3D-Printed Lesion-Conformal Light-Guiding Patches for Precise and Personalized Psoriasis Phototherapy

Abstract

Psoriasis is a chronic inflammatory skin disorder marked by epidermal hyperplasia and hyperkeratosis, with lesions presenting highly irregular geometric patterns and a discrete distribution. Traditional phototherapy, lacking spatial selectivity, often causes radiation damage to surrounding healthy tissue, thereby limiting treatment dosage and frequency. In this study, we developed a 3D-Printed Lesion-Conformal Light-Guiding Patches, precisely customized based on lesion characteristics, marking a significant advancement from traditional point light sources to high-performance uniform surface light sources. The system integrates titanium dioxide nanoparticles (TiO₂ NPs) within a polydimethylsiloxane (PDMS) matrix to form scattering centers. Through a lateral coupling design, it redirects photons, generating a highly uniform surface-emitting light field. This approach overcomes the intensity attenuation in-herent to point sources, enabling the simultaneous irradiation of multiple plaques while sparing surrounding healthy tissue with precision. In an imiquimod (IMQ)-induced mouse model, this system significantly mitigated damage to normal skin while effectively repairing psoriatic lesions. Histopathological (HE) analysis revealed a dramatic increase in epidermal thickness in the model group, which was five times greater than that of the control group. In contrast, the patterned group ex-hibited notable improvements in the pathological features of the lesions, with epi-dermal thickness returning to levels comparable to those of healthy controls. Im-munohistochemical analysis showed that patterned group substantially reduced the expression of the keratinocyte proliferation marker K16 and the inflammatory cyto-kine IL-17, demonstrating superior efficacy over conventional point-source irradia-tion. Additionally, this closed-loop system demonstrated promising therapeutic po-tential for refractory plaques in preliminary clinical cases, providing new insights for the development of next-generation personalized and precision dermatology treat-ment devices.