NanoTandems for Complex Diagnostic Assays

In AcZon NanoTandems, the silica matrix hosts up to six species of fluorescent dye which act as a chain of donors and acceptors exploiting FRET phenomenon.

AcZon NanoTandems were designed to overcome the well-known drawbacks of conventional tandem dyes in flow cytometry as exhaustively depicted by Jensen and his colleagues in their work published in 2020 and previously by Morawski in 2019, Johansson in 2014 and Le Roy in the far 2009.

On par with conventional tandem dyes, AcZon NanoTandems are activated through Förster resonance energy transfer (FRET). In the silica core of NanoTandems are covalently bound up to six different dyes acting among them as donor and acceptor. The laser beam hits the first dye (donor) of the chain which emits energy to excite the following one (acceptor) as represented in the figure below. The presence of the protective shield prevents the dye degradation, resulting in the signal increase but moreover, in the prolonged stability of the reagent avoiding repeated instrument resetting and unfriendly leftovers.

Whole blood samples from healthy donors, were stained with Mouse anti Human CD4 (EDU-2; IgG2a) labelled with different dyes. Alexa Fluor® fluorescent dyes are a trademark of Life Technologies Corp.

The inclusion of different kinds of dyes in different, optimized, proportions, allows for a unique fluorescent fingerprint which ensures important advantages in spectral cytometry where the whole spectrum is the key parameter for antigen discrimination.

• Robinson JP. Flow cytometry: past and future. Biotechniques. 2022 Apr;72(4):159-169.
• Jensen IJ, McGonagill PW, Lefebvre MN, Griffith TS, Harty JT, Badovinac VP. Worry and FRET: ROS Production Leads to Fluorochrome Tandem Degradation and impairs Interpretation of Flow Cytometric Results. Immunity. 2020 Mar 17;52(3):419-421.
• Morawski PA, Motley SJ, Campbell DJ. Rapid Light-Dependent Degradation of Fluorescent Dyes in Formulated Serum-Free Media. Immunohorizons. 2019 Dec 16;3(12):585-592.
• Johansson U, Macey M. Tandem dyes: Stability in cocktails and compensation considerations. Cytometry B Clin Cytom. 2014 May;86(3):164-74.
• Le Roy C, Varin-Blank N, Ajchenbaum-Cymbalista F, Letestu R. Flow cytometry APC-tandem dyes are degraded through a cell-dependent mechanism. Cytometry A. 2009 Oct;75(10):882-90.