Search

Materials play a key role in tissue engineering for the construction of 3-dimensional scaffolds that support the formation of a new extracellular matrix. They should be biocompatible, and for the fabrication of functional scaffolds, they should be mechanically robust, provide high resolution and printability factors to use in one-photon polymerization micro-stereolithography (OPP mu-SLA) technologies. Furthermore, applications where those materials are used, such as tissue regeneration or tissue substitutes, require fabrication approaches that allow the scalability of 3D scaffold for their clinical use. Therefore, both materials and technology need to be optimized and improved. We tackle two research tracks, one to provide high resolution and biocompatible materials that can be used in OPP- mu-SLA, and a second one to obtain a new mu-SLA configuration that can boost large-size scaffold fabrication for tissue engineering applications. In this work, we report our progress towards the formulation of a hydrogel based on the prototype resin X HYDRORES INX X100 from XPECT INX and we describe the configuration based on the beam shaping of a laser source to print centimeter scale scaffolds while conserving micro-scale features. We printed scaffolds with a commercial ABS resin and the bio-inert hydrogel from XPECT INX that allow us to compare resolution, printability, and mechanical stability. Our results evidence structures with voxel widths up to 20 mu m and lengths up to 23 mm by using uniform light sheets illumination patterns. This work set new alternatives for the material and the fabrication aspects of additive manufacturing for 3D biofabrication.

Optically indistinguishable copies of 3D real objects or holograms are known to be suitable to replace exhibited artistic pieces in museums. In this paper, we discuss holography as an alternative to protect, share and preserve finely crafted gold pieces belonging to the indigenous treasure inherited by Colombians. We present high diffraction efficiency monocolor and color holograms of native goldwork. As reference objects and proof of concept, we use replicas of the renowned and emblematic Poporo Quimbaya, pre-Hispanic gold pendants and anthropomorphic gold pieces. We report experimental details to deal with different types of commercial holographic recording materials, as for example, PFG-03M and PFG- 03C silver halides or C-RT20 photopolymers. And its general feasibility for reproducing high-quality holograms suitable for museum exhibitions or traveling art-collections.

Synthetic holograms have achieved a great impact in a variety of fields like architecture, advertising, army and art, and have proven their importance in advancing the holographic displays as visual communication media. Printing synthetic holograms needs the development of a holographic printer that from a set of 2D images allows to create 3D holographic images of real objects and computer generated objects. With the purpose of developing a holoprinter, we have implemented three related components: i) design and implementation of an optical system for direct writing of hogels, ii) a computational implementation to generate parallax 2D images and finally, iii) the implementation of an opto-mechanical and control system for automatic recording of the synthetic holograms. The three components have been developed under the restricted conditions of our holographic laboratory. In this way, a direct write optical setup was implemented using He-Ne laser, and an optical system for hogel writing with a field of view (FOV) of 60° was designed by using commercial lenses. To generate 2D parallax images, an application was created in the free computer graphics software Blender, applying different camera configurations. And a LabView application was made to automatically control obturation and displacement of the holographic plate. The system developed can record computer generated objects and real objects. Real objects are digitized by using a conventional photographic camera. Reflection full parallax holographic stereograms were recorded on PFG-01 plates and their holographic reconstructions are presented and discussed.

The holoprinter technology based on holographic stereograms has generated a fast development in holographic display applications by the holographic recording of a 2D image sequence with information of a 3D scene, which could be real or computer generated. The images used in holographic stereograms initially start from the acquisition of the different image perspectives of the 3D scene by the re -centering camera configuration and then, this images must be rearranged before the optical recording. This paper proposes a method to acquire the required images or hogel images in one step without using rearrange algorithms, the method uses a virtual camera that moves along a virtual rail by conventional computer graphic s software. The proposed method reduced the time required to ob tain the hogel images and enhance the quality of the 3D holographic images; it also can be applied in different computer graphic s software. To validate the method, a full parallax holographic stereogram was made for a computer generated object. Key words: Holographic displays, Holographic stereograms, Holoprinter, Hogel images .