Adaptation of a Microfluidic Device for Use in Scalable Cell Encapsulation

To combat degenerative conditions like cardiovascular disease, billions of cells such as cardiomyocytes are required for cell therapy; however, current manufacturing processes are inadequate for producing clinically relevant numbers of cells. Stem cells (SCs) are optimal candidates for use in cell production since adult cells cannot be expanded or cultured long-term in vitro given their limited regenerative capacity. Conventional 2D monolayers for SC differentiation require large surface areas for culturing thereby limiting commercial scalability. Scalable 3D approaches such as bioreactors slightly improve upon 2D shortcomings but are inconsistent as formed embryoid bodies lack size and shape uniformity impacting SC differentiation and yield. Previously, our lab has established a novel microfluidic platform capable of producing functional engineered cardiac tissues (ECTs) from the direct differentiation of human induced pluripotent SCs within poly- (ethylene glycol) fibrinogen hydrogel microspheres (MS). During MS encapsulation, an expensive, high-intensity visible halide lamp has been used for rapid photocrosslinking of the hydrogel; however, this causes issues such as light output consistency, heat regulation, adjustability of photoinitiator type, and user-friendliness. Such drawbacks cause added maintenance costs, batch-to-batch variability, and may interfere with cell viability. Here, we describe cost-effective and scalable improvements to our platform to support clinically relevant production of ECTs and commercial scalability. Using an iterative design approach, we redesigned the platform using optomechanical components from THOR labs. By utilizing two plates each mounted with four three-watt LED modules in series, encapsulated MS can achieve similar levels of cross-linking as the original, more expensive halide lamp without high maintenance and heat. The use of optomechanical components provides both precise axial and radial adjustability of light source plates for accurate and effortless positioning during cell encapsulation. Additionally, both UV and visible light LED modules can be easily interchanged to allow for crosslinking with various photoinitiators such as LAP and Eosin Y. As proof of concept, HT29 colorectal cancer cells were encapsulated using both our original and optimized microfluidic platform and cell viability was compared using live/dead staining. Preliminary results indicate fewer dead cells in MS produced by new platform; however, further validation is required. Overall, by improving function and utility while preserving its reliability, our platform has high potential for clinically relevant production of ECTs and long-term commercial scalability.