Skip to main content
. 2020 Jun 1;7:100058. doi: 10.1016/j.mtbio.2020.100058

Fig. 5.

Fig. 5

Three-dimensional printing as a tool to align Col 1 fibers and produce microscopically anisotropic scaffolds. (A) Confocal microscopy of immunofluorescent staining against Col 1 and (C) SHG images demonstrate anisotropic fibers in the THA-Col 1 biomaterial ink (scale bar = 100 μm). Unidirectional orientation of parallel Col 1 fibers aligning along the printing direction (white arrow indicated printing direction). (B and D) Bar diagrams (mean values ± standard deviation) display the quantification of fiber alignment in casted Col 1, casted THA-Col 1 (ID = 1.0 mm), and printed THA-Col 1 (15G: ID = 1.36 mm, 0.25″ cylindrical needle) from images acquired either using the confocal microscope (B, green) or SHG (D, blue). Independent of the microscopical method, the printed THA-Col 1 samples resulted in unidirectional orientation, which was more random for casted THA-Col 1 and Col 1. The white arrow in the bar diagram indicates the peak width at a normalized gray value of 0.5. (E) Schematic illustration of Col 1 fiber alignment in articular cartilage. (F) Polarized light image of articular cartilage illustrating horizontal fibers in the superficial zone (SZ) and vertical orientation in the deep zone (DZ) (scale bar = 50 μm). (G) Macroscopic image of the complex microstructured scaffold (1.4 × 1.6 cm in size, 18G: ID = 0.84 mm, 0.25″ cylindrical needle) mimicking collagen fiber orientation present in articular cartilage (scale bar = 500 μm). (H) Confocal images of immunofluorescent-labeled Col 1 mimicking hierarchical fiber orientation in articular cartilage with parallel horizontal fibers in the SZ, more isotropic fibers in the middle zone (MZ), and parallel vertical fibers in the DZ (scale bar = 50 μm). SHG = second-harmonic generation; THA = tyramine derivative of hyaluronan; ID = inner diameter; SZ = superficial zone; MZ = middle zone; DZ = deep zone.