Purpose: Due to the lack of effective local therapeutic strategies for oral squamous cell carcinoma (OSCC), this study aimed to develop a novel gelatin/lignin hydrogel loaded with mesenchymal stem cell (MSC)-derived exosomes enriched in microRNA-185 (miR-185 EV) for intraoral delivery, followed by systematic evaluation of its therapeutic efficacy and underlying molecular mechanisms. Materials and Methods: The gelatin/lignin hydrogel was prepared and subsequently loaded with miR-185 EV. The physicochemical properties of the hydrogel, including microstructure, swelling behavior, chemical composition, and rheological characteristics, were systematically evaluated. Next, the stability, viscosity, biocompatibility, and exosome release kinetics of the hydrogel were further assessed. A 4-nitroquinoline-1-oxide (4NQO)-induced mouse tongue carcinogenesis model was established to assess the in vivo antitumor activity of the hydrogel via intraoral administration. Moreover, a proteomic analysis was conducted to investigate the molecular mechanisms of miR-185 EV on OSCC. Results: The miR-185 EV-loaded gelatin/lignin hydrogel exhibited favorable physicochemical properties, stability, and biocompatibility while prolonging the tissue retention time of miR-185 EV. In vivo antitumor efficacy experiments showed that the miR-185 EV-loaded hydrogel significantly inhibited tumor occurrence and alleviated epithelial dysplasia. Immunohistochemical analyses revealed significant suppression of tumor proliferation and epithelial–mesenchymal transition (EMT) of the hydrogel. Proteomic analysis indicated that miR-185 EV suppressed OSCC progression by downregulating interleukin-1β (IL-1β), consequently inhibiting the NF-κB signaling pathway. Conclusion: The findings demonstrate the successful development of the miR-185 EV-loaded gelatin/lignin hydrogel that represents an effective nanomedicine platform for intraoral drug delivery, providing a promising strategy for the clinical treatment of OSCC.

Oral squamous-cell carcinoma (OSCC) is a prevalent malignancy of the head and neck region. A delay in the diagnosis of OSCC often results in a high metastatic tendency, which is the main reason for the high patient mortality. Dynamic monitoring and management of the onset and progression of OSCC are critical for improving patient survival rates. Liquid biopsy technology—characterized by its non-invasive nature, procedural convenience, and capacity for longitudinal monitoring—is a promising adjunct to histopathological examination for the early diagnosis of OSCC. Epigenetic alterations, characterized by reversibility and long-term stability in physiological fluids, are critical enablers of liquid biopsy and its clinical utility. Advances in detection technologies, including quantitative polymerase chain reaction (qPCR), digital droplet PCR (ddPCR), next-generation sequencing (NGS), and electrochemical biosensors, have significantly facilitated the research and clinical translation of epigenetic biomarkers in oral liquid biopsies. However, translating epigenetic biomarkers from research discovery to clinical practice for OSCC remains hindered by several critical challenges: the scarcity of large-scale, rigorously designed cohort studies, limited multicenter validation, inconsistent preprocessing protocols, and a lack of harmonized analytical platforms. Finally, we propose a conceptual framework to outline potential clinical application models for these biomarkers.