The NCRC Researcher in Focus for May is Alice Shannon, an Irish Research Council and National Children’s Research Centre funded PhD student supervised by Prof. Leonard O’ Sullivan, Dr. Seamus Clifford, and Mr. Kevin O’Sullivan (University of Limerick). In collaboration with clinical colleagues, Dr. Barry Linnane (University Hospital Limerick) and Prof. Paul McNally (Children’s Health Ireland at Crumlin), Alice is trying to develop a novel anti-bacterial material that can be used to 3D print percutaneous endoscopic gastrostomy (PEG) feeding tube accessories for patients with Cystic Fibrosis.
Cystic Fibrosis is a progressive genetic disease characterised by persistent lung infections and deteriorating lung function over time. It is extremely common in Ireland with approximately 1 in 19 people carrying the CF gene. As Alice explains; “Cystic fibrosis is an inherited disease that affects around 500 children in Ireland. There is currently no cure for CF but medicines to help treat symptoms are improving, which can greatly improve quality of life. CF causes very thick mucus to build up in the body, which can trap bacteria in the lungs, increasing the risk of infections and the likelihood of a hospital visit. Daily airway clearance exercises can help to loosen thick mucus, reducing the risk of infection and improving lung function”.
In addition to problems in the lungs, digestive system issues are also extremely common in children with CF and in extreme cases can lead to malnutrition. “Children with CF need at least one and a half times the amount of food compared to a healthy child of the same age. This is because their bodies are constantly fighting infection and they cannot absorb all the nutrients from their food. Because it is hard to take in this much food every day, children with CF are often underweight” explained Alice.
To help children with CF meet their daily nutritional needs, PEG feeding tubes may be sometimes used. “As it is very important to meet their food intake goals, feeding tubes can be used to help with nutrition. Feeding tubes are inserted into the stomach through the skin. Generally, better nutrition means better overall health for children with CF” said Alice.
Figure 1: Cystic Fibrosis is genetic disease caused by a mutation in the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene. The CFTR gene produces a protein that helps maintain the balance of salt and water on the surfaces of many organs, including the lung. When the CFTR protein is not working properly, this causes an imbalance and a thick mucus can build up and block the lung airways as well as the pancreatic and bile ducts.
However, the long-term use of feeding tubes can lead to complications. Alice explained further “These feeding tubes are fantastic for providing nutrition but can have some drawbacks. These tubes are intended to last for 12 months. However, they are sometimes left in the body for longer. If the tube is in place for a few years they can sometimes tear, causing feeding to be interrupted. If a child is too sick for surgery to replace a leaking tube, the only option is to repair the tube. Some other issues include infection or scar tissue developing on the skin where the tube enters the body”.
Previous work from the Rapid Innovation Unit at the University of Limerick has led to development of 3D printed PEG feeding tube accessories that can limit many of the traditional complications associated with percutaneous endoscopic gastrostomy. “Our research group has developed custom-made 3D printed devices to seal feeding tube leaks and reduce scar tissue around the skin” explained Alice.
Their use of 3D printing to produce feeding tube accessories has significant benefits over traditional manufacturing process. “3D printing builds a 3D object, layer by layer, using materials such as plastic, metal or mixed material. The printers we have in our lab all use plastic as an input material. Detailed objects can be 3D printed with much less material waste than traditional manufacturing – as you gradually build up to the shape, rather than paring away from a block of material. As this is always automated, the parts are completely customisable, high quality and reproducible. 3D printing is usually only used in hospitals for rare cases but is gradually becoming more popular. It can be used to plan and practice surgeries before bringing a patient into the operating theatre as well as customised implants, false limbs, and low risk devices, such as casts. 3D printing is relatively cheap for one-off items and therefore devices can be customised for patients” said Alice.
However, one drawback of 3D printed feeding tube accessories is their potential to act as sites for bacterial colonisation that can increase risk of infection. “These devices could be an additional place for bacteria to hide and potentially cause more infections” explained Alice.
In Alice’s PhD project, she is trying to develop an anti-bacterial material that can be used to 3D print feeding tube accessories. “The key aim of my project is to create a 3D printable material which kills bacteria that are most harmful to children with CF. This material will be used to 3D print improved feeding tube repair devices and shielding devices to reduce scar tissue”.
Ultimately, the ability to produce feeding accessories with anti-bacterial properties will increase the safety of percutaneous endoscopic gastrostomy feeding tubes. “This material could reduce the risk of infections associated with feeding tubes for children with CF. Reducing the chance of infections could reduce the number of yearly hospital visits, improving quality of life [for children with CF]” said Alice.
Alice is in the third year of her PhD and has already made significant progress on her project. You can find out more about her research through the following links:
Publication: Alice Shannon, Aine O’Connell, Aidan O’Sullivan, Michael Byrne, Seamus Clifford, Kevin J. O’Sullivan, and Leonard O’Sullivan. A Radiopaque Nanoparticle-Based Ink Using PolyJet 3D Printing for Medical Applications. 3D Printing and Additive Manufacturing VOL. 7, NO. 6. https://doi.org/10.1089/3dp.2019.0160