DEVICE AND METHOD FOR PROCESSING A 3D POLYMER STRUCTURE

Abstract

A device and method for processing a 3D polymer structure with a paramagnetic substance distributed homogeneously in the material of the 3D polymer structure is disclosed. A magnetic field generator generates a static magnetic field in a working zone of the device. Gradient coils for generating magnetic gradient fields in at least all three spatial directions x, y, z, where the paramagnetic substance can be spatially encoded in a defined voxel V of the 3D polymer structure. An RF field generator irradiates RF radiation into the working zone. A control unit controls the RF field generator in such a way that the spatially encoded paramagnetic substance in the voxel V can be excited by a field frequency of the RF radiation which is tuned to the paramagnetic substance, in order to destroy or decompose the 3D polymer structure solely in the defined voxel V.

Claims

1. A device configured for processing a 3D polymer structure with a paramagnetic substance distributed as homogeneously as possible in the material of the 3D polymer structure, comprising: a magnetic field generator configured for generating a static magnetic field B.sub.0 in a working zone of the device, in which the 3D polymer structure can be arranged; Gradient coils configured for generating magnetic gradient fields B.sub.1, B.sub.2, B.sub.3 in at least all three spatial directions x, y, z, by means of which the paramagnetic substance can be spatially encoded in a defined voxel V of the 3D polymer structure; a radio frequency field generator for irradiating RF radiation into the working zone (26); and a control unit which is configured to control the RF field generator in such a way that the spatially encoded paramagnetic substance in the voxel V can be excited by means of a field frequency of the RF radiation tuned to the paramagnetic substance (32) in order to destroy the 3D polymer structure solely in the defined voxel V.

2. The device according to claim 1, wherein the device also serves to generate the 3D polymer structure from a polymer precursor with a paramagnetic substance distributed homogeneously or essentially homogeneously distributed therein, wherein the polymer precursor can be arranged in the working zone of the device, wherein magnetic gradient fields B.sub.1, B.sub.2, B.sub.3 can be generated in at least all three spatial directions x, y, z by means of the gradient coils in order to spatially encode the paramagnetic substance sequentially in time in defined voxels V of the polymer precursor, and the control unit is configured to control the RF field generator in such a way that the paramagnetic substance in the respective spatially encoded voxel V can be excited by means of a field frequency f of the RF radiation tuned to the paramagnetic substance in such a way that thermal polymerization of the polymer precursor is ensured in the defined voxel V.

3. The device according to claim 1, wherein the field frequency f of the RF radiation is between between 1 KHz and 789 THz.

4. The device according to claim 1, wherein the field frequency f of the RF radiation is between 100 KHz or 108 KHz and 789 THz.

5. The device according to claim 1, wherein the field frequency f of the RF radiation is between 108 KHz and 789 THz.

6. The device according to claim 1, wherein the device comprises an MRI unit or a different imaging appliance for obtaining image data.

7. The device according to claim 6, wherein the control unit is configured to compare image data of the 3D polymer structure with CAD/CAM data for the 3D polymer structure and, if deviations of the partially processed/partially generated 3D polymer structure from the CAD/CAM data are detected, being geometric deviations, to take into account the image data and/or the deviations during the further processing/generation of the 3D polymer structure.

8. The device according to claim 1, wherein the working zone is arranged within a housing.

9. The device according to claim 8, wherein the paramagnetic substance comprises metal particles in the form of nanoparticulate magnetite particles or nanoparticulate iron particles or metal organyls.

10. The device according to claim 8, wherein the metal particles are present in a concentration of >1000 particles per cubic millimetre of 3D polymer structure and/or the polymer precursor.

11. The device according to claim 8, wherein the metal particles are present in a concentration of >10,000 particles per cubic millimetre of the 3D polymer structure and/or the polymer precursor.

12. The device according to claim 1, wherein the material of the 3D polymer structure or of the polymer precursor comprises one or more additives, being from the group of fibers, dyes, antibacterial substances, growth factors, nanoparticles/tubes, mineral fillers, metallic materials, glycosaminoglycans, MMC substances, polypeptide motifs, promoters, terminators, inhibitors, catalysts, sensitizers and/or immunomodulators.

