Heterogeneous silicon mesostructures for lipid-supported bioelectric interfaces

Abstract

Silicon-based materials have widespread application as biophysical tools and biomedical devices. Here we introduce a biocompatible and degradable mesostructured form of silicon with multiscale structural and chemical heterogeneities. The material was synthesized using mesoporous silica as a template through a chemical-vapor-deposition process. It has an amorphous atomic structure, an ordered nanowire-based framework, and random submicrometre voids, and shows an average Young’s modulus that is 2–3 orders of magnitude smaller than that of single crystalline silicon. In addition, we used the heterogeneous silicon mesostructures to design a lipid-bilayer-supported bioelectric interface that is remotely controlled and temporally transient, and that permits non-genetic and subcellular optical modulation of the electrophysiology dynamics in single dorsal root ganglia neurons. Our findings suggest that the biomimetic expansion of silicon into heterogeneous and deformable forms can open up opportunities in extracellular biomaterial or bioelectric systems.

Thermal Transients Excite Neurons through Universal Intramembrane Mechanoelectrical Effects

“…It is stipulated that the INS phenomenon is mediated by temperature transients induced by IR absorption [15][16][17]; such transients can alternatively be induced using other forms of photoabsorption [18][19][20], or potentially by any other physical form of thermal neurostimulation that can be driven rapidly enough [21,22]. Shapiro et al [16] showed that these rapid temperature variations are directly accompanied by changes in the cell membrane's capacitance and resulting displacement currents which are unrelated to specific ionic channels; their findings on the thermal capacitance increase have been supported by experiments from several additional groups [19,20,[23][24][25]. Shapiro et al [16] also developed a theoretical model where the temperature elevation was seen to give rise to membrane capacitance increase at the membrane's boundary regions (see also Liu et al [26] and Rabbit et al [27]).…”

Rational Design of Semiconductor Nanostructures for Functional Subcellular Interfaces

“…Jiang et al employed a nanocasting approach to synthesize 3D nanoporous Si particles (Figure 1C). 8 In this work, silane was decomposed using a CVD system inside the pores of an ordered mesoporous silica 31 (SBA-15) template, consisting of hexagonally arranged channels. Wet chemical etching of the SBA-15 was used to generate unidirectionally aligned SiNW arrays interconnected by microbridges, as shown in Figure 1C.…”

“…Jiang et al used mesoporous Si particles to induce photothermal excitation of primary dorsal root ganglion neurons as shown in Figure 4E–G. 8 After illuminating the plasma-membrane-supported Si particles, the fast photothermal effect from the Si induced a local temperature elevation, which subsequently caused a transient capacitance increase in the lipid bilayer and a depolarization of the bilayer due to capacitive current injection into the cells. Finally, recent work by Parameswaran et al demonstrated photoelectrochemical modulation of primary dorsal root ganglion neuron activity with coaxial p-i-n SiNWs.…”

“…The isosurface is plotted at 60 wt % Si. Adapted with permission from ref 8. Copyright 2016 Macmillan Publishers Ltd. (D) A schematic diagram (left) and a TEM image (right) of a SiNW with massively parallel sidewall grooves.…”

“…1–10 With appropriate compositions and structures, they can be both biocompatible and biodegradable. 3,8,11,12 For instance, one can readily control the doping profiles and morphologies in silicon (Si) nanowires via a vapor–liquid–solid (VLS) growth process and specifically by modulating synthesis parameters such as pressure and temperature. 6,13–20 These synthetic controls can effectively encode micro- and nanoscale features, yielding a large toolbox of Si-based biomaterials.…”