Parylene photonics: a flexible, broadband optical waveguide platform with integrated micromirrors for biointerfaces

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Targeted light delivery is crucial for optogenetics and in vivo tissue imaging.
• Existing implants often lack the required compactness, flexibility, and biocompatibility.
• Minimizing tissue damage is essential for chronic in vivo applications.

Purpose of the Study:

• To demonstrate a novel implantable photonic platform for precise light delivery into biological tissues.
• To develop a compact, soft, and flexible implant that minimizes tissue damage.
• To enable applications like chronic optogenetic stimulation and in vivo imaging.

Main Methods:

• Fabrication of a high-density, flexible array of ultracompact optical waveguides using Parylene C and polydimethylsiloxane (PDMS).
• Integration of embedded input/output micromirrors for perpendicular light redirection.
• Characterization of waveguide loss at various wavelengths (450–680 nm).

Main Results:

• Demonstrated ultracompact (30 μm × 5 μm) and low-loss optical waveguides.
• Achieved efficient light redirection using embedded micromirrors.
• Developed a fully flexible, integrated photonic system.

Conclusions:

• The novel photonic platform offers a promising solution for targeted light delivery in biological tissues.
• The flexible and biocompatible design minimizes tissue damage, suitable for chronic in vivo applications.
• This technology advances capabilities in optogenetics and in vivo tissue imaging.