Microneedle-guided ultraviolet phototherapy with local calcipotriol delivery for enhanced psoriasis treatment

Narrow-band ultraviolet B (NB-UVB) phototherapy is clinically regarded as a first-line treatment for moderate-to-severe plaque psoriasis owing to its high tolerance, broad applicability and easy affordability. However, the therapeutic efficacy of short-wave UV light is limited by poor penetration through the thickened stratum corneum of psoriatic skin, whereas excessive NB-UVB irradiation may provoke cutaneous photodamage. Moreover, NB-UVB administration necessitates trained personnel and frequent hospital visits, resulting in poor patient compliance. Here, we developed microneedles with high UV transmittance (UVMNs) to enhance the transdermal delivery efficiency of NB-UVB, thereby reducing the required irradiation dosage and mitigating the risk of photodamage without compromising therapeutic effect. A vitamin D analog, calcipotriol, was further coated onto the UVMN patch to augment the overall efficacy of the phototherapeutic regimen. After insertion into the skin, the calcipotriol is released from the dissolvable coating within minutes to suppress keratinocyte proliferation, followed by UVMN-guided NB-UVB therapy for regulation of regulatory T/T helper 17 cell balance as well as inhibition of keratinocyte proliferation. The integration of phototherapy and topical therapy effectively ameliorated symptoms in a psoriatic mouse model.