TY - JOUR

T1 - Polymeric nanoparticles with embedded Eu(III) complexes as molecular probes for temperature sensing

AU - Kuznetsov , Kirill M.

AU - Baigildin, Vadim A.

AU - Solomatina, Anastasia I.

AU - Galenko, Ekaterina E.

AU - Khlebnikov, Alexander F.

AU - Sokolov , Victor V.

AU - Tunik , Sergey P.

AU - Shakirova, Julia R.

PY - 2022/12/12

Y1 - 2022/12/12

N2 - Three novel luminescent Eu(III) complexes, Eu1–Eu3, have been synthesized and characterized with CHN analysis, mass-spectrometry and 1H NMR spectroscopy. The complexes display strong emission in dichloromethane solution upon excitation at 405 and 800 nm with a quantum yield from 18.3 to 31.6%, excited-state lifetimes in the range of 243–1016 ms at 20 °C, and lifetime temperature sensitivity of 0.9%/K (Eu1), 1.9%/K (Eu2), and 1.7%/K (Eu3). The chromophores were embedded into biocompatible latex nanoparticles (NPs_Eu1–NPs_Eu3) that prevented emission quenching and kept the photophysical characteristics of emitters unchanged with the highest temperature sensitivity of 1.3%/K (NPs_Eu2). For this probe cytotoxicity, internalization dynamics and localization in CHO-K1 cells were studied together with lifetime vs. temperature calibration in aqueous solution, phosphate buffer, and in a mixture of growth media and fetal bovine serum. The obtained data were then averaged to give the calibration curve, which was further used for temperature estimation in biological samples. The probe was stable in physiological media and displayed good reproducibility in cycling experiments between 20 and 40 °C. PLIM experiments with thermostated CHO-K1 cells incubated with NPs_Eu2 indicated that the probe could be used for temperature estimation in cells including the assessment of temperature variations upon chemical shock (sample treatment with mitochondrial uncoupling reagent).

AB - Three novel luminescent Eu(III) complexes, Eu1–Eu3, have been synthesized and characterized with CHN analysis, mass-spectrometry and 1H NMR spectroscopy. The complexes display strong emission in dichloromethane solution upon excitation at 405 and 800 nm with a quantum yield from 18.3 to 31.6%, excited-state lifetimes in the range of 243–1016 ms at 20 °C, and lifetime temperature sensitivity of 0.9%/K (Eu1), 1.9%/K (Eu2), and 1.7%/K (Eu3). The chromophores were embedded into biocompatible latex nanoparticles (NPs_Eu1–NPs_Eu3) that prevented emission quenching and kept the photophysical characteristics of emitters unchanged with the highest temperature sensitivity of 1.3%/K (NPs_Eu2). For this probe cytotoxicity, internalization dynamics and localization in CHO-K1 cells were studied together with lifetime vs. temperature calibration in aqueous solution, phosphate buffer, and in a mixture of growth media and fetal bovine serum. The obtained data were then averaged to give the calibration curve, which was further used for temperature estimation in biological samples. The probe was stable in physiological media and displayed good reproducibility in cycling experiments between 20 and 40 °C. PLIM experiments with thermostated CHO-K1 cells incubated with NPs_Eu2 indicated that the probe could be used for temperature estimation in cells including the assessment of temperature variations upon chemical shock (sample treatment with mitochondrial uncoupling reagent).

KW - luminescent europium complexes

KW - lifetime temperature sensitivity

KW - latex nanospecies

KW - phosphorescence lifetime imaging

KW - intracellular localization

KW - cell thermometry

UR - https://www.mdpi.com/1420-3049/27/24/8813

UR - https://pubmed.ncbi.nlm.nih.gov/36557943/

U2 - 10.3390/molecules27248813

DO - 10.3390/molecules27248813

M3 - Article

VL - 27

JO - Molecules

JF - Molecules

SN - 1420-3049

IS - 24

M1 - 8813

ER -