Determination of iron(II) and iron(III) via static quenching of the fluorescence of tryptophan-protected copper nanoclusters

Triple-mode sensing platform for acetylcholinesterase activity monitoring and anti-Alzheimer's drug screening based on a highly stable Cu (I) compound

Acetylcholinesterase (AChE) and AChE inhibitors play critical roles in the early diagnosis and treatment of Alzheimer's disease (AD). Herein, a fluorescence/colorimetry/smartphone triple-mode sensing platform was constructed for both AChE activity monitoring and AChE inhibitor screening by exploring a Cu (I) compound, Cu3I (SR)2 (R = CH2CH2NH2), as a fluorescent probe. In comparison of most other fluorescent probes, Cu3I (SR)2 presented exceptional stability against pH, temperature, UV irradiation, redox agents, and metal ions, as well as good recyclability due to its unique chemical structure. We further found the fluorescence emission of Cu3I (SR)2 could be quenched by MnO2 nanosheet (NS) via inner filter effect, and restored by thiocholine (TCh) generated from the hydrolysis of acetylthiocholine iodide (ATCh) in the catalysis of AChE. On this basis, a fluorescence "turn-on" assay was developed for monitoring AChE activity with a detection limit of 0.03 U/L and a detection range of 0.25-50 U/L. This method demonstrates great potential for real-time detection of AChE activity in biological samples and screening of AChE inhibitors obtained from herbal extracts as anti-AD agents. Additionally, Cu3I (SR)2/MnO2 NS sensing system also exhibited a color change from brown to colorless as the increasing AChE activity, which allowed the colorimetric and smartphone detection of AChE activity.

Multifunctional Au-Ag NCs for luminescence and colorimetric double signal sensing of H2S and catalytic reduction of nitrophenol

In this study, the N-Acetyl-l-Cysteine (NAC)-capped gold and silver bimetallic nanoclusters (NAC@Au-Ag NCs) was synthesized by reflux method. Due to the silver effect, the NAC@Au-Ag NCs exhibited strong photoluminescence at far-red/near-infrared regions and better catalytic performance than Au or Ag NCs. Upon addition of H2S, the Au-Ag NCs exhibited obvious fluorescence quench and color changes through the generation of metal sulfides and a static quenching process. The Au-Ag NCs displayed a wide linear luminescence response for H2S (18.5-217 μmol/L) with a detection limit of 0.269 μmol/L. Moreover, the visible color of Au-Ag NCs changed from white to brown-yellow along with increased H2S, the corresponding RGB values also displayed good linearity with the concentration of H2S (90.1-678 μmol/L). Notably, the fabrication of test strips provided a convenient and intuitive tool to screen the freshness of eggs by the color change of test strips. Au-Ag NCs could be used for living HeLa cells bioimaging and recognition of H2S abnormalities. Furthermore, it can be used as a catalyst to reduction of nitrophenols (NPhs), specific included 2NP, 3NP and 4NP. The reaction was regarded as a pseudo-first-order kinetic reaction due to the presence of excess NaBH4. At 298K, the catalytic rate constants(k) of 2NP, 3NP and 4NP were 0.1754 min-1, 0.1734 min-1 and 0.2782 min-1, respectively. The NAC@Au-Ag NCs catalyst still showed good catalytic activity and reusability after five cycles. Therefore, this study developed a H2S sensor for food samples and biological systems. And this nanocatalyst had great application potential for removed the nitrophenol pollutants in water.

Sensitive and reliable hybrid nanosensor (Co2+-CDs@R-CDs) for ratiometric fluorescent and colorimetric detecting NO2. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024;321:124661. [PMID: 38909562 DOI: 10.1016/j.saa.2024.124661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

A ratiometric fluorescent and colorimetric detecting assay for NO2- was realized by a hybrid nanosensor (Co2+-CDs@R-CDs) utilizing firstly through the redox reaction of nitrite (NO2-) with Co2+, of which the hybrid nanosensor Co2+-CDs@R-CDs was fabricated by Co2+-doped carbon dots (Co2+-CDs) and a reference of red-emitting carbon dots (R-CDs). The ratiometric fluorescent linear detection range of NO2- was 2.5-45 μM and the limit of detection (LOD) was 0.068 μM with the response time of 120 s. While, the colorimetric linear detection range of NO2- was 2.5-60 μM and the LOD was 0.075 μM. In addition, a portable smartphone system which could measure the R (red), G (green), and B (blue) values of the fluorescence and the visible color of the coated Co2+-CDs@R-CDs paper strip-based sensor had also been developed and successfully applied to detect NO2- in sausage, pickles and tap water samples.

