Smart hydrogels for 3D bioprinting

Abstract

Hydrogels are 3D networks that have a high water content. They have been widely used as cell carriers and scaffolds in tissue engineering due to their structural similarities to the natural extracellular matrix. Among these, "Smart" hydrogels refer to a group of hydrogels that is responsive to various external stimuli such as pH, temperature, light, electric, and magnetic field. Combining the potential of 3D printing and smart hydrogels is an exciting new paradigm in the fabrication of a functional 3D tissue. In this article, we provide a state-of-the-art review on smart hydrogels and bioprinting. We identify the critical material properties needed for the most commonly used bioprinting techniques, namely extrusion-based, inkjet-based, and laser-based techniques. The latest progress in different smart hydrogel systems and their applications in bioprinting are presented. The challenges of printing these hydrogel systems are also highlighted. Lastly, we present the potentials and the future perspectives of smart hydrogels in 3D bioprinting.

Enhancing the Hydrophilicity and Cell Attachment of 3D Printed PCL/Graphene Scaffolds for Bone Tissue Engineering

“…These characteristics can provide an appropriate environment for cells and play an important role as a physical substrate for cell attachment, proliferation, and differentiation, as well as integration to the host tissue in order to regenerate the defect [4,5,6]. Although some new methods using shape memory materials, such as bioprinting and 4D printing, are under development [7,8,9,10], they are very much at infancy and less mature than scaffold technology.…”

Bioprinting in cardiovascular tissue engineering: a review

“…Nanocomposite hydrogel and electronics printing can be engineered Heterogeneous aortic valve conduits [64] Tissue model [74] Vascular branches [75] Vascular tubular grafts [76] 3D model [77] Material Jetting onto cardiac patches to enhance electrical properties of engineered cardiac construct [84,85] . Hydrogel's architecture and microenvironment can be tuned to illicit certain cellular response [86,87] . Oxygen-rich hydrogel can be engineered to sustain high metabolic demand of engineered cardiac tissue before angiogenesis occurs [88,89] .…”

3D bioprinting for tissue engineering: Stem cells in hydrogels

“…Furthermore, early consideration of the interaction between stem cells, the encapsulating material and other cell types used during the bioprinting process could also increase overall viability and help maintain pluripotency [114][115][116] . As stem cells are sensitive to topography, the scaffold design could strongly influence cell morphology, proliferation and differentiation without the need for additional biological cues [117,118] . Eliminating the addition of growth factors or growth factor-like cues, to reduce bioink complexity, could help improve bioprinting resolution and the overall quality of the product.…”

“…As well as creating complex blends of bioinks, this would require heterogeneous material fabrication and precision-printing to create organized gradients or complex patterns of cells and functional motifs which mimic native ECM more closely. One approach currently being explored to meet these requirements is the use of smart materials, i.e., materials that are able to change their shape, mechanical strength and permeability in response to external or physiological stimuli [117] . Smart hydrogels can respond to changes in pH [122] , temperature [123] and electric and magnetic fields [124,125] .…”