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Biology subjects

Perez, J. E.

Publications and source records attributed to Perez, J. E..

2 recordsLinked to original sources
bioRxiv2022

Magnetic bioprinting of stem-cell based tissues

An attractive approach in cell therapies and medically oriented nanotechnologies is to interface magnetic nanoparticles with cells. This will supply the cells with sufficient magnetization for theranostic applications and for external magnetic field manipulation. In tissue engineering, one challenge is to produce tissue analogues that are large, precisely organized, and responsive to stimuli, preferably without the need for an artificial supporting scaffold. One powerful tool for such biofabrication is certainly the bioprinting technology. In magnetic tissue engineering, it appears possible to use magnetic forces to manipulate cells, both individually and within aggregates, and thereby to produce three-dimensional artificial tissues with inherent capacities for further physical stimulation, a possibility that bioprinting does not offer yet. We here introduce the feasibility of using magnetic forces created by external (micro)magnets to form 3D tissue-like scaffold-free structures. Because stem cells are essential in tissue engineering, such magnetic technologies were developed with magnetized stem cells, and applied for instance to vascular or cartilage tissue engineering. One precondition to this approach, which lies in the magnetization of (stem) cells endowed through internalization of iron oxide magnetic nanoparticles, is to ensure the safety of magnetic nanoparticles with respect to cellular functions, which is initially discussed. Finally, we introduce a magnetic tissue stretcher which, in a single step, allows to create a tissue composed of any type of component cell, then to mature it, stimulate it by compression or stretching at any desired frequency, e.g. cyclically, opening new possibilities in the cardiac muscle tissue engineering field.

bioengineering↗
bioRxiv2022

Surface tension drives neuronal sorting in magnetically engineered brain-like tissue

Engineered 3D brain-like models have advanced the understanding of neurological mechanisms and disease, yet their mechanical signature, while fundamental for brain function, remains understudied. The surface tension for instance controls brain development and is a marker of cell-cell interactions. Here, we engineered 3D magnetic brain-like tissue spheroids composed of intermixed primary glial and neuronal cells at different ratios. Remarkably, the two cell types self-assemble into a functional tissue, with the sorting of the neuronal cells towards the periphery of the spheroids, whereas the glial cells constitute the core. The magnetic fingerprint of the spheroids then allows their deformation when placed under a magnetic field gradient, at a force equivalent to a 70 g increased gravity at the spheroid level. The tissue surface tension and elasticity can be directly inferred from the resulting deformation, revealing a transitional dependence on the glia/neuron ratio, with the surface tension of neuronal tissue being much lower. This provides the underlying mechanical explanation for the exclusion of the neurons towards the outer spheroid region, and depicts the glia/neuron organization as a surface tension-driven sophisticated mechanism that should in turn influence brain development and homeostasis.

bioengineering↗