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Formation of a keratin layer with silk fibroin-polyethylene glycol composite hydrogel fabricated by digital light processing 3D printing
摘要： Silk fibroin (SF)-incorporated 4-arm polyethylene glycol acrylate (PEG4A) was used as a bioink for digital light processing three-dimensional printing. A visible range of light was adopted for the process to assure the safety of the cells in the bioink. Fibroblast cells were embedded in the printed hydrogels, and the keratinocyte cells were cultured at the surfaces of the hydrogels. The proliferation of cells with the bioink materials, PEG4A and SF-PEG4A, and the toxicity of these materials, were verified by live/dead and alamarBlue assays. The primary human keratinocytes on the SF-PEG4A hydrogel scaffold generated a keratin layer by the tissue culture at the air-liquid interface, promoting maturation and stratification. SF-polyethylene glycol hydrogels showed higher cell proliferation and cell spreading, and the thicker keratin layer was formed with SF-PEG4A hydrogels compared with PEG4A hydrogels.
关键词： Digital light processing,Silk fibroin,3D printing,4-arm polyethylene glycol acrylate,Keratin
更新于2025-09-23 15:23:52
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Rheological and Curing Behavior of Acrylate-Based Suspensions for the DLP 3D Printing of Complex Zirconia Parts
摘要： The present study demonstrates the possibility of fabricating zirconia parts with a complex shape and internal architecture using a low-cost stereolithography-based technique. One of the critical steps in ceramics stereolithography is the preparation of a photo-curable slurry with properties that fulfil specific requirements, such as having a low viscosity, high solids loading and appropriate curing characteristics. Slurries with different acrylic monomers and ceramic fillers were studied concerning their rheological and curing behavior. New formulations based on mono- and tri-functional acrylic monomers revealed the following excellent rheological properties: The viscosity of the mono-/tri-acrylate-based slurry with 75 wt.% of zirconia was 1.6 Pa·s at 30 s?1. Zirconia stabilized with 3 mol.% yttria was found to be more favorable than zirconia with 8 mol.% yttria for slurry preparation, because of its lower surface area and higher tapped density. It was shown that the cure depth of the suspensions was suitable for printing objects with a 50 μm layer thickness, good interlayers connection and surface finishing.
关键词： ceramic,digital light processing,additive manufacturing,zirconia,stereolithography
更新于2025-09-23 15:22:29
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[ASME ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems - San Antonio, Texas, USA (Monday 10 September 2018)] Volume 2: Mechanics and Behavior of Active Materials; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting; Emerging Technologies - Manufacture of Lenses and Diffraction Gratings Using DLP As an Additive Manufacturing Technology
摘要： This document condenses the results obtained when 3D printing lenses and their potential use as diffraction gratings using Digital Light Processing (DLP), as an additive manufacturing technique. This project investigated the feasibility of using DLP additive manufacturing for producing custom designed lenses and gratings. DLP was identified as the preferred manufacturing technology for gratings fabrication. Diffraction gratings take advantage of the anisotropy, in additive manufacturing processes, to produce a collated pattern of multiple fringes on a substrate with completely smooth surfaces. The gratings are transmissive and were manufactured with slit separations of 10, 25 and 50 μm. More than 50 samples were printed at various build angles and mechanically treated for maximum optical transparency. The variables of the irradiance equation were obtained from photographs taken with an optical microscope. These values were used to estimate theoretical irradiance patterns of a diffraction grating and compared against the experimental 3-D printed grating. The resulting patterns were found to be remarkably similar in amplitude and distance between peaks when compared to theoretical values.
