High-brightness Fluorophores by Dye-Filled Boron Nitride Nanotubes

Organic dyes have found applications in life sciences because of their cost efficiency and biocompatibility. We recently demonstrated that boron nitride nanotubes (BNNTs) can be used as the nano-carriers of organic dyes to formulate high-brightness fluorophores (HBFs) for flow cytometry applications [1-5]. We showed that the electrically insulating and optically transparent BNNTs are the ideal carriers to retain the quantum yield (Φ) of the organic dyes while allowing us to systematically scale the molar extinction coefficient (ε) by two to three orders of magnitudes. Our approach led to the formation of HBFs with fluorescent brightness up to 1000X brighter than individual organic dye molecules.

Recently it has been found that organic dyes can be passivated and can be made photostable when encapsulated inside carbon or boron nitride nanotubes [6]. Unfortunately, the quantum yield of the fluorophores is very low. Herein we demonstrate the encapsulation of Rhodamine B dye inside boron nitride nanotubes (RhB@BNNTs). The RhB@BNNTs are spectroscopically characterized for their photoemission intensity. Additionally, photobleaching experiments were conducted to demonstrate the encapsulated dye's long-term photostability. We will discuss the formulation of our HBFs, and their photophysical properties in the meeting.

[1]. Y.K. Yap, D. Zhang, N.B. Yapici, US Patent App. 20180296705A1 (2018).

[2]. Y.K. Yap, in CYTO 2019, 34th Congress of the International Society for Advancement of Cytometry, Vancouver, Canada, Late-Breaking Posterpaper B386, June 22–26 (2019).

[3]. (Invited) N.B. Yapici, R. Oakley, X. Liu, D. Zhang, Y. K. Yap, In 2020 Virtual MRS Fall Meeting, Symposium F.NM03: Nanotubes, Graphene and Related Nanostructures, paper F.NM03.04.02, 2020.

[4]. (Invited) D. Zhang, S. Zhang, N. Yapici, R. Oakley, S. Sharma, V. Parashar, Y.K. Yap, ACS Omega 6(32), 20722 (2021).

[5]. (Invited) D. Zhang, N. Yapici, R. Oakley, and Y. K. Yap, J. Mater. Res. 37, 4605-4619 (2022).

[6]. C. Allard, L. Schué, F. Fossard, G. Recher, R. Nascimento, E. Flahaut, A. Loiseau, P. Desjardins, R. Martel and E. Gaufrès, Adv. Mater. 32(29), 2001429 (2020).