13. A method for processing the 3D polymer structure with the paramagnetic substance distributed as homogeneously as possible in the material of the 3D polymer structure by means of the device according to claim 1, comprising the following steps: a. defining CAD/CAM data for the 3D polymer structure; b. arranging the 3D polymer structure in the working zone of the device; c. spatially encoding a voxel V within the 3D polymer structure as a function of the CAD/CAM data by applying magnetic gradient fields B.sub.1, B.sub.2, B3; d. destroying the 3D polymer structure solely in the at least one spatially encoded voxel V by irradiating RF radiation by means of which the paramagnetic substance in the respective voxel V is excited to destructive thermogenic oscillations; and e. repeating the steps c) and d) for further voxels V within the 3D polymer structure (28), i.e., sequential: i. spatially encoding further, preferably spatially adjacent, voxels V in the 3D polymer structure as a function of the CAD/CAM data; and ii. destroying the 3D polymer structure of the respective further spatially encoded voxel V by irradiating RF radiation, by means of which the paramagnetic substance in the respective further voxel V is excited to destructive thermogenic oscillations.

14. The method according to claim 13, wherein the 3D polymer structure is generated by means of the device.

15. The method according to claim 13, including the further steps of: f. arranging a polymer precursor with a paramagnetic substance homogeneously or substantially homogeneously distributed therein; g. spatially encoding at least one voxel V within the 3D polymer precursor as a function of the CAD/CAM data by applying magnetic gradient fields B.sub.1, B.sub.2, B.sub.3; and h. polymerizing the polymer precursor in the at least one spatially encoded first voxel V by irradiating RF radiation by means of which the paramagnetic substance in the respective voxel V is excited to thermogenic oscillations; and i. repeating the steps g) and h) to generate the 3D polymer structure.

16. The method according to claim 13, wherein the frequency f of the RF radiation, i.e., of the applied RF field, is selected depending on the (known) resonant frequency f.sub.0 of the paramagnetic substance to be excited with the RF radiation.

17. The method according to claim 13, wherein the voxels V are each defined with a uniform (volume) size or in that the voxels V are at least partially defined with a different (volume) size.

18. The method according to claim 13, wherein (image) data are obtained for the 3D polymer structure, being by magnetic resonance tomography, and the further processing of the 3D polymer structure or the further manufacturing of the 3D polymer structure takes place taking into account these magnetic resonance tomography data.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0178] Detailed description of the invention and drawing

[0179] FIG. 1 is the schematic structure of a device according to the invention and with a polymer precursor or 3D polymer structure that can be arranged in the working zone of the device;

[0180] FIG. 2 is the 3D polymer structure or polymer precursor with the paramagnetic substance in a selected voxel;

[0181] FIG. 3 is a housing within which the polymer structure/polymer precursor can be arranged during the 3D machining or manufacturing process; and

[0182] FIG. 4 is a block diagram of the method according to the invention for processing or generating a 3D polymer structure with its individual method steps.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0183] FIG. 1 is a device 10 with a housing 12, having a magnetic field generator 14 for generating a static magnetic field B.sub.0, optional shimming coils 16 and gradient coils 18, an RF field generator 20, a control unit 22 with a computer system 24 and an input and operating console 24a, as well as a working zone 26 arranged in the housing 12. A 3D polymer structure 28 (at least partially polymerized or polymerized) to be processed and/or a polymer precursor 30 (=a prepolymer), which serves as a starting material for the 3D polymer structure to be produced with the device 10, can be arranged in the working zone 26.

[0184] The magnetic field generator 14 serves to generate a homogeneous static magnetic field B.sub.0 (hereinafter referred to as the B.sub.0 field) in the working zone 26. The field strength of the B.sub.0 field is greater than the earth's magnetic field by orders of magnitude. The magnetic field generator 14 can, for example, comprise a permanent magnet or a superconducting magnet. This homogeneous B.sub.0 field can be modified by the gradient coils 18 in a targeted manner. The gradient coils 18 are preferably located on the circumference of the working zone 26. With these gradient coils 18, continuously increasing or decreasing magnetic fields, so-called gradient fields can be superimposed on the static B.sub.0 field in at least all three spatial directions x, y, z in a defined manner.