Approaching Tryptophan-Derived Polynorbornene Fluorescent Chemosensors: Synthesis, Characterization, and Sensing Ability for Biomedical Applications as Biomarkers for Detecting Fe2+ Ions

We present a novel group of tryptophan (Trp)-based fluorescent polymeric probes synthesized via ring-opening metathesis polymerization (ROMP) of Trp-derived norbornene monomers. These probes, in mono- and disubstituted forms, incorporate amide and ester anchoring groups. The quantity of Trp substituents did not affect fluorescence selectivity but influenced quenching percentage. Poly-diamide-Trp, Poly-monoamide-Trp, Poly-diester-Trp, and Poly-monoester-Trp probes displayed selective detection of Fe2+ and Fe3+ ions with fluorescence on-off characteristics. Poly-diamide-Trp and Poly-monoamide-Trp exhibited a limit of detection (LOD) for Fe2+ and Fe3+ ions of 0.86-11.32 μM, while Poly-diester-Trp and Poly-monoester-Trp showed higher LODs (21.8-108.7 μM). These probes exhibited high selectivity over Fe2+, a crucial metal ion in the body known for its redox properties causing oxidative stress and cell damage. Cell cytotoxicity tests in various cell types confirmed biocompatibility. Additionally, Poly-diamide-Trp displayed excellent cell permeability and iron ion detection in EA.hy926 cells, suggesting potential for bioimaging and clinical applications.

Ferrous sulfide nanoparticles can be biosynthesized by sulfate-reducing bacteria: Synthesis, characterization and removal of heavy metals from acid mine drainage

Ferrous sulfide nanoparticles (nFeS) have proven to be effective in removing heavy metals (HMs) from wastewater. One such approach, which has garnered much attention as a sustainable technology, is via the in situ microbial synthesis of nFeS. Here, a sulfate-reducing bacteria (SRB) strain, Geobacter sulfurreducens, was used to initially biosynthesize ferrous sulfide nanoparticles (SRB-nFeS) and thereafter remove HMs from acid mine drainage (AMD). SRB-nFeS was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) coupled to an energy dispersive spectrometer (EDS), three-dimensional excitation-emission matrix (3D-EEM) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Such characterization showed that SRB mediated the reduction of SO42- to S2- to form nFeS, where the metabolized substances functioned as complexing agents which coordinated with nFeS to form biofunctional SRB-nFeS with improved stability. One advantage of this synthetic route was that the attachment of nFeS to the bacterial surface protected SRB cells from HM toxicity. Furthermore, due to a synergistic effect between nFeS and SRB, HM removal from both solution and AMD by SRB-nFeS was enhanced relative to the constituent components. Thus, after 5 consecutive cycles of HM removal, SRB-nFeS removed, Pb(Ⅱ) (92.6%), Cd(Ⅱ) (78.7%), Cu(Ⅱ) (76.0%), Ni(Ⅱ) (62.5%), Mn(Ⅱ) (62.2%), and Zn(Ⅱ) (88.5%) from AMD This study thus provides new insights into the biosynthesis of SRB-nFeS and its subsequent practical application in the removal of HMs from AMD.

Tryptophanhydroxamic Acid-Stabilized Ultrasmall Gold Nanoclusters: Tuning the Selectivity for Metal Ion Sensing

