Integration of cyanine dyes and metal ions into one nanoplatform via metal-coordination interactions is an effective strategy to build multimodality phototheranostics. The multifunctionalities of the formed nanoscale metal-organic particles (NMOPs) have been widely explored. However, the effect of metal-coordination interaction on the aggregation behavior of cyanine dyes is rarely reported. Herein, we reported the H-aggregation behavior of cyanine dye Cy-3COOH induced by different metal ions M (Fe2+ or Mn2+ ). Moreover, the extent of H-aggregates varied with different metal-coordination interactions. Upon NIR irradiation, H-aggregates of Cy-3COOH remarkably promoted photothermal conversion efficiency. Interestingly, we also find that H-aggregates of Cy-3COOH induced by metal ions can generate the reactive oxygen species (ROS) involving singlet oxygen (1 O2 ) and superoxide anion radical (O2 - ⋅) upon light irradiation. In addition, the ROS efficiency varies depending on the extent of H-aggregates. Additionally, the photoinduced ROS could disassemble aggregates and decompose cyanine dye Cy-3COOH, which limits the photothermal capability of Cy-3COOH/M NPs. Therefore, the photothermal performance of Cy-3COOH/M NPs could be manipulated by the degree of H-aggregation. This would provide a new insight to develop efficient phototheranostics NMOPs for cancer treatment.
Keywords: H-aggregates; cancer therapy; cyanine dyes; nanoscale metal-organic particles; phototherapy.
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