[0185] The 3D polymer structure 28/polymer precursor 30 comprises, according to the schematic representation of a voxel V of in FIG. 2, a paramagnetic substance 32, which is preferably arranged homogeneously distributed in the 3D polymer structure 28/polymer precursor 30. The paramagnetic substance 32 is preferably formed by superparamagnetic nanoparticulate metal particles 34 (=nano-oscillators). The metal particles 34 may in particular consist of nanoparticulate magnetite (Fe.sub.3O.sub.4) or a silver halide (Ag.sub.nX.sub.n). One cubic millimeter (mm.sup.3) of the 3D polymer structure 28 or the polymer precursor 30 preferably contains more than 1000, preferably more than 10,000, and up to 10.sup.17 the metal particles 34.

[0186] In the static B.sub.0 field, all metal particles 34 align their rotational moments parallel or antiparallel to the magnetic field lines of the B.sub.0 field. This is accompanied by a synchronization of their resonance frequency sensitivity for irradiated RF radiation or RF pulses. In addition to the material, polarity, geometry and size of the metal particles 34, the resonant frequency susceptibility depends on the field strength of the B.sub.0 field. For each field strength of the B.sub.0 field therefore, only one single specific frequency of the electromagnetic RF radiation exists, which maximally stimulates all metal particles configurated in the same way as oscillatorsthe so-called resonant frequency.

[0187] In simple (theoretical) systems without damping, the resonant frequency is equal to the undamped natural frequency (characteristic frequency) f.sub.0 of the paramagnetic metal particles 34. In attenuated systems, the frequency at which the maximum amplitude occurs is always lower than the unattenuated natural frequency.

[0188] Under resonance conditions, all metal particles 34 excitable by the RF radiation thus have a maximum energy absorption susceptibility with regard to the specific alternating RF field. This results in a significantly increased oscillatory movement of the metal particles 34. These oscillation movements are converted (at the molecular level) into thermal energy due to resistance and friction effects with a minimum spatial coupling distance. This can lead to the (locally limited) destruction of the 3D polymer structure 28 or to the polymerization of the polymer precursor 30. The metal particles 34 can thus be referred to as nano-oscillators.

[0189] The dynamic gradient fields (B1, B2, B3; not shown in the drawing) of the device 10 serve in a manner corresponding to that of nuclear magnetic resonance tomography imaging for slice selection and location encoding in at least 3 spatial directions, i.e., functionally for indirect focusing of the RF radiation irradiated into the working zone by means of the RF field generator 20.

[0190] The gradient fields are characterized by a continuous increase or decrease in the respective magnetic field strength along their characteristic axes x, y, z, relative to the B.sub.0 field. At this point, reference is made to the similar gradient fields familiar to the person skilled in the art in nuclear magnetic resonance tomography. A switched-on gradient field in the x-axis is therefore superimposed on the previously homogeneous permanent static B.sub.0 field, and thus leads to a linear increase or decrease of the total static field strength along the x-axis. The same applies to each introduced gradient field along the y-axis and z-axis. As a result, each metal particle 34 or each spatial volume or voxel of the polymer precursor 30 in three-dimensional space has its own individual electromagnetic niche (=spatial encoding) inherent to it in the intersection of the at least three gradient fields.

[0191] Thus, if the magnetic microenvironment of each oscillator or each voxel of the 3D polymer structure 28/polymer precursor 30 differs linearly in at least all three spatial directions from the magnetic microenvironment of its neighboring oscillator or adjacent voxel (=neighboring voxel), then each nanoparticle or the nanoparticles of each individual voxel has/have its own individual resonant frequency, and can therefore be individually addressed in isolation, and selectively excited by an undirected electromagnetic RF field. In this case, the respective steepness of the x, y, z gradient fields defines the edge lengths of the voxels in all 3 spatial directions x, y, z, ideally by a simultaneous total superposition of their local field strength, alternatively, sequentially, e.g., using the inverse Fourier transformation.

