小川 良磨

The use of 3D cell culture for tissue engineering and regenerative medicine applications often challenges conventional biochemical and optical assays. Impedance‐based cellular assays have shown their potential to retrieve dielectric parameters pertaining to cell behavior such as viability, proliferation, and differentiation for 2D adherent cell culture. Herein, simultaneous 3D impedance imaging and viability measurements of multiple large (>2 mm) 3D cell cultures embedded in collagen gels are demonstrated. The method is facilitated by low‐resistance 3D printed scaffolds that can hold a 3D cell–gel system throughout cell culture while being transparent to impedance imaging. It is shown in silico and in vitro that frequency‐difference electrical impedance tomography (fd‐EIT) can nondestructively and in a label‐free way differentiate a variety of cell concentrations with a single miniature sensor in real time. This study paves the way toward the development of EIT imaging for the quantitative and noninvasive evaluation of tissue engineering products.

Abstract There is a strong need for a non-invasive measurement technique that is capable of accurately identifying the physiological condition change or heterogeneity of subcutaneous adipose tissue (SAT) by localizing the abnormalities within the compartment. This paper aims to investigate the feasibility of Electrical Impedance Tomography (EIT) to assess the interstitial fluid in subcutaneous adipose tissue as an enhancement method of bioelectrical impedance spectroscopy (BIS). Here, we demonstrate the preliminary result of EIT with a wearable 16 electrodes sensor. The image-based reference EIT with fat weighted threshold method is proposed. In order to evaluate the performance of our novel method, a physiological swelling experiment is conducted, and Multi-Frequency Bioelectrical Impedance Analysis (MFBIA) is also applied as a comparison with EIT results. The experimental results showed that the proposed method was able to distinguish the physiological swelling condition and effectively to remove the unexpected background noise. Furthermore, the conductivity variation in the subcutaneous layer had a good correlation with extracellular water volume change from MFBIA data; the correlation coefficient R² = 0.927. It is concluded that the proposed method provides a significant prospect for SAT assessment.