Figure 4. Introducing biochemical cues into fibrous hydrogels.

(A, left to right): Dextran-vinyl sulfone (DexVS) fibers (magenta) were seeded with human lung fibroblasts (nuclei shown in yellow) in the presence of RGD or RGD + heparin. Conjugation of RGD + heparin to DexVS fibers increased the secretion and subsequent binding of fibronectin (white) onto the fibrous matrix. (A) Reprinted and adapted with permission from Davidson et al., copyright 2020 Elsevier⁸⁷; scalebar = 200 μm. (B, left to right): spatial patterning of thiolated fluorophores onto NorHA fibers via thiol-ene click chemistry. Zoomed in images show high pattern fidelity, and the ability to pattern multiple biomolecules on the same scaffold – indicated by the red, green, and blue fluorophores on the fibers. The ability to pattern adhesive regions, using an RGD motif, allows for preferential cellular localization in RGD+ regions that elongate in the direction of fiber alignment. (B) Reprinted and adapted with permission from Wade et al., copyright 2015 John Wiley and Sons⁸⁶; scalebars (left to right) = 100 μm, 25 μm, 100 μm, and 100 μm. (C, left to right): Patterning of bioactivity on synthetic fibers using UV irradiation. Rat Schwann cells exhibited a less elongated morphology on non-bioactive substrates (far left) when compared to substrates that were activated with UV light (middle left). The use of photomasks allowed for introduction of linear bioactive regions (middle right) which promoted cell attachment over non-bioactive regions (far right). (C) Reprinted and adapted with permission from Girão et al. 2019¹⁴⁷; scalebars (left to right) = 200 μm, 200 μm, 100 μm, and 100 μm.