One-pot synthesis of near-infrared fluorescent gold clusters for cellular fluorescence lifetime imaging

High sensitive Ratiometric fluorescent Aptasensor with AIE properties for Deoxynivalenol (DON) detection

An emerging fluorescent ratiometric aptasensor based on gold nanoclusters (AuNCs) with aggregation-induced emission (AIE) properties was prepared and studied for deoxynivalenol (DON) detection. The ratiometric aptasensor used red fluorescent AuNCs620 labelled with DON aptamer (Apt-AuNCs620) as an indicator and green fluorescent AuNCs519 modified by complementary DNA (cDNA) and magnetic beads (MBs) as internal reference, namely MBs-cDNA-AuNCs519. Under the optimal conditions, the aptasensor exhibited two good linear ranges of 0.1-50 and 50-5000 pg/mL for DON detection with coefficient of determination (R2) of 0.9937 and 0.9928, respectively, and the low detection limit (LOD) of 4.09 pg/mL was achieved. Furthermore, this aptasensor was feasible to detect DON in positive wheat samples, and the results were in line with those from HPLC and ELISA, thus providing a promising route to detect DON with high sensitivity in cereals, even for other mycotoxins by replacing the suitable aptamer and cDNA.

Synthesis and crystallization of a carboxylate functionalized N-heterocyclic carbene-based Au13 cluster with strong photo-luminescence

Here we report the synthesis and crystallization of a -COOH-capped N-heterocyclic carbene (NHC)-protected Au13 cluster. The single-crystal structure of the -COOH-capped NHC-Au13 cluster reveals a classic icosahedral core with one Au atom in its center. The icosahedral core is surrounded by five NHC ligands with pseudo C5 symmetry and exposed carboxyls in a pentagonal antiprism fashion. The detailed formula of the Au cluster was identified as Au13(bi-NHC carboxyl)5Cl2 (hereafter abbreviated as Au13-c). The density functional theory (DFT) calculations confirm that Au13-c is an electronically stable eight-electron super-atom cluster and elucidate its optical transitions in the UV-Vis range. The Au13-c cluster exhibits excellent thermal and chemical stability under bio-relevant conditions. Additionally, this cluster shows a strong red emission in DMF and H2O with an excellent quantum yield (QY) of 40% and 12.6%, respectively. The high QY of Au13-c enables its use in cell imaging on both cancer and noncancerous cells.

Research progress of fluorescent composites based on cyclodextrins: Preparation strategies, fluorescence properties and applications in sensing and bioimaging

Fluorescence analysis has been regarded as one of the commonly used analytical methods because of its advantages of simple operation, fast response, low cost and high sensitivity. So far, various fluorescent probes, with noble metal nanoclusters, quantum dots, organic dyes and metal organic frameworks as representatives, have been widely reported. However, single fluorescent probe often suffers from some deficiencies, such as low quantum yield, poor chemical stability, low water solubility and toxicity. To overcome these disadvantages, the introduction of cyclodextrins into fluorescent probes has become a fascinating approach. This review (with 218 references) systematically covers the research progress of fluorescent composites based on cyclodextrins in recent years. Preparation strategies, fluorescence properties, response mechanisms and applications in sensing (ions, organic pollutants, bio-related molecules, temperature, pH) and bioimaging of fluorescent composites based on cyclodextrins are summarized in detail. Finally, the current challenges and future perspectives of these composites in relative research fields are discussed.

Ångstrom-scale gold particles loaded with alendronate via alpha-lipoic acid alleviate bone loss in osteoporotic mice

Osteoporosis is a highly prevalent metabolic disease characterized by low systemic bone mass and deterioration of bone microarchitecture, resulting in reduced bone strength and increased fracture risk. Current treatment options for osteoporosis are limited by factors such as efficacy, cost, availability, side effects, and acceptability to patients. Gold nanoparticles show promise as an emerging osteoporosis therapy due to their osteogenic effects and ability to allow therapeutic delivery but have inherent constraints, such as low specificity and the potential for heavy metal accumulation in the body. This study reports the synthesis of ultrasmall gold particles almost reaching the Ångstrom (Ång) dimension. The antioxidant alpha-lipoic acid (LA) is used as a dispersant and stabilizer to coat Ångstrom-scale gold particles (AuÅPs). Alendronate (AL), an amino-bisphosphonate commonly used in drug therapy for osteoporosis, is conjugated through LA to the surface of AuÅPs, allowing targeted delivery to bone and enhancing antiresorptive therapeutic effects. In this study, alendronate-loaded Ångstrom-scale gold particles (AuÅPs-AL) were used for the first time to promote osteogenesis and alleviate bone loss through regulation of the WNT signaling pathway, as shown through in vitro tests. The in vivo therapeutic effects of AuÅPs-AL were demonstrated in an established osteoporosis mouse model. The results of Micro-computed Tomography, histology, and tartrate-resistant acid phosphatase staining indicated that AuÅPs-AL significantly improved bone density and prevented bone loss, with no evidence of nanoparticle-associated toxicity. These findings suggest the possible future application of AuÅPs-AL in osteoporosis therapy and point to the potential of developing new approaches for treating metabolic bone diseases using Ångstrom-scale gold particles.

