Xiaobiao Dong

Aggregation-induced emission nanoparticles as photosensitizer for two-photon photodynamic therapy

Two-photon excited fluorescence microscopy and nanoparticle-assisted photodynamic therapy (PDT) are two important areas in biomedical research, and their combination can be more beneficial. A type of red emissive photosensitizer (PS) with aggregation-induced emission (AIE) features, which is called tetraphenylethylene (TPE-red), was synthesized and further encapsulated with poly(styrene-co-maleic anhydride) (PSMA) to form nanoparticles. Two-photon fluorescence, as well as two-photon excited reactive oxygen species (ROS) generation by TPE-red–PSMA nanoparticles, was characterized. A large two-photon absorption cross-section was observed at 1040 nm with a femtosecond (fs) laser. PDT via two-photon excitation was well realized on tumor cells, using TPE-red–PSMA nanoparticles as PSs under 1040 nm fs laser excitation. Based on our study, we believe that two-photon excited PDT with AIE-active PSs has great potential applications in deep tissue imaging-guided therapy.

An AIE based tetraphenylethylene derivative for highly selective and light-up sensing of fluoride ions in aqueous solution and in living cells

An AIE based tetraphenylethylene derivative (MOTIPS-TPE) with a pyridinium pendant was synthesized for light-up sensing of F− in aqueous solution without additives. The fluoride ion promoted cleavage reaction gave MOTIPS-TPE high selectivity toward F− over other common anions. Moreover, MOTIPS-TPE can be used to monitor F− in living HeLa cells.

Targeted and imaging-guided in vivo photodynamic therapy for tumors using dual-function, aggregation-induced emission nanoparticles

Imaging-guided photodynamic therapy (PDT) has been regarded as a promising strategy for precise cancer treatment. Because of their excellent modifiability and drug-loading capacity, nanoparticles have played an important role in PDT. Nonetheless, when traditional photosensitizers are made into nanoparticles, both their fluorescence and reactive oxygen species generation efficacy decrease due to a phenomenon known as aggregation-caused quenching. Fortunately, in recent years, several kinds of organic dyes with “abnormal” properties (termed aggregation-induced emission, AIE) were developed. With enhanced fluorescence emission in the nanoaggregation state, the traditional obstacles mentioned above may be overcome by AIE luminogens. Herein, we provide a better combination of photosensitizers and nanoparticles, namely, dual-function AIE nanoparticles capable of producing reactive oxygen species, to implement targeted and imaging-guided in vivo PDT. Good contrast of in vivo imaging and obvious therapeutic efficacy were observed at a low dose of AIE nanoparticles and low irradiance of light, thus resulting in negligible side effects. Our work shows that AIE nanoparticles may play a promising role in imaging-guided clinical PDT for cancer in the near future.