4D anisotropic skeletal muscle tissue constructs fabricated by staircase effect strategy

Abstract

Like the morphology of native tissue fiber arrangement (such as skeletal muscle), unidirectional anisotropic scaffolds are highly desired as a means to guide cell behavior in anisotropic tissue engineering. In contrast, contour-like staircases exhibit directional topographical cues and are judged as an inevitable defect of fused deposition modeling (FDM). In this study, we will translate this staircase defect into an effective bioengineering strategy by integrating FDM with surface coating technique (FCT) to investigate the effect of topographical cues on regulating behaviors of human mesenchymal stem cells (hMSCs) toward skeletal muscle tissues. This integrated approach serves to fabricate shape-specific, multiple dimensional, anisotropic scaffolds using different biomaterials. 2D anisotropic scaffolds, first demonstrated with different polycaprolactone concentrations herein, efficiently direct hMSC alignment, especially when the scaffold is immobilized on a support ring. By surface coating the polymer solution inside FDM-printed sacrificial structures, 3D anisotropic scaffolds with thin wall features are developed and used to regulate seeded hMSCs through a self-established rotating bioreactor. Using layer-by-layer coating, along with a shape memory polymer, smart constructs exhibiting shape fix and recovery processes are prepared, bringing this study into the realm of 4D printing. Immunofluorescence staining and real-time quantitative polymerase chain reaction analysis confirm that the topographical cues created via FCT significantly enhance the expression of myogenic genes, including myoblast differentiation protein-1, desmin, and myosin heavy chain-2. We conclude that there are broad application potentials for this FCT strategy in tissue engineering as many tissues and organs, including skeletal muscle, possess highly organized and anisotropic extracellular matrix components.

Scaffold-based developmental tissue engineering strategies for ectodermal organ regeneration

“…In most works, the mechanical properties are only tested after tissue/organ regeneration and compared to those of native mature tissues to demonstrate functionality has been achieved [ 100 ]. In classical TE approaches, scaffolds are mainly designed to target the properties of the mature tissue to be regenerated [ [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] ]. For developmental TE approaches, it is more likely that the properties of the scaffold should mimic those of the metastable environment where the native developmental process occurs and that the mechanical properties of the construct dynamically change following the developmental regeneration process [ 20 ].…”

“…In addition to incorporating fundamental features such as biocompatibility and biodegradability, classical TE scaffolds are designed to mimic the microarchitecture and mechanical properties of the mature tissue to be regenerated [ 9 , 10 ]. For instance, different scaffold designs include relatively stiff scaffolds with tuned porous structure for bone [ 11 , 12 ] and gradient porosity for osteochondral regeneration [ 13 , 14 ], scaffolds with preferential orientation for the regeneration of anisotropic tissues [ 15 , 16 ], or scaffolds with relatively soft mechanical properties and big pores for adipose tissue regeneration [ 17 , 18 ]. Classical TE strategies mainly aim at cell growth in a 3D structure and differentiation into the desired phenotype to form the mature tissue, pursued by guiding cell fate by modulating the scaffolds properties (e.g.…”

Next Stage Approach to Tissue Engineering Skeletal Muscle

“…Scaffolds created by electrospinning have also been widely used as a method for examining cell migration and organization [ 93 , 94 , 95 ]. Furthermore, it has been proven in multiple studies that the physiochemical properties of the ECM scaffolds can promote muscle cell orientation and maturation [ 96 ] and support satellite cell growth and myogenic protein expression, [ 97 ] as well as the differentiation of mesenchymal stem cells [ 98 , 99 , 100 ]. Apsite et al developed a technique whereby a bilayer of electrospun fibers could be induced to self-fold and incapsulate myoblasts.…”

4D Self‐Morphing Culture Substrate for Modulating Cell Differentiation

“…[ 22,23 ] Within the diverse 4D mechanisms, shape memory polymers (SMPs) have attracted particular attention owing to their reversible “temporary‐permanent” thermomechanical reprogramming characteristics. [ 24,25 ] Based on our previous experience in 4D fabrication, [ 24,26,27 ] it was expected that the addition of the 4th dimension (time) would benefit the field of neural tissue engineering. This is because the dynamic 4D effect may better mimic the unique differentiation microenvironments of neural tissue and provide a potential method for recreating the different neurodevelopmental stages undergone by NSCs.…”