Advanced Hydrogels as Exosome Delivery Systems for Osteogenic Differentiation of MSCs: Application in Bone Regeneration

Abstract

Hydrogels are known as water-swollen networks formed from naturally derived or synthetic polymers. They have a high potential for medical applications and play a crucial role in tissue repair and remodeling. MSC-derived exosomes are considered to be new entities for cell-free treatment in different human diseases. Recent progress in cell-free bone tissue engineering via combining exosomes obtained from human mesenchymal stem cells (MSCs) with hydrogel scaffolds has resulted in improvement of the methodologies in bone tissue engineering. Our research has been actively focused on application of biotechnological methods for improving osteogenesis and bone healing. The following text presents a concise review of the methodologies of fabrication and preparation of hydrogels that includes the exosome loading properties of hydrogels for bone regenerative applications.

Keywords: advanced hydrogels; bone tissue engineering; exosome.

Figure 1

A representation of methods for 3D printing by inkjet, micro-extrusion, and laser-assisted bioprinters. (A) Inkjet printing (thermal and piezoelectric). In thermal inkjet printers, a heater creates air-pressure pulses resulting in the generation of droplets on the print. For piezoelectric inkjet printing, a mechanical pulse is generated by an actuator that forces the bio-ink droplets from the nozzle. (B) In 3D printing by micro-extrusion, three dispensing systems (pneumatic, piston-driven, and screw-driven robotics) are used to produce a continuous stream of hydrogel containing cells. (C) In laser-assisted bioprinting, laser energy induces bubble nucleation and forces droplets of bio-ink towards the substrate.

Figure 2

Schematic representation of exosome generation, secretion, and cargo transfer from the donor cells to the recipient cells.

Figure 3

Targeting miRNAs/simvastatin in mesenchymal stem cells using exosomes to enhance osteogenesis.