Researchers from the University of Oregon (UO) have developed 3D printed scaffolds that glow when exposed to ultraviolet (UV) light. This process could be used to create fluorescent biomedical implants, allowing practitioners to more accurately monitor their condition when placed inside a patient.
The technique combines melt electrowriting (MEW), a 3D printing technique that can produce large, high-resolution objects, with nanohoops. The latter, circular carbon-based molecules, emit different colors depending on their size and structure.
Previous attempts to produce glowing scaffolds have failed as most fluorescent molecules degrade when exposed to the prolonged heat of MEW 3D printing. However, UO’s nanohoops, developed by Professor Ramesh Jasti’s chemistry lab, are more stable under high temperatures, allowing them to be successfully extruded.
“Making nanohoops is really hard, and melt electrowriting is really hard to do, so the fact that we were able to merge these two really complex and different fields into something that’s really simple is incredible,” commented Harrison Reid, a graduate student in Jasti’s lab.
The UO team, led by Jasti and Associate Professor Paul Dalton, has filed a patent application for the 3D printing process and hopes to commercialize it in the future.
The researcher’s findings, titled ‘[n]Cycloparaphenylenes as Compatible Fluorophores for Melt Electrowriting,’ have been published in the journal Small.
New research enhances fluorescent 3D printing
The new study was born from a collaboration between Dalton’s engineering lab in the Phil and Penny Knight Campus for Accelerating Scientific Impact and Jasti’s chemistry lab in the UO’s College of Arts and Sciences. Dalton’s lab developed the University’s MEW 3D printing technique, while Jasti’s specializes in the development of fluorescent nanohoops.
OU’s engineering lab has already demonstrated the biomedical value of MEW 3D printing. Earlier this year, Dalton’s team collaborated with cosmetics firm L’Oréal to 3D print realistic artificial skin using its MEW scaffold process. The technique enabled the creation of a two-layered structure with each layer separated by a membrane, mirroring the structure of natural skin.
In the new study, three blends of fluorescent nanohoop dyes were tested, with each emitting blue, green, or yellow light at different wavelengths. According to Jasti, the team initially thought that 3D printing these blends “probably wouldn’t work.” However, these doubts were soon dispelled.
The researchers determined the most effective concentration for mixing the [n]cycloparaphenylenes ([n]CPPs) nanohoops with biocompatible poly(ε-caprolactone) (PCL) polyester material was 0.1 wt%. This produced scaffold structures that remained fluorescent even after being continuously heated to 80°C for one week.
Tests conducted by Dalton and graduate student Patrick Hall confirmed that adding the fluorescent molecule didn’t make the material toxic to cells. This is essential for ensuring that the 3D printable material can be used for medical applications, such as implants. Further testing also found that adding the nanohoops didn’t reduce the strength or stability of the scaffolds.
The new approach could reportedly make medical implants easier to track and monitor over time inside the body. In particular, the material’s fluorescence could allow researchers and medical practitioners to more accurately distinguish between the implant and cells or tissue.
Jasti also believes the customizable material could offer value for security-related applications. Although they glow when exposed to fluorescent light, the 3D printed structures look clear under normal conditions.
3D printed biomedical implants
3D printed implants are nothing new, with medical professionals increasingly adopting additive technology to produce medical devices that are personalized for each patient.
Last year 3D printer manufacturer 3D Systems used its point-of-care offering to produce a patient-specific 3D printed cranial implant for a procedure at the University Hospital Basel in Switzerland.
Designed to replace a section of a patient’s disintegrating skull, the biocompatible implant was 3D printed using Evonik’s VESTAKEEP i4 3DF PEEK material on 3D Systems’ EXT 220 MED extrusion platform.
The project marked the creation of the first cranial implant produced at the point of care that complies with current Medical Devices Regulations (MDR). This reflects 3D Systems’ efforts to disrupt the growing cranial implant market, which is projected to reach approximately $2.1 billion by 2030.
Following the success of this operation, 3D Systems secured FDA 510K clearance for its Cranial Implant solution earlier this year.
Elsewhere, the first 3D printed ceramic subperiosteal jaw implant was successfully implanted into a patient at Kepler University Hospital.
Developed by Austrian ceramic 3D printing specialist Lithoz and led by Profactor GmbH, the dental device was developed through the INKplant project, an EU-funded initiative. It was designed for patients suffering from severe jaw atrophy. This condition sees the loss of teeth cause significant bone deterioration, making traditional dentures or implants untenable.
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Featured image shows a close-up of a scaffold made with nanohoops, glowing blue under UV light. Image via the University of Oregon.
