Optical Microneedle-Enhanced Transdermal Light Scattering for In Situ Photothermal Therapy Targeting Basal-Layer...

Area of Science:

• Biomedical Engineering
• Dermatology
• Photomedicine

Background:

• Near-infrared (NIR) light therapies show promise for skin disease treatment but face challenges due to skin's light absorption.
• Melanin in the epidermis limits NIR light penetration, reducing therapeutic efficacy and risking off-target damage.

Purpose of the Study:

• To develop subcutaneous light response-enhanced microneedles (SLE MNs) for improved transdermal NIR light therapy.
• To enable basal layer-localized drug delivery and efficient light transmission for enhanced photothermal and photodynamic therapy (PDT).

Main Methods:

• Designed ultraoptical SLE MNs with physical channels for transdermal light transmission.
• Integrated a two-segmented microneedle structure with light-guiding channels and photoresponsive therapeutics.
• Evaluated NIR light penetration and therapeutic efficacy in subcutaneous tissues.

Main Results:

• SLE MNs significantly increased NIR light penetration, reaching 80% power at 500 μm depth (160% increase vs. controls).
• The microneedle design facilitated in situ scattered light activation at the basal layer.
• Minimized surface hyperenergy and tissue attenuation, enabling precise, localized treatment.

Conclusions:

• The developed optical SLE MN patch is a transformative platform for transdermal light therapy.
• This technology offers enhanced efficacy and safety for treating skin diseases via photothermal and photodynamic therapies.
• Significant clinical potential for nonsurgical treatment of various skin conditions is demonstrated.