Structurally anisotropic hydrogels for tissue engineering

Filamented Light (FLight) Biofabrication of Highly Aligned Tissue‐Engineered Constructs

“…Lastly, we explored the FLight's potential to create anisotropic tissue‐engineered constructs mimicking in vivo tissue structures. [ 7 ] Varying hydrogel constructs with detailed features were produced using 2.88% w/v Gel‐NB/4PEG‐SH photoresin including hollow structures ( Figure a and Figure S14, Supporting Information) and a hydrogel QR code (7 × 7 mm) with ≈220 µm feature size. Also, cell‐laden tubular hydrogel structures were created, and the encapsulated NHDFs were stained with calcein‐AM after 7 days of culture (Figure 6b).…”

“…[1][2][3] Lately, rapid biofabrication of complex cellular architectures has been possible through tomographic projection of laser light beams. [4][5][6] However, most light-guided tissue fabrication strategies have limited potential for efficient cell alignment when it comes to the creation of anisotropic tissues such as muscle and tendons, [7,8] because most approaches focus on macrofeatures (>100 µm) that lack the topographical cues necessary for the highly aligned cellular and extracellular organization found in these tissues. For techniques such as two-photon polymerization and ultrahigh resolution digital light processing that can achieve cell-scale (<30 µm) resolution, the incoherent light sources restrict the photopolymerization occurring in a small range (<mm), which needs layerby-layer strategies to achieve fabrication of large tissue-engineered constructs.…”

“…Instructive guidance cues (e.g., fiber components and a combination of fiber and extrusion-based bioprinting) have been widely studied for their potential to advance cell alignment and maturation of aligned tissue-engineered constructs, such as muscle, tendons, nerves, and cartilage tissues. [7,[11][12][13][14] Topological cues with an increased aspect ratio have been shown to affect the bioactivity of cells in/on the substrate. For example, the rod-shaped microgels (aspect ratio of 10) fabricated by microfluidics or soft lithography are able to increase cell orientation, which is better achieved through the void between high-aspect-ratio microrods compared to microspheres.…”

“…Using the multicellular/multimaterial FLight process, (bio)photoresins can be cured at desired locations to create complex tissue constructs that better mimic the hierarchical organization of native tissues, such as muscle. [7] Hydrogel constructs containing multiple directional microfilaments can be achieved by performing the FLight process from different directions (Cross-FLight), which is promising for biofabrication of anisotropic tissues such as the myocardium. [30,31] Finally, we demonstrate the ability to fabricate larger hydrogel constructs (approximately cm) by multiple step FLight strategy (Multi-FLight), in which single hydrogel constructs can be stacked on top of each other to result in a long hydrogel construct featuring microfilaments throughout its length for cell guidance and alignment.…”

Strong and Tough Conductive Organo‐Hydrogels via Freeze‐Casting Assisted Solution Substitution

“…Flexible hydrogels have promising applications in the fields of tissue engineering, [1] drug delivery, [2] energy storage, [3] and flexible electronics. [4,5] For the application of electronic engineering materials, hydrogels need to possess not only electrical conductivity but also excellent mechanical properties, including high strength and high toughness.…”