Sub-nanometer-sized gold nanoclusters (Au NCs) were prepared via the spontaneous reduction of [AuCl4]-- ions with a hydroxamate derivative of L-tryptophan (Trp) natural amino acid (TrpHA). The prepared TrpHA-Au NCs possess intense blue emission (λem = 470 nm; λex = 380 nm) with a 2.13% absolute quantum yield and 1.47 ns average lifetime. The Trp-stabilized noble metal NCs are excellent metal ion sensors for Fe3+, but in this work, we highlighted that the incorporation of the hydroxamate functional group with an excellent metal ion binding capability can tune the selectivity and sensitivity of these NCs, which is a promising way to design novel strategies for the detection of other metal ions as well. Moreover, their simultaneous identification can also be realized. By decreasing the sensitivity of our nano-sensor for Fe3+ (limit of detection (LOD) ~11 µM), it was clearly demonstrated that the selectivity for Cu2+-ions can be significantly increased (LOD = 3.16 µM) in an acidic (pH = 3-4) condition. The surface-bounded TrpHA molecules can coordinate the Cu2+ confirmed by thermodynamic data, which strongly generates the linking of the NCs via the Cu2+ ions in acidic pH, and a parallel fluorescence quenching occurs. In the case of Fe3+, the degree of quenching strongly depends on the metal ion concentration, and it only occurs when the NCs are not able to bind more Fe3+ (~10 µM) on the surface, causing the NCs' aggregation.

Enzyme-Assisted Amplification and Copper Nanocluster Fluorescence Signal-Based Method for miRNA-122 Detection

At present, a large number of studies have demonstrated that miRNAs can be used as biological indicators for the diagnosis and treatment of diseases such as tumours and cancer, so it is important to develop a new miRNA detection platform. In this work, miRNA-122 is used as the basis for targeting detection agents. We have designed an unlabelled DNA1 that undergoes partial hybridisation and has a 20 T base long strand. The fluorescent signal in this experiment is derived from copper nanoclusters (CuNCs) generated on the circular T-long strand of DNA1. At the same time, DNA1 is able to react with miRNA-122 and achieve hydrolysis of the part bound to miRNA-122 via the action of nucleic acid exonuclease III (Exo III), leaving a part of the DNA, called DNA3, while releasing miRNA-122 to participate in the next reaction, thus achieving circular amplification. DNA3 is able to react with DNA2, which is bound to streptavidin magnetic beads (SIBs) and separated from the reaction solution via the application of a magnetic field. Overall, this is a fluorescence signal reduction experiment, and the strength of the fluorescence signal from the copper nanoclusters can determine whether the target miRNA-122 is present or not. The degree of fluorescence reduction indicates how much DNA1, and thus the amount of target miRNA-122, has been hydrolysed. By evaluating the variations in the fluorescence signal under optimised conditions, we discovered that this method has good sensitivity, with a detection limit as low as 0.46 nM, better than many other previous works on fluorescence signal-based biosensors for miRNA detection. This technique offers high discrimination and selectivity and can serve as a persuasive reference for early diagnosis.

Rapid Detection of Ag(I) via Size-Induced Photoluminescence Quenching of Biocompatible Green-Emitting, l-Tryptophan-Scaffolded Copper Nanoclusters

Atomically precise metal nanoclusters capped with small molecules like amino acids are highly favored due to their specific interactions and easy incorporation into biological systems. However, they are rarely explored due to the challenge of surface functionalization of nanoclusters with small molecules. Herein, we report the synthesis of a green-emitting (λex = 380 nm, λem = 500 nm), single-amino-acid (l-tryptophan)-scaffolded copper nanocluster (Trp-Cu NC) via a one-pot route under mild reaction conditions. The synthesized nanocluster can be used for the rapid detection of a heavy metal, silver (Ag(I)), in the nanomolar concentration range in real environmental and biological samples. The strong green photoluminescence intensity of the nanocluster quenched significantly upon the addition of Ag(I) due to the formation of bigger nanoparticles, thereby losing its energy quantization. A notable color change from light yellow to reddish-brown can also be observed in the presence of Ag(I), allowing its visual colorimetric detection. Portable paper strips fabricated with the Trp-Cu NC can be reliably used for on-site visual detection of Ag(I) in the micromolar concentration range. The Trp-Cu NC possesses excellent biocompatibility, making it a suitable nanoprobe for cell imaging; thus, it can act as an in vivo biomarker. The nanocluster showed a significant spectral overlap with anticancer drug doxorubicin and thus can be used as an effective fluorescence resonance energy transfer (FRET) pair. FRET results can reveal important information regarding the attachment of the drug to the nanocluster and hence its role as a potential drug carrier for targeted drug delivery within the human body.

