage of 100 V to 300 V to both ends of the formed body, To < RTI ID = 0.0 > 2 < / RTI > hours, and then cooling the resulting electrically poled dielectric material.

The electrically polarized dielectric material may include a dielectric material having a hydroxyapatite formed on its surface by subjecting the electrically poled dielectric powder to hydrothermal treatment.

The biocompatible polymer may include at least one of polyglycolic acid, polylactic acid, and polylactic acid glycolic acid.

The above objects are also achieved by a method for manufacturing a scaffold for tissue engineering according to the present invention, comprising the steps of: forming a dielectric material in a bulk or thin film form; Applying a voltage of 100 V / mm to 300 V / mm to both ends of the molded body, holding the temperature of 100 ° C to 400 ° C or more for 30 minutes to 2 hours, and cooling; Preparing an electrically polarized dielectric material by pulverizing the dielectric material that has undergone electroless polarization after cooling; And mixing the electrically polarized dielectric material with the biocompatible polymer to produce a scaffold for tissue engineering.

The dielectric material may include at least one of hydroxyapatite, titanium dioxide, and calcium titanate.

The preparation of the electrically polarized dielectric material may further include hydrothermally processing the electrically poled dielectric powder to prepare a dielectric material having hydroxyapatite on its surface.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is easy to manufacture a tissue engineering scaffold having various three-dimensional shapes by blending an electrically polarized dielectric powder into a biocompatible polymer.

In addition, according to the present invention, it is possible to manufacture a scaffold in which an electrically polarized dielectric powder can easily bind to an organic matter such as protein or polarity-possessing bone growth factor by electrostatic attraction, thereby increasing bioactivity.

Further, according to the present invention, since the electrically-polarized dielectric powder material itself can be adsorbed by electrostatic attraction with substances having electrical polarity, it can be used even when it is desired to adsorb a positively or negatively charged specific substance .

1 is a schematic view of a process for manufacturing an electrically poled dielectric material according to the present invention,
FIG. 2 (a) is a schematic view of an apparatus for producing an electrically polarized dielectric material according to the present invention,
2 (b) is a schematic view of a scaffold manufacturing apparatus according to the present invention,
FIGS. 3A and 3B show the degree of protein attachment of the electrically poled dielectric material of the present invention,
Figure 4 shows the degree of scaffold bioactivity including the electrically poled dielectric material of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

The electrically polarized dielectric material may comprise 5 to 30 wt%, preferably 10 to 20 wt%, based on the total weight.

The biocompatible polymer may include at least one of polyglycolic acid (PGA), polylactic acid (PLLA), and polylactic acid glycol (PLGA).

The electropolished dielectric material according to the present invention includes at least one of hydroxyapatite, titanium dioxide, and calcium titanate (CaTiO ₃ ) subjected to an electric polarization treatment followed by pulverization . It is the electrical dipole that materials with such dielectric properties can have electrical polarization properties. This polarizable dipole is attributed to the arrangement characteristics of the unit cell which forms the crystal structure of the material. In materials that do not undergo a forced polarization process, the polarity of the dipole is zero because the dipole does not have a particular directionality in the material and is randomly distributed.

Accordingly, in the present invention, at least one of the hydroxyapatite, titanium dioxide, and calcium titanate is formed into a bulk or thin film form to impart the electrical polarization characteristic of the dielectric material, and the temperature is raised in the formed dielectric material, And applying a high voltage to both ends (or both sides) causes the dipoles to align in one direction, causing polarization to the positive and negative electrodes. When the dipole is aligned and the temperature is lowered while the voltage is applied, the polarization state is maintained as it is.

1 is a schematic diagram of a process for manufacturing an electrically poled dielectric material according to the present invention. Referring to FIG. 1, the following will be described.

The dielectric material of at least one of the hydroxyapatite, titanium dioxide, and calcium titanate comprises an electrical dipole and the polarity of the dipole is zero because the dipoles are randomly distributed in the material without any specific directionality. Such a dielectric material is molded into a bulk or thin film form (FIG. 1A). A voltage of 100 V / mm to 300 V / mm, preferably a voltage of 100 V / mm to 200 V / mm is applied to both ends of the molded body and a temperature of 100 to 400 ° C, preferably 150 to 300 ° C, For 30 minutes to 2 hours, and preferably for 1 hour to 1 hour and 30 minutes so that the temperature can be sufficiently transferred into the molded body (B in FIG. 1). Thereafter, while the application of the voltage is maintained, the temperature is cooled to room temperature to maintain an electrically polarized state, and when the molded body is formed into a powder form, the electrically poled dielectric powder can be obtained. Since dipoles originating in electrical polarization properties occur at the unit cell level of the crystal structure, microparticles of powder may also have a large number of dipoles (Fig. 1C). Therefore, when a powdered dielectric material is formed into a perc form by using a compressor and subjected to an electric polarization treatment, the dipoles present in the respective powder particles can also be aligned in one direction. When the thus poled bulk is pulverized and re-pulverized, the individual powder particles can serve as independent polarised particles that remain polarized to the anode and the cathode. The polarized particles are particles having both positive and negative electrodes, and can be easily combined with other ions having polarity by an electrostatic attractive force. Particularly, organic substances such as proteins have functional groups (for example, carboxyl groups, hydroxyl groups) and negatively charged functional groups (for example, amine groups) of the amino acids, It can be easily combined by electrostatic attraction.

