Deciphering Multiple Critical Parameters of Polymeric Self-Assembly by Fluorescence Spectroscopy of a Single Molecular Rotor BODIPY-C12

Abstract

Comprehensive characterization of self-assembled materials is crucial for plethora of different applications, however, remains tedious multi-instrument process. To tackle this issue, fluorescence properties of a boron-dipyrromethene derivative containing lipophilic tail (BODIPY-C12) were employed to extensively characterize two self-assembling polymers (Pluronics P123 and F127). We demonstrate that at least five different parameters, i.e. critical micelle concentration, critical micelle temperature, internal microviscosity within the micelles, micelle core glass transition temperature, and the sol-gel transition temperature are possible to obtain by means of steady-state and time-resolved fluorescence spectroscopy utilizing a single BODIPY-C12 sensor. This represents a unified methodology for multiparameter characterization of supramolecular polymeric structures and their self-assembly processes. The approach is a compelling non-destructive alternative to the conventional use of several different techniques for the same analytical purposes.

Unravelling a Novel Sol-Gel Transition Mechanism in Polymer Self-Assemblies: An Order-Order Transition Based on Specific Molecular Interactions Between Hydrophilic and Hydrophobic Polymer Blocks

“…An indirect method to determine (macro)molecular mobility and polymer self-assembly is the use of viscosity sensitive fluorescent probes, namely molecular rotors such as 4,4´-difluoro-4-bora-3a,4adiaza-s-indacene meso-substituted with para-dodecylphenyl, BODIPY-C12 (BPC12) and 2-(4dimethylamino)styryl)-1-methylpyridinium iodide, Daspmi (Figure S2). 31 The fluorescence lifetime of a molecular rotor is affected by a rotation ability of its structural segments with respect to each other, which is strongly dependent on the immediate molecular environment. However, it has to be kept in mind that it is not always clear what this immediate molecular environment is in the presence of selfassembled species.…”

Unravelling a novel mechanism in polymer self-assemblies: An order-order transition based on molecular interactions between hydrophilic and hydrophobic polymer blocks

“…Viscosity sensitive fluorescent probes, namely molecular rotors such as 4,4´-difluoro-4bora-3a,4a-diaza-s-indacene meso-substituted with para-dodecylphenyl, BODIPY-C12 (BPC12) and 2-(4-(dimethylamino)styryl)-1-methylpyridinium iodide, Daspmi have been used in this context. 26 The fluorescence lifetime of a molecular rotor is affected by the ability to rotate its structural segments with respect to each other, which in turn is strongly dependent on the immediate molecular environment. However, it has to be kept in mind that it is not always clear what this immediate molecular environment is.…”

Phototoxicity of BODIPY in long-term imaging can be reduced by intramolecular motion

“…The probability of IMR strongly depends on the micro-environment of the dye (e.g., solvent viscosity and polarity [7]). Consequently, BODIPY-based molecular rotors are an excellent choice for measuring intracellular temperature [8] and viscosity [9][10][11][12], for the characterization of a polymer selfassembly [13], as apoptosis markers [14] and as selective ion [15] or gas [16] sensors.…”