Magnetically Activated Piezoelectric 3D Platform Based on Poly(Vinylidene) Fluoride Microspheres for Osteogenic Differentiation of Mesenchymal Stem Cells

Assemblable 3D biomimetic microenvironment for hMSC osteogenic differentiation

Adequate simulation mimicking a tissue's native environment is one of the elemental premises in tissue engineering. Although various attempts have been made to induce human mesenchymal stem cells (hMSC) into an osteogenic pathway, they are still far from widespread clinical application. Most strategies focus primarily on providing a specific type of cue, inadequately replicating the complexity of the bone microenvironment. An alternative multifunctional platform for hMSC osteogenic differentiation has been produced. It is based on poly(vinylidene fluoride) (PVDF) and cobalt ferrites magnetoelectric microspheres, functionalized with collagen and gelatin, and packed in a 3D arrangement. This platform is capable of performing mechanical stimulation of piezoelectric PVDF, mimicking the bones electromechanical biophysical cues. Surface functionalization with extracellular matrix biomolecules and osteogenic medium complete this all-round approach. hMSC were cultured in osteogenic inducing conditions and tested for proliferation, surface biomarkers, and gene expression to evaluate their osteogenic commitment.

Stimuli-responsive microcarriers and their application in tissue repair: A review of magnetic and electroactive microcarrier

Microcarrier applications have made great advances in tissue engineering in recent years, which can load cells, drugs, and bioactive factors. These microcarriers can be minimally injected into the defect to help reconstruct a good microenvironment for tissue repair. In order to achieve more ideal performance and face more complex tissue damage, an increasing amount of effort has been focused on microcarriers that can actively respond to external stimuli. These microcarriers have the functions of directional movement, targeted enrichment, material release control, and providing signals conducive to tissue repair. Given the high controllability and designability of magnetic and electroactive microcarriers, the research progress of these microcarriers is highlighted in this review. Their structure, function and applications, potential tissue repair mechanisms, and challenges are discussed. In summary, through the design with clinical translation ability, meaningful and comprehensive experimental characterization, and in-depth study and application of tissue repair mechanisms, stimuli-responsive microcarriers have great potential in tissue repair.

From emerging modalities to advanced applications of hydrogel piezoelectrics based on chitosan, gelatin and related biological macromolecules: A review

The rapid development of functional materials and manufacturing technologies is fostering advances in piezoelectric materials (PEMs). PEMs can convert mechanical energy into electrical energy. Unlike traditional power sources, which need to be replaced and are inconvenient to carry, PEMs have extensive potential applications in smart wearable and implantable devices. However, the application of conventional PEMs is limited by their poor flexibility, low ductility, and susceptibility to fatigue failure. Incorporating hydrogels, which are flexible, stretchable, and self-healing, providing a way to overcome these limitations of PEMs. Hydrogel-based piezoelectric materials (H-PEMs) not only resolve the shortcomings of traditional PEMs but also provide biocompatibility and more promising application potential. This paper summarizes the working principle of H-PEMs. Recent advances in the use of H-PEMs as sensors and in vitro energy harvesting devices for smart wearable devices are described in detail, with emphasis on application scenarios in human body like fingers, wrists, ankles, and feet. In addition, the recent progress of H-PEMs in implantable medical devices, especially the potential applications in human body parts such as bones, skin, and heart, are also elaborated. In addition, challenges and potential improvements in H-PEMs are discussed.