Tumor hypoxia can seriously impede the effectiveness of
photodynamic therapy (
PDT). To address this issue, two approaches, termed in situ
oxygen generation and
oxygen delivery, were developed. The in situ
oxygen generation method uses catalysts such as
catalase to decompose excess H2O2 produced by
tumors. It offers specificity for
tumors, but its effectiveness is limited by the low H2O2 concentration often present in
tumors. The
oxygen delivery strategy relies on the high
oxygen solubility of
perfluorocarbon, etc., to transport
oxygen. It is effective, but lacks
tumor specificity. In an effort to integrate the merits of the two approaches, we designed a multifunctional nanoemulsion system named CCIPN and prepared it using a sonication-phase inversion composition-sonication method with orthogonal optimization. CCIPN included
catalase, the methyl
ester of 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic
acid (
CDDO-Me),
photosensitizer IR780, and
perfluoropolyether.
Perfluoropolyether may reserve the
oxygen generated by
catalase within the same nanoformulation for
PDT. CCIPN contained spherical droplets below 100 nm and showed reasonable cytocompatibility. It presented a stronger ability to generate cytotoxic
reactive oxygen species and consequently destroy
tumor cells upon light irradiation, in comparison with its counterpart without
catalase or
perfluoropolyether. This study contributes to the design and preparation of
oxygen-supplementing
PDT nanomaterials.