Mesoscopic Fluorescence Imaging of Light-Triggered Chemotherapeutic Release in Cancer Spheroid Models

Background/Objectives: Peritoneal micrometastases (micromets) remain a major barrier to durable cytoreduction in ovarian and other intra-abdominal cancers because lesions are difficult to visualize and are often resistant to systemic therapy. Liposomal doxorubicin (Dox) improves pharmacokinetics but can be limited by slow intratumoral release. Porphyrin-phospholipid (PoP) liposomes enable near-infrared light-triggered release of Dox (chemophototherapy (CPT)), creating an opportunity for intraoperative fluorescence-guided treatment planning and monitoring. Here, we evaluate a laparoscopic fluorescence imaging platform for quantifying light-triggered drug delivery. Methods: LC-Dox-PoP was applied to SCC2095sc and SKOV-3 cultures in 2D monolayers and 3D spheroid clusters. Dox fluorescence was quantified using a laparoscopic fluorescence imaging system over 1-9 μg/mL concentrations and compared with standard well-plate reader measurements. Porphyrin fluorescence was monitored to assess spheroid localization and photobleaching after activation light exposure. Results: For both cell lines, Dox fluorescence exhibited an approximate 4-fold increase at the maximum administered LC-Dox-PoP concentration, following a linear trend in both SCC2095sc and SKOV-3 cultures (R² = 0.97, 0.98 for 2D and R² = 0.98, 0.98 for spheroids). Laparoscope-derived fluorescence measurements agreed with well-plate reader measurements (R² = 0.89-0.96). Porphyrin fluorescence provided stronger complementary contrast for localizing spheroid constructs and decreased after activation light exposure, consistent with photobleaching during triggered release. Conclusions: These results support a quantitative imaging framework for fluorescence-guided monitoring of light-triggered liposomal drug release and may enable individualized CPT dosimetry for peritoneal micrometastases. Findings in SCC2095sc additionally suggest potential relevance of fluorescence-guided CPT for head and neck/oral cancer, where localized post-resection adjuvant treatment may improve control of residual disease.