Novel 3D printed probe for bioimpedance spectroscopic measurement of oral mucosa: design and testing with ex vivo porcine oral tissues

Abstract

Three-dimensional (3D) printing has a high potential in various biomedical applications. We hypothesise that 3D printing could be a viable option to construct bioimpedance spectroscopic (BIS) sensors suitable for electrochemical characterization of oral mucosal tissues. Previous BIS studies have been relied on hand-made probes possessing significant limitations related to single patient disposable use, great inter-probe differences and weak reproducibility of measurement. There is also uncertainty related to effect of varying loading pressure between the probe and biological tissue. Here, we introduced three different sized rectangular shaped 3D printed probes and test those using four-terminal measurement principle on various porcine oral tissue samples. We found that constructing fully 3D printed probe is a challenging task and prone to issues relating to short circuiting or electrochemical corrosion. However, our final protype version constructed with silver-coated copper electrodes showed favourable characteristics in BIS experiments. All three different sized probes were able to differentiate between different tissue types with excellent reproducibility. The effect of loading pressure was found to be almost negligible when using small and medium sized probes. However, further studies are needed to measure tissues with uneven surfaces, such as palatinum, and to avoid manual or electrochemical surface finishing steps.