3D printing electronics in vitro and in vivo

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Dr John Hardy, Senior Lecturer in Materials Chemistry at Lancaster University and one of the lead authors of 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 revolutionize 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.” 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, 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 Electronic Engineering at University of Liverpool, both co-authors on the study who lead 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. This study also 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, 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 (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 researchers believe these results 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 already underway 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. Their findings are reported in the paper ‘Creating 3D objects with integrated electronics via multiphoton fabrication in vitro and in vivo’ which is published in the academic journal https://onlinelibrary.wiley.com/doi/10.1002/admt.202201274. The research was supported with funding from a variety of sources including: the Engineering Physical Sciences Research Council (EPSRC), the Biotechnology and Biological Sciences Research Council (BBSRC), the Medical Research Council (MRC), the Royal Society, the Wellcome Trust, and Alzheimer’s Research UK.

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