Microgel assembly: Fabrication, characteristics and application in tissue engineering and regenerative medicine

Abstract

Microgel assembly, a macroscopic aggregate formed by bottom-up assembly of microgels, is now emerging as prospective biomaterials for applications in tissue engineering and regenerative medicine (TERM). This mini-review first summarizes the fabrication strategies available for microgel assembly, including chemical reaction, physical reaction, cell-cell interaction and external driving force, then highlights its unique characteristics, such as microporosity, injectability and heterogeneity, and finally itemizes its applications in the fields of cell culture, tissue regeneration and biofabrication, especially 3D printing. The problems to be addressed for further applications of microgel assembly are also discussed.

3D Printing of Cell‐Laden Microgel‐Based Biphasic Bioink with Heterogeneous Microenvironment for Biomedical Applications

“…[22] Another strategy pioneered by Burdick et al is called jammed microgel (JM) bioink, in which microgels were jammed into inks with remarkable shear-thinning and self-healing properties; [23,24] however, the JM bioink printed structures often lack long-term mechanical stability as they rely solely on physical interactions between microgels, such as electrostatic interaction and hydrogen bonding. [25] To address these challenges for extrusion bioprinting, here we propose a broadly applicable strategy to formulate a cellladen microgel-based biphasic (MB) bioink that enables the 3D printing of a range of hydrogels at different polymer concentrations. This MB bioink comprises two components, that is, microgels occupying the major space as discrete phase, and a hydrogel precursor forming a second polymer network as continuous phase to integrate the microgels together.…”

Rheology Applied to Microgels: Brief (Revision of the) State of the Art

“…The information and control over the composition and microgel microstructure and, therefore, over the rheological properties, are very relevant since they could facilitate a further self-assembly, for instance, toward scaffold formation applicable in tissue regeneration [ 122 , 123 , 124 ] or as biomaterials for 3D printing and cell culture applications [ 125 ]. An example of this can be found in the recent work of De Rutte et al [ 123 ], in which they describe an approach to fabricate highly uniform bioactive microgel building blocks in a continuous scalable way, allowing the formation of highly modular microporous scaffolds for cell and tissue growth.…”

Engineering Biological Tissues from the Bottom-Up: Recent Advances and Future Prospects

“…In bottom-up tissue engineering, the assembly of units is the key to the formation of a functional organizational structure [8,12,45,[48][49][50][51]. At present, the assembly of module units is faced with the following problems: (1) Preparing materials with biomimetic mechanical properties; (2) building a complex organization with a controllable microstructure; (3) forming a network of functional blood vessels; (4) compatibility.…”

“…The history of tissue engineering can be traced back to the 1980s, when Professors Joseph P. Vacanti and Robert Langer first proposed the research and exploration of tissue engineering [5]. In the early stages, scientists successfully used tissue engineering technology to create human auricle cartilage with the skin of mice [4], which symbolizes that tissue engineering technology can form tissues and organs with complex three-dimensional spatial structures for clinical application [2,[8][9][10][11][12][13][14]. Current tissue engineering techniques can be used to reconstruct a variety of tissues, such as muscle, bone, cartilage, tendon, ligament, blood vessels and skin [13,15].…”