Development of Fluorescent Aptasensors Based on G-Quadruplex Quenching Ability for Ochratoxin A and Potassium Ions Detection

G-quadruplexes have received significant attention in aptasensing due to their structural polymorphisms and unique binding properties. In this work, we exploited the fluorescence-quenching properties of G-quadruplex to develop a simple, fast, and sensitive platform for fluorescence detection of ochratoxin A (OTA) and potassium ions (K+) with a label-free fluorophore and quencher strategy. The quenching ability of G-quadruplex was confirmed during the recognition process after the formation of the G-quadruplex structure and the quenching of the labeled fluorescein fluorophore (FAM). The fluorescence-quenching mechanism was studied by introducing specific ligands of G-quadruplex to enhance the quenching effect, to show that this phenomenon is due to photo-induced electron transfer. The proposed fluorescence sensor based on G-quadruplex quenching showed excellent selectivity with a low detection limit of 0.19 nM and 0.24 µM for OTA and K+, respectively. Moreover, we demonstrated that our detection method enables accurate concentration determination of real samples with the prospect of practical application. Therefore, G-quadruplexes can be excellent candidates as quenchers, and the strategy implemented in the study can be extended to an aptasensor with G-quadruplex.

A dual-mode optical assay for iron (II) and gallic acid based on Fenton reaction

The hydroxyl radicals (·OH) produced by the Fenton reaction of iron (II) and hydrogen peroxide (H₂ O₂ ) can oxidize the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidized TMB (Ox-TMB), resulting in a decrease in the fluorescence intensity of the reaction system and an increase in ultraviolet absorption. Ox-TMB had a visible absorption peak at 625 nm and a fluorescence peak around 420 nm. When gallic acid (GA) was added to the system, Ox-TMB was reduced to TMB, which made the color of the system disappear and the fluorescence recover. The linear ranges for determination of iron (II) were 0.5-10 μM (fluorometric) and 0.5-20 μM (colorimetric), and the detection limits were 0.25 μM (fluorometric) and 0.28 μM (colorimetric). The linear ranges for determination of GA were 0-80 μM (fluorometric) and 0-60 μM (colorimetric), and the detection limits were 0.31 μM (fluorometric) and 0.8 μM (colorimetric). The results of anti-interference experiments shew that this dual-mode assay had very good selectivity for the determination of iron (II) and GA.

CuII Ion Doping Enhances the Water Stability of Luminescent Metal–Organic Framework, Realizing the Detection of Fe3+ and Antibiotics in Aqueous Solutions

Luminescent metal–organic frameworks (LMOFs) have been widely developed in the field of chemical sensing owing to their outstanding photoluminescence performance, high selectivity, anti-interference, high sensitivity, and fast response, and have become one of the research hotspots of emerging functional materials. However, in practical applications, many tests are carried out in the water environment, and fragile water stability greatly limits the application of MOFs in the field. Therefore, it is important to develop a method to enhance the water stability of MOFs. Herein, a new complex {[Zn(L)]·CH₃CN}_n (Zn-MOF, H₂L = 5-(benzimidazol-1-yl) isophthalic acid) with a superior photophysical property has been synthesized first. Its water stability was highly enhanced by the doping of Cu^II ions by the one-pot method. In addition, the detection performances of doping material Cu_0.1/Zn-MOF for sixteen metal ions and thirteen antibiotics were well studied. It was found that Cu_0.1/Zn-MOF displays high sensitivity, fast response, lower detection limit, and long-term stability for the detection of Fe³⁺, NFT, NFZ, FZD, and TC in the aqueous medium.

Highly Sensitive Detection of Iron Ions in Aqueous Solutions Using Fluorescent Chitosan Nanoparticles Functionalized by Rhodamine B

Detection of iron ions in aqueous solutions is of significant importance because of their important role in the environment and the human body. Herein, a fluorescent rhodamine B-functionalized chitosan nanoparticles probe is reported for the efficient detection of iron ions. The chitosan nanospheres-rhodamine B (CREN) was prepared by grafting rhodamine B onto the surface of chitosan nanospheres through an amidation reaction. The as-prepared CREN fluorescent probes exhibit high fluorescence intensity under ultraviolet light. When iron ions are added to the CREN solution, they can be coordinated with weak-field ligands such as N and O on the surface of chitosan nanoparticles (CSNP) by a high-spin method. The self-assembly of Fe³⁺ on the surface of the CREN led to the generation of single electrons and the presence of high paramagnetism, resulting in fluorescence quenching. The quenching effect of Fe³⁺ on the CREN fluorescent probe can achieve the efficient detection of Fe³⁺, and the detection limit reaches 10^-5 mol/mL. Moreover, this fluorescence quenching effect of Fe³⁺ on the CREN fluorescent probe is specific, which could not be disturbed by other metal ions and counteranions.

