Method and apparatus for volumetric additive manufacturing of cell-loaded resins
The present invention is related to a method and apparatus for the volumetric fabrication of three-dimensional objects or articles from photoresponsive materials loaded with scattering particles, by adjusting the refractive index of said photoresponsive material ( 12 ) so as to match the refractive index of said scattering particles ( 30 ), and/or using a light source emitting light of a wavelength longer than 630 nm, preferably in a range from 630 nm to 1050 nm, more preferably in a range from 650 nm to 900 nm.
1 . A method of fabricating a three-dimensional article comprising the steps of:
providing, in a transparent container of an apparatus for tomographic additive manufacturing, a photoresponsive material, wherein said photoresponsive material contains scattering particles,
adjusting a refractive index of said photoresponsive material so as to match the refractive index of said scattering particles;
generating from a light source of said apparatus two-dimensional light-patterns based on computed tomographic projections of said three-dimensional article, and
projecting two-dimensional light-patterns into said photoresponsive material and defining a three-dimensional dose distribution, thereby creating a distribution of alterations in said photoresponsive material, and thereby creating said article.
2 . The method according to claim 1 , wherein the refractive index of said photoresponsive material is adjusted by adding to said photoresponsive material a medium having a different refractive index that will act as a tunable refractive index medium.
3 . The method according to claim 2 , wherein said medium having a different refractive index is selected from the group consisting of iodixanol, Ethoxylated (4) Bisphenol A Dimethacrylate (BPA4EODMA), Ethoxylated (10) Bisphenol A Dimethacrylate (BPA10EODMA), Ethoxylated (2) Bisphenol A Dimethacrylate (BPA2EODMA), Ethoxylated (3) Bisphenol A Dimethacrylate (BPA3EODMA), 2-Phenoxyethyl Methacrylate, Tricyclodecanedimethanol Diacrylate, Ethoxylated (10) Bisphenol A Diacrylate (BPA10EODA), Ethoxylated (4) Bisphenol A Diacrylate (BPA4EODA), Ethoxylated (3) Bisphenol A Diacrylate (BPA3EODA), Ethoxylated 4 Phenyl Acrylate (P(4E0)A), 2-Phenoxyethyl Acrylate (2-PEA), and combinations thereof.
4 . The method according to claim 1 , wherein adjusting the refractive index of said photoresponsive material so as to match the refractive index of said scattering particles is performed such that the refractive indices of said photoresponsive material and of said scattering particles differ from each other by not more than 2%.
5 . The method according to claim 2 , wherein the match of the refractive index of said photoresponsive material to the refractive index of said scattering particles is achieved by the following steps:
measuring an average refractive index <n part > of the scattering particles;
mixing said photoresponsive material with said medium having a different refractive index in different volume ratios V m , and measuring a refractive index n mixt of each of the mixtures;
interpolating said measurements of n mixt for different volume ratios V m so as to derive an optimal volume ratio V opt of the photoresponsive material and the medium having a different refractive index to yield a mixture of refractive index n mixt (V opt )=<n part >;
mixing said photoresponsive material and the medium having a different refractive index in said volume ratio V opt and measuring a refractive index n mixt,2 of said mixture;
assessing that the refractive index n mixt,2 of said mixture matches with the average refractive index <n part > of the scattering particles.
6 . The method according to claim 1 , wherein the scattering particles are cells.
7 . The method according to claim 1 , wherein said two-dimensional light-patterns are projected into said photoresponsive material using a light source emitting light of a wavelength longer than 630 nm.
8 . The method according to claim 7 , wherein said photoresponsive material additionally contains up-conversion nanoparticles.
9 . The method according to claim 8 , wherein said up-conversion nanoparticles are selected from the group consisting of a core-shell nanoparticle composed of a core of sodium yttrium fluoride doped with neodymium and a shell composed of sodium yttrium fluoride doped with ytterbium, a core-shell nanoparticle composed of a core of sodium yttrium fluoride doped with neodymium and a shell composed of sodium yttrium fluoride doped with ytterbium, erbium and neodymium, and combinations thereof.
10 . A method of fabricating a three-dimensional article comprising the steps of:
providing, in a transparent container of an apparatus for tomographic additive manufacturing, a photoresponsive material, wherein said photoresponsive material contains scattering particles,
generating from a light source of said apparatus a first set of two-dimensional light-patterns based on computed tomographic projections of said three-dimensional article, and
generating a second set of two-dimensional light-patterns obtained from said first set of two-dimensional light-patterns by applying a computed pre distortion to compensate for a distortion effect caused by light propagation in said photoresponsive material, and
projecting said second set of two-dimensional light-patterns into said photoresponsive material and defining a three-dimensional dose distribution, thereby creating a distribution of alterations in said photoresponsive material, and thereby creating said article,
wherein said second set of two-dimensional light-patterns are projected into said photoresponsive material using a light source emitting light of a wavelength, and wherein said computed pre distortion is obtained by decomposing said first set of two-dimensional light-patterns as a linear superposition of invariant optical modes of said photoresponsive material.