关键词： 3D printing,lenses,Digital Light Processing (DLP),additive manufacturing,diffraction gratings
更新于2025-09-23 15:21:01
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Oxygen Tolerant PET-RAFT Facilitated 3D Printing of Polymeric Materials under Visible LEDs
摘要： Photopolymerization-based 3D printing process is typically conducted using free radical polymerization, which leads to fabrication of immutable materials. An alternative 3D printing of polymeric materials using trithiocarbonate (TTC) reversible addition-fragmentation chain transfer (RAFT) agents has always been a challenge for material and polymer scientists. Herein we report 3D printing of RAFT-based formulations that can be conducted fully open to air using standard digital light processing (DLP) 3D printer and under mild conditions of visible light at blue (λ max = 483 nm, 4.16 mW/cm2) or green (λ max = 532 nm, 0.48 mW/cm2) wavelength. Our approach is based on activation of TTC RAFT agents using eosin Y (EY) as a photoinduced electron-transfer (PET) catalyst in the presence of a reducing agent (triethylamine (TEA)), which facilitated oxygen tolerant 3D printing process via a reductive PET initiation mechanism. Re-activation of the TTCs present within the polymer networks enables post-printing monomer insertion into the outer layers of an already printed dormant object under a second RAFT process, which provides a pathway to design a more complex 3D printing. To our best knowledge, this is the first example of oxygen tolerant EY/TEA catalyzed PET-RAFT facilitated 3D printing of polymeric materials. We believe that our strategy is a significant step forward in the field of 3D printing.
关键词： Oxygen Tolerant,Trithiocarbonate,3D Printing,Visible Light-Induced PET-RAFT Polymerization,Digital Light Processing,Photoinduced Electron-Transfer
更新于2025-09-16 10:30:52
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[ASEE Conferences 2015 ASEE Annual Conference and Exposition - Seattle, Washington (2015.06.14-2015.06.17)] 2015 ASEE Annual Conference and Exposition Proceedings - A Capstone Project on Design and Development of a Digital Light Processing 3D Printer
摘要： This paper documents an undergraduate 3D printer design and development capstone project spanning multiple semesters. Recently, a team of five undergraduate mechanical and manufacturing engineering students were given the task of rebuilding a non-functional Digital Light Processing (DLP) printer which was originally designed and built at this institution. DLP process is based on curing heat sensitive resin in printing 3D objects in layers, patented by EnvisionTec. This project had been worked on two previous semesters before this team took charge and had multiple problems needed to be addressed. The project team also inherited an overheated projector as the heat source, inefficient resin box, and old resin supply. The team’s task was to fix the necessary problems with the 3D printer, make alterations to its design and equipment to increase its functionality, and get the printer to a working condition by printing a 3D part before the semester ended.
关键词： Capstone Project,Engineering Education,3D Printing,Digital Light Processing
更新于2025-09-10 09:29:36
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Study of Physical and Degradation Properties of 3D-Printed Biodegradable, Photocurable Copolymers, PGSA-co-PEGDA and PGSA-co-PCLDA
摘要： As acrylated polymers become more widely used in additive manufacturing, their potential applications toward biomedicine also raise the demand for biodegradable, photocurable polymeric materials. Polycaprolactone diacrylate (PCLDA) and poly(ethylene glycol) diacrylate (PEGDA) are two popular choices of materials for stereolithography (SLA) and digital light processing additive manufacturing (DLP-AM), and have been applied to many biomedical related research. However, both materials are known to degrade at a relatively low rate in vivo, limiting their applications in biomedical engineering. In this work, biodegradable, photocurable copolymers are introduced by copolymerizing PCLDA and/or PEGDA with poly(glycerol sebacate) acrylate (PGSA) to form a network polymer. Two main factors are discussed: the effect of degree of acrylation in PGSA and the weight ratio between the prepolymers toward the mechanical and degradation properties. It is found that by blending prepolymers with various degree of acrylation and at various weight ratios, the viscosity of the prepolymers remains stable, and are even more 3D printable than pure substances. The formation of various copolymers yielded a database with selectable Young’s moduli between 0.67–10.54 MPa, and the overall degradation rate was significantly higher than pure substance. In addition, it is shown that copolymers fabricated by DLP-AM fabrication presents higher mechanical strength than those fabricated via direct UV exposure. With the tunable mechanical and degradation properties, the photocurable, biodegradable copolymers are expected to enable a wider application of additive manufacturing toward tissue engineering.
关键词： additive manufacturing,poly(glycerol sebacate) acrylate,photocurable polymer,poly(ethylene glycol) diacrylate,digital light processing,polycaprolactone diacrylate,biodegradable polymer
更新于2025-09-09 09:28:46