Microscopic Projection Lithography for Integrating Metallic Microstructures on Silk Protein for Biodevice...

Area of Science:

• Biomaterials Engineering
• Nanotechnology
• Biomedical Device Fabrication

Background:

• Precise patterning of metallic micro/nanostructures on silk protein is crucial for biomedical devices.
• Current micro/nanofabrication methods are expensive and hinder rapid prototyping in research.
• Silk protein offers biocompatibility but requires robust fabrication techniques.

Purpose of the Study:

• To develop a cost-effective, high-resolution projection lithography method for fabricating metallic microstructures on silk protein.
• To demonstrate the feasibility of rapid prototyping for silk-based biomedical devices.
• To evaluate the performance of fabricated silk-based devices.

Main Methods:

• Utilized light-emitting diode (LED)-based projection lithography with inkjet-printed patterns and a commercial camera/microscopic objective lens.
• Employed a two-step photolithography process with 100× and 500× demagnification ratios.
• Integrated gold (Au) patterns using a lift-off process on the lithographically patterned resist/silk layer.

Main Results:

• Successfully fabricated various gold microstructures with sizes less than 2 μm on silk protein layers.
• Demonstrated silk protein's high chemical resistance and strong adhesion to gold.
• Confirmed low cytotoxicity of the silk protein material.
• Validated dopamine sensing and transistor operating capabilities of the fabricated Au patterns.

Conclusions:

• The proposed LED-based projection lithography is a cost-effective and simple approach for rapid prototyping of silk-based biomedical devices.
• The method enables the creation of high-resolution metallic microstructures essential for advanced human-machine interfaces.
• Silk protein proves to be a suitable and robust material for these advanced biomedical applications.