Approach of resource expenditure estimation toward mechanization in the manufacturing of cell-based products

Approach of design for air mass balance in an aseptic processing area for cell-based products

Introduction

The manufacture of cell-based products requires assuring sterility through all processes, with aseptic processing in a cleanroom. The environment consists of a critical processing zone (CPZ) that can ensure a level of cleanliness that allows cell culture containers to be opened, and a support zone (SZ) adjacent to it and accessed by an operator. In this study, an environment for cell manufacturing was proposed by designing an air mass balance in an aseptic processing area (APA).

Methods

We considered the distribution of particle concentration related to the airflow of clean air passing through a high efficiency particulate air (HEPA) filter and the location of the particle emission sources and set up a model dividing the SZ into two zones vertically: the upper and lower zones in a cleanroom, considering three cases practically. Both the air inlet and outlet were located outside the cleanroom and were connected to the CPZ directly by air ducts (Case 1). The inlets of the CPZ were located in the lower or upper zones of the SZ inside the cleanroom, and the outlets were located in the upper zone (Case 2 or Case 3, respectively). We analyzed how the cleanliness of the APA was affected by different locations of the inlet and outlet of the CPZ by varying the particle emission rate or air change rate.

Results

In Case 1, changes in the particle emission rate or air change rate within the SZ did not affect the particle concentration in the CPZ. In Case 2, an increase in the particle emission rate led to an increase in the particle concentration of the CPZ. In Case 3, the particle concentration of the CPZ was not affected by the particle emission rate. Cases 2 and 3 showed differences in particle concentrations between the CPZ and SZ, indicating that the location of the air inlet of the CPZ had an impact on the cleanliness of both zones. The partial circulation of air between the SZ and CPZ exhibited an additional air cleaning effect, leading to a reduction in the particle concentration in the SZ in Cases 2 and 3.

Conclusions

These results suggest that the appropriate location of the air inlet and outlet can construct the cleanliness of the APA, which reduces the risk of microbial contamination. In addition, we consider that this approach can realize an APA design policy, which eliminates the need for air ducts between the outside of the cleanroom and the equipment for the CPZ, reduces the requirements for gowning, thereby reducing the required air change rate.

Status and prospects for the development of regenerative therapies for corneal and ocular diseases

Among the regenerative therapies being put into clinical use, the field of corneal regenerative therapy is one of the most advanced, with several regulatory approved products. This article describes the progress from initial development through to clinical application in the eye field, with a particular focus on therapies for corneal epithelial and endothelial diseases that have already been regulatory approved as regenerative therapy products. The applications of regenerative therapy to the corneal epithelium were attempted and confirmed earlier than other parts of the cornea, following advancements in basic research on corneal epithelial stem cells. Based on these advances, four regenerative therapy products for corneal epithelial disease, each employing distinct cell sources and culture techniques, have been commercialized since the regulatory approval of Holoclar® in Italy as a regenerative therapy product for corneal epithelial disease in 2015. Corneal endothelial regenerative therapy was started by the development of an in vitro method to expand corneal endothelial cells which do not proliferate in adults. The product was approved in Japan as Vyznova® in 2023. The development of regenerative therapies for retinal and ocular surface diseases is actively being pursued, and these therapies use somatic stem cells and pluripotent stem cells (PSCs), especially induced pluripotent stem cells (iPSCs). Accordingly, the eye field is anticipated to play a pioneering role in regenerative therapy development going forward.

Noninvasive total counting of cultured cells using a home-use scanner with a pattern sheet

The inherent variability in cell culture techniques hinders their reproducibility. To address this issue, we introduce a comprehensive cell observation device. This new approach enhances the features of existing home-use scanners by implementing a pattern sheet. Compared with fluorescent staining, our method over- or underestimated the cell count by a mere 5%. The proposed technique showcased a strong correlation with conventional methodologies, displaying R2 values of 0.91 and 0.99 compared with the standard chamber and fluorescence methods, respectively. Simulations of microscopic observations indicated the potential to estimate accurately the total cell count using just 20 fields of view. Our proposed cell-counting device offers a straightforward, noninvasive means of measuring the number of cultured cells. By harnessing the power of deep learning, this device ensures data integrity, thereby making it an attractive option for future cell culture research.

Robotic cell processing facility for clinical research of retinal cell therapy

The consistent production of high-quality cells in cell therapy highlights the potential of automated manufacturing. Humanoid robots are a useful option for transferring technology to automate human cell cultures. This study evaluated a robotic cell-processing facility (R-CPF) for clinical research on retinal cell therapy, incorporating the versatile humanoid robot Maholo LabDroid and an All-in-One CP unit. The R-CPF platform consists of a robot area for handling cells and an operator area for the maintenance of the robot, designed with a clean airflow to ensure sterility. Monitoring the falling, floating, and adhering bacteria demonstrated that the required cleanliness and aseptic environment for cell manufacturing were satisfied. We then conducted cell manufacturing equivalent to the transplantation therapy of induced pluripotent stem cell (iPSC)-derived retinal pigment epithelial cells that met the clinical quality standards for transplantation. These results indicate that R-CPF is suitable for cell manufacturing purposes and suggest that utilizing the same robotic system in basic and clinical research can accelerate the translation of basic research findings into clinical applications.

Assessing Tumorigenicity in Stem Cell-Derived Therapeutic Products: A Critical Step in Safeguarding Regenerative Medicine

Stem cells hold promise in regenerative medicine due to their ability to proliferate and differentiate into various cell types. However, their self-renewal and multipotency also raise concerns about their tumorigenicity during and post-therapy. Indeed, multiple studies have reported the presence of stem cell-derived tumors in animal models and clinical administrations. Therefore, the assessment of tumorigenicity is crucial in evaluating the safety of stem cell-derived therapeutic products. Ideally, the assessment needs to be performed rapidly, sensitively, cost-effectively, and scalable. This article reviews various approaches for assessing tumorigenicity, including animal models, soft agar culture, PCR, flow cytometry, and microfluidics. Each method has its advantages and limitations. The selection of the assay depends on the specific needs of the study and the stage of development of the stem cell-derived therapeutic product. Combining multiple assays may provide a more comprehensive evaluation of tumorigenicity. Future developments should focus on the optimization and standardization of microfluidics-based methods, as well as the integration of multiple assays into a single platform for efficient and comprehensive evaluation of tumorigenicity.