Hydrogel-based patient-friendly photodynamic therapy of oral potentially malignant disorders

Oral potentially malignant disorders (OPMDs) are precursor lesions with an increased risk of malignant transformation. Topical photodynamic therapy (PDT) mediated by 5-aminolevulinic acid (ALA) (ALA-PDT) is a promising therapeutic method in the treatment of OPMDs. However, the clinical application of topical ALA-PDT is restricted by several limitations, including low delivery efficiency, poor comfort, and easy influence by saliva. Here, we designed a highly adhesion-strength dry polyacrylic acid (PAA)-chitosan (CHI)-ALA interpenetrating network hydrogel (PACA) patch after investigating the spatiotemporal dynamics of ALA drug delivery via diffusion-based finite-element models. The PACA patch could adhere to the moist oral mucosa fast and stably and deliver ALA. PACA hydrogel-mediated PDT (PACA-PDT) effectively improved OPMDs in vitro and in a hamster oral carcinogenesis model. In particular, we conducted a trial to recruit 60 OPMD volunteers to demonstrate the feasibility and comfort of the PACA hydrogel patch. This study provides evidence that PACA hydrogel-mediated PDT could be a patient-friendly treatment modality for OPMDs.