Anti-Inflammatory Effects of Encapsulated Human Mesenchymal Stromal/Stem Cells and a Method to Scale-Up Cell Encapsulation

Engineered stem cell-based strategy: A new paradigm of next-generation stem cell product in regenerative medicine

Stem cells have garnered significant attention in regenerative medicine owing to their abilities of multi-directional differentiation and self-renewal. Despite these encouraging results, the market for stem cell products yields limited, which is largely due to the challenges faced to the safety and viability of stem cells in vivo. Besides, the fate of cells re-infusion into the body unknown is also a major obstacle to stem cell therapy. Actually, both the functional protection and the fate tracking of stem cells are essential in tissue homeostasis, repair, and regeneration. Recent studies have utilized cell engineering techniques to modify stem cells for enhancing their treatment efficiency or imparting them with novel biological capabilities, in which advances demonstrate the immense potential of engineered cell therapy. In this review, we proposed that the "engineered stem cells" are expected to represent the next generation of stem cell therapies and reviewed recent progress in this area. We also discussed potential applications of engineered stem cells and highlighted the most common challenges that must be addressed. Overall, this review has important guiding significance for the future design of new paradigms of stem cell products to improve their therapeutic efficacy.

A rapid and sensitive method to measure numbers of live cells in alginate capsules following depolymerization with ethylenediaminetetraacetic acid

Cell encapsulation in alginate prevents migration and extends cell survival in vivo while allowing the secretion of factors across semipermeable capsules. Confocal microscopy is used to measure numbers of cells/capsule, but is time-consuming and limited to capsule diameters <0.4 mm for accurate counting. A rapid, accurate and inexpensive method for measuring the number of cells per capsule by using 50 mM ethylenediaminetetraacetic acid to collapse capsules into a single plane was developed. This assay was used to accurately count the number of live cells/capsule for capsules crosslinked with 50 mM BaCl₂ with diameters up to 0.8 mm. This assay is ideal for counting cells/capsule during optimization to scale up the production of encapsulated cells, and for determining dosing in translational studies.

3D Microcapsules for Human Bone Marrow Derived Mesenchymal Stem Cell Biomanufacturing in a Vertical-Wheel Bioreactor

Microencapsulation of human mesenchymal stromal cells (MSCs) via electrospraying has been well documented in tissue engineering and regenerative medicine. Herein, we report the use of microencapsulation, via electrospraying, for MSC expansion using a commercially available hydrogel that is durable, optimized to MSC culture, and enzymatically degradable for cell recovery. Critical parameters of the electrospraying encapsulation process such as seeding density, correlation of microcapsule output with hydrogel volume, and applied voltage were characterized to consistently fabricate cell-laden microcapsules of uniform size. Upon encapsulation, we then verified ~ 10x expansion of encapsulated MSCs within a vertical-wheel bioreactor and the preservation of critical quality attributes such as immunophenotype and multipotency after expansion and cell recovery. Finally, we highlight the genetic manipulation of encapsulated MSCs as an example of incorporating bioactive agents in the capsule material to create new compositions of MSCs with altered phenotypes.