According to the present invention, it is easy to prepare a scaffold for tissue engineering (c) having various three-dimensional shapes by blending the prepared electrically polarized dielectric powder (b) into a biocompatible polymer, The dielectric powder can easily bind to an organic material such as protein or polarity-possessing bone growth factor (a) by electrostatic attraction, and thus it is possible to manufacture a scaffold having increased bioactivity. Also, since the electrically polarized dielectric powder material produced according to the present invention can be adsorbed by electrostatic attraction with materials having electrical polarity, it can be used even when it is desired to adsorb a specific substance charged positively or negatively (Fig. 1D).

According to another embodiment of the present invention, the electrically polarized dielectric material may include a dielectric material having hydroxyapatite formed on its surface by subjecting the electrically polarized dielectric powder to hydrothermal treatment.

According to another embodiment of the present invention, there is provided a method of manufacturing a scaffold for tissue engineering comprising the steps of: forming a dielectric material into a bulk or thin film form; Applying a voltage of 100 V / mm to 300 V / mm to both ends of the molded body, holding the temperature of 100 ° C to 400 ° C or more for 30 minutes to 2 hours, and cooling; Preparing an electrically polarized dielectric material by pulverizing the dielectric material that has undergone electroless polarization after cooling; And mixing the electrically polarized dielectric material with the biocompatible polymer to produce a tissue engineering scaffold. This is the same as or similar to that described above with reference to FIG. 1, so that the same description will be omitted here.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

EXAMPLE 1 Preparation of Electropolarized Dielectric Material According to the Invention

In order to form the calcium titanate powder in the form of a disk having a thickness of about 2 mm in the dielectric material, the compressor shown in Fig. 2 (a) was used. The compressor includes an electrical insulator and Teflon having heat resistance. This has the effect of forming the calcium titanate powder into a disk shape and facilitating the electric polarization treatment.

The above shaped body of the disk was subjected to an electric polarization treatment using the electric polarization treatment apparatus of FIG. 2 (b). The disk-shaped molded body was inserted into the electric polarization processing apparatus of FIG. 2 (b), a voltage of 100 V / mm or more was applied, the temperature of the shaped body was raised to 250 ° C. by using a heater, And maintained for about 1 hour so that the temperature could be sufficiently transferred to the molded body.

Thereafter, the heater was turned off under the condition that the voltage was applied, and the temperature was cooled until the temperature of the molded body reached room temperature. The cooled molded body was completed by the electric polarization treatment and was again made into a powder form using a mortar bowl or the like.

EXAMPLE 2 Preparation of a Scaffold Containing Electro Polarized Dielectric Material According to the Invention

The electropolished calcium titanate powder prepared in Example 1 was subjected to hydrothermal treatment at a temperature of 200 ° C for 15 hours in a? -Glycerophosphoric acid-containing hydrothermal solution adjusted to pH 11 So that hydroxyapatite was formed on the surface of the electrically polarized calcium titanate powder particles. 10% by weight of the calcium titanate powder formed by mixing the hydroxyapatite was mixed with 90% by weight of PLGA (PLA: PGA = 85: 15), which is a biocompatible polymer scaffold material, to prepare a porous scaffold using a slat leaching method.

Experimental Example 1. Protein adhesion of the electrically poled dielectric powder of Example 1

The following experiment was conducted to confirm the degree of protein attachment of the electrically poled dielectric powder of Example 1 of the present invention. (FITC-BSA, FITC-bovine serum albumin) labeled with 4 mg of fluorescent substance (FITC) was prepared in 20 ml of tertiary distilled water. 5 mg of the polarized calcium titanate powder of Example 1 and 5 mg of calcium titanate powder which had not been subjected to the electric polarization treatment as a control group were placed in a 1.5 ml tube and 1 ml of the prepared bovine serum albumin solution was added thereto. Lt; / RTI > The supernatant was removed from the tube using a centrifugal separator, and 1 ml of distilled water was added thereto. The solution was then removed by centrifugal separation to wash the powder. 1 ml of distilled water was further added to the powder, and the degree of fluorescence of the powder solution was measured using a laser confocal scanning microscope (LCSM, Leica TCS SP5 / Tandem / AOBS). The 488nm laser line of Ar laser was used, and the emission was about 495-560nm bandwidth. From the measured images, the average fluorescence per particle was calculated using an image analysis program (Leica LASAF), and the difference of each sample was analyzed.

The results of the experiment are shown in FIGS. 3A and 3B.

FIG. 3A is an image photograph showing the degree of BSA adhesion of Example 1 of the present invention and a control group. FIG. 3A, CTO-P represents Example 1 of the present invention, and CTO-T represents a control group. As shown in FIG. 3A, it can be seen that the fluorescence of Example 1 (CTO-P) of the present invention is more intense than that of the control (CTO-T). This can prove that the embodiment of the present invention binds better with the protein than the control.

