Scientists from theUniversity at Buffalo已经开发了一种快速的新3D生物打印方法,该方法可以代表迈向全印刷的人体器官的重要一步。
该团队使用一种新型的基于VAT-SLA的方法,能够减少创建含有细胞的水凝胶结构所需的时间,从6个小时以上到19分钟。加快生物制造方法还可以生产嵌入式血管网络,这可能使其成为迈出的救生3D打印器官迈出的重要一步,这些器官在移植候补名单上所需的人需要。
“我们的方法允许快速打印厘米大小的水凝胶模型,”该研究的主要合着者Chi Zhou解释说。“这大大减少了由于您在常规3D打印中通常看到的环境应力的长时间暴露而造成的部分变形和细胞损伤。”
“The technology we’ve developed is 10-50 times faster than the industry standard, and it works with large sample sizes that have been very difficult to achieve previously.”
Taking bioprinting up a gear
Although bioprinted cell‐laden structures hold significant potential when it comes to human tissue and organ transplants, the technology is still at a nascent stage. One of the main hurdles facing the wider adoption of these processes is print speed, as the deposition rates of hydrogels have so far been limited to avoid damaging their incumbent cells.
Nozzle-based techniques have other drawbacks too, as they can cause prolonged cellular exposure to shear stress as well as low oxygen levels and temperatures, damaging them in the process. What’s more, the hydrogel scaffolds produced using conventional methods often exhibit low mechanical strength, making it difficult to incorporate soft overhanging structures like vascular channels.
尽管使用牺牲支持使科学家能够部分克服这种缺陷,但这种方法背后的挤压方法的简单性继续限制其能力。相比之下,最近开发的连续液体界面生产(夹子)技术有可能大大提高生物打印过程的速度。
By continuously building layers above a ‘dead zone,’ CLIP methods allow materials to constantly be replenished, increasing production capacity, but at the cost of only being able to create thin-walled parts. Building on this approach, the Buffalo team have now developed a ‘FLOAT’ method, in which hydrogels can be deposited at a higher velocity, enabling the production of larger vascularized tissues.
The ‘FLOAT’ bioprinting approach
During the researchers’ optimized FLOAT method, objects are essentially cured through a glass plate inside a vat of hydrogel at low suction forces, yielding thick parts with high elasticity. To prove the biocompatibility of their approach, the team initially fabricated a set of specimens from the cell-compatible PEGNB polymer.
有趣的是,尽管测试零件表现出足够的刚度,但它们也缩小了多达51%,导致研究人员改用PEGDA材料作为较大型号。在更雄心勃勃的测试跑中,布法罗团队随后3D打印了几个2.6×1.7×5.6厘米的手动水凝胶结构,“手指”弯曲在压缩下。
使用普通SLA 3D打印机制作相同的型号花费了大约6.5个小时,比基于浮点的机器的19分钟时间长大。科学家的基于水凝胶的手还具有血管通道,这意味着它们最终可以用内皮细胞播种,以创建功能性,可移植的肢体。
Ultimately, the scientists were able to seed patches of cells into microchannels ex-vivo, but they also found that integrating these into higher-strength structures yielded low cell viability. In future, the team believe that switching to nanomaterial-doped polymers could provide the answer to balancing rigidity and compatibility, and enable the rapid production of hydrogel-based vascularized structures.
Inching bioprinting towards reality
尽管3D生物打印仍在很大程度上是实验阶段,但有迹象表明,该技术正在逐渐发展朝着更多的最终用途应用发展。
3D printer OEM3D Systemsannounced a major breakthrough in its打印到灌注生物打印平台earlier this year. The system is now capable of creating fully-sized vascularized lung scaffolds, and the company has indicated that the technology will soon play a key role within its healthcare business.
Biotechnology firmUnited Therapeuticsand Israeli companyCollPlanthave also made significant advances in their bid to质量制造3D印刷肾脏. The companies have turned a former tobacco factory into a modern 3D bioprinting production line, which could be capable of churning out additive organs.
Elsewhere, efforts to create functional human organs have been limited to miniaturized models, such as thetiny 3D bioprinted heartscreated by scientists at the德克萨斯大学埃尔帕索. The vascularized structures were sent to theInternational Space Station(ISS) to test how microgravity affects the human heart.
The researchers’ findings are detailed in their paper titled “大规模生物相容性水凝胶模型的快速立体光刻印刷. ” The study was co-authored by Nanditha Anandakrishnan, Hang Ye, Zipeng Guo, Zhaowei Chen, Kyle I. Mentkowski, Jennifer K. Lang, Nika Rajabian, Stelios T. Andreadis, Zhen Ma, Joseph A. Spernyak, Jonathan F. Lovell, Depeng Wang, Jun Xia, Chi Zhou and Ruogang Zhao.
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特色图像显示了Buffalo 3D Bioprinted Hand的一所大学。通过高级医疗材料杂志的照片。