Multistimuli-Responsive and Antifreeze Aggregation-Induced Emission-Active Gels Based on CuNCs

Multistimuli-responsive fluorescent gelsbased small molecular gelator by supramolecular assembly, possessing excellent dynamic and reversible characteristic, have caused much concern. In this article, aggregation-induced emission-active fluorescence gels (AIE-gels) with chirality were developed by combining Cu nanoclusters (CuNCs) and natural amino acids, l-tryptophan (l-Trp) or d-Tryptophan (d-Trp). In DMSO/H₂O mixed solvents, CuNCs can self-assemble to form intertwined fibersbased nanoparticles with numerous pores by introducing Zn²⁺. Fibers as second networks of heteronetwork structures are characterized with the participation of l-Trp or d-Trp for cross-linking to reinforce mechanical strength and chiral regulation of gel networks. Aggregation-induced emission enhancement (AIEE) of CuNCs endows the gels with excellent fluorescent properties by introducing solvents and gelation process. The fluorescent gels exhibit sufficient fluorescence intensity (FI) at -20 °C to -80 °C and possess sensitive responsibility including gel-sol transition and fluorescence behavior for stimuli of mechanical force, heating, pH, H₂O₂, and ethylene diamine tetraacetic acid (EDTA).

Turn-on fluorescence ferrous ions detection based on MnO2 nanosheets modified upconverion nanoparticles

A turn on upconversion fluorescence probe based on the combination of ~32 nm NaYF₄: Yb/Tm nanoparticles and MnO₂ nanosheets has been established for rapid, sensitive detection of Fe²⁺ ions levels in aqueous solutions and serum. X-ray diffraction (XRD), transmission electron microscopy (TEM), absorption and emission spectra have been used to characterize the crystal structure, morphology and optical properties of the samples. MnO₂ nanosheets on the surface of UCNPs act as a fluorescence quencher, resulting in the quenching of the blue fluorescence (with excitation/emission maximum of 980/476 nm) via fluorescence resonance energy transfer from upconversion nanoparticles to MnO₂ nanosheets. With the adding of Fe²⁺, upconversion fluorescence of the nanocomposites recovers due to the reduction of MnO₂ to Mn²⁺. Because of the low background of the probe offered by upconversion fluorescence, this probe can be used for detecting Fe²⁺ in aqueous solutions in the range of 0.1-22 μM with detection limit of 0.113 μM. The developed method has also been applied to detect 10 μM Fe²⁺ ions in serum with recoveries ranging from 97.6 to 105.3% for the five serum samples. Significantly, the probe shows fast response and stable signal, which is beneficial for long-time dynamic sensing. Thus, the proposed strategy holds great potential for disease diagnosis and treatment.

The synthesis of novel fluorescent bimetal nanoclusters for aqueous mercury detection based on aggregation-induced quenching

In this research, new bimetal nanoclusters (DAMP-AuAg BNCs) with 4,6-diamino-2-mercaptopyrimidine (DAMP) as a reducing agent and stabilizer ligand were exploited. The nanoclusters displayed excellent fluorescent properties, very small size, good stability, and water solubility. It was found that the as-prepared DAMP-AuAg BNCs exhibited strong fluorescent emission at 640 nm under an excitation wavelength of 473 nm with a large Stokes shift of 167 nm, and the red fluorescence could be readily quenched with aqueous Hg²⁺. The DAMP-AuAg BNCs showed good specificity and sensitivity toward Hg²⁺ in aqueous solution, and the fluorescence analysis of Hg²⁺ showed a wide linear range from 0.85 μM to 246 μM and a detection limit of 20 nM. It is demonstrated that strong Hg²⁺-Au⁺ interactions led to the aggregation of nanoclusters, which caused the quenching of the fluorescence, and the affinity of Hg²⁺ for nitrogen should also be considered. Due to the relevant good performance of DAMP-AuAg BNCs, they were applied to the fluorescence analysis of Hg²⁺ in real water samples and were found to be a potential fluorescent sensor for aqueous mercury ions.

