CN1318001C - Photocureable rapid shaping indirect manufacturing method for controllable microtube structure stand - Google Patents

Abstract

The invention discloses a light-cured rapid prototyping indirect manufacturing method of a controllable micro-pipe structure support. The method is based on computer-aided design (CAD) and light-cured rapid prototyping equipment, precisely designs and controls the internal microstructure of the support, and realizes the shape and shape of the support. Integrated manufacturing of internal controllable microstructure. According to the actual CT data, three-dimensional CAD software is used to reconstruct the bone shape; according to the principle of promoting cell growth and osteogenesis, the internal microchannels of different structures are designed, and the size, shape, direction, branching and interconnection of the microchannels are controlled. Use photocuring rapid prototyping equipment to construct corresponding resin molds, fill the molds with biomaterials, and after curing, remove the resin molds by thermal decomposition to form tissue engineering scaffolds with controllable microstructures.

Description

Light-curing rapid prototyping indirect manufacturing method of controllable microchannel structure scaffold

technical field

The invention belongs to the light-curing rapid prototyping manufacturing technology, relates to the preparation of a tissue engineering support, in particular to the indirect manufacturing method of the light-curing rapid prototyping of the controllable micro-pipe structure support.

Background technique

As we all know, in bone tissue engineering, as a temporary carrier of cells, the scaffold should not only have the same appearance as the replaced part, but also the internal microstructure must meet the following conditions: it is conducive to the growth of cells/tissues, and the absorption of nutrients and blood. supply, which is conducive to the exchange of gases, etc. Because the shape of the bone is very complex, it is very difficult to manufacture a bracket that matches the shape of the bone using traditional processing methods. The pore-making methods of traditional scaffolds (such as: phase separation/emulsification, fiber bonding, solution casting/particle leaching, fusion molding, gas foaming and the combination of these methods) have been widely used. However, there are fatal shortcomings in the traditional scaffold manufacturing method, mainly manifested in the fact that the manufacturing process is manual, using toxic organic solvents, it is difficult to manufacture a shape that matches the bone, and it is impossible to accurately control the internal micropores or microchannels of the scaffold. Structural features such as distribution, size, spatial orientation, and connectivity.

Rapid Prototyping (RP) technology is a new manufacturing technology formed in recent years. Its biggest advantage is that it is directly driven by numbers, and it is not limited by the complexity of the shape, and it can directly form a three-dimensional entity. The use of rapid prototyping technology to manufacture bone tissue engineering scaffolds can not only avoid the above shortcomings, but also effectively combine CAD technology to realize the optimization and bionic design of the scaffold structure, as well as the precise control of the scaffold manufacturing process. The application of rapid prototyping technology in scaffold construction has been reported at home and abroad, and most of them use fused deposition (FDM) and three-dimensional printing (3DP) technologies to directly construct three-dimensional porous scaffolds. The stent constructed by this method is mostly made of polymer, and thus lacks sufficient mechanical strength. Not intended as a bone substitute in weight-bearing areas.

Contents of the invention

The object of the present invention is to provide a method for indirectly preparing a controllable micro-pipe structure support by using photocuring rapid prototyping manufacturing technology.

The technical solution to achieve the above purpose is an indirect manufacturing method of light-cured rapid prototyping of controllable micro-pipe structure support, based on clinical CT data and computer-aided design, using light-cured rapid prototyping equipment combined with rapid casting to prepare controllable The micro-pipe structure support is characterized in that it comprises the following steps:

1) According to the actual clinical CT data of bone tissue matched with the prepared part, CAD software is used to realize the three-dimensional reconstruction of the bone shape and design the internal microstructure of the scaffold;

2) Convert the entity data designed by the above-mentioned CAD software into an STL format file, and after layered slicing processing by the Rpdata software, generate the default format file of the light-curing rapid prototyping equipment, and input it into the light-curing rapid prototyping equipment;

The laser light source of the above photocuring rapid prototyping equipment is a solid-state laser with a wavelength of 230-355nm, and its control parameters are as follows:

Filling scanning speed: Vs ₁ =5000mm/s

Contour scanning speed: Vs ₂ =3000mm/s

Scanning distance: Gs＝0.10mm

Layer thickness: Lh=0.10mm

Spot diameter: D1＝0.2mm

3) Manufacture the resin mold of the above-mentioned corresponding bracket by light-curing rapid prototyping equipment; and fill the injection-type self-curing calcium phosphate bone cement, β-tricalcium phosphate bioceramic or hydroxyapatite biomaterial in the above-mentioned resin mold, and wait for the After curing, thermally decompose and remove the mold and sinter to form a controllable micro-pipe structure support;

The methods for thermally decomposing and sintering the filled biomaterials to remove the resin mold are as follows:

