June 9, 2020 by admin 0 Comments

3D Printed Bioresponsive Devices with Selective Permeability Inspired by Eggshell Membrane for Effective Biochemical Conversion

Authors
Yale Jeon, Min Soo Jeon, Jongoh Shin, Sangrak Jin, Jonghun Yi, Seulgi Kang, Sun Chang Kim, Byung-Kwan Cho, Jung-Kul Lee, and Dong Rip Kim*
Abstract
Eggshell membrane has selective permeability that enables gas or liquid molecules to pass through while effectively preventing migration of microbial species. Herein, inspired by the architecture of the eggshell membrane, we employ three-dimensional (3D) printing techniques to realize bioresponsive devices with excellent selective permeability for effective biochemical conversion. The fabricated devices show 3D conductive carbon nanofiber membranes in which precultured microbial cells are controllably deployed. The resulting outcome provides excellent selective permeability between chemical and biological species, which enables acquisition of target responses generated by biological species confined within the device upon input signals. In addition, electrically conductive carbon nanofiber networks provide a platform for real-time monitoring of metabolism of microbial cells in the device. The suggested platform represents an effort to broaden microbial applications by constructing biologically programmed devices for desired responses enabled by designated deployment of engineered cells in a securely confined manner within enclosed membranes using 3D printing methods.

January 6, 2020 by admin 0 Comments

NiCHE Platform: Nature-Inspired Catechol-Conjugated Hyaluronic Acid Environment Platform for Salivary Gland Tissue Engineering

Authors
Sang-woo Lee, Ji Hyun Ryu, Min Jae Do, Eun Namkoong, Haeshin Lee* and Kyungpyo Park*
Abstract
Recently, there has been growing interest in replacing severely damaged salivary glands with artificial salivary gland functional units created in vitro by tissue engineering approaches. Although various materials such as poly(lactic-co-glycolic acid), polylactic acid, poly(glycolic acid), and polyethylene glycol hydrogels have been used as scaffolds for salivary gland tissue engineering, none of them is effective enough to closely recapitulate the branched structural complexity and heterogeneous cell population of native salivary glands. Instead of discovering new biomaterial candidates, we synthesized hyaluronic acid–catechol (HACA) conjugates to establish a versatile hyaluronic acid coating platform named “NiCHE (nature-inspired catechol-conjugated hyaluronic acid environment)” for boosting the salivary gland tissue engineering efficacy of the previously reported biomaterials. By mimicking hyaluronic acid-rich niche in the mesenchyme of embryonic submandibular glands (eSMGs) with NiCHE coating on substrates including polycarbonate membrane, stiff agarose hydrogel, and polycaprolactone scaffold, we observed significantly enhanced cell adhesion, vascular endothelial and progenitor cell proliferation, and branching of in vitro-cultured eSMGs. High mechanical stiffness of the substrate is known to inhibit eSMG growth, but the NiCHE coating significantly reduced such stiffness-induced negative effects, leading to successful differentiation of progenitor cells to functional acinar and myoepithelial cells. These enhancement effects of the NiCHE coating were due to the increased proliferation of vascular endothelial cells via interaction between CD44 and surface-immobilized HAs. As such, our NiCHE coating platform renders any kind of material highly effective for salivary gland tissue culture by mimicking in vivo embryonic mesenchymal HA. Based on our results, we expect the NiCHE coating to expand the range of biomaterial candidates for salivary glands and other branching epithelial organs.

January 1, 2018 by admin 0 Comments

Design, fabrication and evaluation of a hybrid biomanufacturing system for tissue engineering

Authors
Fengyuan Liu
Abstract
Plasma-assisted Bio-extrusion System (PBS System) is an innovative hybrid bio-manufacturing system to produce complex multi-material and functionally graded scaffolds combining multiple pressure-assisted and screw-assisted printing heads and plasma jets. This approach, which represents a step forward regarding the current state of the art technology in the field of biomanufacturing, enables to design and fabricate more effective scaffolds matching the mechanical and surface characteristics of the surrounding tissue, enabling the incorporation of high number of cells uniformly distributed and the introduction of multiple cell types with positional specificity. The system requires complex control software to manipulate different materials, scaffold designs and processing parameters. This software, developed using MATLAB GUI, is detailed in this paper. It provides high freedom of design allowing the users to create single or multi-material constructs with uniform pore size or pores size gradients by changing the operation parameters, such as geometric parameters, lay-down pattern, filament distance, feed rate and layer thickness. Functionally graded scaffolds can also be designed considering different layer-by-layer coating/surface modification strategies using the multi-jet plasma system. Based on the user definition, G programming codes are generated enabling fully integration and synchronization with the hardware of the PBS system. Examples will be provided describing the design of single, multi-material and functionally graded scaffolds.