Membrane cholesterol enrichment and folic acid functionalization lead to increased accumulation of erythrocyte-derived optical nano-constructs within the ovarian intraperitoneal tumor implants in mice

Cytoreductive surgery remains as the gold standard to treat ovarian cancer, but with limited efficacy since not all tumors can be intraoperatively visualized for resection. We have engineered erythrocyte-derived nano-constructs that encapsulate the near infrared (NIR) fluorophore, indocyanine green (ICG), as optical probes for NIR fluorescence imaging of ovarian tumors. Herein, we have enriched the membrane of these nano-constructs with cholesterol, and functionalized their surface with folic acid (FA) to target the folate receptor-alpha. Using a mouse model, we show that the average fraction of the injected dose per tumor mass for nano-constructs with both membrane cholesterol enrichment and FA functionalization was - sixfold higher than non-encapsulated ICG, twofold higher than nano-constructs enriched with cholesterol alone, and 33 % higher than nano-constructs with only FA functionalization at 24-h post-injection. These results suggest that erythrocyte-derived nano-constructs containing both cholesterol and FA present a platform for improved fluorescence imaging of ovarian tumors.