1 research outputs found
Chlorosome-Inspired Synthesis of Templated Metallochlorin-Lipid Nanoassemblies for Biomedical Applications
Chlorosomes
are vesicular light-harvesting organelles found in
photosynthetic green sulfur bacteria. These organisms thrive in low
photon flux environments due to the most efficient light-to-chemical
energy conversion, promoted by a protein-less assembly of chlorin
pigments. These assemblies possess collective absorption properties
and can be adapted for contrast-enhanced bioimaging applications,
where maximized light absorption in the near-infrared optical window
is desired. Here, we report a strategy for tuning light absorption
toward the near-infrared region by engineering a chlorosome-inspired
assembly of synthetic metallochlorins in a biocompatible lipid scaffold.
In a series of synthesized chlorin analogues, we discovered that lipid
conjugation, central coordination of a zinc metal into the chlorin
ring, and a 3<sup>1</sup>-methoxy substitution were critical for the
formation of dye assemblies in lipid nanovesicles. The substitutions
result in a specific optical shift, characterized by a bathochromically
shifted (72 nm) Q<sub><i>y</i></sub> absorption band, along
with an increase in absorbance and circular dichroism as the ratio
of dye-conjugated lipid was increased. These alterations in optical
spectra are indicative of the formation of delocalized excitons states
across each molecular assembly. This strategy of tuning absorption
by mimicking the structures found in photosynthetic organisms may
spur new opportunities in the development of biophotonic contrast
agents for medical applications