Melt Electrowriting Allows Tailored Microstructural and Mechanical Design of Scaffolds to Advance Functional Human Myocardial Tissue Formation

Abstract

Engineering native-like myocardial muscle, recapitulating its fibrillar organization and mechanical behavior is still a challenge. This study reports the rational design and fabrication of ultrastretchable microfiber scaffolds with controlled hexagonal microstructures via melt electrowriting (MEW). The resulting structures exhibit large biaxial deformations, up to 40% strain, and an unprecedented compliance, delivering up to 40 times more elastic energy than rudimentary MEW fiber scaffolds. Importantly, when human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) are encapsulated in a collagen-based hydrogel and seeded on these microstructured and mechanically tailored fiber scaffolds, they show an increase in beating rate (1.5-fold), enhanced cell alignment, sarcomere content and organization as well as an increase in cardiac maturationrelated marker expression (Cx43 1.8-fold, cardiac Actin 1.5-fold, SERCA2a 2.5-fold, KCNJ2 1.5-fold, and PPARGC1a 3.6-fold), indicative of enhanced iPSC-CM maturation, as compared to rudimentary fiber scaffolds. By combining these novel fiber scaffolds with clinically relevant human iPSC-CMs, a heart patch that allows further maturation of contractile myocytes for cardiac tissue engineering is generated. Moreover, the designed scaffold allows successful shape recovery after epicardial delivery on a beating porcine heart, without negative effects on the engineered construct and iPSC-CM viability.

3D printed magneto-active microfiber scaffolds for remote stimulation of 3D in vitro skeletal muscle models

“…Altogether, this leads to a greater degree of fiber bending and more potential for fiber delamination under tension along the y-direction. These observations are in good agreement with previous works on melt-electrowritten PCL hexagonal scaffolds [10] . Regarding the effect of composition, the incorporation of rGNP@ significantly increases the tangent modulus values of 2% and 10% filler-containing scaffolds with respect to PCL along the x-direction, while there is no such significant change along the y-direction (Figure 4D).…”

“…Altogether, this leads to a greater degree of fiber bending and more potential for fiber delamination under tension along the y-direction. These observations are in good agreement with previous works on melt-electrowritten PCL hexagonal scaffolds [10] .…”

Electrohydrodynamic Printing of Microscale Fibrous Scaffolds with a Sinusoidal Structure for Enhancing the Contractility of Cardiomyocytes

“…These results highlight the significant enhancement in cardiomyocytes’ beating behavior when they are cultured on the sinusoidal PCL scaffolds in comparison to straight ones. Our findings are consistent with previous studies , that the flexible structure could easily be deformed and accommodate the cell contraction, thereby facilitating the beating behavior of primary cardiomyocytes.…”

Fabrication of human myocardium using multidimensional modelling of engineered tissues

“…Synchronous contractions started to appear after a week in culture and were maintained for the duration of the experiments (4 weeks, movies S2 and S3 respectively). Live/dead staining (figures 3(c) and (d)) showed that most cells remained viable at both time points examined (1 and 4 weeks), with dead cells constituting a small minority, well in line with results for similar systems in cardiac tissue engineering [24,40]. During this period and as shown in figure 3(a), tissues remained largely intact, with their beat rate becoming stabilized at 0.5-1 Hz after 1 week (figure 3(e)).…”