March 26, 2019 by admin 0 Comments

Three-Dimensional Bioprinting of Cell-Laden Constructs Using Polysaccharide-Based Self-Healing Hydrogels

Authors
Sang Woo Kim, Do Yoon Kim, Hyun Ho Roh, Hyun Seung Kim, Jae Won Lee, Kuen Yong Lee*
Abstract
Development of biomaterial-based bioinks is critical for replacement and/or regeneration of tissues and organs by three-dimensional (3D) printing techniques. However, the number of 3D-printable biomaterials in practical use remains limited despite the rapid development of 3D printing techniques. Controlling the flow properties of bioinks and mechanical properties of the resultant printed objects is key considerations in the design of biomaterial-based bioinks for practical applications. In this study, a printable hydrogel comprising biocompatible polysaccharides that has potential for cartilage regeneration via tissue engineering approaches was designed. Self-healing hydrogels were prepared from partially oxidized hyaluronate (OHA) and glycol chitosan (GC) in the presence of adipic acid dihydrazide (ADH). The self-healing ability of OHA/GC/ADH hydrogels was attributed to the combination of two dynamic bonds in the gels, including imine bonds obtained via a Schiff base reaction between OHA and GC, as well as acylhydrazone bonds formed by the reaction between OHA and ADH. The OHA/GC/ADH hydrogels did not require any postgelation or additional cross-linking processes for use in the fabrication of 3D constructs using an extrusion-based 3D printer. The concentrations and molecular weights of the constituent polymers were found to be critical parameters affecting the flow and mechanical properties of the self-healing hydrogels, which showed great potential as bioinks for fabricating cell-laden structures using a 3D printer. The expression of chondrogenic marker genes such as SOX-9 and collagen type II of ATDC5 cells encapsulated in the OHA/GC/ADH hydrogel was not significantly affected by the printing process. This self-healing hydrogel system may have the potential in tissue engineering applications, including cartilage regeneration.

March 11, 2019 by admin 0 Comments

로킷헬스케어, 美정형외과학회서 ‘맞춤 자가세포 연골재생’ 플랫폼 발표

로킷헬스케어가 미국정형외과학회에서 세계최초로 3D 프린터를 이용한 ‘맞춤 자가세포 연골재생 치료기술’을 선보인다고 11일 밝혔다.– ROKIT Healthcare

  • ‘미국정형외과학회(American Academy of Orthopaedic Surgeons·AAOS) 2019 연례회의’는 현지시각으로 오는 12일부터 16일까지 미국 네바다주 라스베이거스에서 나흘간 개최된다.

킷헬스케어는 이 학회에서 골관절염에 대한 새로운 ‘맞춤 자가세포 연골재생 치료 플랫폼’ 개발에 관한 최신 연구를 발표 할 예정이다. 이 기술은 세계 최초로 3D 바이오 프린터를 이용해 자가 줄기 세포와 세포외 기질 (Extracellular matrix; ECM)을 조합한 연골재생 치료법이다.

로킷헬스케어 측은 “맞춤 자가세포 연골재생은 자가줄기세포를 추출하며 승인된 인체유래 ECM과 바이오 잉크를 사용해 빠른 시간 안에 3D 바이오 프린팅을 기술로 손상된 연골 조직의 형상을 그대로 재현한다”며 “맞춤 자가 줄기세포로 최소 침습법을 이용해 손상된 부위에 접합함으로써 한번의 시술로 영구적인 자가연골 재생이 가능할 것”이라고 전망했다. 이어 “환자자신의 줄기세포를 활용해 다른 연골치료제가 재생할 수 없는 본래의 초자연골로 재생될 수 있다”며 “관절염 1~4기 환자에게 적용 될 것으로 예상돼 세계최초로 획기적인 맞춤 자가세포 연골재생을 선보인다는 큰의미가 있다”고 덧붙였다.

로킷헬스케어는 현재 국내와 미국 하버드의대 부속 메사추세츠종합병원(MGH)에서 진행 중인 전임상을 완료한 후 곧 바로 임상 적용을 모색하고 있다. 국가별로 인체 자가연골 재생시술에 대한 규제 전략을 달리하여 임상 적용에 속도를 낸다는 방침이다.

유석환 로킷헬스케어 대표는 “자사의 연골재생시술법으로 제작된 연골조직은 섬유화연골이 아닌 초자연골로 재생되는 것이 확인돼 이번 AAOS 2019에서 정형외과 전문가들에게 높은 관심을 받을것으로 예상하고 있다”며 “자체 기술로 생산한 3D 바이오 프린터를 학회에 소개해 무릎연골 재생 치료법을 포함한 다양한 환자 맞춤형 정형외과적 연구를 위한 바이오 프린터 및 소프트웨어 기술을 소개할 계획”이라고 강조했다.

March 7, 2019 by admin 0 Comments

Surface Engineered Biomimetic Inks Based on UV Cross-Linkable Wood Biopolymers for 3D Printing

Authors
Wenyang Xu, Xue Zhang, Peiru Yang, Otto Långvik, Xiaoju Wang*, Yongchao Zhang, Fang Cheng, Monika Österberg, Stefan Willför and Chunlin Xu*
Abstract
Owing to their superior mechanical strength and structure similarity to the extracellular matrix, nanocelluloses as a class of emerging biomaterials have attracted great attention in three-dimensional (3D) bioprinting to fabricate various tissue mimics. Yet, when printing complex geometries, the desired ink performance in terms of shape fidelity and object resolution demands a wide catalogue of tunability on the material property. This paper describes surface engineered biomimetic inks based on cellulose nanofibrils (CNFs) and cross-linkable hemicellulose derivatives for UV-aided extrusion printing, being inspired by the biomimetic aspect of intrinsic affinity of heteropolysaccharides to cellulose in providing the ultrastrong but flexible plant cell wall structure. A facile aqueous-based approach was established for the synthesis of a series of UV cross-linkable galactoglucomannan methacrylates (GGMMAs) with tunable substitution degrees. The rapid gelation window of the formulated inks facilitates the utilization of these wood-based biopolymers as the feeding ink for extrusion-based 3D printing. Most importantly, a wide and tunable spectrum ranging from 2.5 to 22.5 kPa of different hydrogels with different mechanical properties could be achieved by varying the substitution degree in GGMMA and the compositional ratio between GGMMA and CNFs. Used as the seeding matrices in the cultures of human dermal fibroblasts and pancreatic tumor cells, the scaffolds printed with the CNF/GGMMA inks showed great cytocompatibility as well as supported the matrix adhesion and proliferative behaviors of the studied cell lines. As a new family of 3D printing feedstock materials, the CNF/GGMMA ink will broaden the map of bioinks, which potentially meets the requirements for a variety of in vitro cell–matrix and cell–cell interaction studies in the context of tissue engineering, cancer cell research, and high-throughput drug screening.