Self‐Assembled Dual Dye‐Doped Nanosized Micelles for High‐Contrast Up‐Conversion Bioimaging

Abstract

Sensitized triplet–triplet annihilation based photon up‐conversion (TTA‐UC) greatly improves the scope and applicability of fluorescence bioimaging by enabling anti‐Stokes detection at low powers, thus eliminating the background autofluorescence and limiting the potential damage of the living tissues. Here the authors present a facile, one‐step protocol to prepare dual dye‐doped, TTA‐UC active nanomicelles starting from the commercially available surfactant Kolliphor EL, a component of several FDA approved preparations. These nanosized micelles show an unprecedented up‐conversion yield of 6.5% under 0.1 W cm−2 excitation intensity in an aqueous, nondeaerated dispersion. The supramolecular architecture obtained preserves the embedded dyes from oxygen quenching, allowing satisfactory anti‐Stokes fluorescence imaging of 3T3 cells. This is the first example of efficient multicomponent up‐converters prepared using highly biocompatible materials approved by the international authority, paving the way for the development of new complex and multifunctional materials for advanced theranostics.

Unusual near infrared (NIR) fluorescent palladium(ii) macrocyclic complexes containing M–C bonds with bioimaging capability

“…6a, S90 and S91 †). 22 As expected, Pd-1-MSN-F127 and Pd-3-MSN-F127 display strong NIR emission centered at 717 and 771 nm in water solution, Fig. 4 Contour plot of time-resolved absorption difference spectra of (a) Pd-1 and (b) Pt-1 for time delays up to 3000 ps in the range of 600-950 nm in toluene.…”

Optimizing photon upconversion by decoupling excimer formation and triplet triplet annihilation

“…[1][2][3][4][5][6][7] The mechanism has recently been successfully incorporated in solar cells, [8][9][10][11][12][13][14] photocatalysts, [15][16][17][18] optical devices, [19][20][21][22][23][24] and light imaging. [25][26][27][28][29][30][31] It requires two functional species, a sensitizer and an annihilator. The sensitizer absorbs a photon and transfers the energy to an annihilator through triplet energy transfer.…”

“…The sensitizer absorbs a photon and transfers the energy to an annihilator through triplet energy transfer. 32 Two annihilator molecules in their triplet excited states undergo triplet-triplet annihilation 29 upon close contact, promoting one molecule to its excited singlet state from where emission of a high energy photon occurs. Perylene is among the most promising annihilator candidates due to its high stability, commercial availability, and excellent photo-physical properties.…”

Syntheses of Organic Semiconductors in Water. Recent Advancement in the Surfactants Enhanced Green Access to Polyconjugated Molecules

“…While working on a recently discovered strategy to achieve anti Stokes Shift fluorescence imaging strategy called Triplet-Triplet Annihilation Up-Conversion (TTA-UC), we faced the task of designing lipophilic pockets in a physiological environment where oxygen would not be present. [45] In a nutshell, the TTA-UC scheme is an antenna process where a Donor (frequently a platinum porphyrin) absorbs red light to reach the corresponding singlet excited state. There, thanks to a particularly efficient inter system crossing, the excited triplet state is populated.…”

“…Reproduced with permission from ref. [45] living tissues, obviously oxygen rich. The task of providing a water-based formulation containing aggregates of two different hydrophobic molecules in a precise stoichiometry and in the absence of oxygen is a complex one.…”