Photoluminescence Quenching of Hydrophobic Ag29 Nanoclusters Caused by Molecular Decoupling during Aqueous Phase Transfer and EmissionRecovery through Supramolecular Recoupling

Exploiting emissive hydrophobic nanoclusters for hydrophilic applications remains a challenge because of photoluminescence (PL) quenching during phase transfer. In addition, the mechanism underlying PL quenching remains unclear. In this study, the PL-quenching mechanism was examined by analyzing the atomically precise structures and optical properties of a surface-engineered Ag29 nanocluster with an all-around-carboxyl-functionalized surface. Specifically, phase-transfer-triggered PL quenching was justified as molecular decoupling, which directed an unfixed cluster surface and weakened the radiative transition. Furthermore, emission recovery of the quenched nanoclusters was accomplished by using a supramolecular recoupling approach through the glutathione-addition-induced aggregation of cluster molecules, wherein the restriction of intracluster motion and intercluster rotation strengthened the radiative transition of the clusters. The results of this work offer a new perspective on structure-emission correlations for atomically precise nanoclusters and hopefully provide insight into the fabrication of highly emissive cluster-based nanomaterials for downstream hydrophilic applications.

Selective Perchlorate Sensing Using Electrochemical Impedance Spectroscopy with Self-Assembled Monolayers of semiaza-Bambusurils

In the last two decades, perchlorate salts have been identified as environmental pollutants and recognized as potential substances affecting human health. We describe self-assembled monolayers (SAMs) of novel semiaza-bambus[6]urils (semiaza-BUs) equipped with thioethers or disulfide (dithiolane) functionalities as surface-anchoring groups on gold electrodes. Cyclic voltammetry (CV) with Fe(CN)6 3-/4- as a redox probe, together with X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and ellipsometry, were employed to characterize the interactions at the interface between the anchoring groups and the metal substrate. Data showed that the anion receptors' packing on the gold strongly depends on the anchoring group. As a result, SAMs of BUs with lipoic amide side chains show a concentration-dependent layer thickness. The BU SAMs are extremely stable on repeated electrochemical potential scans and can selectively recognize perchlorate anions. Our electrochemical impedance spectroscopy (EIS) studies indicated that semiaza-BU equipped with the lipoic amide side chains binds perchlorate (2-100 mM) preferentially over other anions such as F- , Cl- , I- , AcO- , H2 PO4 - , HPO4 2- , SO4 2- , NO2 - , NO3 - , or CO3 2- . The resistance performance is 10 to 100 times more efficient than SAMs containing all other tested anions.

6-Aza-2-Thiothymine-Capped Gold Nanoclusters as Robust Antimicrobial Nanoagents for Eradicating Multidrug-Resistant Escherichia coli Infection

Multidrug-resistant bacterial infections, especially those caused by multidrug-resistant Escherichia coli (E. coli) bacteria, are an ever-growing threat because of the shrinking arsenal of efficacious antibiotics. Therefore, it is urgently needed to develop a kind of novel, long-term antibacterial agent effectively overcome resistant bacteria. Herein, we present a novel designed antibacterial agent-6-Aza-2-thiothymine-capped gold nanoclusters (ATT-AuNCs), which show excellent antibacterial activity against multidrug-resistant E. coli bacteria. The prepared AuNCs could permeabilize into the bacterial cell membrane via binding with a bivalent cation (e.g., Ca2+), followed by the generation of reactive oxygen species (e.g., •OH and •O2-), ultimately resulting in protein leakage from compromised cell membranes, inducing DNA damage and upregulating pro-oxidative genes intracellular. The AuNCs also speed up the wound healing process without noticeable hemolytic activity or cytotoxicity to erythrocytes and mammalian tissue. Altogether, the results indicate the great promise of ATT-AuNCs for treating multidrug-resistant E. coli bacterial infection.

Polymer-Enabled Assembly of Au Nanoclusters with Luminescence Enhancement and Macroscopic Chirality

The construction of macroscopic chiral luminescent aggregates with well-defined structures not only contributes to the development of functional materials but also has significant implications for analyzing chiral transfer and amplification in biological systems and self-assembly systems. Meanwhile, achieving water-soluble chiral metal nanoclusters (NCs) with high photoluminescence (PL) intensity through a convenient method remains a challenge. Herein, we reported the enhanced luminescence of gold nanoclusters stabilized by D-/L-penicillamine (D-/L-AuNCs) induced by poly(allylamine hydrochloride) (PAH) through supramolecular self-assembly strategies. FT-IR spectra and zeta potential measurements revealed that supramolecular assembly was driven by the synergistic effect of hydrogen bonds and electrostatic interactions, which effectively limited the intramolecular vibration and rotation of the ligand and reduced nonradiative relaxation, thus improving the luminescence properties of nanoclusters. Interestingly, during the slow solvent evaporation process, chiral entanglement of assemblies was enhanced, forming macroscopic wheat-shaped superstructures. This study enriches the understanding of the self-assembly mechanism of nanoclusters and provides a pathway for constructing NC-based chiroptical materials.

Potential impact of various surface ligands on the cellular uptake and biodistribution characteristics of red, green, and blue emitting Cu nanoclusters

Surface functionalization has a prominent influence on tuning/manipulating the physicochemical properties of nanometer scaled materials. Ultrasmall sized nanoclusters with very few atoms have received enormous attention due to their bright fluorescence, biocompatibility, lower toxicity, good colloidal stability and strong photostability. These properties make them suitable for diagnostic applications. In this work, we intend to study the effect of surface functional ligands on their biodistribution both in vitro and in vivo organelle systems for bioimaging applications.

