PEGylated liposomal photosensitizers as theranostic agents for dual-modal photoacoustic and fluorescence imaging-guided photodynamic therapy

The photosensitizer (PS) as photodynamic therapy (PDT) agent, can also serve as the contrast agent for dual-modal fluorescence imaging (FLI) and photoacoustic imaging (PAI) for precise cancer theranostics. In this study, the PAI capability of commercial PS, benzoporphyrin derivative monoacid ring-A (BPD) were examined and compared with that from the other PSs and dyes such as TPPS4, Cy5 dye and ICG. We discovered that BPD exhibited its advantage as contrast agent for PAI. Meanwhile, BPD can also serve as the contrast agent for enhanced FLI. In particular, the PEGylated nanoliposome (PNL) encapsulated BPD (LBPD) was produced for contrast enhanced dual-modal FLI and PAI and imaging-guided high-efficiency PDT. Enhanced FLI and PAI results demonstrated the signifficant accumulation of LBPD both within and among individual tumor during 24 h monitoring for in vivo experiment tests. In-vitro and in-vivo PDT tests were also performed, which showed that LBPD have higher PDT efficiency and can easily break the blood vessel of tumor tissues as compared to that from BPD. It was discovered that LBPD has great potentials as a diagnosis and treatment agent for dual-modal FLI and PAI-guided PDT of cancer.