[0192] The control unit 22 of the device 10 is set up to control the RF field generator 20 in such a way that RF radiation with a field frequency tuned to the resonant frequency of the metal particles/oscillators is irradiated into the working zone 26 in order to heat and destroy the 3D polymer structure 28 or the polymer precursor 30 in the previously spatially encoded voxel V or in the previously spatially encoded contiguous volume unit of the 3D polymer structure 28/polymer precursor 30 locally en bloc and/or in case of the polymer precursor 30 to polymerize it.

[0193] The typical field frequency of the RF radiation for oscillation excitation of the paramagnetic substance is between 100 or 108 KHz and 789 THz.

[0194] The control unit 22 of the device 10 preferably has an operating mode which serves to obtain image data (e.g., magnetic resonance tomography imaging data) from the working zone 26 and/or the 3D polymer structure 28 and/or the polymer precursor 30. The control unit 22, in particular the computer system 24, serves to control all operating processes of the device 10 on the basis of predetermined CAD/CAM data. Furthermore, the control unit 22 is preferably configured to evaluate the image data. The control unit 22 can thus in particular be configured to compare the CAD/CAM data with the previously obtained image data and, when a discrepancy greater than a predefined permissible maximum deviation is detected, to continue the further machining and/or manufacturing process on the basis of the image data. Here, the control unit can in particular be configured (programmed) to modify the CAD/CAM data for the remaining 3D polymer structure to be processed or produced. In this way, the 3D polymer structure can be processed/produced with particularly tight tolerances.

[0195] During in-vivo processing and/or manufacturing (fabrication) of the 3D polymer structure 28, information on the anatomical structures adjacent to or interacting with the 3D polymer structure can furthermore be taken into account in real time in the manufacturing process. Here, the use of artificial intelligence or a software application with AI capability can be advantageous. Systematic deviations detected during the machining and/or manufacturing process, possibly as a function of the polymer precursor used, the paramagnetic substance, the milieu variables, etc., can be taken into account and prospectively incorporated in the creation of the CAD/CAM data for the 3D polymer structure in question and/or the machining or manufacturing process.

[0196] According to FIG. 3, the working zone 26 of the device can be encompassed by means of a, preferably gas-tight housing 36. For example, the housing 36 can be made of plastic or glass or another material that does not shield against RF fields or magnetic fields. The housing can be formed, for example, by a plastic film.

[0197] A pump 38 (FIG. 1) can be assigned to the working zone of the device 10, by means of which the atmosphere in the housing 36 can be evacuated or substantially evacuated and/or by means of which the working zone within the housing 36 can be filled with a fluid, in particular a working atmosphere A, specified for the manufacturing process. In this way, for example, undesired oxidative processes of the 3D polymer structure 28/polymer precursor 30 by oxygen contained in the working atmosphere A can be counteracted.

[0198] The device 10 can be formed in particular by a modified MRI unit whose control unit 22 is adapted to the processing and/or production of the 3D polymer structure in the manner explained above.

[0199] The polymer precursor 30 can have identical or different monomers and/or polymers (especially also dimers, oligomers). Furthermore, the 3D polymer structure 28/polymer precursor 30 may comprise fibers and/or one or more other additives as explained at the outset. By way of example only, additives from the group of dyes, antibacterial substances, antibiotics or growth factors may be mentioned here.

[0200] Depending on the mechanical, electrical or biological requirements demanded from the 3D polymer structure, the polymer precursor 30 may have a viscosity of approximately 10.sup.2 mPa.Math.s to 10.sup.5 mPa.Math.s or greater. If the 3D polymer structure 28 is to be used, for example, as an implant in humans/animals, the polymer precursor 30 in the non-polymerized state is preferably non-toxic to the animal/human organism and preferably degradable by the body's own enzymes and/or eliminable from the human/animal body per viam naturalis.

[0201] The device 10 can be used universally. For example, medical implants, in particular bone replacements, scaffolds for tissue/organs or vascular prostheses, can thus be produced. This can be done in vitro or directly in vivo.

[0202] Below, the method 100 for processing or producing a 3D polymer structure with a paramagnetic substance 32 (see FIG. 2) dispersed as homogeneously as possible in the material of the 3D polymer structure is explained in more detail with additional reference to the block diagram shown in FIG. 4.