Ultrasmall Gold Nanoparticles as Clients of Biomolecular Condensates

Liquid-liquid phase separation (LLPS) of biopolymers to form condensates is a widespread phenomenon in living cells. Agents that target or alter condensation can help uncover elusive physiological and pathological mechanisms. Owing to their unique material properties and modes of interaction with biomolecules, nanoparticles represent attractive condensate-targeting agents. Our work focused on elucidating the interaction between ultrasmall gold nanoparticles (usGNPs) and diverse types of condensates of tau, a representative phase-separating protein associated with neurodegenerative disorders. usGNPs attract considerable interest in the biomedical community due to unique features, including emergent optical properties and good cell penetration. We explored the interaction of usGNPs with reconstituted self-condensates of tau, two-component tau/polyanion and three-component tau/RNA/alpha-synuclein coacervates. The usGNPs were found to concentrate into condensed liquid droplets, consistent with the formation of dynamic client (nanoparticle) - scaffold (tau) interactions, and were observable thanks to their intrinsic luminescence. Furthermore, usGNPs were capable to promote LLPS of a protein domain which is unable to phase separate on its own. Our study demonstrates the ability of usGNPs to interact with and illuminate protein condensates. We anticipate that nanoparticles will have broad applicability as nanotracers to interrogate phase separation, and as nanoactuators controlling the formation and dissolution of condensates.

Gold nanoclusters with enhanced near-infrared emission and its application as sensors for biological molecules

Ultrasmall gold nanoclusters (NCs) have been engineered as a new kind of functional material due to their excellent photoluminescence properties. However, the synthesis of highly luminescent water-soluble nanoclusters with near-infrared (NIR) emission remains limited. Herein, we developed a pH-regulated strategy to facilitate the construction of self-assemblies with enhanced luminescence based on aggregation-induced emission (AIE) strategy. Using 2-mercaptobenzoic acid (MBA) as reductant and stabilizer, the original weakly luminescent AuNCs exhibited intense emission by adjusting pH controllably. The formation of compact organized nanostructures could effectively restrict the rotation and vibration of capping ligands by non-covalent interactions, which reduced the nonradiative relaxation from excited states and finally improved the emission properties of AuNCs. Moreover, the assemblies possess many intriguing features including bright NIR luminescence and excellent biocompatibility, which could be used as luminous probes in biological molecules sensing (tyrosinase (TYR) and dopamine (DA)) and promising candidates for cell imaging. This study provides a simple and feasible strategy for developing metal NCs-based smart optical materials in the field of bioscience.

Ultra-Sensitive MicroRNA Biosensor Based on Strong Aggregation-Induced Electrochemiluminescence from Bidentate Ligand-Stabilized Copper Nanoclusters in Polymer Hydrogel

Herein, dihydrolipoic acid (DHLA)-stabilized copper nanoclusters (Cu NCs) with high aggregation-induced electrochemiluminescence (AIECL) in polymer hydrogel were prepared to construct an ECL biosensor for detection of microRNA-21. DHLA, a small molecule ligand with two sulfhydryl groups, was used as a protective agent to synthesize Cu NCs, which improved the ECL stability and intensity of Cu NCs. Furthermore, the Cu NCs were loaded into the (PVP-PVA)hydrogel to form the DHLA-Cu NCs@(PVP-PVA)hydrogel composite, which showed effective AIECL performance. The confinement of Cu NCs into the hydrogel increased the local concentration of Cu NCs, which could not only prevent oxides from entering the copper core, but also limit the vibration to reduce non-radiative transitions of Cu NCs, leading to a distinct AIECL emission. Then, combined with the self-priming clip trigger isothermal amplification (SCTIA) technology, an ECL biosensor was constructed to realize the sensitive detection of miRNA-21. Interestingly, SCTIA technology was a simple and efficient strategy that realized multiple-cycle amplified processes to acquire a mass of output DNA, achieving remarkable signal amplification. Therefore, this strategy provided an efficient approach in the preparation of Cu NCs with high AIECL emission and target amplification technology, which might have promising potential in clinical application.

Fluorescent glyco-gold nanocluster induced EGFR mediated targeting of cancer cells

A lot of attention has been focused on the functionalization of carbohydrate ligands on specific sizes and shapes of gold nanoparticles (AuNPs), where ultrasmall fluorescent AuNPs have not been well explored for direct imaging. Herein, we have engineered fluorescent gold nanoclusters with sulfated oligo-iduronic acid ligands (I34), which strongly bind to the HB-EGF receptor over FGF2, and regulate EGF receptor-mediated cancer cell homing in both two- and three-dimensional (2D and 3D) cell culture systems. These results offer a new practical and direct imaging tool for carbohydrate research.

Viewing Aggregation-Induced Emission of Metal Nanoclusters from Design Strategies to Applications

Aggregation-induced emission (AIE)-type metal nanoclusters (NCs) represent an innovative type of luminescent metal NCs whose aggregates exhibit superior performance over that of individuals, attracting wide attention over the past decade. Here, we give a concise overview of the progress made in this area, from design strategies to applications. The representative design strategies, including solvent-induction, cation-induction, crystallization-induction, pH-induction, ligand inheritance, surface constraint, and minerals- and MOF-confinement, are first discussed. We then present the typical practical applications of AIE-type metal NCs in the various sectors of bioimaging, biological diagnosis and therapy (e.g., antibacterial agents, cancer radiotherapy), light-emitting diodes (LEDs), detection assays, and circularly polarized luminescence (CPL). To this end, we present our viewpoints on the promises and challenges of AIE-type metal NCs, which may shed light on the design of highly luminescent metal NCs, stimulating new vitality and serving as a continuous boom for the metal NC community in the future.

