Nanotransducer-Enabled Deep-Brain Neuromodulation with NIR-II Light

Abstract

The second near-infrared window (NIR-II window), which ranges from 1000 to 1700 nm in wavelength, exhibits distinctive advantages of reduced light scattering and thus deep penetration in biological tissues in comparison to the visible spectrum. The NIR-II window has been widely employed for deep-tissue fluorescence imaging in the past decade. More recently, deep-brain neuromodulation has been demonstrated in the NIR-II window by leveraging nanotransducers that can efficiently convert brain-penetrant NIR-II light into heat. In this Perspective, we discuss the principles and potential applications of this NIR-II deep-brain neuromodulation technique, together with its advantages and limitations compared with other existing optical methods for deep-brain neuromodulation. We also point out a few future directions where the advances in materials science and bioengineering can expand the capability and utility of NIR-II neuromodulation methods.

Ultrasound-Induced Cascade Amplification in a Mechanoluminescent Nanotransducer for Enhanced Sono-Optogenetic Deep Brain Stimulation

“…The high energy transfer efficiency ensured that these liposomes could be effectively activated. As shown in Figure b, the synchronous blue light with power intensity 1.21 mW/mm 2 was generated under the FUS stimulation, which should be sufficient to achieve more than 60% wild-type ChR2 spike probability. , Furthermore, it is worth noting that the ultrasound’s thermal effect can activate neurons through temperature-sensitive ion channels. , Therefore, we assessed the local temperature at the targeted brain area during sono-optogenetic stimulation. Our findings revealed a mere 1.0 °C increase during the 20 s ultrasound stimulation, with no significant intracranial heating observed that could potentially alter neuronal physiology (Figure S10).…”

pH-Activated Ce-Doped Molybdenum Oxide Nanoclusters for Tumor Microenvironment Responsive Photothermal and Chemodynamic Therapy

“…PTT converts near-infrared (NIR) laser light into heat at specific tumor sites for targeted therapy via a photothermal agent. NIR lasers include NIR-I (700–900 nm) and NIR-II (1000–1700 nm) wavelengths, with the latter exhibiting greater penetration depth, which is more conducive to the ablation of tumor tissue in the body. , Recently, Mo-based nanocomposites have been shown as ideal photothermal conversion nanoreagents for PTT-based theranostic strategy. For instance, Liu et al investigated a Mo 2 C-derived polyoxometalate (POM) with efficient photothermal therapeutic ability in the NIR-II window; Ni et al investigated Mo-based POM for pH-responsive PA imaging-guided tumor eradication and PTT .…”

Conjugated Polymer Coupled with Nonconjugated Segments for NIR-II Fluorescence/NIR-II Photoacoustic Imaging-Guided NIR-II Photothermal Therapy

“…Moreover, for the low band gap NIR-II absorption conjugated polymers, the nonradiative decay is much stronger than radiative decay and consequently encounters problems with the low NIR-II fluorescence quantum yield. To address these issues, Wu and Tang groups synthesized aggregation-induced emission segments containing conjugated polymers that increase the NIR-II FL. ,− Our group has developed a series of weak electron donor-doped conjugated polymers that enabled NIR-II FL imaging-guided NIR-II PTT therapy. − However, these developed conjugated polymers have low solubility in organic solution and formed π–π stacking interactions between polymers in the aggregated state of water-soluble nanoparticles (NPs), significantly reducing the NIR-II FL imaging quality. Hence, a significant challenge remains to develop NIR-II absorption conjugated polymers with promising antiquenching capability for performing NIR-II FL and NIR-II PA imaging-guided NIR-II PTT of tumors.…”