Experimental Validation of Diffraction Lithography for Fabrication of Solid Microneedles

Area of Science:

• Materials Science
• Biomedical Engineering
• Optics

Background:

• Microneedles are valuable for drug delivery and cosmetics.
• Current manufacturing methods are complex and limit applications.

Purpose of the Study:

• To experimentally validate ultraviolet light diffraction lithography for microneedle fabrication.
• To investigate the influence of fabrication parameters on microneedle shape and morphology.
• To explore novel microneedle array designs and characterize their mechanical properties.

Main Methods:

• Utilizing ultraviolet light diffraction to control the liquid-to-solid transition of photosensitive resin.
• Investigating parameters: photopattern size, UV light intensity, and exposure time.
• Characterizing microneedle shapes, morphologies, and mechanical properties through insertion and force-displacement tests.

Main Results:

• Microneedle height and size increased with higher experimental parameter values.
• Identified four distinct crosslinked resin morphologies: microlens, first harmonic, first bell-tip, and second harmonic.
• Successfully fabricated a novel inclined microneedle array by tilting the UV light exposure direction.

Conclusions:

• UV light diffraction lithography offers a simplified approach to microneedle manufacturing.
• Fabrication parameters can be tuned to control microneedle dimensions and shapes.
• The method enables predictable microneedle properties for mass production in biomedical and cosmetic fields.