Illuminating the Underlying Mechanism of Intracellular Optoelectronic Modulation Using Silicon Nanowires

Area of Science:

• Bioelectronic research
• Cellular stimulation
• Nanotechnology

Background:

• Minimally invasive electrical cell stimulation with subcellular resolution is crucial for bioelectronic research.
• Silicon nanowires (SiNWs) are promising due to biocompatibility, internalization, and photoelectrochemical properties.
• Mechanisms of SiNW-induced intracellular calcium transients are not fully understood.

Purpose of the Study:

• To mechanistically investigate how SiNWs optically induce intracellular calcium transients.
• To differentiate between photothermal and photoelectrochemical contributions.
• To elucidate the pathways involved in SiNW-mediated calcium modulation.

Main Methods:

• Depletion of intracellular calcium stores.
• Utilizing intrinsic, photoanodic (n-i-p), and photocathodic (p-i-n) SiNWs.
• Pharmacological inhibition of organelles and signaling pathways.
• Analysis of reactive oxygen species (ROS) generation.

Main Results:

• Optically induced calcium transients originate from intracellular calcium stores.
• Both photoanodic and photocathodic SiNW interfaces yield significant calcium responses, surpassing photothermal effects.
• Photoanodic response is dominated by ROS, while photocathodic response modulates calcium via organelle channels.
• Mechanistic insights into SiNW-mediated intracellular calcium modulation were obtained.

Conclusions:

• SiNWs offer a viable platform for precise, cell-specific intracellular bioelectric modulation.
• Understanding these mechanisms is key for developing advanced SiNW-based optoelectronic systems.
• This research enables safe, efficient, and spatially precise subcellular bioelectric modulation.