Figure 4:
FRESH printed scaffolds evaluated with HemoLens. A) Simplified workflow of FRESH biorprinting of test scaffolds. (i) CAD model showing designed 450 μm ID and 1200 μm OD. (ii) Visualized GCODE/Machine pathing. (iii) Graphical representation of FRESH bioprinting. (iv) Stereomicroscope image of FRESH printed test scaffold array. SB= 1000 μm. (v) Post processing measurements of the printed scaffold using the measurement tool in LasX v3.9 (Leica). OD = 1172 ± 25.88 μm (n=5), ID = 430 ± 11.88 μm (n=5). (vi) Photo showing excised test vessel during HemoLens mounting step. B). Burst pressure testing showing crosslinked collagen scaffolds have nearly double the burst pressure of native collagen vessels, 464.34 mmHg and 218.18 mmHg, respectively. C) Representative waveforms of each scaffold condition under RAMP generated pressure waves. Crosslinked collagen vessels under physiological pressure changes (blue). Crosslinked collagen vessels under pathological pressure conditions (80/180+ mmHg) (red), show a similar pattern to native collagen vessels at physiological conditions (black). D) Spectra graph of a Fast Fourier Transform (FFT) on the wave forms of C showing that crosslinked collagen vessel at pathological (red) and native collagen vessel at physiological (black) have similar frequencies, while no uniform frequency is seen with crosslinked collagen vessel at physiological conditions (blue). E) Calculated diameters change per pulse for native collagen vessel under physiological conditions and crosslinked collagen vessel under pathological conditions are shown to be non-significantly different. F) Calculated dynamic compliance for native collagen vessel under physiological conditions (3–4 ± 9.9–5 mmHg−1, n= 140) is significantly more dynamically compliant and crosslinked collagen vessel under pathological conditions (6.23−5 ± 2.83–5 mmHg−1, n= 92). Data are represented as mean ± SD **** = p<0.001.