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Published on: September 17, 2013
Liposome-Based Nanoencapsulation of a Mitochondria-Stapling Photosensitizer for Efficient Photodynamic Therapy
Mingyu Tian1, Wenlong Chen1, Yingnan Wu2
1State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, People's Republic of China.
Abstract:
Mitochondria-targeting photodynamic therapy (PDT) can block mitochondrial function and trigger the inherent proapoptotic cascade signal of mitochondria, which has been considered to have the potential to amplify the efficiency of PDT. However, the dynamic change of mitochondrial membrane potential (MMP) makes most cationic photosensitizers easily fall off from the mitochondria, which greatly limits the efficiency of PDT. Here, we have developed a smart liposome encapsulation method based on a mitochondria-stapling photosensitizer for efficient theranostic photodynamic therapy. The stapling photosensitizer can be covalently bound inside mitochondria via two reaction sites without a falloff effect, regardless of the change of MMP. As a result, the liposome-based nanophotosensitizer showed a high efficiency of PDT (IC50 = 0.98 μM) under 630 nm light. At the same time, the nanophotosensitizer had fluorescence imaging-guided ability to monitor abnormal mitochondrial morphology during PDT. Importantly, the results of mice experiments also showed that the liposome-based nanophotosensitizer possessed excellent antitumor PDT activity because the released photosensitizer can stay inside mitochondria during the whole process of PDT.
Insights
Researchers developed a novel photosensitizer that securely binds to mitochondria, overcoming detachment issues. This innovation enhances photodynamic therapy (PDT) efficiency and enables fluorescence imaging for cancer treatment monitoring.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Photodynamic Therapy
Background:
- Mitochondria-targeting photodynamic therapy (PDT) shows promise for cancer treatment by disrupting mitochondrial function and inducing apoptosis.
- A key challenge in mitochondria-targeted PDT is the detachment of cationic photosensitizers due to dynamic changes in mitochondrial membrane potential (MMP), limiting therapeutic efficacy.
- Efficient delivery and retention of photosensitizers within mitochondria are crucial for amplifying PDT effectiveness.
Purpose of the Study:
- To develop a novel photosensitizer delivery system that overcomes the limitations of photosensitizer detachment from mitochondria during PDT.
- To create a mitochondria-stapling photosensitizer encapsulated in liposomes for enhanced theranostic photodynamic therapy.
- To evaluate the efficiency, retention, and antitumor activity of the developed nanophotosensitizer.
Main Methods:
- Development of a mitochondria-stapling photosensitizer capable of covalent binding within mitochondria via two reaction sites.
- Encapsulation of the photosensitizer into a smart liposome system for targeted delivery.
- Evaluation of PDT efficacy (IC50), fluorescence imaging capabilities, and in vivo antitumor activity in mice.
Main Results:
- The liposome-based nanophotosensitizer demonstrated high PDT efficiency with an IC50 of 0.98 μM under 630 nm light.
- The stapling photosensitizer exhibited a 'no falloff' effect, remaining covalently bound to mitochondria irrespective of MMP fluctuations.
- The nanophotosensitizer facilitated fluorescence imaging for monitoring mitochondrial morphology changes during PDT and showed excellent in vivo antitumor activity.
Conclusions:
- The developed liposome-based nanophotosensitizer effectively addresses the challenge of photosensitizer detachment, significantly improving mitochondria-targeted PDT.
- The 'no falloff' characteristic ensures sustained photosensitizer presence within mitochondria, enhancing therapeutic outcomes.
- This theranostic approach offers a promising strategy for efficient cancer treatment with integrated imaging guidance.
