Bioinspired nanotransducers for neuromodulation

The field of neuromodulation has experienced significant advancements in the past decade,owing to breakthroughs in disciplines such as materials science,genetics,bioengineering,photonics,and beyond.The convergence of these fields has resulted in the development of nanotransducers,devices that harness the synergies of these diverse disciplines.These nanotransducers,essential for neuromodulation,often draw inspiration from energy conversion processes found in nature for their unique modalities.In this review,we will delve into the latest advancements in wireless neuromodulation facilitated by optical,magnetic,and mechanical nanotransducers.We will examine their working principles,properties,advantages,and limitations in comparison to current methods for deep brain neuromodulation,highlighting the impact of natural systems on their design and functionality.Additionally,we will underscore potential future directions,emphasizing how continued progress in materials science,neuroscience,and bioengineering might expand the horizons of what is achievable with nanotransducer-enabled neuromodulation.

Exo/endogenous factors co-activatable nanodevice for spatiotem-porally controlled miRNA imaging and guided tumor ablation

Remote activation of biomarker sensing holds a great promise of shifting the success of in vitro diagnostics to spatiotemporally controlled in vivo visualization of tumor,and in turn,imaging guided therapy.Herein,a"dual-key-one-lock"nanodevice was designed and built by assembling thermo-activatable probe of trimeric DNA hybrids into a mesoporous polydopamine nanoparticle-based multifunctional nanotransducer(probe host,fluorescence quencher,and photothermal conversion agent),enabling precisely switchable theranostic operations under the co-activation of exo/endogenous stimulations(near-infrared(NIR)light and microRNA(miRNA)).By this design,the NIR irradiation-induced local heat through the porous nanotransducer can be transferred to the DNA nanothermometer for triggering the exposure of the miRNA recognition segment,as well as the subsequent fluorescence activation by strand displacement reactions(SDR).A programmable application of short-(3 min)and long-duration(10 min)NIR irradiation was administered sequentially to induce a milder and a stronger hyperthermia,respectively,to activate the localized miRNA imaging,and in turn,tumor thermoablation under the fluorescence guidance in vivo.By reducing nonspecific activation,dual factor co-activatable nanodevices exhibited a high tumor-to-background ratio(TBR)value of 8.9,as well as a significantly lower(6-9-fold)normal tissue fluorescence as compared with those sensing miRNA solely.The in vivo results show that the tumors were significantly suppressed after the photothermal therapy with the assistance of the accurate miRNA diagnosis.This rationally integrated nanoplatform may pave a new avenue for advanced theranostic systems with high spatiotemporal precision by activatable designs.