Electroactive Biomaterials for Facilitating Bone Defect Repair under Pathological Conditions

Abstract

Bone degeneration associated with various diseases is increasing due to rapid aging, sedentary lifestyles, and unhealthy diets. Living bone tissue has bioelectric properties critical to bone remodeling, and bone degeneration under various pathological conditions results in significant changes to these bioelectric properties. There is growing interest in utilizing biomimetic electroactive biomaterials that recapitulate the natural electrophysiological microenvironment of healthy bone tissue to promote bone repair. This review first summarizes the etiology of degenerative bone conditions associated with various diseases such as type II diabetes, osteoporosis, periodontitis, osteoarthritis, rheumatoid arthritis, osteomyelitis, and metastatic osteolysis. Next, the diverse array of natural and synthetic electroactive biomaterials with therapeutic potential are discussed. Putative mechanistic pathways by which electroactive biomaterials can mitigate bone degeneration are critically examined, including the enhancement of osteogenesis and angiogenesis, suppression of inflammation and osteoclastogenesis, as well as their anti‐bacterial effects. Finally, the limited research on utilization of electroactive biomaterials in the treatment of bone degeneration associated with the aforementioned diseases are examined. Previous studies have mostly focused on using electroactive biomaterials to treat bone traumatic injuries. It is hoped that this review will encourage more research efforts on the use of electroactive biomaterials for treating degenerative bone conditions.

Electrical Stimulation for Immunomodulation

“…70,71,77−81 The modulation of macrophage behavior is typically dependent on the material surface properties such as surface potential, surface roughness, and hydrophobicity. 70,81 Particularly for piezoelectric materials, the dynamic surface potential generated at the cell−material interface is known to influence the cell behavior significantly. 79,80 For instance, Zhou et al in 2023 studied the influence of differing surface potential generation from piezoelectric PVDF−TrFE films on macrophage polarization for accelerated wound recovery.…”

“…Due to their high biocompatibility and biodegradability, piezoelectric polymers such as PVDF–TrFE and poly­(hydroxybutyrate- co -valerate) (PHBV) have shown promising results in transitioning the phenotypes of macrophages for the systematic repair of wounds in a self-powered manner. ,,− The modulation of macrophage behavior is typically dependent on the material surface properties such as surface potential, surface roughness, and hydrophobicity. , Particularly for piezoelectric materials, the dynamic surface potential generated at the cell–material interface is known to influence the cell behavior significantly. , For instance, Zhou et al in 2023 studied the influence of differing surface potential generation from piezoelectric PVDF–TrFE films on macrophage polarization for accelerated wound recovery . The as-prepared PVDF–TrFE films were first polarized with electric field intensities of 50 V/μm (low polarized) and 100 V/μm (high polarized), which generated surface potentials of 19 ± 13 and 232 ± 7 mV, respectively, and macrophages were seeded on their surfaces.…”

Osteogenic potential of a 3D printed silver nanoparticle-based electroactive scaffold for bone tissue engineering using human Wharton's jelly mesenchymal stem cells

“…Among them, electrical stimulation is an attractive option because it has been demonstrated that sending signals across cell membranes with −10 to −90 mV would encourage cells to travel to the site of injury, 10 and also boost cardiac, 11 nerve, 12,13 and bone tissue regeneration. 14,15 Therefore, electroactive scaffolds have emerged as a promising solution for bone therapies because they could deliver electrical stimulation directly to cells to improve incorporation, growth, and formation of new bone tissue. 9,16…”

“…Among them, electrical stimulation is an attractive option because it has been demonstrated that sending signals across cell membranes with À10 to À90 mV would encourage cells to travel to the site of injury, 10 and also boost cardiac, 11 nerve, 12,13 and bone tissue regeneration. 14,15 Therefore, electroactive scaffolds have emerged as a promising solution for bone therapies because they could deliver electrical stimulation directly to cells to improve incorporation, growth, and formation of new bone tissue. 9,16 Electroactive scaffolds can be prepared by combining nonconductive biocompatible and biodegradable polymers, such as polycaprolactone (PCL), with conductive fillers, such as carbonbased, 17,18 conductive polymeric-based, 9,19 or metallic-based nanoparticles.…”

Modulating Electrochemical CO2 Reduction Performance via Sulfur-Containing Linkages Engineering in Metallophthalocyanine Based Covalent Organic Frameworks

“…Covalent organic frameworks (COFs) are an emerging class of crystalline porous material with structural regularity, simple accessibility, chemical stability, and built-in functional tunability at the molecular level. − To date, many COFs have been synthesized and have shown great potential for applications in various fields such as gas separation and storage, optoelectronics, − energy storage, − and catalysis. − Among all COFs, owing to the photosensitive 18π aromatic macrocyclic nature of MPc, constructing COFs with MPc units provides an opportunity for the development of electrochemical materials and has recently become a hot research topic. − In 2021, two novel pyrazine (pz)-linked metal-phthalocyanine (MPc)-based conjugated 2D COFs were constructed by the Feng group . Most relevantly, Jiang et al reported that phenazine-linked Co-phthalocyanine COFs (CoPc-PDQ-COFs) with high stability and conductivity were used as efficient electrocatalysts for the CO 2 RR .…”