New Chemistry of Making Porphyrin-based Nanostructures

点击翻译按钮获取中文摘要

Porphyrins are the endogenous chromophores of nature such as hemes in red blood cells and chlorophylls in green plants. Porphyrins and porphyrin-like molecules are well known for their applications in energy (as dye-sensitized solar cells) and in medicine (as photodynamic therapy agents and fluorescent probes) but rarely investigated for its potential for its nanoscale properties until now. Supported by the previous NSERC discovery grant, my lab discovered ‘porphysomes’, the first all-organic nanoparticles with intrinsic multimodal photonic properties (Nature Materials 2011), hailed as “one particle to rule them all” (Nature Methods 2011) and named as one of the “Top Ten Cancer Breakthroughs in 2011” by the Canadian Cancer Society. The discovery of porphysome not only turned one of nature’s most fascinating molecules, porphyrins, into photonic nanomaterials but also shifted the simple nanoscaffold support role of lipids in supramolecular structures to an intrinsic multimodal platform, which subsequently opened the door for the grand exploration of different porphyrin nanostructures based on the intrinsic multimodal porphyrin building blocks. Since its inception, this concept has already been extended to other theranostic platforms including porphyrin polymers, micelles, liposomes, cerasome, and other hybrid nanoparticle. The long term goal of my research program is to study and develop new porphyrin nanochemistry by learning how porphyrins form supramolecular structures and how they function in nature (e.g., light harvesting bacteria) and adapting these nature’s lesson into building new porphyrin nanomaterials with different sizes, shapes and functions, which could have broad applications in both energy and medicine. The short term goals are to explore three directions that could lead to entirely new porphyrin-lipid nanostructures. These are: 1) to understand the fundamental chemistry of porphyrin supramolecular assembly by creating a library of porphyrin-lipid building blocks varying in porphyrins (e.g., expanded porphyrins, porphyrin analogs, their metal-chelation, etc.), lipids (e.g., cationic, with different side chain length, w/o spacers, etc.) and porphyrin/lipid ratios; 2) to create a new mechanism of ‘stimuli-driven light transmission’ using novel phase change porphyrin nanostructures by learning from nature’s ordered dye aggregates; 3) to study the chemistry of micro-to-nano conversion by using ultrasound-triggered transformation of porphyrin shell microbubbles into porphyrin nanoparticles. I believe the proposed fundamental studies will lead to exponential growth of porphyrin nanomaterials with versatile utilities and will also help to maintain the world leadership position of this new exciting nanotechnology field, for which we pioneered.