Wirelessly Powered Electrical-Stimulation Based on Biodegradable 3D Piezoelectric Scaffolds Promotes the Spinal Cord Injury Repair

Abstract

An electroactive scaffold integrated with noninvasive in vivo electrical-stimulation (ES) capability shows great promise in the repair and regeneration of damaged tissues. Developing high-performance piezoelectric biomaterials which can simultaneously serve as both a biodegradable tissue scaffold and controllable electrical stimulator remains a great challenge. Herein, we constructed a biodegradable high-performance 3D piezoelectric scaffold with ultrasound (US)-driven wireless ES capability, and demonstrated its successful application for the repair of spinal cord injuries in a rat model. The 3D multichannel piezoelectric scaffold was prepared by electrospinning of poly­(lactic acid) (PLA) nanofibers incorporated with biodegradable high-performance piezoelectric potassium sodium niobate (K0.5Na0.5NbO3, KNN) nanowires. With programmed US irradiation as a remote mechanical stimulus, the on-demand in vivo ES with an adjustable timeline, duration, and strength can be delivered by the 3D piezoelectric scaffold. Under proper US excitation, the 3D tissue scaffolds made of the piezoelectric composite nanofibers can accelerate the recovery of motor functions and enhance the repair of spinal cord injury. The immunohistofluorescence investigation indicated that the 3D piezoelectric scaffolds combined with the US-driven in vivo ES promoted neural stem cell differentiation and endogenous angiogenesis in the lesion. This work highlights the potential application of a biodegradable high-performance piezoelectric scaffold providing US-driven on-demand electrical cues for regenerative medicine.

Highly piezoelectric, biodegradable, and flexible amino acid nanofibers for medical applications

“…S13). This value is slightly higher than the piezoelectric constant of the piezoelectric nanofiber PLLA (d14 = ~19 pC/N) and comparable to the KNN-based materials (d33 = ~20 pC/N) (20,50). However, with the impact experiment and the piezometer, we are only able to assess the effective piezoelectric constant d 33 of our materials at a bulk scale, and this value does not fully represent the piezoelectricity for shear piezoelectric materials like glycine.…”

Worldwide productivity and research trend of publications concerning electroactive materials and spinal cord injury: A bibliometric study

“…Conductive biomaterials mainly include conductive polymers (CPs), piezoelectric materials, and carbon-based nanomaterials. Piezoelectric materials and carbon-based nanomaterials are characterized by ultra-thin film structures with large surface areas, high adhesion levels, and tunable mechanical properties, which can be used as electrical or nanocarriers for synaptic modulation, reduction of neuroinflammation, regulation of stem cell fate and repair of damaged neural cells/tissues (He et al, 2022); Nanowire-based degradable piezoelectric material driven by ultrasound (US) accelerates motor recovery, promotes neural stem cell differentiation and endogenous angiogenesis (Chen et al, 2022). However, a single thin film material cannot repair cystic cavities in the CNS caused by trauma or vascular injury, which prevent cell survival and axonal regeneration within the cavity (Hong et al, 2017).…”

Wearable and implantable bioelectronics as eco‐friendly and patient‐friendly integrated nanoarchitectonics for next‐generation smart healthcare technology

“…(I) Reproduced with permission: 2016, Springer Nature 217 . (J) Reproduced with permission: 2022, American Chemical Society 218 . (K) Reproduced with permission: 2021, Elsevier 219 .…”

“…Some researchers focused on fundamental treatment and spinal nerve regeneration. Chen et al reported restoration of the original CNS using wirelessly powered electrical stimulation, as described in Figure 6J 218 . Implanted 3D piezoelectric scaffolds received power and signal from the ultrasound transducer and provided spinal nerve regeneration.…”