A. Put the resin mold of cured and injected self-curing calcium phosphate bone cement into a high-temperature box-type resistance furnace. The furnace temperature is room temperature, and the heating rate is set at 100°C/h. Change it to 300°C/h, raise it to 900°C, and keep it warm for 180 minutes. After cooling to room temperature with the furnace, take it out, and the resin mold can be removed to obtain a controllable micropipeline structure support that matches the design;

B. Put the resin mold of the cured β-tricalcium phosphate bioceramic into a high-temperature box-type resistance furnace, and the sintering temperature is 1150°C; when the temperature reaches 900°C, the resin mold is thermally decomposed, and then further sintered to obtain Controllable micro-channel structure scaffold;

C. Put the cured hydroxyapatite resin mold into a high-temperature box-type resistance furnace. The sintering temperature is 1250°C. When the temperature reaches 900°C, the resin mold is thermally decomposed and further sintered to obtain a controllable micropipe structural support.

The method of the present invention overcomes the shortcomings of difficult shape and structure and uncontrollable internal micro-pipe structure in the traditional scaffold manufacturing method, and can be conveniently and accurately designed by using CAD technology, which is beneficial to cell-tissue growth and survival, oxygen and nutrient supply, A three-dimensional structure that facilitates the excretion of metabolites. Accurate control of the manufacturing process is achieved through rapid prototyping technology, so that the bone tissue engineering scaffold that is completely consistent with the design in terms of shape, size, distribution, spatial orientation, and interconnectivity of the internal microchannels can be constructed.

Description of drawings

Fig. 1 is a picture of the support and its negative CAD model;

Fig. 2 is the CAD model picture of the reconstructed dog femur distal end shape and the designed internal micro-canal structure;

Fig. 3 is a flowchart of preparing a controllable microstructure scaffold by the method of the present invention.

The present invention will be described in further detail below in conjunction with the examples given by the inventor.

Detailed ways

According to the technical scheme of the present invention, the CAD design software adopted in the present invention selects commercialized three-dimensional CAD design software Unigraphics 18.0 as a design tool. The designed support is a cylinder with a spoke-shaped internal structure. 14.5mm in diameter and 11.6mm in height; as shown in Figure 1a. The corresponding scaffold negative is shown in Fig. 1b. Its internal features are described as follows: in the x-y plane is a rectangular channel of 300 μm × 300 μm, extending radially from the center of the scaffold to the outer surface; in the z direction is a cylindrical channel with a diameter of 500 μm running from the top to the bottom of the scaffold, and these cylindrical The channels are connected by circular channels in the x-y plane. The porosity generated by these microchannels is 21.6%.

The negative CAD entity data of the bracket is converted into the triangular surface (STL) data format, and after the Rpdata software layered slice processing, the default format file of rapid prototyping is generated, and then input to the light-curing rapid prototyping equipment (SPS600) to manufacture the corresponding resin prototype mold. The control parameters of the photocuring rapid prototyping equipment are as follows:

Filling scanning speed Vs ₁ =5000mm/s

Contour scanning speed Vs ₂ =3000mm/s

Scanning distance Gs＝0.10mm

Layer thickness Lh＝0.10mm

Spot diameter D1=0.2mm

Laser light source: solid-state laser (355nm wavelength)

Fill the injection-type self-curing calcium phosphate cement (Calcium phosphate cement, CPC) bone cement biomaterial into the resin mold, and put it into a high-temperature box-type resistance furnace after it is cured. The furnace temperature is room temperature, and the heating rate is set at 100°C /h, after rising to 500°C, change the heating rate to 300°C/h, rise to 900°C, and keep it warm for 180 minutes, then take it out after cooling to room temperature with the furnace, and then remove the resin mold, and get a controllable Structural Scaffolds for Micropipes.

If the shape of the scaffold is square and its internal structure is in the shape of an orthogonal network frame, it is also easy to obtain a controllable micropipe structure scaffold conforming to the design according to the above steps.

Provide the specific embodiment of dog femur distal end bionic support below:

