In recent years, the demand for more sophisticated medical technologies has prompted the development of many advanced medical equipment, sensors, etc. In particular, implantable sensors are superior to other measurement methods in terms of sensitivity, resolution, precision, etc. and are expected for further technological development in the future. We are currently creating nerve-regenerative biochips that are specifically targeted for application to brain-machine interface (BMI), for which high mechanical adaptability, medical functionality and advanced biocompatibility are all essential. Carbon nanotube (CNT) is a representative material used in nanotechnology, application of which to implantable sensors appears promising due to its high conductivity and outstanding mechanical strength. However, there is a strong concern about the fact that there is little knowledge about its toxicity to living organisms and the environment, or interaction among them. Therefore, in this research, we have embedded the CNTs, which we actually use in creating our devices, subcutaneously in rats and examined the effect of functional group-added CNTs, which were formed by the plasma activation method (P-A method), to the living organisms. As for the evaluation method, in addition to weight measurement, leukocyte estimation test, and observation of change in organizational form, semi-quantitative analysis of expressed genes using molecular biological method was performed to assess the existence/non-existence of inflammatory reaction and the biocompatibility under each set of conditions. Consequently, it was suggested that, by applying the P-A process, the biocompatibility improved compared to the CNTs unprocessed by the P-A method. This result indicates the possibility that CNTs, to which functional group modification is applied, may be directly implanted in living organisms for a relatively long period of time.
