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.

May 12, 2020 by admin 0 Comments

Bactericidal Lubricating Synthetic Materials for Three-Dimensional Additive Assembly with Controlled Mechanical Properties

Authors
Jihoon Ahn, Yale Jeon, Kang Won Lee, Jonghun Yi, Sun Woo Kim, and Dong Rip Kim*
Abstract
3D printable synthetic materials have been developed to realize desired surface and mechanical properties. Lubricating synthetic surfaces have broad technological impacts on many applications including food packaging, microfluidic systems, and biomedical devices. However, combining soft materials with lubricants leads to significant phase separation and swelling phenomena, together with lowered mechanical strength, impeding full utilization of lubricating synthetic surfaces with desired shapes in a highly controllable manner. Here, we report a new platform to create a 3D printable lubricant–polymer composite (3D-LUBRIC) for the seamless fabrication of multidimensional structures with diverse functionalities. The rationally designed lubricant–polymer mixtures including silica aerogel particles not only exhibit suitable rheological properties for direct ink writing without phase separation but also enable the deterministic additive assembly of heterogeneous materials, which have large mismatches of oil permeability, with no distinct shape distortion. While exhibiting excellent lubricating properties for a variety of liquids, 3D-LUBRIC shows tunable mechanical properties with desired functionalities, such as optical transparency, flexibility and stretchability, and anti-icing and antibacterial/bactericidal properties. We employ the proposed platform to fabricate self-cleanable containers and antibacterial/bactericidal medical tubes. Our platform can offer new opportunities for building low-adhesive, multifunctional synthetic materials with customized shapes for diverse applications.

April 23, 2020 by admin 0 Comments

3D Bioprinted Vascularized Tumour for Drug Testing

Authors
Seokgyu Han 1, Sein Kim 2, Zhenzhong Chen 1, Hwa Kyoung Shin 3,4,5, Seo-Yeon Lee 6, Hyo Eun Moon 7,8, Sun Ha Paek 7,8 and Sungsu Park 1,2,9,10,*
Abstract
An in vitro screening system for anti-cancer drugs cannot exactly reflect the efficacy of drugs in vivo, without mimicking the tumour microenvironment (TME), which comprises cancer cells interacting with blood vessels and fibroblasts. Additionally, the tumour size should be controlled to obtain reliable and quantitative drug responses. Herein, we report a bioprinting method for recapitulating the TME with a controllable spheroid size. The TME was constructed by printing a blood vessel layer consisting of fibroblasts and endothelial cells in gelatine, alginate, and fibrinogen, followed by seeding multicellular tumour spheroids (MCTSs) of glioblastoma cells (U87 MG) onto the blood vessel layer. Under MCTSs, sprouts of blood vessels were generated and surrounding MCTSs thereby increasing the spheroid size. The combined treatment involving the anti-cancer drug temozolomide (TMZ) and the angiogenic inhibitor sunitinib was more effective than TMZ alone for MCTSs surrounded by blood vessels, which indicates the feasibility of the TME for in vitro testing of drug efficacy. These results suggest that the bioprinted vascularized tumour is highly useful for understanding tumour biology, as well as for in vitro drug testing.

January 1, 2018 by admin 0 Comments

Proliferation of HDFs on gelatin based three-dimensional scaffolds by 3D bioprinting

Authors
Dong Jin Choi (1,2), Sang Jun Park (1), Bon Kang Gu, Seok Chung (2), Chun-Ho Kim (1,*)
Abstract
Full replacement, restoration, or, regeneration of defective or injured functional living, tissues is important goal in tissue engineering. In order to, achieve these goal, 3D shape of the biomedical scaffold, should be highly porous and with an appropriate pore, size, pore interconnectivity, and exhibit a high surface, area-to-volume ratio1, . In particular, uncontrollable pore, size and porosity may obstruct successful tissue, regeneration. 3D bioprinting technologies is appropriate, method to fabricate these 3D scaffold. Natural, biopolymers, such as gelatin, chitosan and alginate, have, been widely used as 3D bioprinting2-3, . In this study, we, fabricate pore size controlled 3D gelatin scaffolds by, using 3D bioprinting and to evaluate their biological, properties. The pore sizes of 3D scaffolds were controlled, in the range of 600 to 1,200 μm. We successfully, fabricated 3D gelatin scaffold with various pore size by, using 3D bioprinting system with a cryogenic plate. To, evaluate the feasibility of this structure as substrates for, scaffold, human dermal fibroblast (HDFs) were cultured, on the scaffold and the cellular response was compared, with that from various mean pore sizes (600, 800, 1,000,, 1,200 μm) of the scaffold.