Remote Magnetic Microengineering and Alignment of Spheroids into 3D Cellular Fibers

Abstract

Developing in vitro models that recapitulate the in vivo organization of living cells in a 3D microenvironment is one of the current challenges in the field of tissue engineering. In particular for anisotropic tissues where alignment of precursor cells is required for them to create functional structures. Herein, a new method is proposed that allows aligning in the direction of a uniform magnetic field both individual cells (muscle, stromal, and stem cells) or spheroids in a thermoresponsive collagen hydrogel. In an all-in-one approach, spheroids are generated at high throughput by magnetic engineering using microfabricated micromagnets and are used as building blocks to create 3D anisotropic tissue structures of different scales. The magnetic cells and spheroids alignment process is optimized in terms of magnetic cell labeling, concentration, and size. Anisotropic structures are induced to form fibers in the direction of the magnetic alignment, with the respective roles of the magnetic field, the mechanical stretching of hydrogel or co-culture of the aligned cells with non-magnetic stromal cells, being investigated. Over days, spheroids fuse into 3D tubular structures, oriented in the direction of the magnetic alignment. Moreover, in the case of the muscle cells model, multinucleated cells can be observed within the fibers.

A continuum model for magnetic particle flows in microfluidics applicable from dilute to packed suspensions

“…Another potential feature that could be added is the ability to handle soft particles. This would be particularly useful for simulating the aggregation of magnetic cells, 47,48 which is encountered in the field of tissue engineering. This could be accomplished by modifying the solid pressure term to allow higher volume fractions than with hard spheres, to account for cell deformation and intercellular tight contact.…”

Three‐dimensional multicellular biomaterial platforms for biomedical application

“…Common auxiliary methods can be divided into four types: physical induction, chemical induction, microstructure induction, and special processing. Physical induction refers to the use of gravity, [31] centrifugal force, [32] magnetic field, [33][34][35] acoustic wave, [36,37] and other physical forces to inhibit cell adhesion to the substrate and to promote cell aggregating. Chemical induction can help or induce cell aggregation behaviors by the use of biological compounds, which can be used to modulate the adhesion of cells to the culture plate, thereby reducing cell adhesion and promoting spheroids formation.…”

“…This can be achieved by inducing spheroidal assembly, but these methods are often complex and less effective. [35,57] A more common method is to apply biomaterials as carriers to load spheroids, [35,51] which also allows us to customize the structure and the way the cells are combined to a certain extent (Figure 2B), [54] but the complexity and precision that can be achieved are very limited.…”

Effect of GelMA Hydrogel Properties on Long-Term Encapsulation and Myogenic Differentiation of C2C12 Spheroids

“…fabricated 3D bioprinted muscle tissue constructs using a C C 12 cell-laden GelMA-alginate hydrogel, wherein they observed that increased cellspreading, cell-cell interaction, and cell-cell fusion offered by the GelMA-alginate bioink supported the myoblast differentiation process [44]. Demri et al proposed a multiscale magnetic approach for anisotropic tissue engineering with a magnetic nanoparticle-loaded muscle cell model, where they observed multinucleated cells within fibers formed from the fusion of spheroids into 3D tubular structures in a thermoresponsive collagen hydrogel, oriented in the direction of magnetic alignment [45]. Thus, the cellular events of sprouting/migration, proliferation, and differentiation result in the successful outcome of tissue constructs with physiological functionality.…”