Dye Encapsulation in Polynorbornene Micelles

Abstract

The encapsulation efficiency of high-Tg polynorbornene micelles was probed with a hydrophobic dye 2,6-diiodo boron-dipyrromethene (BODIPY). Changes in the visible absorption spectra of aggregated versus monomeric dye molecules provided a probe for assessing encapsulation. Polynorbornene micelles are found to be capable of loading up to one BODIPY dye per ten polymers. As the hydrophilic block size increased in the polymeric amphiphiles, more of the dye was incorporated within the micelles. This result is consistent with the dye associating with the polymer backbone in the shell of the micelles. Encapsulation rate varied significantly with temperature, and a slight dependence on micellar morphology was also noted. Additionally, we report a 740 µs triplet lifetime for the encapsulated BODIPY dye. The lifetime is the longest ever recorded for a BODIPY triplet excited state at room temperature, and is attributed to hindered triplet-triplet annihilation in the high viscosity micellar shell.

Near infrared imaging-guided photodynamic therapy under an extremely low energy of light by galactose targeted amphiphilic polypeptide micelle encapsulating BODIPY-Br2

“…Synthesis of PMAGP-POEGMA-PLys (14). At room temperature, 13 (150 mg, 9.3 μmol) was stirred in 5 mL 80% formic acid for 2 days.…”

“…In particular polymeric nanostructures, due to their adaptable compositions, surface properties and sizes, have displayed efficiency in drug delivery, and imaging, even in therapeutic fields. [14][15][16][17][18][19] Natural polymers as well as synthetic polymers, such as PEG, polypeptides, polycaprolactone (PCL) and polylactic acid (PLA) have been widely used to prepare polymeric NMs for their biocompatibility and biodegradability. In many cases, they consist of a hydrophilic surface layer for their stabilization in blood circulation and a hydrophobic interior core for anticancer and imaging agents' loading, forming core-shell structures.…”

Diketopyrrolopyrrole assembly into J‐aggregates

“…More recently, sophisticated models have been developed to describe the assembly of considerably more complex supramolecular systems, such as clusters and supramolecular polymers, which consider binding events in a series to create larger architectures. Understanding and anticipating the behavior of supramolecular systems through quantitative structure‐activity relationships are now a commonplace and have led to breakthrough advances in the fields of molecular electronics, drug delivery, and energy harvesting, to name just a few, and these studies confirm that systematic structure‐activity relationships continue to be an invaluable tool for understanding even the most cutting‐edge chemical systems.…”

Encapsulation induced aggregation: a self-assembly strategy for weakly pi-stacking chromophores

“…While the importance of non-covalent interactions between chromophore and solvent molecules cannot be overstated, 10 the role of physical confinement in dye aggregation has not been adequately explored. 11 In this work, we demonstrate aggregation of weakly pi-stacking cNDIs within the hydrophobic core of a polymer micelle. Though the enthalpic gain associated with cNDI pi-stacking is poor, its physical confinement within the micellar core offers a two-fold advantage: there is a significant increase in the local concentration of the dye, along with a marked reduction in the total entropy such that even a small enthalpic gain can lead to spontaneous aggregation.…”