Engineering gold nanoparticles for molecular diagnostics and biosensing

Advances in nanotechnology and medical science have spurred the development of engineered nanomaterials and nanoparticles with particular focus on their applications in biomedicine. In particular, gold nanoparticles (AuNPs) have been the focus of great interest, due to their exquisite intrinsic properties, such as ease of synthesis and surface functionalization, tunable size and shape, lack of acute toxicity and favorable optical, electronic, and physicochemical features, which possess great value for application in biodetection and diagnostics purposes, including molecular sensing, photoimaging, and application under the form of portable and simple biosensors (e.g., lateral flow immunoassays that have been extensively exploited during the current COVID-19 pandemic). We shall discuss the main properties of AuNPs, their synthesis and conjugation to biorecognition moieties, and the current trends in sensing and detection in biomedicine and diagnostics. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > In Vitro Nanoparticle-Based Sensing Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

An Oligopeptide-Protected Ultrasmall Gold Nanocluster with Peroxidase-Mimicking and Cellular-Imaging Capacities

Recent decades have witnessed the rapid progress of nanozymes and their high promising applications in catalysis and bioclinics. However, the comprehensive synthetic procedures and harsh synthetic conditions represent significant challenges for nanozymes. In this study, monodisperse, ultrasmall gold clusters with peroxidase-like activity were prepared via a simple and robust one-pot method. The reaction of clusters with H₂O₂ and 3,3',5,5'-tetramethylbenzidine (TMB) followed the Michaelis-Menton kinetics. In addition, in vitro experiments showed that the prepared clusters had good biocompatibility and cell imaging ability, indicating their future potential as multi-functional materials.

Advances in Ultra-small Fluorescence Nanoprobes for Detection of Metal Ions, Drugs, Pesticides and Biomarkers

Identification of trace level chemical species (drugs, pesticides, metal ions and biomarkers) plays key role in environmental monitoring. Recently, fluorescence assay has shown significant advances in detecting of trace level drugs, pesticides, metal ions and biomarkers in real samples. Ultra-small nanostructure materials (metal nanoclusters (NCs), quantum dots (QDs) and carbon dots (CDs)) have been integrated with fluorescence spectrometer for sensitive and selective analysis of trace level target analytes in various samples including environmental and biological samples. This review summarizes the properties of metal NCs and ligand chemistry for the fabrication of metal NCs. We also briefly summarized the synthetic routes for the preparation of QDs and CDs. Advances of ultra-small fluorescent nanosensors (NCs, QDs and CDs) for sensing of metal ions, drugs, pesticides and biomarkers in various sample matrices are briefly discussed. Additionally, we discuss the recent challenges and future perspectives of ultra-small materials as fluorescent sensors for assaying of wide variety of target analytes in real samples.

New Paradigm for Nano-Bio Interactions: Multimolecular Assembly of a Prototypical Disordered Protein with Ultrasmall Nanoparticles

Understanding the interactions between nanoparticles (NPs) and proteins is crucial for the successful application of NPs in biological contexts. Protein adsorption is dependent on particle size, and protein binding to ultrasmall (1-3 nm) NPs is considered to be generally weak. However, most studies have involved structured biomacromolecules, while the interactions of ultrasmall NPs with intrinsically disordered proteins (IDPs) have remained elusive. IDPs are abundant in eukaryotes and found to associate with NPs intracellularly. As a model system, we focused on ultrasmall gold nanoparticles (usGNPs) and tau, a cytosolic IDP associated with Alzheimer's disease. Using site-resolved NMR, steady-state fluorescence, calorimetry, and circular dichroism, we reveal that tau and usGNPs form stable multimolecular assemblies, representing a new type of nano-bio interaction. Specifically, the observed interaction hot spots explain the influence of usGNPs on tau conformational transitions, with implications for the intracellular targeting of aberrant IDP aggregation.

Bone-Targeting Nanoparticles of a Dendritic (Aspartic acid)3-Functionalized PEG-PLGA Biopolymer Encapsulating Simvastatin for the Treatment of Osteoporosis in Rat Models

Simvastatin (SIM) is a lipid-lowering drug that also promotes bone formation, but its high liver specificity may cause muscle damage, and the low solubility of lipophilic drugs limits the systemic administration of SIM, especially in osteoporosis (OP) studies. In this study, we utilized the bone-targeting moiety of dendritic oligopeptides consisting of three aspartic acid moieties (dAsp3) and amphiphilic polymers (poly(ethylene glycol)-block-poly(lactic-co-glycolic acid); PEG-PLGA) to create dAsp3-PEG-PLGA (APP) nanoparticles (NPs), which can carry SIM to treat OP. An in vivo imaging system showed that gold nanocluster (GNC)-PLGA/APP NPs had a significantly higher accumulation rate in representative bone tissues. In vivo experiments comparing low-dose SIM treatment (0.25 mg/kg per time, 2 times per week) showed that bone-targeting SIM/APP NPs could increase the bone formation effect compared with non-bone-targeting SIM/PP NPs in a local bone loss of hindlimb suspension (disuse) model, but did not demonstrate good bone formation in a postmenopausal (ovariectomized) model of systemic bone loss. The APP NPs could effectively target high mineral levels in bone tissue and were expected to reduce side effects in other organs affected by SIM. However, in vivo OP model testing showed that the same lower dose could not be used to treat different types of OP.

Fluorescent Nanoparticles for Super-Resolution Imaging

Super-resolution imaging techniques that overcome the diffraction limit of light have gained wide popularity for visualizing cellular structures with nanometric resolution. Following the pace of hardware developments, the availability of new fluorescent probes with superior properties is becoming ever more important. In this context, fluorescent nanoparticles (NPs) have attracted increasing attention as bright and photostable probes that address many shortcomings of traditional fluorescent probes. The use of NPs for super-resolution imaging is a recent development and this provides the focus for the current review. We give an overview of different super-resolution methods and discuss their demands on the properties of fluorescent NPs. We then review in detail the features, strengths, and weaknesses of each NP class to support these applications and provide examples from their utilization in various biological systems. Moreover, we provide an outlook on the future of the field and opportunities in material science for the development of probes for multiplexed subcellular imaging with nanometric resolution.

