BSA–AuNPs@Tb–AMP metal–organic frameworks for ratiometric fluorescence detection of DPA and Hg²⁺

Abstract

An easy and effective strategy for synthesizing a ratiometric fluorescent nanosensor has been demonstrated in this work. Novel fluorescent BSA-AuNPs@Tb-AMP (BSA, bovine serum albumin; AMP, adenosine 5'-monophosphate; AuNPs, Au nanoparticles) metal-organic framework (MOF) nanostructures were synthesized by encapsulating BSA-AuNPs into Tb-AMP MOFs for the detection of 2,6-pyridinedicarboxylic acid (DPA) and Hg . DPA could strongly co-ordinate with Tb to replace water molecules from the Tb center and accordingly enhanced the fluorescence of Tb-AMP MOFs. The fluorescence of BSA-AuNPs at 405 nm remained constant. While the fluorescence of BSA-AuNPs at 635 nm was quenched after Hg was added, the fluorescence of Tb-AMP MOFs remained constant. Accordingly, a ratiometric fluorescence nanosensor was constructed for detection of DPA and Hg . The ratiometric nanosensor exhibited good selectivity to DPA over other substances. The F /F linearly increased with increase of DPA concentration in the range of 50 nM to 10 μM with a detection limit as low as 17.4 nM. F /F increased linearly with increase of Hg concentration ranging from 50 nM to 1 μM with a detection limit as low as 20.9 nM. Additionally, the nanosensor could be successfully applied for the determination of DPA and Hg in running water.

Eu3+-Postdoped UIO-66-Type Metal–Organic Framework as a Luminescent Sensor for Hg2+ Detection in Aqueous Media

“…Compared with some previously reported sensors based on MOFs for the Hg 2+ ion, the sensor prepared by us possesses a lower detection line (Table S4). ,− These indicate that this luminescent MOF probe as a fluorescence material exhibits great potential in detecting Hg 2+ .…”

Ratiometric fluorescence detection of Cu2+ based on carbon dots/bovine serum albumin–Au nanoclusters

“…The luminescence properties of CDs, BSA–AuNCs and CDs/BSA–AuNCs were explored. As shown in Figure A, BSA–AuNCs had a weak absorption peak at about 470–600 nm (curve b), which was generally the absorption peak of AuNCs as reported previously, indicating the successful synthesis of BSA–AuNCs . CDs had a significant absorption peak at 275 nm (curve a).…”

“…As discussed earlier, AuNCs were mainly associated with the S atom of cysteine residues in BSA to form BSA–AuNCs, whereas electron‐rich or functional groups of substances could effectively enhance the fluorescence of several‐nanosized AuNCs through a surface effect . The addition of Cu 2+ might destroy the interaction between BSA and AuNCs due to the formation of Cu–S bonds by Cu instead of Au, which resulted in BSA leaving the AuNC surface and accordingly the fluorescence intensity of AuNCs was decreased …”

“…The ratiometric fluorescent nanoprobe had good water dispersibility, low cytotoxicity and stable emission, and was ideal for water environment testing . With the addition of Cu 2+ , BSA–AuNCs fluorescence was quenched because interaction of Cu 2+ with the S of cysteine weakened the interaction between BSA and AuNCs to cause a decrease in fluorescence intensity . As the fluorescence of CDs is relatively stable, it could be used as a reference signal for the detection of Cu 2+ .…”

Ratiometric fluorescent detection of Cu2+ based on dual‐emission ZIF‐8@rhodamine‐B nanocomposites

“…These experimental conditions are usually difficult to control in the experimental process. Moreover, as the concentration of analyte changes, the color of the ratio probe changes step‐by‐step, thereby enabling visual detection of the analyte, and semi‐quantitative and qualitative analysis of the analyte can be achieved depending on the color of the ratio probe . Therefore, the construction of ratiometric fluorescence sensors is of great significance.…”