Researchers take step towards 3D laser printed medical devices

A team of scientists, led by researchers at Lancaster University, have developed a method to 3D print flexible electronics using the conducting polymer polypyrrole, and they have shown that it is possible to directly print these electrical structures on or in living organisms (roundworms). Although at a proof-of-concept stage, researchers believe this type of process, when fully developed, has the potential to print patient-specific implants for a variety of applications.

Dr John Hardy, one of the lead authors of the study, said this approach could potentially transform the manufacture of complex 3D electronics for technical and medical applications — including structures for communication, displays, and sensors. Such approaches could also be used to fix broken implanted electronics through a process similar to laser dental/eye surgery. In a two-stage study, the researchers used a Nanoscribe (a high-resolution laser 3D printer) to 3D print an electrical circuit directly within a silicone matrix (using an additive process). They demonstrated that these electronics can stimulate mouse neurones in vitro (similar to how neural electrodes are used for deep brain stimulation in vivo).

Dr Damian Cummings, a co-author of the study, said the researchers took 3D printed electrodes and placed them on a slice of mouse brain tissue that was 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,” Cummings said.

The researchers then 3D printed conducting structures directly in nematode worms demonstrating that the full process (ink formulations, laser exposure and printing) is compatible with living organisms. Dr Alexandre Benedetto, another lead author of the study, said the researchers 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,” Benedetto said.

L–R: Researcher using nanoscribe — the printing has to be undertaken in orange light; examples of shapes printed using this technique; material was printed in worms that included an embedded star shape from printed ink (unpolymerised material, such as the ink, shines green under UV light). Image credit: Dr Alexandre Benedetto.

The research findings are an important step highlighting the potential for additive manufacturing approaches to produce next-generation advanced material technologies — in particular, integrated electronics for technical and bespoke medical applications. The next steps in the development in research are exploring the materials in which it is possible to print, the types of structures it is possible to print, and developing prototypes to showcase to potential end users who may be interested in co-development of the technology. The researchers believe the technology is around 10 to 15 years from being fully developed.

The research findings were published in the academic journal Advanced Material Technologies.

Top image credit: iStock.com/Михаил Руденко