Ablative Fractional Lasers Versus Needle-Based Devices for Poly- l -Lactic Acid Delivery: An Optical Coherence...

Area of Science:

• Dermatology
• Biomaterials Science
• Laser Technology

Background:

• Poly-l-lactic acid (PLLA) is a common dermatological filler, typically administered via injection.
• Interest is growing in alternative PLLA delivery methods like ablative fractional lasers (AFLs) and microneedle devices.
• Limited data exists on the comparative efficacy of these novel PLLA delivery systems.

Purpose of the Study:

• To evaluate the effectiveness of AFLs and needle-based devices for transdermal PLLA delivery.
• To investigate how the morphology of treatment channels influences PLLA uptake.
• To compare PLLA penetration depth and distribution across different device types.

Main Methods:

• Human abdominal skin samples were treated with fractional CO2 laser, fractional difference frequency generation (DFG) laser, fractional microneedle radiofrequency (MNRF), and microneedle (MN) devices.
• Topical PLLA was applied, and its movement into treatment channels was visualized in real-time using optical coherence tomography (OCT).
• Histological analysis quantified PLLA distribution and depth within the skin.

Main Results:

• OCT confirmed PLLA particle entry into channels created by AFLs, but not by MNRF or MN devices.
• Histology showed significant PLLA uptake in CO2 (up to 80.3%) and DFG (up to 61.9%) laser channels.
• MNRF and MN devices demonstrated minimal PLLA uptake (1.4% and 0.7%, respectively).
• CO2 lasers created deeper channels (120-240 μm) compared to DFG lasers (0-120 μm).

Conclusions:

• Ablative fractional lasers are effective for transdermal PLLA delivery, whereas needle-based devices show limited efficacy.
• The geometry of channels generated by AFLs influences the vertical distribution of PLLA within the skin.
• Further in vivo and clinical studies are necessary to determine PLLA retention and its long-term effects on tissue remodeling.