In this issue of “From Academia”, we included four recent research publications related to “seeing”, including articles focusing on how to create smart contact lenses, cornea, glass optics, and microscope leveraging 3D printing technologies. In the first article, researchers presented a way to create hydrogel-based contact lenses that can have biosensing capabilities, including sensing eye blinking (peristaltic pressure), PH, and Na+ level, adding another tool to the future wearable market. In the second article, researchers demonstrated how additive manufacturing of gradient index (GRIN) silica-titania glass via direct ink writing method could potentially create a variety of conventional and unconventional optical functions in a flat glass component with no surface curvature. In the third article, the researchers described a way to create a 3D corneal stroma using an orthogonally oriented pure electro-compacted collagen (EC). The researchers believe this technique could potentially be used to create a future full-thickness corneal replacement. In the final article, the authors presented UC2 (You. See. Too.), a low-cost, 3D-printed, open-source, modular microscopy toolbox. The authors demonstrate its versatility by realizing a complete microscope development cycle from concept to experimental phase and aim to develop an open standard in optics to facilitate interfacing with various complementary platforms. “From Academia” features recent, relevant, close to commercialization academic publications. Subjects include but not limited to healthcare 3D printing, 3D bioprinting, and related emerging technologies.
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Authored by Yihang Chen, Shiming Zhang, Qingyu Cui, Jiahua Ni, Xiaochen Wang, Xuanbing Cheng, Halima Alem, Peyton Tebon, Chun Xu, Changliang Guo, Rohollah Nasiri, Rosalia Moreddu, Ali K. Yetisen, Samad Ahadian, Nureddin Ashammakhi, Sam Emaminejad, Vadim Jucaud, Mehmet R. Dokmeci and Ali Khademhosseini. Lab on a Chip. 13 October 2020
Microchannels in hydrogels play an essential role in enabling a smart contact lens. However, microchannels have rarely been created in commercial hydrogel contact lenses due to their sensitivity to conventional microfabrication techniques.
Here, we report the fabrication of microchannels in poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels that are used in commercial contact lenses with three-dimensional (3D) printed mold.
We investigated the corresponding capillary flow behaviors in these microchannels. We observed different capillary flow regimes in these microchannels, depending on their hydration level.
In particular, we found that a peristaltic pressure could reinstate flow in a dehydrated channel, indicating that the motion of eye-blinking may help tears flow in a microchannel-containing contact lens.
Colorimetric pH and electrochemical Na+ sensing capabilities were demonstrated in these microchannels. This work paves the way for the development of micro-engineered poly(HEMA) hydrogels for various biomedical applications such as eye care and wearable biosensing.
Authored by Rebecca Dylla-Spears, Timothy D. Yee, Koroush Sasan, Du T. Nguyen, Nikola A. Dudukovic, Jason M. Ortega, Michael A. Johnson, Oscar D. Herrera, Frederick J. Ryerson and Lana L. Wong, Science Advances. 18 November 2020
We demonstrate an additive manufacturing approach to produce gradient refractive index glass optics. Using direct ink writing with an active inline micromixer, we three-dimensional print multi-material green bodies with compositional gradients, consisting primarily of silica nanoparticles and varying concentrations of titania as the index-modifying dopant.
The green bodies are then consolidated into glass and polished, resulting in optics with tailored spatial profiles of the refractive index. We show that this approach can be used to achieve a variety of conventional and unconventional optical functions in a flat glass component with no surface curvature.
– Authored by Zhi Chen, Xiao Liu, Jingjing You, Yihui Song, Eva Tomaskovic-Crook, Gerard Sutton, Jeremy M.Crook, Gordon G.Wallace. Acta Biomaterialia, 1 September 2020
Engineering substantia propria (or stroma of cornea) that mimics the function and anatomy of natural tissue is vital for in vitro modeling and in vivo regeneration. There are, however, few examples of the bioengineered biomimetic corneal stroma.
Here we describe the construction of an orthogonally oriented 3D corneal stroma model (3D-CSM) using pure electro-compacted collagen (EC). EC films comprise aligned collagen fibrils and support primary human corneal stromal cells (hCSCs). Cell-laden constructs are analogous to the anatomical structure of the native human cornea.
The hCSCs are guided by the topographical cues provided by the aligned collagen fibrils of the EC films. Importantly, the 3D-CSM are biodegradable, highly transparent, glucose-permeable, and comprise quiescent hCSCs. Gene expression analysis indicated the presence of aligned collagen fibrils is strongly coupled to downregulation of active fibroblast/myofibroblast markers α-SMA and Thy-1, with a concomitant upregulation of the dormant keratocyte marker ALDH3. The 3D-CSM represents the first example of an optimally robust biomimetic engineered corneal stroma that is constructed from pure electro-compacted collagen for cell and tissue support. The 3D-CSM is a significant advance for synthetic corneal stroma engineering, with the potential to be used for full-thickness and functional cornea replacement, as well as informing in vivo tissue regeneration.
Authored by Benedict Diederich, René Lachmann, Swen Carlstedt, Barbora Marsikova, Haoran Wang, Xavier Uwurukundo, Alexander S. Mosig & Rainer Heintzmann. Nature Communications. 25 November 2020
Modern microscopes used for biological imaging often present themselves as black boxes whose precise operating principle remains unknown, and whose optical resolution and price seem to be in inverse proportion to each other.
With UC2 (You. See. Too.) we present a low-cost, 3D-printed, open-source, modular microscopy toolbox and demonstrate its versatility by realizing a complete microscope development cycle from concept to experimental phase. The self-contained incubator-enclosed brightfield microscope monitors monocyte to macrophage cell differentiation for seven days at cellular resolution level (e.g. 2 μm). Furthermore, by including very few additional components, the geometry is transferred into a 400 Euro light-sheet fluorescence microscope for volumetric observations of a transgenic zebrafish expressing green fluorescent protein (GFP).
With this, we aim to establish an open standard in optics to facilitate interfacing with various complementary platforms. By making the content and comprehensive documentation publicly available, the systems presented here lend themselves to easy and straightforward replications, modifications, and extensions.