Recent advances in the visual detection of ions and molecules based on gold and silver nanoclusters

Gold and silver nanoclusters (Au/AgNCs) exhibit excellent application potential in optical biosensors because of their low toxicity, excellent biocompatibility, and unique optical properties. Au/AgNCs-based visual analysis methods have emerged as powerful tools for detecting various targets with convenient readout. In this review, the applications of Au/AgNCs in the visual detection and bioimaging of metal ions, inorganic anions, small molecules, and biomacromolecules in various devices are summarized. Furthermore, this review also discusses the future perspectives of the field.

Levonorgestrel-protected Au8 and Au10 clusters with different antimicrobial abilities

Gold nanoclusters exhibit significant potential in antimicrobial applications due to their good stability and desirable biocompatibility in the mammalian cell model. However, most of the previously reported gold nanocluster antimicrobial agents do not have an atomic-precise structure, causing difficulties in understanding the structure-property correlation. In this study, structurally defined gold-levonorgestrel clusters, named Au₈(C₂₁H₂₇O₂)₈ (Au₈NCs) and Au₁₀(C₂₁H₂₇O₂)₁₀ (Au₁₀NCs), with the same ligand-to-metal ratio but different inner cores were prepared for antibacterial activity investigations, demonstrating that Au₈NCs exhibited a stronger antibacterial activity owing to the more significant damage it causes on the bacteria wall and membrane, and a stronger inhibition of glutathione reductase activity in bacteria. The leakage of the intracellular components and enzyme inhibition caused an imbalance of the intracellular antioxidant defence system, and consequently killed bacteria. These results indicated that the structure of gold nanoclusters has an important effect on their biological activity, indicating that it as a key factor to consider in the future design of antimicrobial agents.

Biomedical applications of metallic nanoparticles in cancer: Current status and future perspectives

The current advancements in nanotechnology are as an outcome of the development of engineered nanoparticles. Various metallic nanoparticles have been extensively explored for various biomedical applications. They attract lot of attention in biomedical field due to their significant inert nature, and nanoscale structures, with size similar to many biological molecules. Their intrinsic characteristics which include electronic, optical, physicochemical and, surface plasmon resonance, that can be changed by altering certain particle characteristics such as size, shape, environment, aspect ratio, ease of synthesis and functionalization properties have led to numerous applications in various fields of biomedicine. These include targeted drug delivery, sensing, photothermal and photodynamic therapy, imaging, as well as the modulation of two or three applications. The current article also discusses about the various properties of metallic nanoparticles and their applications in cancer imaging and therapeutics. The associated bottlenecks related to their clinical translation are also discussed.

Immunofluorescent-aggregation assay based on anti-Salmonella typhimurium IgG-AuNCs, for rapid detection of Salmonella typhimurium

Sensitive and rapid detection of pathogenic bacteria plays an important role in avoiding food poisoning. However, the practical application value of conventional assays for detection of foodborne bacteria, are limited by major drawbacks; these include the laboriousness of pure culture preparation, complexity of DNA extraction for polymerase chain reaction, and low sensitivity of enzyme-linked immunosorbent assay. Herein, we designed a non-complex strategy for the sensitive, quantitative, and rapid detection of Salmonella typhimurium with high specificity, using an anti-Salmonella typhimurium IgG-AuNC-based immunofluorescent-aggregation assay. Salmonella typhimurium was agglutinated with fluorescent anti-Salmonella typhimurium IgG-AuNC on a glass slide, and observed using a fluorescence microscope with photoexcitation and photoemission at 560 nm and 620 nm, respectively. Under optimized reaction conditions, the AuNC-based immunofluorescent-aggregation assay had a determination range between 7.0 × 10³ and 3.0 × 10⁸ CFU/mL, a limit of detection of 1.0 × 10³ CFU/mL and an assay response time of 3 min. The technique delivered good results in assessing real samples.

Shell-Isolated Assembly of Atomically Precise Nanoclusters on Gold Nanorods for Integrated Plasmonic-Luminescent Nanocomposites

In this work, we integrate atomically precise noble metal nanoclusters (NCs) on gold nanorods (AuNRs) to create hybrid plasmonic-luminescent nanomaterials. Initially, we assemble luminescent Ag₂₉(LA)₁₂ NC (LA = lipoic acid) to silica shell-encapsulated AuNRs. The resulting nanostructure shows plasmon-enhanced luminescence in aqueous medium as well as in the solid state. Atomic precision of the fluorophores used in this case allows detailed characterization of individual nanocomposites by diverse techniques, including transmission electron microscopy (TEM) and 3D electron tomographic reconstruction. We extend this strategy to prepare similar structures with gold NC protected with bovine serum albumin (Au₃₀BSA). These two examples demonstrate the generic nature of the present strategy in preparing plasmonic-luminescent hybrid nanostructures using atomically precise NCs.

Synthesis of metal nanoclusters and their application in Hg2+ ions detection: A review

Mercuric (Hg²⁺) ions released from human activities, natural phenomena, and industrial sources are regarded as the global pollutant of world's water. Hg²⁺ ions contaminated water has several adverse effects on human health and the environment even at low concentrations. Therefore, rapid and cost-effective method is urgently required for the detection of Hg²⁺ ions in water. Although, the current analytical methods applied for the detection of Hg²⁺ ions provide low detection limit, they are time consuming, require expensive equipment, and are not suitable for in-situ analysis. Metal nanoclusters (MNCs) consisting of several to ten metal atoms are important transition missing between single atoms and plasmonic metal nanoparticles. In addition, sub-nanometer sized MNCs possess unique electronic structures and the subsequent unusual optical, physical, and chemical properties. Because of these novel properties, MNCs as a promising material have attracted considerable attention for the construction of selective and sensitive sensors to monitor water quality. Hence this review is focused on recent advances on synthesis strategies, and optical and chemical properties of various MNCs including their applications to develop optical assay for Hg²⁺ ions in aqueous solutions.

