Engineering Microsphere-Loaded Non-mulberry Silk-Based 3D Bioprinted Vascularized Cardiac Patches with Oxygen-Releasing and Immunomodulatory Potential

Abstract

A hostile myocardial microenvironment post ischemic injury (myocardial infarction) plays a decisive role in determining the fate of tissue-engineered approaches. Therefore, engineering hybrid 3D printed platforms that can modulate the MI microenvironment for improving implant acceptance has surfaced as a critical requirement for reconstructing an infarcted heart. Here, we have employed a non-mulberry silk-based conductive bioink comprising carbon nanotubes (CNTs) to bioprint functional 3D vascularized anisotropic cardiac constructs. Immunofluorescence staining, polymerase chain reaction-based gene expression studies, and electrophysiological studies showed that the inclusion of CNTs in the bioink played a significant role in upregulating matured cardiac biomarkers, sarcomere formation, and beating rate while promoting cardiomyocyte viability. These constructs were then microinjected with calcium peroxide and IL-10-loaded gelatin methacryloyl microspheres. Measurements of oxygen concentration revealed that these microspheres upheld the oxygen availability for maintaining cellular viability for at least 5 days in a hypoxic environment. Also, the ability of microinjected IL-10 microspheres to modulate the macrophages to anti-inflammatory M2 phenotype in vitro was uncovered using immunofluorescent staining and gene expression studies. Furthermore, in vivo subcutaneous implantation of microsphere-injected 3D constructs provided insights toward the extended time frame that was achieved for dealing with the hostile microenvironment for promoting host neovascularization and implant acceptance.

2D Materials for Cardiac Tissue Repair and Regeneration

“…Then, they also used microspheres loaded with IL-10, in order to immunomodulate the native MI environment with IL-10 delivery. They have concluded that IL-10 loaded microspheres increase oxygen availability and modulate the macrophages into anti-inflammatory M2 phenotype (131). It is a promising immunomodulatory study for the transplantation of biomaterial-based 3D construct into rat MI models for disease therapy.…”

Biomaterial inks for extrusion-based 3D bioprinting: Property, classification, modification, and selection

“…Due to the potential, conductive materials have been used in smart biosensors, functional tissue engineering scaffolds, and implants. In extrusion-based bioprinting applications, conductive biomaterial inks can be formed by using different conductive materials including conductive polymers (e.g., polypyrrole [ 112 ] , polyaniline [ 142 ] , polythiophene [ 143 ] , and polyethylene dioxythiophene [ 144 ] ), conductive metal nanoparticles (e.g., gold [ 145 ] and silver [ 146 ] ), conductive carbon-based materials (e.g., carbon nanotube [ 147 ] and graphene [ 148 ] ), or ionic liquids [ 149 ] . Metal nanoparticles and carbon-based materials have long-term cytotoxicity, which can be a limitation for tissue engineering and regenerative medicine [ 112 ] .…”

Nanomaterials-Mediated Therapeutics and Diagnosis Strategies for Myocardial Infarction

“…Nowadays, nanomaterials combined with engineering 3D printing platforms to improve the acceptability of implants and reconstruct infarction hearts is a very promising research direction. Mehrotra et al used a conductive bioink containing carbon nanotubes (CNTs) to bioprint functional 3D vascularized anisotropic heart structures (Mehrotra et al, 2021). It was found that in addition to upregulating mature cardiac biomarkers, sarcomere formation, and beat rate, CNTs also promoted cardiomyocyte activity through immunofluorescence staining, polymerase chain reactionbased gene expression studies, and electrophysiological studies.…”