CellFiber launches Zeito cell fiber systems in Japan and the US

CellFiber Co., Ltd., a Tokyo start-up founded in 2015 on University of Tokyo research, began selling its Zeito series of cell fiber fabrication systems in Japan and the United States on October 8, 2026. There are two models. The Zeito Plus Cell Encapsulation System is built for GMP manufacturing, and the Zeito Lite is a benchtop unit for early research. On October 1 the company opened a US subsidiary, CellFiber, Inc., in Philadelphia.

A cell fiber is a hair-thin tube of alginate gel with cells packed inside. CellFiber presents it as a 3D culture format that can be run closed, automated and at larger scale. The gel shell sits between the cells and the surrounding flow, so cells in a bioreactor should see less shear, while nutrients and oxygen pass through the shell. The usual way to expand adherent cells at volume is microcarrier culture, in which cells attach to the outside of beads about 0.2 mm across and take the flow directly. Cell fibers put the cells inside instead. Cells that are easily damaged by flow, such as iPS cells and mesenchymal stem cells (MSCs), are the obvious candidates.

The Zeito Plus is the production model that CellFiber first showed in December 2025 as the CellFiber Extruder. It uses a dedicated single-use kit and reagent kit and connects to culture bags through aseptic connectors. Cells reach the bag without exposure to room air, and the disposable flow path needs no cleaning, which helps when a GMP process has to stay closed. The Zeito Lite was previously sold as the CellFiber SSP and is meant for feasibility work and new applications.

According to Nikkei, CellFiber is aiming for sales of ¥1 billion or more and profitability by fiscal 2028. The US unit has an office and lab at CIC Philadelphia. It plans to work with drug makers, biotech companies, CDMOs and research institutes on onboarding, process development and joint R&D, with iPS cell, MSC and CAR-T cell manufacturing as the stated targets. This summer CellFiber started a joint evaluation with Tidewave Bio of Los Angeles that compares flat culture with cell fibers for immune cells aimed at solid tumors. Whether that goes further depends on a separate agreement.

Two practical questions are left to each user: how cells are recovered from the fibers, and how the alginate used for encapsulation is quality-controlled. Both have to be tested with the user's own cells before the method can be weighed against microcarriers.