Immunoassay based on Au-Ag bimetallic nanoclusters for colorimetric/fluorescent double biosensing of dicofol

The high toxicity of dicofol (DICO) to nontarget organisms has resulted in the contamination of food materials and caused a threat to human health. Developing a rapid and sensitive detection method of DICO in food samples is essential and still pursued. Fluorescent nanomaterials have been widely applied in biosensors to improve the sensitivity of detection. Herein, glutathione-capped Au-Ag bimetallic nanoclusters (Au-Ag NCs) exhibited the outstanding fluorescence characteristic with the average fluorescence lifetime of 1971.08 ns and photoluminescence quantum yield of 9.84% when the molar ratio of Au to Ag was 5:1. Polyethyleneimine modified gold nanoparticles (PEI-Au NPs) with the positive charge were prepared to generate a strong colorimetric signal. A dual-model colorimetric/fluorescent immune probe based on the Au-Ag NCs and PEI-Au NPs was successfully constructed by electrostatic force, and could be applied in both ic-ELISA and LFIA methods for rapid and ultrasensitive detection of DICO. In the ic-ELISA method, the introduction of fluorescence signal significantly increased the sensitivity of detection with the limit of detection (LOD) of 0.62 ng/mL and exhibited an excellent linear relationship within the range of 1.36 ng/mL-19.92 ng/mL. In the LFIA method, the fluorescence signal of Au-Ag NCs was accumulated on the test line and control line for the fluorescence model detection with a quantitative LOD at the level of 1.59 ng/mL. Such a dual-model colorimetric/fluorescent immunoassay serves as a promising candidate to develop new approaches in field detection.

Ligand-protected nanoclusters and their role in agriculture, sensing and allied applications

Nano biotechnology, when coupled with green chemistry, can revolutionize human life because of the vast opportunities and benefits it can offer to the quality of human life. Luminescent metal nanoclusters (NCs) have recently developed as a potential research area with applications in different areas like medical, imaging, sensing etc. Recently these new candidates have proved to be beneficial in the food supply chain enabling controlled release of nutrients, pesticides and as nanosensors for the detection of contaminants and play roles in healthy food storage and maintaining food quality. An assortment of nanomaterials has been employed for these applications and reviews have been published on the use of nanotechnology in agriculture. Ligand-protected metal nanoclusters are a distinctive class of small organic-inorganic nanostructures that garnered immense research interest in recent years owing to their stability at specific "magic size" compositions along with tunable properties that make them promising candidates for a wide range of nanotechnology-based applications. This review tries to consolidate the recent developments in the area of ligand-protected nanoclusters in connection with the detection of pesticides, food contaminants, heavy metal ions and plant growth monitoring for healthy agricultural practices. Its antimicrobial activity to manage the microbial contamination is highlighted. The review also throws light on the various perspectives by which food production and allied areas will be transformed in future.

Interactions of cationic gold nanoclusters with serum proteins and effects on their cellular responses

Cationic nanoparticles (NPs) have shown great potential in biological applications owing to their distinct features such as favorable cellular internalization and easy binding to biomolecules. However, our current knowledge of cationic NPs' biological behavior, i.e., NP-protein interactions, is still rather limited. Herein, we choose ultrasmall-sized fluorescent gold nanoclusters (AuNCs) coated by (11-mercaptoundecyl) - N, N, N - trimethylammonium bromide (MUTAB) as representative cationic NPs, and systematically study their interactions with different serum proteins at nano-bio interfaces. By monitoring the fluorescence intensity of MUTAB-AuNCs, all proteins are observed to bind with roughly micromolar affinities to AuNCs and quench their fluorescence. Transient fluorescence spectroscopy, X-ray photoelectron spectroscopy and isothermal titration calorimetry are also adopted to characterize the physicochemical properties of MUTAB-AuNCs after the protein adsorption. Concomitantly, circular dichroism spectroscopy reveals that cationic AuNCs can exert protein-dependent conformational changes of these serum proteins. Moreover, protein adsorption onto cationic AuNCs can significantly influence their cellular responses such as cytotoxicity and uptake efficiency. These results provide important knowledge towards understanding the biological behaviors of cationic nanoparticles, which will be helpful in further designing and utilizing them for safe and efficient biomedical applications.

Water-Dispersible Gold Nanoclusters: Synthesis Strategies, Optical Properties, and Biological Applications

Atomically precise gold nanoclusters (AuNCs) are an emerging class of quantum-sized nanomaterials. Intrinsic discrete electronic energy levels have endowed them with fascinating electronic and optical properties. They have been widely applied in the fields of optoelectronics, photovoltaics, catalysis, biochemical sensing, bio-imaging, and therapeutics. Nevertheless, most AuNCs are synthesized in organic solvents and do not disperse in aqueous solutions; this restricts their biological applications. In this review, we focus on the recent progress in the preparation of water-dispersible AuNCs and their biological applications. We first review different methods of synthesis, including direct synthesis from hydrophilic templates and indirect phase transfer of hydrophobic AuNCs. We then discuss their photophysical properties, such as emission enhancement and fluorescence lifetimes. Next, we summarize their latest applications in the fields of biosensing, biolabeling, and bioimaging. Finally, we outline the challenges and potential for the future development of these AuNCs.

