Development of Silk Fibroin Scaffolds by Using Indirect 3D-Bioprinting Technology

Due to the excellent biocompatibility of natural polymers, a variety of natural polymers have been widely used as biomaterials for manufacturing tissue engineered scaffolds. Despite the excellent biological activity of natural polymers, there have been obstacles in using them on their own to prepare 3D scaffolds with sufficient mechanical strength. Although multiple 3D-bioprinting technologies have recently emerged as effective manufacturing tools for scaffold preparation, scaffold preparation using only natural polymers with tunable mechanical properties is still difficult. Herein, we introduce novel scaffold fabrication methods using the natural polymer silk fibroin via indirect 3D-bioprinting technology. The developed silk fibroin scaffolds showed biocompatibility and tunable mechanical strength by changing the concentration of the silk fibroin. Furthermore, controlling the flexibility of the silk fibroin scaffolds was made possible by changing the solvent for the silk fibroin solution used to fabricate the scaffold. Consequently, silk fibroin scaffolds fabricated via our method can be considered for various applications in the bioengineering of either soft or musculoskeletal tissues.

Multiscale-Engineered Muscle Constructs: PEG Hydrogel Micro-Patterning on an Electrospun PCL Mat Functionalized with Gold Nanoparticles

The development of new, viable, and functional engineered tissue is a complex and challenging task. Skeletal muscle constructs have specific requirements as cells are sensitive to the stiffness, geometry of the materials, and biological micro-environment. The aim of this study was thus to design and characterize a multi-scale scaffold and to evaluate it regarding the differentiation process of C2C12 skeletal myoblasts. The significance of the work lies in the microfabrication of lines of polyethylene glycol, on poly(-caprolactone) nanofiber sheets obtained using the electrospinning process, coated or not with gold nanoparticles to act as a potential substrate for electrical stimulation. The differentiation of C2C12 cells was studied over a period of seven days and quantified through both expression of specific genes, and analysis of the myotubes’ alignment and length using confocal microscopy. We demonstrated that our multiscale bio-construct presented tunable mechanical properties and supported the different stages skeletal muscle,as well as improving the parallel orientation of the myotubes with a variation of less than 15°. These scaffolds showed the ability of sustained myogenic differentiation by enhancing the organization of reconstructed skeletal muscle. Moreover, they may be suitable for applications in mechanical and electrical stimulation to mimic the muscle’s physiological functions.

Designing a 3D Printing Based Auxetic Cardiac Patch with hiPSC-CMs for Heart Repair

Myocardial infarction is one of the largest contributors to cardiovascular disease and reduces the ability of the heart to pump blood. One promising therapeutic approach to address the diminished function is the use of cardiac patches composed of biomaterial substrates and cardiac cells. These patches can be enhanced with the application of an auxetic design, which has a negative Poisson’s ratio and can be modified to suit the mechanics of the infarct and surrounding cardiac tissue. Here, we examined multiple auxetic models (orthogonal missing rib and re-entrant honeycomb in two orientations) with tunable mechanical properties as a cardiac patch substrate. Further, we demonstrated that 3D printing based auxetic cardiac patches of varying thicknesses (0.2, 0.4, and 0.6 mm) composed of polycaprolactone and gelatin methacrylate can support induced pluripotent stem cell-derived cardiomyocyte function for 14-day culture. Taken together, this work shows the potential of cellularized auxetic cardiac patches as a suitable tissue engineering approach to treating cardiovascular disease.

Hydrogel-Based Biomaterials Engineered from Natural-Derived Polysaccharides and Proteins for Hemostasis and Wound Healing

Rapid and effective hemostasis is of great importance to improve the quality of treatment and save lives in emergency, surgical practice, civilian, and military settings. Traditional hemostatic materials such as tourniquets, gauze, bandages, and sponges have shown limited efficacy in the management of uncontrollable bleeding, resulting in widespread interest in the development of novel hemostatic materials and techniques. Benefiting from biocompatibility, degradability, injectability, tunable mechanical properties, and potential abilities to promote coagulation, wound healing, and anti-infection, hydrogel-based biomaterials, especially those on the basis of natural polysaccharides and proteins, have been increasingly explored in preclinical studies over the past few years. Despite the exciting research progress and initial commercial development of several hemostatic hydrogels, there is still a significant distance from the desired hemostatic effect applicable to clinical treatment. In this review, after elucidating the process of biological hemostasis, the latest progress of hydrogel biomaterials engineered from natural polysaccharides and proteins for hemostasis is discussed on the basis of comprehensive literature review. We have focused on the preparation strategies, physicochemical properties, hemostatic and wound-healing abilities of these novel biomaterials, and highlighted the challenges that needed to be addressed to achieve the transformation of laboratory research into clinical practice, and finally presented future research directions in this area.