Biomedical materials have achieved great advances in targeted drug delivery, biological imaging, and cell regeneration/differentiation. Energy-converting materials represents one of the multidisciplinary frontier researches from natural areas of chemistry, materials, physics, and energy. Their applications in neuroscience are just ascending.
Central nervous system is networks or circuits of numerous neurons, which are responsible for information transmission, storage, integration, and processing. It builds the foundation for study, motion, and memory. Neurodegenerative diseases, such as Parkinson's and Alzheimer's diseases, and other injuries of central nervous system, usually lead to irreversible apoptosis of the neurons, and subsequently, the motor dysregulation or cognitive dysfunction. The drug, neurosurgery, gene therapy, and cell transplantation are effective in treating these diseases. Cell transplantation is a promising technique that transplants therapeutic cells (such as exogenous neural stem cells) to the lesions, and then induces these cells to differentiate into the neurons. However, targeted delivery and directed differentiation of the therapeutic cells are the major challenges for cell transplantation.
Prof. Qun-Dong Shen's research team at the Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, and Dr. Xiangzhong Chen from the Bradley J. Nelson team at the Swiss Federal Institute of Technology Zurich designed and constructed a spiral microrobot, which integrated the function of the targeted cell delivery and in-situ stimulating cell differentiation (Adv. Funct. Mater. 2020, 30, 1910323).The 3D printing technology was applied to fabricate the spiral microstructure from biodegradable hydrogel, which was used as the carrier for supporting the neuron growth. In order to remotely control the precise movement of microrobots and in-situ regulate nerve cell differentiation, a core-shell structured magnetoelectric nanoparticle was prepared by hydrothermal and sol-gel method.The microrobot was obtained by integration of the spiral microstructure and magnetoelectric nanoparticle. After loading with neurocyte, the microrobot could achieve the targeted delivery of neurocyte under a rotating magnetic field, and then was biodegraded by the collagenase secreted from the neurocyte when reaching the targeted site.Especially, under the high-frequency magnetic field, the magnetoelectric nanoparticles in the microrobot could stimulate the differentiation of neurocyte, which exhibited multi-dendritic growth and upregulated expression of the neuron-specific axonal membrane proteins (Growth Associated Protein 43, GAP43). This microrobot provides a new strategy for the treatment of neurodegenerative diseases and brain damage. It also serves as an inspiration to energy-converting materials in regulation of neuron differentiation or regeneration.
Scheme. 3D-printed soft magnetoelectric microrobots for delivery and differentiation of neurons.
In recent years, Professor Shen's group has focused on application of the energy-converting materials in regulating cell behaviors. The first author, Mei Dong, has carried out a series of work on the regulation of neuron differentiation by energy-converting nanomaterials and the promotion of tumor apoptosis by regulating intracellular microenvironment (Small 2019, 15, 1900212). The research was supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China.