FIG. 3B is a graph numerically showing the degree of adhesion of BSA in Example 1 of the present invention and a control group. FIG. As shown in FIG. 3B, Example 1 of the present invention shows that the degree of binding to bovine serum albumin is about 200 (au), which is twice as high as the binding degree of bovine serum albumin of about 100 (au) And it was able to confirm that it was excellent.

Experimental Example 2. Evaluation of bioactivity of scaffold of Example 2

In order to evaluate the bioactivity of the scaffold prepared in Example 2 of the present invention, the following experiment was conducted. For this experiment, a scaffold containing only the biocompatible polymer without the polarization-treated calcium titanate powder of Example 1 of the present invention as the control group 1 and a scaffold containing calcium pyrophosphate as the control group 2 were prepared Respectively. The scaffolds of the control group 1 and the control group 2 were prepared in the same manner as in Example 2, except for the kind and the inclusion of the dielectric material.

In order to evaluate the bioactivity of the scaffold of Example 2, Control 1 and Control 2, a biocompatible solution (141 mM NaCl, 4.0 mM KCl, 0.5 mM MgSO ₄ , 1.0 mM MgCl ₂ , 4.2 mM NaHCO ₃ , 5.0 mM CaCl 2 ₂ .2H ₂ O, and 2.0 mM KH ₂ PO ₄ , adjusted to pH 6.8 with NaOH) for 4 days and then photographed using a scanning microscope to evaluate the degree of calcium phosphate formation on the surface .

The results of the experiment are shown in FIG. Fig. 4 shows a scanning electron microscope photograph of Example 2, Control 1 and Control 2 before and after precipitation of a biosynthetic solution. 4 (A) is a scanning electron micrograph of the control group 1 before the precipitation of the biocompatible solution, (B) is the scanning electron microscope photograph of the biocompatible solution of Example 2 before precipitation, (E) is a scanning electron microscope photograph of the biocompatible solution after precipitation of the biocompatible solution of Example 2, (F) is a scanning electron microscope photograph of the biocompatible solution of Control 2 It is a scanning microscope photograph after sedimentation. As shown in FIG. 4, calcium phosphate was hardly formed in the case of the control group 1 as seen from (D), but calcium phosphate was formed in the case of the example 2 (E) and the control 2 (F) there was. It was confirmed that the calcium phosphate compound of Example 2 (E) had a thicker calcium phosphate compound than that of the control 2 (F). Thus, it was confirmed that Example 2 had the highest bioactivity as compared with the control 1 and the control 2. Accordingly, it has been confirmed that the scaffold containing the dielectric material subjected to the electropolishing according to the present invention promotes bioactivity.

Although several embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various modifications may be made without departing from the principles and spirit of the invention . The scope of the invention will be determined by the appended claims and their equivalents.

Claims

A biocompatible polymer;
Wherein the scaffold comprises an electrically poled dielectric material.

The method according to claim 1,
The dielectric material may be,
Wherein at least one of hydroxyapatite, titanium dioxide, and calcium titanate is electrically polarized and then powdered.

3. The method of claim 2,
The dielectric material may be,
At least one of the hydroxyapatite, titanium dioxide and calcium titanate is molded into a bulk or thin film form, a voltage of 100 V to 300 V is applied to both ends of the molded body, and a temperature of 100 to 400 ° C is maintained for 30 minutes to 2 hours Lt; RTI ID = 0.0 > electrochemically < / RTI > treated dielectric material.

The method of claim 3,
Wherein the electrically poled dielectric material is a < RTI ID = 0.0 >
Wherein the dielectric material comprises hydrothermal treatment of the electrically poled dielectric powder to form hydroxyapatite on its surface.

5. The method of claim 4,
The biocompatible polymer may be,
Polyglycolic acid, polylactic acid, and polylactic acid glycolic acid.

A method for manufacturing a scaffold for tissue engineering,
Molding the dielectric material into a bulk or thin film form;
Applying a voltage of 100 V / mm to 300 V / mm to both ends of the molded body, holding the temperature of 100 ° C to 400 ° C or more for 30 minutes to 2 hours, and cooling;
Preparing an electrically polarized dielectric material by pulverizing the dielectric material that has undergone electroless polarization after cooling;
And mixing the electrically polarized dielectric material with a biocompatible polymer to produce a tissue engineering scaffold.

The method according to claim 6,
The dielectric material may be,
Hydroxyapatite, titanium dioxide, and calcium titanate. &Lt; RTI ID = 0.0 > 11. < / RTI >

8. The method of claim 7,
The preparation step of the electrically polarized dielectric material,
Further comprising hydrothermally processing the electrically poled dielectric powder to prepare a dielectric material having hydroxyapatite on its surface.

9. The method of claim 8,
The biocompatible polymer may be,
A polylactic acid, and a polylactic acid, and a polylactic acid, a polyglycolic acid, a polylactic acid, and a polylactic acid glycol acid.