Chronic wounds are defined by being unable to fully heal naturally, persisting at an inflammatory stage due to imbalances in the wound microenvironment. These wounds, including diabetic ulcers and pressure sores, can linger for months or even years. Wound dressings function to provide a protective barrier over the injured region, facilitating new tissue and vascular structure growth. However, conventional dressings sometimes have insufficient moisture balance, limited bioactivity, poor mechanical strength, and difficulty in sustaining the release of therapeutic agents. That’s why researchers at the University of Mississippi School of Pharmacy are 3D printing medicated patches to treat persistent sores and ulcers. This mission of this research was to optimize scaffold composition for printability and mechanical performance, evaluate in vitro drug release, and assess antibacterial efficacy.
The wound scaffold developed by the University of Mississippi team offers natural, biodegradable antibacterials over time to encourage healing. This isn’t the first time wound dressings have been 3D printed. For instance, in 2023 researchers from the Queen’s University Belfast published a study in which they 3D printed scaffolds for ulcers. However, the difference is in the production methods and the novel materials used, which you might find surprising.
Graphical abstract of the study. (Image credit: Alshammari et al.)
What Materials Are in the Scaffolds?
The base material of the scaffolds is chitosan (CS), a biopolymer derived from chitin, which is naturally present in the exoskeletons of crustaceans and insects. This biopolymer has attracted attention for wound healing due to its distinct combination of biocompatibility, biodegradability, and antibacterial characteristics. The researchers combined this biopolymer with Para-Coumaric acid (P-CA), a naturally occurring phenolic compound that is abundant in plants, especially fruits, cereals, tea, and wine. Additionally, they incorporated polycaprolactone (PCL) for mechanical stability, and polyethylene oxide (PEO) for improving hydrophilicity and processability. PCL and PEO reinforced the CS-based scaffolds, to maintain structural integrity during healing.
Importantly, this combination of materials is biodegradable. Nouf Alshammari, doctoral candidate and one of the study’s authors, explained: “With time, the scaffold is going to be absorbed into the skin. And it’s an inactive material, so we don’t have to worry about side effects or toxic residuals.”
While specialized scaffolds have traditionally been produced through techniques such as electrospinning, solvent casting, and freeze-drying, each of these methods presents manufacturing drawbacks. To overcome these limitations, the Mississippi team turned to 3D printing.
The workflow begins with hot-melt extrusion (HME) to synthesize the custom filament, which is then processed via fused deposition modeling (FDM). On the digital side, the researchers utilized Rhinoceros and Meshmixer to design the initial STL files before optimizing them in UltiMaker CURA for printing. The team then deployed a Bowden FDM 3D printer to produce the patches. These patches are customizable, allowing the medication and geometry to be tailored to the specific dimensions of a wound anywhere on the body.
Surface morphology and 3D topography of 3D-printed scaffolds and filaments. (Image credit: Alshammari et al.)
Possible Applications for 3D Printed Wound Care
Chronic wounds affect an estimated 1.67 per 1,000 individuals worldwide. However, these specialized bandages might not be necessary for every case. “Depending on what kind of wound it is, a regular bandage might work well and this wouldn’t be necessary,” Michael Repka, distinguished professor of pharmaceutics and drug delivery said. “But there are a lot of applications for this technology. These could be printed in the field for, say, military applications. If you have a generator that can run these 3D printers, you can print the scaffold you need based on what kind of wound has occurred.”
Beyond external applications, the material composition of these patches offers a distinct advantage for internal medicine. “Being biodegradable also means that if the material is applied to wounds inside the body, health care professionals don’t have to make a second incision to remove it,” postdoctoral researcher Sateesh Vemula added.
Before these 3D-printed scaffolds can be deployed in a medical setting, they must undergo extensive human clinical trials and a comprehensive review by the U.S. Food and Drug Administration. To learn more, read the study here.
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*Cover Image: Michael Repka, distinguished professor of pharmaceutics and drug delivery, works with a 3D-printed medical device in his lab. (Photo Credit: Thomas Graning/Ole Miss Digital Imaging Services)