Water-Soluble Cationic Eu³⁺-Metallopolymer with High Quantum Yield and Sensitivity for Intracellular Temperature Sensing

Abstract

Lanthanide-based (Ln3+) luminescent materials are ideal candidates for use in fluorescence intracellular temperature sensing. However, it remains a great challenge to obtain a Ln3+-ratiometric fluorescence thermometer with high sensitivity and quantum yield in an aqueous environment. Herein, a cationic Eu3+-metallopolymer was synthesized via the coordination of Eu(TTA)3·2H2O with an AIE active amphipathic polymer backbone that contains APTMA ((3-acrylamidopropyl) trimethylammonium) and NIPAM (N-isopropylacrylamide) units, which can self-assemble into nanoparticles in water solution with APTMA and NIPAM as the hydrophilic shell. This polymer exhibited highly efficient dual-emissive white-light emission (Φ = 34.3%). Particularly, when the temperature rises, the NIPAM units will transform from hydrophilic to hydrophobic in the spherical core of the nanoparticle, while the VTPE units are moved from inside the nanoparticle to the shell, activating its nonradiative transition channel and thereby decreasing its energy transfer to Eu3+ centers, endowing the Eu3+-metallopolymer with an extremely high temperature sensing sensitivity within the physiological temperature range. Finally, the real-time monitoring of the intracellular temperature variation is further conducted.

Design of Cr–Ba-doped γ-Ga2O3 persistent luminescence nanoparticles for ratiometric temperature sensing and encryption information transfer

“…Thus, the luminescence intensity ratio (LIR) was selected to achieve ratiometric temperature sensing. LIR thermometry was obtained with the relationship between ln(LIR) values and temperature with eqn (6): 45–47 where A is constant, B is the slope, and T is the absolute temperature. The linear fitting results showed that A is −8.111 and B is 0.034 with a correlation coefficient R 2 of 0.995, as shown in Fig.…”

“…Thus, the luminescence intensity ratio (LIR) was selected to achieve ratiometric temperature sensing. LIR thermometry was obtained with the relationship between ln(LIR) values and temperature with eqn (6): [45][46][47] lnðLIRÞ ¼ ln…”

Swallowed Embedding of Nanopetal-Rich Microflowers in Flexible Photocatalytic and Thermoresponsive Functional Composite Fibers

“…Materials with Er-doping have become the main choice for optical temperature sensing by FIR technology, which benefits from the transition luminescence corresponding to the thermal coupling levels 2 H 11/2 and 4 S 3/2 of Er 3+ , and high intensity of a green thermal fluorescence signal captured easily by detection. − Here, based on the FIR analysis, the best sample of BOB-E 0.25 Y 0.25 MFs is excited at 977 nm. The spectra of UC luminescence in the temperature range from 303 to 433 K with an interval of 10 K are shown in Figure a,b.…”

Application of AIEgens in Temperature Detection

“…Poly­( N -isopropylacrylamide) ( PNIPAM ) has attracted wide attention due to its extremely temperature-sensitive conformation, clear temperature response mechanism, and adjustable LCST close to human body temperature and is often used to design thermosensitive AIEgen-grafted polymers. − Tang et al synthesized PNIPAM-TPE copolymers (Probe 13) by grafting the AIE fluorophore TPE to PINPAM and precisely adjusted the LCST by changing the content of TPE. , The copolymers doped with 0.1% to 2% TPE emit weakly in good solvents at low temperature , but agglomerate and shrink under the thermal stimulation, thus emitting strong fluorescence due to the restricted intramolecular motion (Figure A). In another example, a polymer thermometer of P­(NIPAM- co -EM) (Probe 14) was constructed by grafting the quinoline-malononitrile ( QM ) derivative into the side chain of PINPAM …”