03/24/2026
Conventional skin cancer treatment — excision, radiation, or topical chemotherapy — leaves scars, requires clinical settings, and causes significant discomfort. 🌞 Bioengineers at Northwestern University have developed a flexible wearable patch that delivers photodynamic therapy (PDT) using ambient sunlight as its sole energy source, eliminating the specialized laser equipment that has historically restricted PDT to clinical environments and making painless, at-home skin cancer treatment a clinical reality.
Published in ACS Nano (2025), the device is a 200-micrometer-thick film incorporating a photosensitizer compound — a chlorin e6 derivative — embedded in a biocompatible elastomeric matrix with a built-in microfluidic oxygen reservoir. When sunlight activates the photosensitizer, it generates singlet oxygen specifically within the patch's contact zone, destroying cancer cells through oxidative stress within a 2-millimeter pe*******on depth that encompasses the full thickness of basal cell and squamous cell carcinomas without reaching healthy subcutaneous tissue. 🔬 In a 65-patient pilot trial, complete histological clearance was achieved in 81% of primary basal cell carcinomas after three 30-minute daily applications.
The microfluidic oxygen enhancement component is the critical differentiator from prior stick-on PDT attempts. Tumor tissue is typically hypoxic — low in oxygen — which limits singlet-oxygen generation and reduces PDT efficacy. The patch's integrated oxygen reservoir delivers supplemental O₂ directly to the treatment zone, overcoming this limitation. Efficacy in hypoxic models improved by 3.2-fold compared to standard PDT.
The patch is manufactured using roll-to-roll printing at a projected cost of under $8 per unit. 💊 Dermatology societies are working with the FDA on an over-the-counter approval pathway for low-risk superficial lesions, reserving prescription use for deeper or higher-risk presentations. The possibility of eliminating surgical management for the majority of common skin cancers — simply by wearing a bandage in daylight — reframes the economics and accessibility of dermatological oncology entirely.
Source: Northwestern University, ACS Nano, 2025