Bioelectronics Manufacturing With Lasers

Conducting or semiconducting materials embedded in insulating polymeric substrates can be useful in bioelectronics applications; however, attainment of this composite configuration by direct chemical processes is challenging. Laser-assisted synthesis has evolved as a fast and inexpensive technique to prepare various materials, but its utility in the construction of biophysical tools or biomedical devices is less explored.

Researchers have used laser writing to convert portions of polydimethylsiloxane (PDMS) into nitrogen-doped cubic silicon carbide (3C-SiC). The dense 3C-SiC surface layer is connected to the PDMS matrix via a spongy graphite layer, facilitating electrochemical and photoelectrochemical activity. They demonstrate the fabrication of arbitrary two-dimensional (2D) SiC-based patterns in PDMS and freestanding 3D constructs (bioelectronics). To establish the functionality of the laser-produced composite, they apply it as flexible electrodes for pacing isolated hearts and as photoelectrodes for local peroxide delivery to smooth muscle sheets.

This work demonstrates 2D and 3D laser writing of nitrogen-doped 3C-SiC over PDMS substrates. The 3C-SiC layer establishes a seamless hard-soft interface with PDMS through a spongy graphite layer. The researchers developed SiC-based flexible bioelectronics devices as pseudocapacitively coupled stimulation electrodes for isolated hearts and photoelectrodes for localized H2O2 production for mammalian and microbial cell modulation. Their results suggest the future utility of seamlessly integrated semiconductor/elastomer composites for organ-on-a-chip or organoid-on-a-chip research or microfluidic systems where photoelectrochemical or electrochemical capabilities are needed.

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