Piezoelectric and Magnetoelectric Microswimmers for Cell Therapy

Neurodegenerative diseases generally result in irreversible neuronal damage and neuronal death. Cell therapy shows promise as a potential treatment for these diseases. However, the therapeutic targeted delivery of these cells and the in situ provision of a suitable microenvironment for their differentiation into functional neuronal networks remain challenging.

A highly integrated multifunctional soft microrobot is developed for targeted cell therapy applications, featuring targeted cell transportation and induced cell differentiation. The micromachines are made of composites consisting of a soft piezoelectric polymer matrix in which magnetic nanoparticles are dispersed. The magnetic nanoparticles serve as the component for the device's magnetic actuation, while the piezoelectric polymer acts as both a steerable scaffold and an acoustically responsive cell electrostimulation platform. With the application of a rotating magnetic field, the microrobots swim in a corkscrew motion in different liquid environments that mimic human body fluids. When the swimmers are subjected to acoustic waves, their piezoelectric body is electrically polarized which induces cell differentiation of neuron-like PC12 cells loaded on the swimmers surface.

Later, a highly integrated multifunctional soft helical microswimmer featuring targeted neuronal cell delivery, on‐demand localized wireless neuronal electrostimulation, and post‐delivery enzymatic degradation is introduced. The helical soft body of the microswimmer is fabricated by two‐photon lithography of the photocurable gelatin–methacryloyl (GelMA)‐based hydrogel. The helical body is then impregnated with composite multiferroic nanoparticles displaying magnetoelectric features (MENPs). While the soft GelMA hydrogel chassis supports the cell growth, and is degraded by enzymes secreted by cells, the MENPs allow for the magnetic transportation of the bioactive chassis, and act as magnetically mediated electrostimulators of neuron‐like cells. The unique combination of the materials makes these microswimmers highly integrated devices that fulfill several requirements for their future translation to clinical applications, such as cargo delivery, cell stimulation, and biodegradability. The authors envision that these devices will inspire new avenues for targeted cell therapies for traumatic injuries and diseases in the central nervous system.

Details can be found at:

1. Dong, M.; Wang, X.; Chen, X. Z.*; Mushtaq, F.; Deng, S.; Zhu, C.; Torlakcik, H.; Terzopoulou, A.; Qin, X.-H.; Xiao, X.; Puigmarti-Luis, J.; Choi, H.; Pêgo, A.; Shen, Q.-D.*; Nelson, B. J.; Pané, S.*, 3D-printed Soft Magnetoelectric Microswimmers for Delivery and Differentiation of Neuron-like Cells. Advanced Functional Materials, 2020, 1910323.

2. Chen, X. Z.; Liu, J.-H.; Dong, M.; Müller, L.; Chatzipirpiridis, G.; Hu, C.; Terzopoulou, A.; Torlakcik, H.; Wang, X.; Mushtaq, F.; Puigmartí-Luis, J.; Shen, Q.-D.; Nelson, B. J.; Pané, S., Magnetically Driven Piezoelectric Soft Microswimmers for Neuron-like Cell Delivery and Neuronal Differentiation. Materials Horizons, 2019, 6 (7), 1512-1516.