ETH Zurich研究人员拥有3D打印的生物可能的支架，旨在为患有气道阻塞的人提供侵入性的氧气减轻。
By combining two monomers, the team has been able to create a novel cell-compatible resin, that once cured by a DLP 3D printer, can be used to fabricate patient-specific tracheal implants. Having tested their devices on rabbits, the scientists believe they could now find end-use clinical applications, preventing patients from choking without the need for intrusive surgical removal.
“这一有希望的发展为快速生产定制的医疗植入物打开了前景，”苏黎世Eth Eth eTh Zurich的药物制定和交付教授Jean-Christophe Leroux表示，以及在需要非常精确，弹性和可降解的设备身体。”
Improving anti-choking devices
In acute cases, diseases such as asthma, cystic fibrosis and bronchitis can cause what’s clinically described as a Central Airway Obstruction (CAO) in the tracheas of affected patients. When this happens it’s effectively a medical emergency, as if the patient doesn’t find help and gets too little oxygen, they risk death by suffocation.
Thankfully, sufferers can often be treated using silicone airway stents, but many commercial devices are rudimentary, not patient-specific and subject to migration, which can cause complications. Similarly, when stents are used within pediatric patients, their throats tend to change shape as they grow, necessitating invasive replacement surgeries.
结果，苏黎世团队已经确定了对可生物降解的设备的需求，该设备可以根据个人患者的需求进行定制。尽管FDM 3D打印以前已经产生了可溶解的植入物，但它们通常太可延展了，并且可能会变形，然后才能将其插入CAO患者的喉咙。
Similarly, researchers have attempted to use DLP systems to fabricate stents before, but found that resin viscosity prevented the approach from being viable. The Zurich team even3D printed dissolvable aluminum implantsthemselves in 2019, and building on this approach, they opted to develop an application-specific bio-resin.
3D printing the bioresorbable stents
To create their material, the scientists mixed DLLA and CL monomers at a very precise ratio that they calculated would provide the formula with bio-friendly properties. The team then deployed a customized DLP 3D printer that only printed at 70 to 90°C, to cure the resin into a polymer, without making it too viscous.
在测试过程中，研究人员发现他们能够通过调整单体的链长度来调整印刷物体的性能，从而影响了交联密度。最合适的材料配方具有长而柔韧的聚合物链，其拉伸应力为10 MPa，明显少于硅酮支架。
Wielding their optimized polymer mix, the Zurich team then 3D printed three different prototypes, and put them through ISO-standard evaluations. Results showed that subjecting the devices to moisture and heat caused them to undergo significant weight loss, and those warmed up to 50°C lost 70% of their total mass.
作为最终测试，科学家拍摄了六只兔子气管的CT图像，并制作支架以适合每个测试对象的喉咙几何形状。在移植设备后，研究人员观察到，尽管引起炎症，但添加剂支架在十个星期内完全溶解了。
According to André Studart, head of the Complex Materials Group at ETH Zurich, the novel devices could soon find their way into end-use scenarios. “Producing such stents on a large scale is a complex undertaking that we still need to study better,” concluded Studart. “It is hopefully only a matter of time before our solution finds its way into the clinic.”
3D打印支架的进步
Although the ETH team’s polymer may be novel, they’re not the first to successfully develop biocompatible stents, and a team from the Ohio-based non-profit克利夫兰诊所have even managed to gain FDA approval for their3D printed patient-specific devices.
Researchers at埃因霍温大学, meanwhile, have developed similar3D printed dissolvable stents, but for pediatric heart surgery applications. The self-expanding devices are specifically designed to open up the arteries of children affected by heart disease.
Similarly, a team based at波哈科学技术大学(POSTECH) have3D printed cell-derived stentsthat help to ease the symptoms of esophagitis. The scientists believe that their device could be loaded with other cells in future, as a means of treating local injuries such as burns or wounds.
The researchers’ findings are detailed in their paper titled “Digital light 3D printing of customized bioresorbable airway stents with elastomeric properties.”
The research was co-authored by Nevena Paunović, Yinyin Bao, Fergal Brian Coulter, Kunal Masania, Anna Karoline Geks, Karina Klein, Ahmad Rafsanjani, Jasmin Cadalbert, Peter W. Kronen, Nicole Kleger, Agnieszka Karol, Zhi Luo, Fabienne Rüber, Davide Brambilla, Brigitte von Rechenberg, Daniel Franzen, André R. Studart and Jean-Christophe Leroux.
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特色图片显示了Eth Zurich团队的3D印刷气道支架的两个。通过《科学进步》杂志的照片。
