This paper describes an autonomous exploration system to optimize electrical stimulation parameters for the maturation of in vitro skeletal muscle tissues with Bayesian optimization. We established a cyclic experimental procedures, where (i) C2C12 myoblasts were cultured under multiple electrical stimulus conditions in parallel to promote the maturation, (ii) the cell maturation levels were scored by microscopic image analysis with immunofluorescence staining, and (iii) each maturation score with electrical stimulus condition were then applied to Bayesian optimization to suggest new experimental stimulus conditions for the next cycle of the C2C12 culture to expect higher maturation scores. We performed this experimental cycle repeatedly and derived the trend of electrical stimulus conditions to obtain high maturation scores. The C2C12 myoblasts cultured under the derived condition were also verified by the increase of myogenic gene expression. We believe that our proposed method could reveal optimal application method for tissue maturation, and would contribute to regenerative medicine or other medical technologies using tissue culture.

In this study, we investigated the conditions for protein synthesis by an in vitro transcription and translation (IVTT) system within giant unilamellar vesicles (GUVs) produced with a microfluidic channel. The commercial IVTT system comprised of purified components (PURE system) and DNA encoding target protein was encapsulated in GUVs and incubated to synthesize the proteins. Synthesis of green fluorescent protein (GFP) and nanopore-forming α-Hemolysin were tested as the water-soluble protein and membrane protein, respectively. The stability of the GUVs and the efficiency of protein synthesis were assessed, focusing on variations in the concentration of the PURE system and the size of the GUVs. Our findings contribute to the development of homogeneous bioreactors and biosensors based on GUV technology.

Prediction of the risk of developing Drug-induced liver injury (DILI) is very important in drug discovery. Although animal tests usually evaluate DILI, the prediction accuracy of DILI is low because experimental animals have different metabolic pathways from humans. A few microphysiological systems (MPS) have been developed as novel evaluation systems for DILI evaluation. However, the proposed system is not yet practical due to operability, throughput issues, and prediction accuracy. Our purpose is to develop a practical DILI evaluation system. In this study, we investigate the influence of perfusion culture on hepatotoxicity tests using our previously developed Kinetic pump integrated microfluidic plate (KIM-Plate). The results of acetaminophen toxicity tests showed that perfusion culture using KIM-Plate improved the detection sensitivity of hepatotoxicity. We suggest that the liver model MPS based on KIM-Plate could be a novel DILI evaluation system that integrates highly functional liver models and coculture with immune cells.