By Alec | 3ders.org
While 3D bioprinting innovations sound life-saving and revolutionary, most are still years away from impacting ordinary people in regular hospitals. However, one Chinese company is already implementing a bioprinted product on a large scale across the world. Called MEDPRIN, they have developed the world’s first 3D printed biological meningioma called ReDura – a replica of tissue covering the brain – and are already applying it in surgical rooms across the world.
MEDPRIN is based in Guangzhou, China and was founded by a team of biomedical scientists in 2008 as a developer of regenerative medical materials and devices. Since then, they have grown out to become a global leader in the field of implantable medical devices, and the ReDura is just one of the many products they have released. It’s full name is the ReDura® Biomimetic-Synthetic-Absorbable Dural Substitute, and has already received a number of medical certificates, including from CE and CFDA. It has also reportedly been applied on tens of thousands of cases across the world and it is also believed to be the first applied bioprinted product to come out of China.
So what exactly is the ReDura? With a thickness of only 0.2 mm, it looks like ordinary tissue paper, but is in fact a tissue with extraordinary qualities. Usually, when patients undergo brain surgery, doctor first need to cut through a layer of protective tissue between the skull and the brain. When patching everything up, they 'paste' an artificial Meningioma layer on the area in question and sew everything together. While these have already been widely and successfully used in brain surgeries everywhere, they are not biological and have a tendency to disrupt a patient’s life - as most artificial meningioma layers contain metal parts and will often case security alarms to beep.
Fortunately, this 3D printed biological ReDura doesn’t suffer from these problems, but instead closely resembles the existing membrane and a patient’s autologous cells. It also features an excellent repair effect. While dry, it resembles a white paper, but when wet it begins to resemble a thin rubber surface perfect for use in surgical rooms.
Yuan Yuyu, the chairman of MEDPRIN, explained how they developed this 3D printed material. They begin by taking meninges tissue out of patients themselves to analyze the fiber structure. They will subsequently use 3D printing technology to create artificial meninges structures. Upon implantation, the brain’s blood vessels crawl into the structures. Over a course of up to three months, a completely new Meningioma beings to grow, while the artificial structure naturally degrades.
It has already been very successfully applied to thousands of patients, Professor Xu Tao from Tsinghua University, the CTO of Medprin, adds.
– Xu Tao
'In March 2011, the product 2011 received the European Union CE certification, and was sold to dozens of countries in Europe and America, and has been used in world renowned hospitals such as Cambridge University Hospital. So far, no reports of adverse reactions have been made,’ he said. ‘The core membrane adopts the most advanced 3D printing based bio-regenerative medical platform, and has launched after five years of development.’
The history of this product goes all the way back to 2001, when Xu Tao was still a PhD student in the US at the team of Thomas Boland – the father of 3D bioprinted organs. In 2003, Xu Tao was successful in live cell printing with a survival rate of more than 90% (a patent was granted two years later). In 2009, Xu Tao teamed up with Yuan Yuyu from Clemson University to found the first bioprinting company in China.
As Xu Tao explains, the key difference between bio 3D printing and traditional printing is in the printhead used.
– Xu Tao
‘There are two kinds of printhead used in bio 3d printing: One is filled with human cells called "bio-ink", with the quantity being in the millions; the other is mainly composed of a 3D printable water gel called “Biology paper”, which can be used as a support for cell growth.’
When printing out membranes, he says, the machine sprays out a fiber-like ink onto biological paper that simulates the collagen structures found in body. Forming hundreds or even thousands of layers of molecular membrane, the result can be adapted to a human environment. Key is the use of a patient’s own autologous cells to prevent immune reactions. In time, this will allow on-demand organ printing to take place.
In case of the ReDura membrane, they only produce tissue of up to 0.2 mm in thickness, but that is all that is needed for a protective layer between the skull and the brain. According to the company, doctors could just use ReDura on the defect areas and sow it together.
‘ReDura is hydrophobic with a more than 90 contact angle that acts as a watertight barrier for the prevention of cerebrospinal fluid (CSF) leakage,’ writes the company. ‘ReDuraTM is manufactured with FDA approved degradable material poly-L-lactic acid which has been extensively tested to prove the biocompatibility and non-toxicity.’
Yuan Yuyu further stated that the ReDura is eventually absorbed into the body.
– Yuan Yuyu
‘Simply put ReDura provides the bracket in which cells and tissue can grow. About two months after a meningeal tissue has grown, the ReDura begins to slowly degrade into toxic-free carbon dioxide and water,' he says. ‘ReDura is fully degraded and absorbed, leaving no foreign body in-situ and is replaced by regenerated dura tissue.’
A second generation version of the ReDura is expected to receive its certificates in August of this year, and will be shipped all over the world soon afterwards.
Meanwhile, MEDPRIN is also looking at a large number of other human tissue products, including a personalized skull and maxillofacial repair system, a female pelvic diaphragm repair system, a tensionless urethral sling, a hernia repair piece, and artificial skin, blood vessels and ligament, many of which rely on the exact same 3D printing technique. In short, they are laying the technical foundations necessary for future development of more complex and advanced 3D printed artificial tissues and organs.
According to Xu Tao, the availability of 3D printed medical tissues could widely change over the coming years.
– Xu Tao
‘Tissue repair is a complex human organ regeneration process, and it has different requirements for different structures, ‘ he said. ‘The plan is to develop more than 10 kinds of implantable medical devices products within the next 5 years. Currently, we are leading the establishment of Guangzhou Research Institute of regenerative medical industry, seeking to integrate global and domestic regenerative medical technology and clinical resources to push 3D printing from biological tissue reconstruction all the way up to 3D printing of organ regeneration.’
In short, the 3D bioprinting revolution is definitely on its way, and Chinese scientists can be found at its forefront.
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