Plug-and-Play Optical Materials from Fluorescent Dyes and Macrocycles

Abstract

Optical materials are needed for various applications that emit light. Highly emissive dyes are expected to be widespread in materials creation but they display emission quenching in the solid state. Flood, Laursen, and colleagues discovered the first universal solution to this 150-year-old problem. They report a class of fluorescent materials and the design rules that allow cationic dyes to be plugged into an ionic lattice to reinstate their bright emission.

Ultrabright Fluorescent Organic Nanoparticles Based on Small‐Molecule Ionic Isolation Lattices**

“…These dyes included cyanines, oxazines, trianguleniums, and rhodamines. All of them provided predictable spectral properties, highly improved fluorescence quantum yields, and high densities of dyes (one dye per ≈4 nm 3 ) leading to very high normalized brightness per volume (>7000 M −1 cm −1 / nm 3 ) surpassing all other organic dye‐based fluorescent materials [5, 17] …”

Fluorophore Multimerization as an Efficient Approach towards Bright Protein Labels

“…In late 2020, Benson et al reported fluorescent materials consisting of cationic fluorescent dyes and anion-binding cyanstar macrocycles that serve as isolation lattices to prevent dye quenching (Figure 7). [127] These small-molecule ionic isolation lattices (SMILES) are capable of packing the fluorophores within close proximity while maintaining great proportions of their fluorescence quantum yields, as it was shown for different fluorophore classes. When using Rhodamine 3B, the authors were able to obtain SMILES exhibiting unprecedented brightness up to 7,000 M À 1 cm À 1 /nm 3[127] making SMILES one of the brightest fluorescent materials reported until now.…”

Ultrabright Fluorescent Organic Nanoparticles Based on Small‐Molecule Ionic Isolation Lattices**

“…Thec ontinuous increase in fluorescence quantum yield beyond 2equivalents of cyanostar was assigned to the positive impact of the excess macrocycle on the passivation of defects that quench the fluorescence.S uch defects are accessible by energy migration within the densely packed SMILES NPs. [17,20] However,t he volume-normalized brightness of SMILES NPs levels off beyond 2.5 molar 3b and Table S3). This is asubstantial increase in performance relative to value seen in the particles of R12 alone ( % 800 M À1 cm À1 /n m 3 )s imply by adding cyanostars.O na ccount of the optimal brightness of NPs seen with 2.5 equivalents of the cyanostar, we used this ratio in all subsequent NP preparations and for the bioimaging (see below).…”