Kang H.-W.,Wake Forest Institute for Regenerative Medicine |
Cho D.-W.,Pohang University of Science and Technology
Tissue Engineering - Part C: Methods | Year: 2012
Tissue engineering, which is the study of generating biological substitutes to restore or replace tissues or organs, has the potential to meet current needs for organ transplantation and medical interventions. Various approaches have been attempted to apply three-dimensional (3D) solid freeform fabrication technologies to tissue engineering for scaffold fabrication. Among these, the stereolithography (SL) technology not only has the highest resolution, but also offers quick fabrication. However, a lack of suitable biomaterials is a barrier to applying the SL technology to tissue engineering. In this study, an indirect SL method that combines the SL technology and a sacrificial molding process was developed to address this challenge. A sacrificial mold with an inverse porous shape was fabricated from an alkali-soluble photopolymer by the SL technology. A sacrificial molding process was then developed for scaffold construction using a variety of biomaterials. The results indicated a wide range of biomaterial selectivity and a high resolution. Achievable minimum pore and strut sizes were as large as 50 and 65μm, respectively. This technology can also be used to fabricate three-dimensional organ shapes, and combined with traditional fabrication methods to construct a new type of scaffold with a dual-pore size. Cytotoxicity tests, as well as nuclear magnetic resonance and gel permeation chromatography analyses, showed that this technology has great potential for tissue engineering applications. © Copyright 2012, Mary Ann Liebert, Inc.
Mhashilkar A.M.,Wake Forest Institute for Regenerative Medicine
Current stem cell research & therapy | Year: 2012
The field of regenerative medicine (RM), encompassing stem cell (SC) technologies, therapeutics, tissue engineering (TE), biomaterials, scaffolds and other enabling technologies provides a wide gamut of tools and tracks to combat, manage and hopefully cure serious human and animal injuries, dysfunctions and diseases. This review illustrates the trends that are becoming the major platforms in this field. The last 10 years in itself has seen major definitive observations, including multi-track directives of adult stem cell translational technologies, tissue and organ engineering protocols, iPS cell applications and understanding of the role of cancer stem cells to develop effective anti-cancer regimens. With the rapid advances of RM translational research, further advances are expected to be implemented for personalized repair and curative outcomes. RM future is bright although laden with challenges of global fragmentation which needs coherent consolidation, stringent cost and time effective regulation and long-term funding mechanisms, so clinical and diagnostic solutions are realized and recognized to combat unmet medical needs.
Atala A.,Wake Forest Institute for Regenerative Medicine |
Kurtis Kasper F.,Rice University |
Mikos A.G.,Rice University
Science Translational Medicine | Year: 2012
Tissue engineering has emerged at the intersection of numerous disciplines to meet a global clinical need for technologies to promote the regeneration of functional living tissues and organs. The complexity of many tissues and organs, coupled with confounding factors that may be associated with the injury or disease underlying the need for repair, is a challenge to traditional engineering approaches. Biomaterials, cells, and other factors are needed to design these constructs, but not all tissues are created equal. Flat tissues (skin); tubular structures (urethra); hollow, nontubular, viscus organs (vagina); and complex solid organs (liver) all present unique challenges in tissue engineering. This review highlights advances in tissue engineering technologies to enable regeneration of complex tissues and organs and to discuss how such innovative, engineered tissues can affect the clinic.
Atala A.,Wake Forest Institute for Regenerative Medicine
Journal of Pediatric Surgery | Year: 2012
Applications of regenerative medicine technology may offer novel therapies for patients with injuries, end-stage organ failure, or other clinical problems. Currently, patients suffering from diseased and injured organs can be treated with transplanted organs. However, there is a severe shortage of donor organs that is worsening yearly as the population ages and new cases of organ failure increase. Scientists in the field of regenerative medicine and tissue engineering are now applying the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. The stem cell field is also advancing rapidly, opening new avenues for this type of therapy. For example, therapeutic cloning and cellular reprogramming may one day provide a potentially limitless source of cells for tissue engineering applications. While stem cells are still in the research phase, some therapies arising from tissue engineering endeavors have already entered the clinical setting successfully, indicating the promise regenerative medicine holds for the future. © 2012 Elsevier Inc. All rights reserved.
Bitar K.N.,Wake Forest Institute for Regenerative Medicine |
Raghavan S.,Wake Forest Institute for Regenerative Medicine
Neurogastroenterology and Motility | Year: 2012
Background and Purpose Functional tissue engineering of the gastrointestinal (GI) tract is a complex process aiming to aid the regeneration of structural layers of smooth muscle, intrinsic enteric neuronal plexuses, specialized mucosa, and epithelial cells as well as interstitial cells. The final tissue-engineered construct is intended to mimic the native GI tract anatomically and physiologically. Physiological functionality of tissue-engineered constructs is of utmost importance while considering clinical translation. The construct comprises of cellular components as well as biomaterial scaffolding components. Together, these determine the immune response a tissue-engineered construct would elicit from a host upon implantation. Over the last decade, significant advances have been made to mitigate adverse host reactions. These include a quest for identifying autologous cell sources like embryonic and adult stem cells, bone marrow-derived cells, neural crest-derived cells, and muscle derived-stem cells. Scaffolding biomaterials have been fabricated with increasing biocompatibility and biodegradability. Manufacturing processes have advanced to allow for precise spatial architecture of scaffolds to mimic in vivo milieu closely and achieve neovascularization. This review will focus on the current concepts and the future vision of functional tissue engineering of the diverse neuromuscular structures of the GI tract from the esophagus to the internal anal sphincter. © 2011 Blackwell Publishing Ltd.