Highly Selective and Sensitive Ratiometric Detection of Sn²⁺ Ions Using NIR-Excited Rhodamine-B-Linked Upconversion Nanophosphors

Abstract

Detection of Sn 2+ ions in environmental and biological samples is essential owing to the toxicological risk posed by excess use tin worldwide. Herein, we have designed a nanoprobe involving upconversion nanophosphors linked with a rhodamine-based fluorophore, which is selectively sensitive to the presence of Sn 2+ ions. Upon excitation with near-infrared (NIR) light, the green emission of the nanophosphor is reabsorbed by the fluorophore with an efficiency that varies directly with the concentration of the Sn 2+ ions. We have explored this NIR-excited fluorescence resonance energy transfer (FRET) process for the quantitative and ratiometric detection of Sn 2+ ions in an aqueous phase. We have observed an excellent linear correlation between the ratiometric emission signal variation and the Sn 2+ ion concentration in the lower micromolar range. The detection limit of Sn 2+ ions observed using our FRET-based nanoprobe is about 10 times lower than that observed using other colorimetric or fluorescence-based techniques. Due to the minimal autofluorescence and great penetration depth of NIR light, this method is ideally suited for the selective and ultrasensitive detection of Sn 2+ ions in complex biological or environmental samples.

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Iron selenide nanorods for light-activated anticancer and catalytic applications

“…Since the industrial revolution, human health has been compromised by the waste generated by the textile and other industries, whose effluents pose a significant threat to the environment. 26,27 Thousands of tonnes of dye have been produced and dumped into waterways without being purified or treated. In the production process, around 15% of dyes are discharged as textile effluents.…”

Dye‐linked Upconverting Nanophosphor‐based Ratiometric Chemosensor for NIR‐excited and FRET‐mediated Ultrasensitive Detection of Sulfide Ions

“…Recently, we have demonstrated the use of a rhodaminederivative (RBD) covalently linked with polyacrylic acid coated UCNPs (UCNP@PAA) for the ultrasensitive, ratiometric detection of stannous (Sn 2 + ) ions, based on FRET between the UCNPs and the fluorescent RBD-Sn 2 + complex. [41] The UCNPs served as an energy donor by converting NIR light (wavelength of 980 nm) into visible light to excite the fluorescent probe (RBD-Sn 2 + ), which serves as an energy acceptor. In this study, we have exploited the specific and high affinity of S 2À anions towards the Sn 2 + cations and developed a chemosensor based on recovery of the FRET process as a function of the concentration of S 2À ions.…”

“…Recently, we have demonstrated the use of a rhodamine‐derivative (RBD) covalently linked with polyacrylic acid coated UCNPs (UCNP@PAA) for the ultrasensitive, ratiometric detection of stannous (Sn 2+ ) ions, based on FRET between the UCNPs and the fluorescent RBD‐Sn 2+ complex [41] . The UCNPs served as an energy donor by converting NIR light (wavelength of 980 nm) into visible light to excite the fluorescent probe (RBD‐Sn 2+ ), which serves as an energy acceptor.…”