Amplified Singlet Oxygen Generation in Semiconductor Polymer Dots for Photodynamic Cancer Therapy

Abstract

This paper described the energy-transfer amplified singlet oxygen generation in semiconductor polymer dots (Pdots) for in vitro and in vivo photodynamic therapy. Hydrophobic photosensitizer tetraphenylporphyrin was facilely doped in the nanoparticles consisting of densely packed semiconductor polymers. Optical characterizations indicated that the fluorescence of Pdots was completely quenched by the photosensitizer, yielding an energy transfer efficiency of nearly 100% and singlet-oxygen generation quantum yield of ∼50%. We evaluated the cellular uptake, dark toxicity, and photodynamic therapy of the Pdot photosensizer in human gastric adenocarcinoma cells. The in vitro studies indicated that cancer cells were efficiently destroyed at very low dose of the Pdots such as 1 μg/mL by using the light dose of 90 J/cm(2), which is considerably less than that in clinical practice. The antitumor effect of the Pdots was further evaluated in vivo with human gastric adenocarcinoma xenografts in Balb/c nude mice, which show that the xenograft tumors were significantly inhibited and eradicated in some cases. Our results indicate the energy transfer amplified Pdot platforms have great therapeutic potential for treating malignant cancers.

Recent Advances in the Development of Highly Luminescent Semiconducting Polymer Dots and Nanoparticles for Biological Imaging and Medicine

“…83,84 Here, tetraphenylporphyrin (TPP) was doped in or conjugated to PFBT Pdots. In their latter work, the TPP monomers were covalently incorporated into the PFBT π -conjugated backbone to form PFBT-TPP Pdots.…”

Polymer Dots as Effective Phototheranostic Agents

“…Phototheranostic applications have attracted worldwide attention in recent years, because they can realize precise and efficient treatment through combining various optical imaging techniques with light-triggered diagnostic therapy (99)(100)(101). Recently, more and more theranostic nanoplatforms based on Pdots were developed as multifunctional imaging and therapy agents for cancer treatment (54,86,(102)(103)(104)(105). Notably, these theranostic nanoplatforms are usually fabricated by encapsulating or conjugating both therapeutic and imaging moieties together to enable simultaneous multimodel imaging and therapy.…”

Therapeutic Considerations and Conjugated Polymer‐Based Photosensitizers for Photodynamic Therapy

“…The hydrophobicity of both the polymer and the photosensitizer can produce densely packed polymer nanoparticles and thus the close proximity of donor–acceptor can greatly facilitate the energy transfer from the conjugated polymer to the photosensitizer. The energy transfer amplified singlet oxygen generation in conjugated polymer nanoparticles can potentially reduce the photosensitizer dosing for a given light dosage, and simultaneously overcome the solubility issue of most hydrophobic photosensitizers . When the size of conjugated polymer nanoparticles are small than 20–30 nm, they are generally called polymer dots (Pdots) .…”

“…Especially, the development of nanoparticles as new type of photosensitizers has brought enormous opportunities for photodynamic therapy . Examples of nanoparticle photosensitizers include inorganic quantum dots, carbon dots, upconversion nanoparticles, organic nanoparticles such as aggregation‐induced emission nanoparticles, and conjugated polymer nanoparticles …”