See Figure 2 for a picture of the bionic scaffold for the distal femur of a dog prepared by the inventive method, and the process flow is shown in Figure 3 . According to the clinical CT data, after a series of image processing, the continuous CT images are input into the Mimics software in order to obtain the point cloud data of the distal femur of the dog, and store them in IGES format files, and then input the obtained point cloud data into the Surface The software performs surface reconstruction. Due to the complex shape of the joint surface of the distal femur, large curvature changes, and certain deviations in the obtained point cloud data, if only traditional faceting methods are used, such as: Loft, Sweep, Through Curve and Through CurveMesh, etc., cannot effectively construct high-quality joint surfaces. Therefore, the three-dimensional reconstruction of the joint surface is completed by using the two faceting methods of point data paste and freeform surface (fit freeform) and point data and boundary curve construction surface (fit freeform with cloud&boundary curve), and the files are stored in IGES format. Then input it into the Unigraphics software to reconstruct the three-dimensional entity of the bone shape, and design the internal microchannel structure according to the principles of facilitating cell/tissue growth, nutrient delivery, and promoting osteogenesis, mainly including the distribution, size, shape, and space of the internal microchannels. Trends, branches, interconnectedness. Figure 2 shows the reconstructed dog's distal femur shape and the designed internal microcanal structure CAD model. Then convert these CAD entity data into STL format files, and after layered slice processing by Rpdata software, the default rapid prototyping format files are generated, and then input to the photocuring rapid prototyping equipment with light source characteristics of 230-355nm light source to construct the corresponding resin model . Fill the resin mold with self-curing CPC biomaterial, put it into a high-temperature box-type resistance furnace after curing, enter the furnace at room temperature, and set the heating rate at 100°C/h. After rising to 500°C, change the heating rate to The temperature is 300°C/h, raised to 900°C to decompose the resin mold and keep it warm for 180 minutes, then take it out after cooling to room temperature with the furnace. In this way, a three-dimensional porous scaffold with a controllable micro-canal structure and an individualized shape matching the distal femur of a dog is formed.

Certainly, the controllable micro-pipe structure scaffold of any shape can be prepared by adopting the above-mentioned steps of the method of the present invention. Other biological materials can also be used, such as β-tricalcium phosphate (TCP) bioceramics, whose sintering temperature is 1150°C; hydroxyapatite (HA), whose sintering temperature is 1250°C. When the temperature reaches 900 °C, the resin mold is thermally decomposed, and then further sintered to obtain a controllable micro-pipe structure scaffold.

Because the invention adopts biomaterials, it can manufacture bioactive artificial bone scaffolds that match the replaced parts in shape and have microchannel structures that are conducive to cell-tissue growth inside. It can overcome the shortcomings of metal (such as stainless steel, titanium alloy) bone substitutes that are widely used in clinical practice that cannot be absorbed and degraded by the human body. At the same time, new bone is continuously generated in the microchannel of the scaffold, and finally the biomaterial is completely degraded, and the new bone tissue based on the scaffold grows together with the original bone tissue in the body to form a new organic whole.

Claims (1)

1. the photocureable rapid shaping indirect manufacturing method of a controllable microtube structure stand, based on Clinical CT data and computer-aided design, adopt light-curing rapid forming equipment and combination casting preparation controllable microtube structure stand fast, it is characterized in that, comprise the following steps:

1) the osseous tissue actual clinical CT data that are complementary according to the position for preparing are used CAD software and are realized skeleton profile three-dimensionalreconstruction, design internal stent micro structure;

2) solid data with above-mentioned CAD software design converts the STL formatted file to, through Rpdata software hierarchy slicing treatment, generates the formatted file of light-curing rapid forming equipment acquiescence, is input in the light-curing rapid forming equipment;

The LASER Light Source of above-mentioned light-curing rapid forming equipment is the solid state laser of 230-355nm wavelength, and its control parameter is as follows:

Fill scanning speed: Vs ₁=5000mm/s

Profile scan speed: Vs ₂=3000mm/s

Sweep span: Gs=0.10mm

Bed thickness: Lh=0.10mm

Spot diameter: D1=0.2mm

3) produce the resin die of above-mentioned support by light-curing rapid forming equipment, and in above-mentioned resin die filling injection type self-curable calcium phosphate bone cement, bata-tricalcium phosphate bioceramic or hydroxylapatite biology material, treat that it solidifies the back thermal decomposition and goes mould and sinter molding, can obtain controllable microtube structure stand;

The method that resin die and sinter molding are removed in the thermal decomposition of filling injection type self-curable calcium phosphate bone cement is, injection-type self-curable calcium phosphate bone cement is filled in the resin die, treat to put into high temperature box type resistance furnace after it solidifies, charging temperature is a room temperature, programming rate is set at 100 ℃/h, after rising to 500 ℃, change programming rate into 300 ℃/h, rise to 900 ℃, and be incubated 180 minutes, take out after cooling to room temperature with the furnace, can remove resin die, obtain and design the controllable microtube structure stand that conforms to;

Fill the thermal decomposition of bata-tricalcium phosphate bioceramic and remove the method for resin die and sinter molding and be, the bata-tricalcium phosphate bioceramic is filled in the resin die, treat to put into high temperature box type resistance furnace after it solidifies, its sintering temperature is 1150 ℃; When temperature reached 900 ℃, resin die was thermal decomposited, and further again sintering obtains controllable microtube structure stand;

The method of filling hydroxylapatite biology material thermal decomposition removal resin die and sinter molding is, hydroxyapatite is filled in the resin die, treat to put into high temperature box type resistance furnace after it solidifies, its sintering temperature is 1250 ℃, when temperature reaches 900 ℃, resin die is thermal decomposited, and further again sintering obtains controllable microtube structure stand.

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