(I-326) Fabrication and Characterization of Magnetic Core-Shell Microcapsules Carrying Human Embryonic Stem Cell Spheroids

Thursday, October 12, 2023

2:00 PM – 3:00 PM PDT

Location: Exhibit Hall - Row I - Poster # 326

Presenting Author(s)

KG

Kihak Gwon

Post doc
Mayo Clinic
Rochester, Minnesota, United States

Co-Author(s)

ED

Ether Dharmesh

Undergraduate Student
Saint Louis University
Chesterfield, Missouri, United States
KN

Kianna M. Nguyen

Graduate student
Mayo Clinic
Rochester, Minnesota, United States
GS

Gulnaz Stybayeva

Professor
Mayo Clinic
Rochester, Minnesota, United States
QP

Quinn P. Peterson

Professor
Mayo Clinic
Rochester, Minnesota, United States

Primary Investigator(s)

AR

Alexander Revzin

Professor
Mayo Clinic
Rochester, Minnesota, United States

Introduction:: Introduction: Encapsulation may enable differentiation and transplantation of stem cells. Our group has established a strategy for fabricating poly(ethylene glycol) (PEG)-based core-shell microcapsules using droplet microfluidics. These microcapsules not only facilitated rapid aggregation of stem cells into spheroids but also provided protection against mechanical damage in a stirred bioreactor. In this presentation, we will describe the next generation of microcapsules containing magnetic nanoparticles. The ability to control microcapsules with external magnetic helps improve media exchange in the bioreactor leading to better differentiation efficiency. In future, magnetic microcapsules may also be used to control delivery of cells in vivo.

Materials and Methods:: Materials and Methods: The microfluidic flow-focusing device is fabricated via soft lithography and consists of 4 inlet channels and a serpentine channel leading to a droplet chemical-crosslinking port. This device is infused with two aqueous streams: 1) the core stream containing PEG MW 35 kDa with human pluripotency stem cells (hPSCs) and 2) the shell stream containing a mixture of 4-arm PEG maleimide (PEG4MAL MW 12 kDa) and magnetic nanoparticles (MNPs). The aqueous droplets were stabilized by the first oil stream and then chemically crosslinked in the second oil stream using DTT. MNPs became entrapped in the hydrogel shell. Encapsulated stem cells were characterized with respect to viability, proliferation, pluripotency and differentiation into definitive endoderm.

Results, Conclusions, and Discussions:: Results and Discussion: The microfluidic system described in Figure A allowed us to created core-shell microcapsules. We confirmed the ability to incorporate MNPs into either the core or the shell of a microcapsule (see Figure B). We also demonstrated that presence of MNPs in either compartment did not interfere with hPSC spheroid formation (Figure C), viability and proliferation (data not shown). Importantly, microcapsules could be manipulated using an external magnet (see capsules collected on the side of a vial in Figure D and moving in the desired direction in Figure E). Importantly, presence of MNPs did not compromise expression of pluripotency and definitive endoderm (Figure F and E). In fact, the latter was significantly improved for magnetic microcapsules because of better efficiency in media exchange during DE differentiation.
Conclusions: We have developed core-shell microcapsules that carry hPSC spheroids and may be manipulated by external magnetic field. These magnetic microcapsules allow for more efficient removal of spent media during cultivation in a stirred bioreactor leading to better differentiation outcomes. These microcapsules may also hold benefits for delivery and retention of stem cells during transplantation.

Acknowledgements (Optional): :

References (Optional): :