Stable J-Aggregation of an aza-BODIPY-Lipid in a Liposome for Optical Cancer Imaging

Significance 

The onset of nanotechnology has been of great benefit to the medical field. Lipid nanoparticles have been used as delivery carriers for drugs and imaging agents owing to their excellent biological properties. Phospholipids are the key building blocks for the success of liposomes in drug delivery applications. Unfortunately, the transformation of liposomes from singular drug delivery vehicles into multimodal nanoplatforms has focused on the “all-in-one” approach which poses a great challenge in the clinical translation. To address those hurdles in clinical translation Dr. Zheng’s lab focuses on the “one-for-all” approach, in which a single nanoparticle building block exhibits multifunctionality upon self-assembly into nanoparticles. As such, aza-boron dipyrromethenes (aza-BODIPYs), a class of near-infrared fluorophores that have attracted significant interest in cancer imaging, were being investigated by the group.

Nanotechnology has been envisioned as an effective tool for resolving the systemic delivery issues of aza-BODIPYs to the tumor site and have instigated the development of new aza-BODIPY nanoparticles for optical imaging applications. Scientists from University of Toronto: Dr. Miffy Cheng, Dr. Kara Harmatys, Danielle Charron, and Dr. Juan Chen, led by Professor Gang Zheng, reported the synthesis of a new aza-BODIPY-lipid building block and its self-assembly into liposome nanoparticles. Specifically, the optical stability of J-aggregated aza-BODIPY-lipid in liposomes was investigated and its feasibility in in vivo applications was also demonstrated. This work can be found in the article Stable J-Aggregation of an aza-BODIPY-Lipid in a Liposome for Optical Cancer Imaging” published in the journal, Angewandte Chemie.

The BODIPYsome is a highly biocompatible nanocarrier exhibiting both optical and colloidal stability. The optical stability of the BODIPYsome was attributed to J-dimerization within the nanostructure, offering unique near-infrared photo-properties in both absorption and fluorescence. BODIPYsomes with cholesterol maintained a relatively high extinction coefficient and high fluorescence quenching with good colloidal stability. This showed the effectiveness of the BODIPYsome, when used in its intact form, as a photoacoustic agent, while the disrupted nanostructure showed excellent near-infrared fluorescence in properties for both in vitro and in vivo applications. The BODIPYsome in healthy mice showed a long blood circulation half-life of 10.56 hours with excellent biocompatibility that was validated from its acute toxicity studies.

Overall, the study demonstrated successful synthesis of a novel aza-BODIPY-lipid building block and its self-assembly into BODIPYsome nanostructures with stable J-aggregation. Based on the results showcasing the interesting properties of the optical imaging agents, Professor Gang Zheng, in a statement to Medicine Innovates, observed that the novelty of the BODIPYsome will pave way for the development of new building blocks for effective design of optically stable biophotonic imaging agents.

Stable J-Aggregation of an aza-BODIPY-Lipid in a Liposome for Optical Cancer Imaging - Medicine Innovates

 

About the author

Miffy Hok Yan Cheng received her B.Sc. (Hons) in Chemistry with Molecular Medicine in 2014, she completed her Ph.D. with Prof Ross Boyle in Biological Organic Chemistry in 2018 with both degree from University of Hull, UK. Her research topic during her PhD studies included the development of near infrared fluorescence probe and the bioconjugation to targeting moieties such as antibodies and peptides. Subsequently after her PhD, she began her postdoctoral fellow position in Princess Margaret Cancer Centre with Prof Gang Zheng and now her research focuses on the synthesis and development of organic building blocks to expand the purview of the porphysome nanotechnologies and the investigation of their application in cancer imaging.

Reference

Cheng, M., Harmatys, K., Charron, D., Chen, J., & Zheng, G. (2019). Stable J-Aggregation of an aza-BODIPY-Lipid in a Liposome for Optical Cancer Imaging. Angewandte Chemie, 131(38), 13528-13533.

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