Ultratrace Naked-Eye Colorimetric Ratio Assay of Chromium(III) Ion in Aqueous Solution via Stimuli-Responsive Morphological Transformation of Silver Nanoflakes

Abstract

In this work, we discover an effective domino-effectbased detection mechanism for the rapid, high-selectivity, and ultrasensitive naked-eye colorimetric ratio assay of chromium(III) ion (Cr 3+ ) in aqueous solutions. This naked-eye colorimetric ratio assay to Cr 3+ relies on changes in absorbance properties that are due to the stimuli response of Cr 3+ for the morphological transformation of silver nanoflakes. In the presence of Cr 3+ , large silver nanoflakes can be stimulated to transform to small nanoparticles (NPs), which promoted a color change in solution from bright yellow to wine red that was detected by the naked eye and spectroscopic absorption methods. The proposed naked-eye sensing strategy was coupled with an ultraviolet (UV)-spectroscopic chemosensor for the detection of trace Cr 3+ . The detection method showed an ultralow detection limit of 1.4 nM (nanomole) for Cr 3+ in ultrapure water and 11.5 nM in human serum sample, respectively. On the basis of colorimetry, the lowest concentration of ∼50 nM for Cr 3+ in ultrapure water and human serum can be detected by the naked eye. This naked-eye-based colorimetric ratio assay for accurate and selective identification and high sensitivity of Cr 3+ is expected to have large potential and wide applications such as pharmaceutical analysis, clinical diagnosis, and environmental monitoring.

Europium(III)-Modified Silver Nanoparticles as Ratiometric Colorimetric and Fluorescent Dual-Mode Probes for Selective Detection of Dipicolinic Acid in Bacterial Spores and Lake Waters

“…The AgNPs were synthesized according to a previously reported method in the literature with minor modification. 33 stirring. Then, 7.5 mg of NaBH 4 was added into the mixture solution, which resulted in an immediate color change.…”

“…In recent years, noble-metal nanoparticles exhibit particularly chemical and physical properties that make them outstanding scaffolds for the fabrication of novel colorimetric probes owing to the strong localized surface plasmon resonance (LSPR) in the visible light region . Among the noble-metal nanoparticles, silver nanoparticles (AgNPs) are considered attractive due to the unique characteristics such as easy preparation, high chemical stability, wide region of LSPR (300–900 nm), and biocompatibility. , In addition, their high extinction coefficients and ease of surface modification make them useful building blocks, which are used to fabricate simple and rapid colorimetric probes for the detection of several analytes such as proteins, DNA, drug, metal ions, and small molecules. − To our knowledge, AgNPs as a building block that was used to fabricate ratiometric colorimetric and fluorescent probes for the detection of DPA have not been reported yet.…”

Porous Oxyhydroxide Derived from Metal–Organic Frameworks as Efficient Triphosphatase-like Nanozyme for Chromium(III) Ion Colorimetric Sensing

“…As an essential trace-element nutrient for humans and animals, chromium­(III) ions play an important role in various biological systems. , However, a high concentration of chromium­(III) ions can cause toxicity; therefore, it is necessary to develop a selective, sensitive, and convenient method for chromium­(III) ion detection. , As mentioned above, the triphosphatase-like activity of GdOOH could be strongly inhibited by chromium­(III) ions (Figure S10c), and therefore, a colorimetric sensing method for chromium­(III) ions was explored. As illustrated in Figure a, phosphate was generated gradually because of the hydrolysis of ATP by GdOOH, yielding a green solution after the malachite green chromogenic reagent was added.…”

Dual Colorimetric and Ratiometric Fluorescent Responses for the Determination of Glutathione Based on Fluorescence Quenching and Oxidase-Like Activity of MnO2 Nanosheets

“…As a nonprotein thiol species, glutathione (GSH) has a wide range of application in biological systems and plays important roles in various biological functions, including metabolism, detoxification, and maintaining intracellular redox states. − Generally, the change of GSH in the biological system is related to a number of diseases, such as leukopenia, psoriasis, cancer, liver injury, and so on. , Therefore, a sensitive and stable platform for the detection of GSH is critical. In the past decades, a lot of research studies have been reported for the assay of GSH. − More attention has focused on optical assays because of their superior sensitivity, rapid response, and high selectivity. ,, However, most of the optical probes for the GSH determination work through the single signal change, − which is influenced by a number of factors, such as environmental conditions, the efficiency of instruments, and probe concentrations. − Comparatively, the dual colorimetric and ratiometric fluorescent assay is of considerable practical value for reducing the influence of the above factors since the response signal can be reflected through the ratio of absorbance or fluorescent intensity at two wavelengths. , Therefore, the dual colorimetric and ratiometric fluorescent assay offers the possibility for eliminating incorrect signals from environmental conditions. Meanwhile, this method takes some advantages of the aspects of improved precision and sensitivity.…”