Fe³⁺-sensing by 3,3′,5,5′-tetramethylbenzidine-functionalized upconversion nanoparticles

Abstract

Detection of Fe 3+ ion is essential for human health because it is an important element of hemoglobin, which carries oxygen to cells in the body. Here, a 3,3′,5,5′-tetramethylbenzidine (TMB) functionalized NaYF 4 : Yb 3+ , Er 3+ @NaYF 4 composite upconversion probe was developed, and demonstrated Fe 3+ sensing ability with high sensitivity and selectivity. The red emission of upconversion nanoparticles (UCNPs) has a higher penetration depth in tissue than green light and works within the biological window. The obtained hydrophobic NaYF 4 : Yb 3+ , Er 3+ @NaYF 4 nanoparticles were treated with HCl to achieve hydrophilic ligand-free nanoparticles with nonsaturated metal ions on their surface. Then, a Fe 3+ responsive TMB-UNCPs composite luminescence probe was formed through linking TMB onto the ligand-free UCNPs by a coordination bond between the NH 2 groups in TMB and the metal ions on the UCNPs. Due to the efficient fluorescence resonance energy transfer from UCNPs to Fe 3+ -TMB, the obtained probe shows high sensitivity for detecting Fe 3+ in the range of 0-100 μM with a detection limit of 0.217 μM. And the color change of the detection system can also be easily recognized by the naked eye. The 3-(4,5-dimethyl-2thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) experiments and the bioimaging experiments show promising prospects in tissue imaging.

A three-dimensional microfluidic flow cell and system integration for improved electrochemical substrate detection in HRP/TMB-based immunoassays

“…This improved signal stability, which is three times higher than the SNR for optical detection (SNR = 19), demonstrates that such an integrated platform can readily serve as an alternative to the optical detection mode for HRP/ H 2 O 2 /TMB-based immunoassays. Compared to existing or already published chromogenic detection methods for TMB, such as spectrometry, 37 optical microscopy, 38 fluorescence 39 or even naked-eye sensing, 40 this method allows for a shorter detection time with a higher signal-to-noise ratio. Also, compared to recent electrochemical sensor studies, the sensitivity and throughput of the developed method for TMB substrate detection is improved significantly.…”

Exploring the use of upconversion nanoparticles in chemical and biological sensors: from surface modifications to point-of-care devices

“…The system presented high sensitivity in the range of 0–100 μM with a detection limit of 0.217 μM. 77 A similar “turn-off” sensor based on the energy transfer pair UCNP-TMB was constructed by Liu et al for simultaneous detection and quantification of H 2 O 2 and glucose. When compared to other sensing systems, the developed platform presented higher sensitivity, detecting glucose in the range of 0.1–5.0 μM with a LOD of 64.0 nM in human serum.…”

Lanthanide ion (Ln3+)‐based upconversion sensor for quantification of food contaminants: A review

“…Similarly, based on the complexation of metal ions, Meng et al. (2019) synthesized 3,3′,5,5′‐tetramethylbenzidine (TMB)‐functionalized UCNPs for the rapid sensing of Fe 3+ (Figure 7b). NaYF 4 :Yb,Er@NaYF 4 with good dispersion was synthesized by thermal decomposition method.…”