IR Luminescence of Polyfunctional Associates of Indocyanine Green and Ag 2 S Quantum Dots
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ANOPHOTONICS
IR Luminescence of Polyfunctional Associates of Indocyanine Green and Ag2S Quantum Dots1 T. S. Kondratenkoa, *, M. S. Smirnova, O. V. Ovchinnikova, I. G. Grevtsevaa, and A. N. Latysheva a Voronezh
State University, Voronezh, 36018 Russia * е-mail: [email protected]
Received January 18, 2020; revised January 18, 2020; accepted April 20, 2020
Abstract—In this work, manifestations of IR luminescence sensitization of Indocyanine Green during conjugation with colloidal Ag2S quantum dots with an average size of 2.2 and 3.7 nm, passivated with thioglycolic acid molecules (Ag2S/TGA QDs) are studied using absorption and luminescence techniques. The possibility of enhancing luminescence in the dye monomer band (820 nm) under excitation at 660 nm by a factor of 6 in the presence of Ag2S/TGA QDs (2.2 nm) due to a decrease in the polymethine dye chain movement via coordination interaction with QDs was demonstrated. The way to switch-over from the first therapeutic window of biological tissue transparency (NIR-I, 700–950 nm) to the second (NIR-II, 1000–1700 nm), based on sensitization of IR luminescence of Ag2S/TGA QDs with an average size of 3.7 nm in the region of 1040 nm due to of resonance non-radiative transfer of excitation energy from Ag2S/TGA (2.2 nm) QDs at 900 nm to Ag2S/TGA QDs (3.7 nm) via the J-aggregate of ICG dye, which acts as an exciton bridge. Keywords: J-aggregate, non-radiative decay, exciton absorption DOI: 10.1134/S0030400X20080172
INTRODUCTION The development of stable multifunctional complexes that provide the direction and localization of active and luminescent agents in vivo is an important problem for the oncological pathologies theranostics. Today, Indocyanine Green (ICG) is tricarbocyanine dye pharmaceutical excipients approved for use in many countries [1, 2]. The advantage of this dye is its ability to produce singlet oxygen, which is provided by the presence of triplet states suitable for the implementation of this process and triplets effective of 0.1– 0.2. Most of the work devoted to ICG photonics is associated with the spectral luminescent properties of ICG in water, ethanol, DMSO, etc. [3–16]. To date, it has been established that ICG belongs to the tricarbocyanine dyes. Its monomeric form absorbs in the region of 800 nm. It has fluorescence with the Stokes shift of 20 nm and luminescence quantum yield of about 10% [3–14]. This dye is capable of the nonluminescent dimers formation in aqueous solution even at low concentrations [3–14]. It was also found that ICG demonstrates irreversible photodegradation during IR fluorescence during imaging and sensitization of singlet oxygen production process of [8–11, 15, 16]. The movement of molecular structure, especially 1 The 2nd International School-Conference for young researchers
“Smart Nanosystems for Life,” St. Petersburg, Russia, December 10–13, 2019.
polymethine chain also contributes to the low quantum yield of ICG luminescence and limit its ability for fluorescence imaging in vitro and in vivo. Encapsulation using th
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