The main objective of this project was to develop a method for soft neural probe insertion into a nerve. These soft probes are made of a silicon elastomer that is a few orders of magnitude less stiff than the nerve, which makes the insertion process particularly challenging. To overcome this challenge a tungsten microwire was used as an insertion shuttle to help penetrate the nerve by increasing the overall stiffness of the probe. At a first stage, the insertion process was tested on a nerve phantom (e.g. agarose gel with PDMS membrane) to control the insertion parameters and validate the insertion platform. Once the envisioned insertion method was established, the probe was implanted in a real rodent nerve. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

Roughly 123 million people worldwide are affected by conditions such as epilepsy, dementia, and cardiovascular diseases. Wearable electrodes are currently used to monitor these conditions short-term. Long-term monitoring would allow for predicting seizures and could be used as a preventive treatment. As opposed to the currently used electrodes, wearables that are intended for long-term use must be soft and flexible in order not to cause harm or discomfort for the user. The electrodes should also have high resolution, meaning that the electrode paths should be as narrow as possible without negatively affecting the performance of the electrode. In this thesis, soft and flexible electrode grids based on silicones are developed using UV laser patterning. Two different methods are evaluated: laser curing of silicones with the addition of a photoinitiator, and laser ablation of conductive composite. The results found in this thesis are that photocuring silicones gives a too low resolution to be useful for patterning soft electrode grids. UV laser ablation on the other hand showed high resolution while the electrodes retained stretchability. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

Electronic devices define our everyday lives. They are often large, rigid, and brittle. Modern medical science has come so far as to start using miniature electronic devices to monitor many types of diseases. Especially, neurological disorders pose obstacles hard to overcome when treating them but it also motivates finding methods that allow for continuous monitoring. Implementing a small electronic device inside the human body adds requirements on the device to be stretchable, biocompatible, and more. Not only is the device limited by these factors, but also, current fabrication methods are not efficient for creating nanoscale versions for these types of devices. patterninglaser ablation is a growing field for cutting out and pattern nano-materialistic devices with high precision and good repeatability. This project is focused on using a laser engraving tool from metaquip on different substrates. This project is focused on the development of methods for laser fabrication of soft neural electrodes. The requiered steps are the alignment of samples to assure good precision when engraving it with the laser engraving tool, that also will be called “laserpatterner”, finding good parameters for cutting out devices and pattern conductors for said devices. On top of that, a linear force stretching will be used to characterize samples that were cut, in the form of strips, using the laserpatterner. The stretching behavior of strips consisting of the elastomer polydimethylsiloxane, which in turn will be the insulator for silver nanowires, is examined in the stretching setup. Parameter optimization is relevant in all experiments done in this project and lay the foundations for cutting and patterning silver nanowires devices. All factors included will eventually lead to a good method for fabricating soft neural electrode devices and this project is stepping stone towards that goal. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

The biological translation between biological and electrical signals have inspired scientists over the last decade and has opened new way of therapeutics. The group of Bioelectronics at the Laboratory of organic electronics (LOE) develops systems that utilizes this translation to reduce the gap between electronics and biology. A known example of devices that does this are called iontronic delivery devices. These devices allow very specific transport and delivery of charged compounds. The most basic iontronic delivery device is the organic electronic ion pump (OEIP). The OEIP have been developed and fabricated into many variations, for example the iontronic micropipette which is a device that has been developed at LOE. In this project, the fabrication and characterization of the iontronic micropipette have been developed to find fabrication parameters that generates stable, high performing and reproduceable devices together with good and reproduceable characterization protocols. The iontronic micropipette is fabricated in a cleanroom and characterized in two steps, optically in a microscope and then electrically by transporting ions through the membrane. Two different membrane materials were tested, 2- acrylamido-2-methylpropane sulfonic acid (AMPSA) and Hyperbranched polyglycerols (HPG). The results that were obtained from the fabrication of the AMPSA showed a reproducibility between many devices, but many AMPSA device broke during the fabrication so the protocol for the AMPSA still need improvement. Regarding the A-HPG fabrication, the results were much more positive and the yield from the fabrication were sufficient. The results that were obtained in the characterization of the AMPSA device showed that these devices had a very equal resistance between the device from the same batch. For the A-HPG, it was a much larger spread in the resistance between the device but the resistance were still much lower than for the AMPSA which is more preferable for most applications on living cells. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>