Periodic Reporting for period 1 - StemStation (On-demand hydrogel microbeads mass production by inkjet bioprinting for stem cell large-scale cultivation)
Reporting period: 2023-06-01 to 2025-05-31
The increasing demand for efficient three-dimensional (3D) cell culture methods, particularly for mesenchymal stem/stromal cells (MSCs), has driven the development of innovative biofabrication techniques. Traditional microcarrier-based bioprocessing faces limitations, such as complex cell separation, sedimentation issues, and scalability constraints. This study aims to address these challenges by developing an on-demand inkjet micro-valve bioprinting method for producing hydrogel microcarriers tailored for adipose-derived MSC (AD-MSC) culture. This approach leverages bioprinting technology to enhance cell viability, proliferation, and scalability, offering a novel alternative for cell therapy and bioproduction applications. By optimizing bioink composition and jetting parameters, this research provides a customizable, efficient, and scalable solution to advance regenerative medicine and industrial bioprocessing.
The study developed a bio-inspired bioink composed of alginate, gelatine, and fibrinogen, adjusted for Newtonian fluid behavior to ensure compatibility with micro-valve bioprinting. High-speed imaging techniques and custom Python algorithms were employed to analyze droplet formation, size distribution, and jetting dynamics. The microcarriers produced were characterized for their ability to support AD-MSC viability, proliferation, and maintenance of stemness markers over 21 days in static and agitated cultures. Additionally, cell expansion studies in shake-flask cultures demonstrated the potential fold increase in cell numbers over 21 days with promising prospects once optimized. The system effectively operated within micro-valve bioprinting seeding density capabilities (1·10⁶ to 2·10⁶ cells/mL) while ensuring cell viability. This method also facilitated an easy separation of cells from microcarriers through enzymatic digestion, enhancing downstream processing efficiency. This proof-of-concept paves the way for further development and scalability towards industrial scale and versatile applicability to other cell technologies.
This research advances the state of the art in bioprinting-based microcarrier production by offering a highly customizable, scalable, and efficient alternative to microfluidic-based approaches. The use of inkjet micro-valve bioprinting enables on-demand production with reduced contamination risks issued from the production process and better control over process parameters. Compared to existing commercial microcarriers and microfluidic devices, this method allows for increased cell carrying capacity and scalable expansion. Future work will focus on optimizing bioreactor integration to further scale up cell expansion while maintaining process control over environmental conditions such as dissolved oxygen, temperature, and pH. This study lays the foundation for transitioning from lab-scale applications to industrial-scale bioproduction of MSCs, addressing critical challenges in regenerative medicine and biopharmaceutical manufacturing.