Nile Red Derivative-Modified Nanostructure for Upconversion Luminescence Sensing and Intracellular Detection of Fe³⁺ and MR Imaging

Abstract

Iron ion (Fe(3+)) which is the physiologically most abundant and versatile transition metal in biological systems, has been closely related to many certain cancers, metabolism, and dysfunction of organs, such as the liver, heart, and pancreas. In this Research Article, a novel Nile red derivative (NRD) fluorescent probe was synthesized and, in conjunction with polymer-modified core-shell upconversion nanoparticles (UCNPs), demonstrated in the detection of Fe(3+) ion with high sensitivity and selectivity. The core-shell UCNPs were surface modified using a synthesized PEGylated amphiphilic polymer (C18PMH-mPEG), and the resulting mPEG modified core-shell UCNPs (mPEG-UCNPs) show good water solubility. The overall Fe(3+)-responsive upconversion luminescence nanostructure was fabricated by linking the NRD to the mPEG-UCNPs, denoted as mPEG-UCNPs-NRD. In the nanostructure, the core-shell UCNPs, NaYF4:Yb,Er,Tm@NaGdF4, serve as the energy donor while the Fe(3+)-responsive NRD as the energy acceptor, which leads to efficient luminescence resonance energy transfer (LRET). The mPEG-UCNPs-NRD nanostructure shows high selectivity and sensitivity for detecting Fe(3+) in water. In addition, benefited from the good biocompatibility, the nanostructure was successfully applied for detecting Fe(3+) in living cells based on upconversion luminescence (UCL) from the UCNPs. Furthermore, the doped Gd(3+) ion in the UCNPs endows the mPEG-UCNPs-NRD nanostructure with effective T1 signal enhancement, making it a potential magnetic resonance imaging (MRI) contrast agent. This work demonstrates a simple yet powerful strategy to combine metal ion sensing with multimodal bioimaging based on upconversion luminescence for biomedical applications.

Core@shell Fe3O4@Mn2+-doped NaYF4:Yb/Tm nanoparticles for triple-modality T1/T2-weighted MRI and NIR-to-NIR upconversion luminescence imaging agents

“…In a typical procedure, 42,43 poly(maleic anhydride-alt-1-octadecene) (10 mg, 0.0286 mmol, C 18 PMH) was reacted with methoxypolyethylene glycol amine (142.85 mg, 0.0286 mmol, mPEG-NH 2 5 kDa) in 10 mL of CH 2 Cl 2 /TEA (9 : 1, v/v) for 2 h at room temperature. Then, EDC$HCl (10.9 mg, 0.055 mmol) was added, and the solution was stirring for another 24 h. The resulting polymer was dialyzed against ultrapure water through a dialysis membrane (molecular weight cut-off of 8000-14 000) for 2 days.…”

Controlled synthesis of soluble conjugated polymeric nanoparticles for fluorescence detection

“…[16][17][18] Therefore, intense research efforts have been devoted to the development of chemosensors for Fe 3+ ion detection. Thus, in this work, we aim to develop a new kind of uorophores in order to detect both glucose and Fe 3+ ion in human body.…”

Sensing materials developed and applied for bio-active Fe3+ recognition in water environment

“…This work maybe opens a novel approach to prepare low cost and high sensitive C-Dots-based sensors for biological and environmental applications. 50 Near recently, using core-shell NaYF 4 :Yb,Er,Tm@NaGdF 4 (UCNPs) as the energy donor and Fe 3+ -responsive Nile red derivative (NRD) as the energy acceptor, Wei, et al, 101 constructed a novel luminescence resonance energy transfer sensing materials for Fe 3+ detection, denoted as mPEG-UCNPs-55 NRD (Fig. 10c).…”