Discriminating detection of dissolved ferrous and ferric ions using copper nanocluster-based fluorescent probe

Discrimination and detection of specific metal ions that belong to the same metallic element with different valence states in a complex matrix is challenging. In the present work, a fluorescence method using polyvinylpyrrolidone stabilized copper nanocluster (CuNCs@PVP) as a probe for discriminating detection of ferrous (Fe³⁺) and ferric (Fe²⁺) ions was developed. The CuNCs@PVP exhibited an excellent selective response to Fe³⁺ ions in contrast to Fe²⁺ ions and other metal ions when the pH value of solution was less than 4.0. Furthermore, the fluorescence of the CuNCs@PVP could be more sensitively quenched by Fe²⁺ ions by virtue of Fenton reaction. The different response of CuNCs@PVP towards Fe³⁺ and Fe²⁺ ions under different conditions offered the potential for the discriminating detection of Fe³⁺ and Fe²⁺ ions. Based on detailed optimization of detection conditions, an excellent linear relationship between the fluorescence quenching efficiency (F/F₀) of the CuNCs@PVP and the concentration of Fe³⁺ ions over the range of 0.4-20.0 μM and of Fe²⁺ ions in the range of 0.01-0.4 μM were obtained, respectively. The detection limits for the Fe³⁺ and Fe²⁺ ions were 0.14 μM and 0.008 μM, respectively. The developed probe showed good selectivity and presented an alternative strategy for discriminating detection of Fe³⁺ and Fe²⁺ ions in complex samples.

Monodisperse functionalized GO for high-performance sensing and bioimaging of Cu2+ through synergistic enhancement effect

The metal ion fluorescence probes based on chemical reactions triggered by specific metal ions is characterized by high selectivity. However, they are also subject to inherent limitations, such as easy aggregation under water solution, poor optical stability, and long response time. In order to solve these problems, a simple and effective method was studied. The specific design is as follows. Fluorescence probe RACD is assembled onto a single layer graphene oxide (GO) via π-π interaction and hydrogen bonding to prepare RACD functionlized graphene oxide RACD/GO. The experimental results show that the resulting RACD/GO possesses very well monodispersion, hydrophilicity and photostability, particularly reduce the aggregation degree of RACD owing to π-π effect. Simultaneously, it was found that due to the strong synergy between GO and RACD, the response time, selectivity, anti-interference ability, detection sensitivity, detection limit and bioimaging ability of RACD/GO were significantly improved compared with RACD. The resulting RACD/GO not only possesses very well photostability, multiple repeated cycles, but also have been triumphantly put into the monitoring Cu²⁺ of environmental water, sewage, cells and zebrafish specimens in practice. The detection limit is as low as 1.76 nM, and the correlation coefficient is 0.9998.

Subsequent monitoring of ferric ion and ascorbic acid using graphdiyne quantum dots-based optical sensors

Graphdiyne (GDY) as an emerging carbon nanomaterial has attracted increasing attention because of its uniformly distributed pores, highly π-conjugated, and tunable electronic properties. These excellent characteristics have been widely explored in the fields of energy storage and catalysts, yet there is no report on the development of sensors based on the outstanding optical property of GDY. In this paper, a new sensing mechanism is reported built upon the synergistic effect between inner filter effect and photoinduced electron transfer. We constructed a novel nanosensor based upon the newly-synthesized nanomaterial and demonstrated a sensitive and selective detection for both Fe³⁺ ion and ascorbic acid, enabling the measurements in real clinical samples. For the first time fluorescent graphdiyne oxide quantum dots (GDYO-QDs) were prepared using a facile ultrasonic protocol and they were characterized with a range of techniques, showing a strong blue-green emission with 14.6% quantum yield. The emission is quenched efficiently by Fe³⁺ and recovered by ascorbic acid (AA). We have fabricated an off/on fluorescent nanosensors based on this unique property. The nanosensors are able to detect Fe³⁺ as low as 95 nmol L^-1 with a promising dynamic range from 0.25 to 200 μmol L^-1. The LOD of AA was 2.5 μmol L^-1, with range of 10-500 μmol L^-1. It showed a promising capability to detect Fe³⁺ and AA in serum samples. Graphical abstract.