Nontemplated Approach to Tuning the Spectral Properties of Cyanine-Based Fluorescent NanoGUMBOS

Abstract

Template free controlled aggregation and spectral properties in fluorescent organic nanoparticles (FONs) is highly desirable for various applications. Herein, we report a non-templated method for controlling the aggregation in NIR cyanine-based nanoparticles derived from a Group of Uniform Materials Based on Organic salts (GUMBOS). The cationic heptamethine cyanine dye, 1,1′,3,3,3′,3′-hexamethylindotricarbocyanine (HMT), was coupled with five different anions viz. [NTf2−], [BETI−], [TFPB], [AOT−] and [TFP4B] by ion exchange method to obtain the respective GUMBOS. The nanoGUMBOS obtained via a reprecipitation method were primarily amorphous and spherical (30-100 nm) as suggested by selected area electron diffraction (SAED) and transmission electron micrographs (TEM). The formation of tunable self-assemblies within the nanoGUMBOS was characterized using absorption and fluorescence spectroscopy, in conjunction with molecular dynamic simulations. Counterion controlled spectral properties observed in the nanoGUMBOS were attributed to variations in J/H ratios with different anions. Association with the anion [AOT−] afforded predominant J-aggregation enabling highest fluorescence intensity, while [TFP4B−] disabled the fluorescence due to predominant H-aggregation in the nanoparticles. Analyses of the stacking angle of the cations based on molecular dynamic simulation results in [HMT][NTf2], [HMT][BETI] and [HMT][AOT] dispersed in water and visual analysis of representative simulation snapshots also imply that the type of aggregation was controlled through the counterion associated with the dye cation.

Irradiation Induced Fluorescence Enhancement in PEGylated Cyanine-Based NIR Nano- and Mesoscale GUMBOS

“…One involves encapsulation of organic molecules in nanocomposite particles; 9 the other uses a reprecipitation method to prepare nanoparticles employing water-insoluble dyes. 20, 21 …”

Sodium Deoxycholate Hydrogels: Effects of Modifications on Gelation, Drug Release, and Nanotemplating

“…nanoGUMBOS, have previously been formed by use of a variety of methods. 24,25,26 GUMBOS is a class of materials with an ever increasing number of applications 27 including optical electronics, 21-30 biological imaging, 24 solar cell sensitizing, 31 cancer targeting, 21,32 antibacterial, 33 and molecular weight sensing functions. 34,35 GUMBOS are solid phase materials with tunable properties similar to ionic liquids, including a broad range of applicabilities.…”

Molecular modelling of ionic liquids in the ordered mesoporous carbon CMK-5

“…carbon nanotubes, templated mesoporous silicas, anodic alumina membranes) is one step in the synthesis of optically active (fluorescent) and magnetic nanomaterials based on ILs. [21][22][23][24][25][26][27] These nanomaterials (dubbed 'GUMBOS' , for Group of Uniform Materials Based on Organic Salts) have the highly tunable properties of ILs and can be prepared via simple procedures, and thus have potential applications in optoelectronics, photovoltaics, separations, analytical chemistry and biomedicine. Furthermore, ILs confined inside sol-gels (ionogels) have potential applications as electrolyte membranes and in optics, catalysis and biocatalysis, drug delivery and sensing and biosensing.…”