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Accueil du site > Equipe Nanochimie et bioimagerie > Fluorescent nanoparticles

Protein-sized nanoparticles

Mise à jour 17 janvier 2018

Figure 1. PEGylated cyanine bis-azides form a covalently attached “corona” on micelles of amphiphilic calixarene bearing alkyne groups. AFM image of CX/Cy3L micelles in water and fluorescence confocal image of HeLa cells incubated with micelles for 3 h. Green corresponds to plasma membrane staining with WGA-Alexa Fluor488 (50 nm), while red (donor channel) and magenta (FRET channel) corresponds to the micelles.

The key challenge in the field of fluorescent nanoparticles (NPs) for biological applications is to achieve superior brightness for sizes equivalent to single proteins (3–7 nm). Recently, we have developed protein-sized (7-nm) ultrabright fluorescent nanoparticles, in which PEGylated cyanine 3 and 5 bis-azides form a covalently attached corona on micelles of amphiphilic calixarene bearing four alkyne groups (Figure 1). In the ON-state, the obtained NPs are 2-fold brighter than quantum dots (QD-585), which makes them the smallest PEGylated organic NPs of this high brightness. FRET studies suggest that they are highly stable in aqueous and organic media as well as in living cells, in which they show excellent imaging contrast.

Another type of our developed small ultrabright fluorescent micelles relay on self-assembling of specially designed cationic dye amphiphiles. We showed that a non-coordinating anion, fluorinated tetraphenylborate, assembles cationic cyanine amphiphiles into 7–8 nm fluorescent nanoparticles that are 40-fold brighter than a single cyanine dye (Figure 2). They exhibited efficient FRET to a single acceptor as well as high stability.

Figure 2. Cyanine amphiphiles and their assembly into micelles in the presence of non-coordinating anions.

References

1) Shulov, I., Y. Arntz, Y. Mely, V.G. Pivovarenko and A.S. Klymchenko, Non-coordinating anions assemble cyanine amphiphiles into ultra-small fluorescent nanoparticles. Chemical Communications, 2016. 52(51) : p. 7962-7965.

2) Shulov, I., R.V. Rodik, Y. Arntz, A. Reisch, V.I. Kalchenko and A.S. Klymchenko, Protein-Sized Bright Fluorogenic Nanoparticles Based on Cross-Linked Calixarene Micelles with Cyanine Corona. Angewandte Chemie-International Edition, 2016. 55(51) : p. 15884-15888.