[0203] The method 100 necessarily presupposes the use of the device 10 described above in the context of FIGS. 1 to 3 and comprises the following steps: [0204] a) defining 102 CAD/CAM data 40 for the 3D polymer structure 28; [0205] b) providing 104 the 3D polymer structure 28 in the working zone 26 of the device 10; [0206] c) spatially encoding 106 a voxel V within the 3D polymer structure 28 as a function of the CAD/CAM data 40 by applying magnetic gradient fields B.sub.1, B.sub.2, B.sub.3; [0207] d) destroying 108 the 3D polymer structure 28 in the at least one spatially encoded voxel V by irradiating 110 RF radiation 42 by means of which the paramagnetic substance 32 in the respective voxel V is excited to destructive thermogenic oscillations; and [0208] e) repeating steps 106 and 108 for further voxels V within the 3D polymer structure 28, i.e., sequentially spatially encoding further, preferably spatially adjacent, voxels V in the 3D polymer structure 28 as a function of the CAD/CAM data and destruction of the 3D polymer structure 28 in the respective further spatially encoded voxels V by irradiating (110) RF radiation 42, by means of which the paramagnetic substance (32) in the respective further voxel V is excited to destructive thermogenic oscillations until the 3D polymer structure (28) has been processed.

[0209] The following process steps serve the generation of the 3D structure 28 within the working zone 26 of the device 10 from a polymer precursor after step 102 of defining the CAD/CAM data of the polymer structure: arranging 114 of a polymer precursor 30 with a paramagnetic substance 32 distributed homogeneously or substantially homogeneously therein in the working zone 26 of the device 10; spatially encoding 116 a voxel V within the polymer precursor 30 as a function of the CAD/CAM data by applying magnetic gradient fields B.sub.1, B.sub.2, B.sub.3; polymerizing 118 the polymer precursor 30 in the at least one spatially encoded voxel V by irradiating 120 RF radiation 42, by means of which the paramagnetic substance 32 in the respective further voxel V is excited to thermogenic oscillations; and subsequently sequentially spatially encoding 122 further voxels V, preferably spatially adjacent to one another in the polymer precursor 30 as a function of the CAD/CAM data 40 and polymerizing 124 of the polymer precursor in the respective further spatially encoded voxels V by irradiating 126 RF radiation 42, by means of which the paramagnetic substance 32 in the respective further voxel V is excited to thermogenic oscillations until the 3D polymer structure to be produced is polymerized.

[0210] The frequency f of the RF radiation 42, i.e., of the applied RF field, is preferably tuned to the respective resonant frequency f.sub.0 of the paramagnetic substance 32 to be excited with the RF radiation and/or to the metal particles 34 of the polymer precursor 30 or coincides with it. The resonant frequency f.sub.0 of the respective paramagnetic substance 32 can be determined experimentally.

[0211] It should be noted that the voxels V of the 3D polymer structure and/or the polymer precursor can each have a uniform size or can differ at least partially in size from one another.

[0212] According to a further embodiment of the invention, image data 44 of the non-polymerized and/or the polymerized polymer precursor 30 may be obtained in an optional step or steps 128, in particular by magnetic resonance tomography or by an alternative imaging method. Steps 124 may occur after any other process step.

[0213] In an optional step 130, the image data 44 can be compared with the CAD/CAM data 40 and the CAD/CAM data 40 for the 3D polymer structure 28 can be modified on the basis of the image data for generating the remaining 3D polymer structure 28 if a maximum deviation of the already generated 3D polymer structure 28 is exceeded. In this way, the 3D polymer structure 28 can be processed or produced with a particularly tight tolerance.

[0214] For medical indications, the 3D polymer structure 28 can be completely processed or generated in a first living being (not shown in the drawing), i.e., in-vivo, in order to be available as an implant for another living being (not shown) after its removal.

[0215] By means of the method 100 according to the invention, as described at the outset, any 3D polymer structures, for example articles of daily use, machine parts, support structures for cells, tissue, organs can be processed and optionally also produced.