Natsuki Takei

A microfabricated platform to form three-dimensional toroidal multicellular aggregate

Techniques that allow cells to self-assemble into three-dimensional (3D) spheroid microtissues provide powerful in vitro models that are becoming increasingly popular in fields such as stem cell research, tissue engineering, and cancer biology. Appropriate simulation of the 3D environment in which tissues normally develop and function is crucial for the engineering of in vitro models that can be used for the formation of complex tissues. We have developed a unique multicellular aggregate formation platform that utilizes a maskless gray-scale photolithography. The cellular aggregate formed using this platform has a toroidal-like geometry and includes a micro lumen that facilitates the supply of oxygen and growth factors and the expulsion of waste products. As a result, this platform was capable of rapidly producing hundreds of multicellular aggregates at a time, and of regulating the diameter of aggregates with complex design. These toroidal multicellular aggregates can grow as long-term culture. In addition, the micro lumen can be used as a continuous channel and for the insertion of a vascular system or a nerve system into the assembled tissue. These platform characteristics highlight its potential to be used in a wide variety of applications, e.g. as a bioactuator, as a micro-machine component or in drug screening and tissue engineering.

Organ-explanted bionic simulator (OBiS): Concurrent microcardiovascular anastomosis of chick embryo

In this paper, we newly propose an organ-explanted bionic simulator (OBiS) using an isolated organ tissue. We use a heart isolated from the chick embryo for proposed simulator. To achieve the OBiS, we perform the concurrent microvascular anastomosis by using suction-induced vascular fixation (SVF) method for easily connection to artificial tubes with blood vessels led to the explanted chicks heart. Through the experiment with a simulated cardiovascular, it is confirmed that vessels can be aligned by using the proposed method. In addition, we have succeeded in connecting the Alg tubes with the blood vessels led to the heart of chick embryo. OBiS is available for the evaluation of new drugs immune response not only without using large animals but also as a response of organs beyond cellular level.

Evaluation of cellular behavior in a multilayer structured tubular tissue with the PLCL scaffold

We proposed a 3D assembly technique of small-diameter blood vessels using a PLCL (poly (L-lactide-co-ε-caprolactone)) scaffold. The technique uses a residual stress of PLCL scaffolds to fabricate a multilayer structured tubular tissue, and gives a tissue mechanical property which blood vessels originally have. In the future, we try to test the circulatory culture system in order to investigate whether the tissue-engineered structure maintains the equivalent mechanical property as the human blood vessel. In this work, we demonstrated that fabricated tissues could attach on the inside of tubular PLCL scaffold in the appropriate conditions.

Circulatory culture system for multilayer-structured tubular tissues

We proposed a 3D assembly technique and a circulatory culture system. The technique gives multilayer-structured tubular tissues for blood vessel models. By the circulatory culture system, this study was aimed to determine whether the tissue-engineered tubular models maintain the normally mechanical property as the development and function. In this work, we were able to fabricate tubular tissues from multilayered tissues rapidly in the suitable conditions and circularly culture the fabricated multilayer-structured tubular tissues.

Assembly techniques for artificial small diameter blood vessel structures

We present our assembly techniques for artificial small diameter blood vessel structures. To rebuild large-scale 3D tissue architectures, it is needed to construct not only capillary blood vessel but also small-diameter blood vessel within them.

Formation of toroidal multicellular aggregate of cardiomyocytes

We have proposed a unique multicellular aggregate formation platform that utilizes a maskless gray-scale photolithography. The cellular aggregate formed using this platform has a toroidal-like geometry and includes a micro-pore that facilitates the supply of the oxygen and growth factors and expels waste products. The toroidal multicellular aggregates were easily and non-invasively retrieved from the PDMS platform. A P19.CL6 toroidal multicellular aggregate, which indicates that most of the cells in the aggregate (> 95%) were still alive after 3 days of culture. By directed assembly of the toroidal multicellular aggregate, the micro-pore can be used as a communicated channel for vascularization and neurogenesis.