• piezoelectric nanoparticles
• nanocomposite hydrogel
• skeletal muscle bioprinting
• ultrasound stimulation

3D bioprinting has the potential for becoming a future breakthrough method in the implementation of skeletal muscle tissue engineering. In this domain, the physico-chemical properties of bioinks constitute a crucial aspect that can drive an appropriate cell differentiation. Material chemical cues and mechanical properties have been widely investigated in the last decade. Less explored, yet intriguing, can be the incorporation of exogenous factors (e.g., electrical, magnetic or mechanical stimulation) to further boost cell differentiative processes.
Piezoelectric nanomaterials have been used as nanoscale transducers able to convert mechanically-induced deformation into an electrical cue when invested by an ultrasound wave (acting as a wireless source of mechanical energy). This paradigm has shown beneficial effects on different cell types, in particular accelerating the differentiation of neural and muscle precursors.
However, no research groups have explored the inclusion of piezoelectric nanoparticles in a bioink used for 3D bioprinting of skeletal muscle cells so far. The aim of this Thesis is to verify the hypothesis that piezoelectric nanoparticles, stimulated with ultrasound, are able to accelerate the differentiation of myoblasts loaded within a nanocomposite hydrogel and printed to form a 3D construct. The idea is to exploit ultrasound as a wireless source of mechanical energy, to locally deform the piezoelectric nanoparticles (in particular, barium titanate nanoparticles) and to verify the effects that this indirect electrical stimulus can have on the differentiation of myoblasts C2C12, encapsulated in constructs generated by controlled pneumatic extrusion.
In the Thesis, a DLS characterization of PGA-coated barium titanate nanoparticles has been carried out and the bioink has been analyzed with DSC and FT-IR. Then 3D constructs loaded with different nanoparticle concentrations have been analyzed with SEM imaging and EDX spectroscopy. Biological analyses have been carried out to evaluate cell viability, proliferation and differentiation (with and without ultrasound stimulation) in the 3D constructs.