Photoactive Nanomaterials for Wireless Neural Biomimetics, Stimulation, and Regeneration

Abstract

Nanomaterials at the neural interface can provide the bridge between bioelectronic devices and native neural tissues and achieve bidirectional transmission of signals with our brain. Photoactive nanomaterials, such as inorganic and polymeric nanoparticles, nanotubes, nanowires, nanorods, nanosheets or related, are being explored to mimic, modulate, control, or even substitute the functions of neural cells or tissues. They show great promise in next generation technologies for the neural interface with excellent spatial and temporal accuracy. In this review, we highlight the discovery and understanding of these nanomaterials in precise control of an individual neuron, biomimetic retinal prosthetics for vision restoration, repair or regeneration of central or peripheral neural tissues, and wireless deep brain stimulation for treatment of movement or mental disorders. The most intriguing feature is that the photoactive materials fit within a minimally invasive and wireless strategy to trigger the flux of neurologically active molecules and thus influences the cell membrane potential or key signaling molecule related to gene expression. In particular, we focus on worthy pathways of photosignal transduction at the nanomaterial−neural interface and the behavior of the biological system. Finally, we describe the challenges on how to design photoactive nanomaterials specific to neurological disorders. There are also some open issues such as long-term interface stability and signal transduction efficiency to further explore for clinical practice.

Control of Neuronal Survival and Development Using Conductive Diamond

“…The effects of light stimulation have been published on cells adhered to various photoelectric materials. − ,− Most previous studies used a single material, only examined cellular responses to one level of stimulation, and only reported the favorable effects of light exposure on cells. ,,,− By applying different surface treatments to N-UNCD, we were able to examine the cellular response to varying magnitudes of the photocurrent and their mechanisms. We generally observed that the 15-h OA N-UNCD sample produced the most beneficial effect on cells.…”

“…3,4 A range of photoelectric materials have been developed and employed to modulate neural activities by converting light into electrical signals. 2,5 Compared to direct electrical stimulation, optical stimulation via these photoelectric materials provides several advantages. 6 First, optical stimulation eliminates the need for wires that connect electronic implants with external devices for powering and data transmission.…”

Functional material-mediated wireless physical stimulation for neuro-modulation and regeneration

“…Materials with optical properties have shown potential for converting light into various forms of stimuli to modulate biological processes or biomolecular activities. [192][193][194] Among these materials, photoelectric materials that generate electric current upon light illumination are crucial for neural modulation, providing new opportunities for remote and wireless electrical stimulation (Fig. 5A).…”

Bioactive cell niche mediating uniform thermal stimulus for BMSC neural differentiation through TRPV1 channel activation

“…[1][2][3] These stimuli all target neuromodulationrelated biological entities such as mechanically activated, voltage-gated, light-gated and thermosensitive ion channels. 4,5 To date, mechanical and electrical stimuli have been extensively studied by designing smart stimulus-responsive scaffolds, while light and thermal modalities have been relatively unexplored. Although with advantages and flexibility due to easy operability, light stimulus is usually combined with an optogenetics tool to modulate neuro-behavior, thus restricting it to the poor tissue penetration of the visible light operator, complex processes and high process costs.…”