CD44 Receptor–Specific and Redox-Sensitive Nanophotosensitizers of Hyaluronic Acid–Chlorin e6 Tetramer Having Diselenide Linkages for Photodynamic Treatment of Cancer Cells

Abstract

For reactive oxygen species (ROS)–sensitive and CD44 receptor–mediated delivery of photosensitizers, chlorin e6 (ce6) tetramer was synthesized using tetra acid (TA) via selenocystamine linkages and then conjugated with hyaluronic acid (HA) (abbreviated as HAseseCe6TA). HAseseCe6TA nanophotosensitizers were fabricated by dialysis procedure. HAseseCe6TA nanophotosensitizers showed spherical morphology with small particle sizes less than 100 nm and monomodal pattern. When H2O2 was added, size distribution was changed to multimodal pattern and morphological observation showed disintegration of nanophotosensitizers, indicating that HAseseCe6TA nanophotosensitizers have ROS sensitivity. Furthermore, H2O2 addition resulted in acceleration of Ce6 release from HAseseCe6TA nanophotosensitizers. In vitro cell culture study, HAseseCe6TA nanophotosensitizers increase Ce6 uptake ratio, ROS production efficiency, and photodynamic therapy efficacy in both B16F10 cells and CT26 cells. Especially, CD44-receptor blocking of cancer cells by pretreatment of HA showed that fluorescence intensity in B16F10 cells was significantly decreased while fluorescence intensity in CT26 cells was not significantly changed, indicating that HAseseCe6TA nanophotosensitizers can be delivered by CD44 receptor–mediated pathway. In vivo animal tumor xenograft study, HAseseCe6TA nanophotosensitizers was selectively delivered to B16F10 tumor rather than CT26 tumor. These results indicated that HAseseCe6TA nanophotosensitizers have ROS sensitivity and have CD44 receptor–recognition properties.