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A new 3D printed process from Lancaster University researchers is claimed to be the first of its kind.

Researchers at Lancaster University have taken a step towards laser 3D printed materials that could potentially be used in surgical procedures to implant or repair medical devices. The team of scientists have developed a method to 3D print flexible electronics using the conducting polymer polypyrrole.

The team says it showed that it was possible to 3D print the electrical structures on or in living organisms by testing on roundworms. Although the project is at a proof-of-concept stage, the team says it believes this type of process has potential to print patient-specific implants for a variety of applications, including real-time health monitoring and medical interventions, such as treating epilepsy or pain, once the process is fully developed.

Dr. John Hardy, Seniro Lecturer in Materials Chemistry at Lancaster University and one of the lead authors on the study said: “This approach potentially transforms the manufacture of complex 3D electronics for technical and medical applications, including structures for communication, displays, and sensors, for example. Such approaches could revolutionise the way we implant but also repair medical devices.

“For example, one day technologies like this could be used to fix broken implanted electronics through a process similar to laser dental/eye surgery. Once fully mature, such technology could transform a currently major operation into a much simpler, faster, safer and cheaper procedure.”

The researchers used a Nanoscribe during the two-stage study, a high-resolution laser 3D printer, to 3D print an electrical circuit directly within a silicone matrix. The system uses a process called multiphoton fabrication, also known as direct laser writing.

Dr. Hungyen Lin, Senior Lecturer in Electronic Engineering at Lancaster University and Prof. Yaochun Shen, Professor in Electrical Engineering at University of Liverpool, both co-authors on the study who led the 3D imaging work said: “We then saw an opportunity to fully characterise the fidelity of these printed structures embedded inside the matrix using a low-cost and high-speed optical coherence tomography process.

“The imaging technology recently developed at the University of Liverpool can capture an entire cross-sectional image of printed 3D objects in a single shot without the need of any scanning, making it attractive to many potential industrial applications such as offline quality inspection and in situ process monitoring. The information obtained from the 3D imaging could be used to inform the design, material choice and process optimisation of these print-outs rapidly and cost-effectively in the future.”

The study also demonstrated that the electronics can stimulate mouse neurones in vitro, similar to how neural electrodes are used for deep brain stimulation in vivo.

Dr. Damian Cummings, Lecturer in Neuroscience at University College London, a co-author of the study who lead the brain stimulation work, said: “We took 3D printed electrodes and placed them on a slice of mouse brain tissue that we kept alive in vitro. Using this approach, we could evoke neuronal responses that were similar to those seen in vivo. Readily customised implants for a wide range of tissues offers both therapeutic potential and can be utilised in many research fields.”

In the second stage of the study, the researchers 3D printed conducting structures directly in nematode worms, demonstrating that the full process, including ink formulations, laser exposure and printing, is compatible with living organisms.

Dr. Alexandre Benedetto, Senior Lecturer in Biomedicine at Lancaster University, and another lead author of the study, said: “We essentially tattooed conductive patches on tiny worms using smart ink and lasers instead of needles. It showed us that such technology can achieve the resolution, safety and comfort levels required for medical applications. Although improvement in infrared laser technology, smart ink formulation and delivery will be critical to translating such approaches to the clinic, it paves the way for very exciting biomedical innovations.” 

The team behind the project believes the results are an important step highlighting the potential for 3D printing approaches to next-generation advanced material technologies, in particular integrated electronics for bespoke medical applications.

The study can be found here. https://doi.org/10.1002/admt.202201274