Regulation of the Enzymatic Activities of Lysozyme by the Surface Ligands of Ultrasmall Gold Nanoclusters: The Role of Hydrophobic Interactions

Nanomaterials for biological applications would inevitably encounter and interact with biomolecules, which have a profound impact on the properties, functions, and even fates of both nanomaterials and biomolecules. Among the biomolecules, lysozyme (Lys) is of great importance in defending the bacterial intruder and maintaining health. Here, the interactions between fluorescent gold nanoclusters (AuNCs) (∼2 nm) capped with different surface ligands and Lys were thoroughly investigated. Fluorescence spectroscopic studies showed that dihydrolipoic acid (DHLA)-capped and glutathione (GSH)-capped AuNCs both quenched the intrinsic fluorescence of Lys by different quenching mechanisms. Agarose gel electrophoresis and zeta-potential assays showed that statistically one DHLA-AuNC could bind one Lys, while one GSH-AuNC could bind 3-4 Lys, providing new examples for the concept of a "protein complex". Activity assays indicated that DHLA-AuNCs heavily inhibited the enzymatic activity of Lys, while GSH-AuNCs had little effect. By synchronous fluorescence and circular dichroism spectroscopic studies, it was deduced that both AuNCs would interact with Lys by electrostatic attractions due to the distinct surface charges, and then DHLA-AuNCs would further interact with Lys by hydrophobic interactions, probably due to the hydrophobic carbon chain of DHLA and the hydrophobic side chains of amino acid residues in Lys, which was proved by the significant secondary structure changes caused by DHLA-AuNCs. Meanwhile, conformational changes induced by GSH-AuNCs with zwitterionic ligands were neglectable. Therefore, this work provided a comprehensive study of the consequences and mechanisms of the interactions between Lys and AuNCs, which was essential for the design and better use of nanomaterials as biological agents.

Interactions between Two Kinds of Gold Nanoclusters and Calf Thymus Deoxyribonucleic Acid: Directions for Preparations to Applications

Gold nanoclusters (AuNCs) have shown promising applications in biotherapy owing to their ultrasmall size and unique molecular-like properties. In order to better guide the preparations and applications of AuNCs, dihydrolipoic acid-protected AuNCs (DHLA-AuNCs) and glutathione-protected AuNCs (GSH-AuNCs) were selected as models and the interactions between them and calf thymus DNA (ctDNA) were studied in detail. The results showed that there was a small difference in the binding mechanisms and forces between both AuNCs and ctDNA. The quenching mechanisms of both AuNCs to (ctDNA-HO) were completely different. The binding constants indicated that the binding strength between DHLA-AuNCs and ctDNA was greater than those of GSH-AuNCs. The conformation investigations showed that GSH-AuNCs had a greater impact on the conformation of ctDNA, and both AuNCs were more inclined to interact with the A-T base pairs of ctDNA. These results indicate that the surface ligand had a significant effect on the interactions between AuNCs and DNA and might also further affect the applications of AuNCs, and these results could guide the preparations of AuNCs. For DHLA-AuNCs, their good biocompatibility made them a potential candidate for application in imaging, drug treatment, sensing, and so on. The resulting base accumulation of ctDNA and weak interactions made GSH-AuNCs have great potential for application in gene therapy, which was consistent with the current reports on the applications of these two AuNCs. This work has pointed out the directions for the preparations and applications of AuNCs.

Bright Future of Gold Nanoclusters in Theranostics

Quantum-sized gold nanoclusters (AuNCs) are emerging as theranostic agents-those that combine diagnostics and therapeutic properties-given their ultrasmall size <3 nm, which makes them behave more like a molecule rather than a nanoparticle. This molecule-like behavior endows AuNCs with interesting properties including photoluminescence, catalytic activity, and paramagnetism-all without the presence of any toxic heavy metal. But despite these fundamental advances, scalable synthetic approaches to produce high-quality AuNCs with well-controlled and programmable properties for biological applications as well as methods to determine their structure-property relationships are not widely available. In this Perspective, we will discuss what is known so far about AuNCs as well as how to move forward to propel AuNCs as a theranostic agent of choice for many biomedical applications.

One-pot synthesis of 68Ga-doped ultrasmall gold nanoclusters for PET/CT imaging of tumors

Gold nanoclusters (AuNCs) have attracted much attention for tumor theranostics in recent years because of their ability of renal clearance and to escape the reticuloendothelial system (RES) sequestration. In this study, we presented a novel method to synthesize ⁶⁸Ga-doped (labeled) AuNCs by simultaneous reduction of ⁶⁸GaCl₃ and HAuCl₄ by glutathione. As synthesized ⁶⁸Ga-doped, glutathione-coated AuNCs (⁶⁸Ga-GSH@AuNCs) were ultrasmall in size (<2 nm), highly stable under physiological conditions and renally clearable, and had high efficiency for tumor targeting. To demonstrate the universality of this ⁶⁸Ga labeling method and further enhance tumor targeting efficiency, arginine-glycine-aspartate (RGD)-containing peptide was introduced as co-reductant to synthesize RGD peptide and glutathione co-coated, ⁶⁸Ga-labeled AuNCs (⁶⁸Ga-RGD-GSH@AuNCs). Introduction of RGD peptide did not interfere the synthesis process but significantly enhanced the tumor targeting efficiency of the AuNCs. Our study demonstrated that it was feasible to label AuNCs with gallium-68 by direct reduction of the radioisotope and HAuCl₄ with reductant peptides, holding a great potential for clinical translation for PET/CT detection of tumors.

