A Photolithographic Approach to Polymeric Microneedles Array Fabrication

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Microneedles offer minimally invasive drug delivery and diagnostic capabilities.
• Existing fabrication methods for microneedles often involve complex etching or molding processes.
• Direct photolithography presents a potential alternative for efficient microneedle production.

Purpose of the Study:

• To present two procedures for fabricating polymeric microneedles using direct photolithography.
• To demonstrate a method for controlling microneedle shape and length without etching or molding.
• To explore the potential of these microneedles for applications such as micro-indentation and drug delivery.

Main Methods:

• Polyethylene glycol (PEG) was cross-linked using ultraviolet (UV) light (365 nm) and a photocatalyzer.
• Direct photolithography was employed by exposing PEG to UV light through a mask.
• Microneedle shape and length were controlled by adjusting the position of the support and the radiation dose (exposure time and power density).

Main Results:

• Polymeric microneedles ranging from 100 micrometers to 2 millimeters in length were successfully fabricated.
• Various microneedle shapes, including cylindrical, conic, and lancet-like structures, were achieved.
• The fabrication process demonstrated precise control over microneedle dimensions through photolithography parameters.

Conclusions:

• Direct photolithography offers an efficient, mask-based method for producing polymeric microneedles.
• The developed technique allows for tunable control over microneedle geometry for diverse applications.
• This fabrication approach avoids complex etching or molding, simplifying microneedle production.