High Stability Au NPs: From Design to Application in Nanomedicine

In recent years, Au-based nanomaterials are widely used in nanomedicine and biosensors due to their excellent physical and chemical properties. However, these applications require Au NPs to have excellent stability in different environments, such as extreme pH, high temperature, high concentration ions, and various biomatrix. To meet the requirement of multiple applications, many synthetic substances and natural products are used to prepare highly stable Au NPs. Because of this, we aim at offering an update comprehensive summary of preparation high stability Au NPs. In addition, we discuss its application in nanomedicine. The contents of this review are based on a balanced combination of our studies and selected research studies done by worldwide academic groups. First, we address some critical methods for preparing highly stable Au NPs using polymers, including heterocyclic substances, polyethylene glycols, amines, and thiol, then pay attention to natural product progress Au NPs. Then, we sum up the stability of various Au NPs in different stored times, ions solution, pH, temperature, and biomatrix. Finally, the application of Au NPs in nanomedicine, such as drug delivery, bioimaging, photothermal therapy (PTT), clinical diagnosis, nanozyme, and radiotherapy (RT), was addressed concentratedly.

Fluorescence Lifetime Imaging Microscopy (FLIM) of Intracellular Transport by Means of Doubly Labelled siRNA Architectures

For monitoring the intracellular pathway of small interfering RNA (siRNA), both strands were labelled at internal positions by two ATTO dyes as an interstrand Förster resonance energy transfer pair. siRNA double strands show red emission and a short donor lifetime as readout, whereas siRNA antisense single strands show green emission and a long donor lifetime. This readout signals if GFP silencing can be expected (green) or not (red). We attached both dyes to three structurally different alkyne anchors by postsynthetic modifications. There is only a slight preference for the ribofuranoside anchors with the dyes at their 2'-positions. For the first time, the delivery and fate of siRNA in live HeLa cells was tracked by fluorescence lifetime imaging microscopy (FLIM), which revealed a clear relationship between intracellular transport using different transfection methods and knockdown of GFP expression, which demonstrates the potential of our siRNA architectures as a tool for future development of effective siRNA.

Surface engineering strategies of gold nanomaterials and their applications in biomedicine and detection

Gold nanomaterials have potential applications in biosensors and biomedicine due to their controllable synthesis steps, high biocompatibility, low toxicity and easy surface modification. However, there are still various limitations including low water solubility and stability, which greatly affect their applications. In addition, some synthetic methods are very complicated and costly. Therefore, huge efforts have been made to improve their properties. This review mainly introduces the strategies for surface modification of gold nanomaterials, such as amines, biological small molecules and organic small molecules as well as the biological applications of these functionalized AuNPs. We aim to provide effective ideas for better functionalization of gold nanomaterials in the future.

Gold nanoclusters as a GSH activated mitochondrial targeting photosensitizer for efficient treatment of malignant tumors

Gold nanoclusters (Au NCs), which have the characteristics of small size, near infrared (NIR) absorption and long triplet excited lifetime, have been used as a new type of photosensitizer for deep tissue photodynamic therapy (PDT). However, the therapeutic efficiency of the nano-system based on Au NCs still needs to be improved. Herein, we proposed a strategy using Mito-Au₂₅@MnO₂ nanocomposites to achieve enhanced PDT. Au₂₅(Capt)₁₈⁻ nanoclusters were applied as photosensitizers and further modified with peptides to target mitochondrial and MnO₂ nanosheets to consume glutathione (GSH). In the presence of GSH, Mito-Au₂₅@MnO₂ dis-integrated and Mito-Au₂₅ nanoparticles realized accurate mitochondrial targeting. Under the irradiation of 808 nm light, the nanocomposite ensured highly efficient PDT both in vitro and in vivo via oxidation pressure elevation and mitochondrial targeting in cancer cells.

This is the first example of mitochondrial targeting Au NCs capable of improving the efficiency of photodynamic therapy. Mito-Au₂₅@MnO₂ can be activated by consuming GSH and elevating oxidation pressure in cancer cells.

Self-assembled anionic and cationic Au nanoparticles with Au nanoclusters for the exploration of different biological responsiveness in cancer therapy

Self-assembly overcomes the biodegradation resistance of some traditional inorganic drug carriers. Herein, we prepared self-assembled Au nanocluster-based nanoparticles with different sizes and charges based on solvent- and cation-induced self-assembly nanotechnology as anti-cancer drug vehicles to solve the potential metabolism problems of solid gold nanoparticles. We also systematically explored the responsiveness of cancer cells to self-assembled Au nanocluster-based nanoparticles with different sizes and surface modified properties. We discovered that self-assembled nanoparticles inherited molecular-like properties of small-size Au NCs and exhibited an aggregation-induced emission (AIE) phenomenon with intense luminescence. Self-assembled Au nanocluster-based nanoparticles (Au NPs and cAu NPs) taking advantage of their size and positive charge exhibited better cell uptake than Au NCs. Encouraged by the excellent biological compatibility and cell uptake of these nanomaterials, we prepared drug-loaded nanomaterials by diffusion absorption and hydrophobic-induced embedding. cAu NPs@DOX showed an excellent anti-cancer effect owing to efficient cell internalization; Au NPs@DOX exhibited slow release of cargo drugs which might be significant to in vivo drug delivery. This work plays a crucial role in the rational design of self-assembled multifunctional gold-based nanoparticles in the application of nanomaterial-assisted multifunctional drug delivery systems (DDSs).

Detection of tetanus toxoid with fluorescent tetanus human IgG-AuNC-based immunochromatography test strip

Assays for detecting tetanus toxoid are of great significance to be applied in the research of the safety testing of tetanus vaccine. Currently, guinea pigs or mice are usually used to evaluate the toxicity in these assays. Herein, a facile and quick biomineralization process was carried out to generate tetanus human immunoglobulin G (Tet-IgG)-functionalized Au nanoclusters (Tet-IgG-AuNCs). The obtained Tet-IgG-AuNCs exhibited strong red emission with a photoluminescence quantum yield of 13%. Based on surface plasmon resonance measurements, the apparent dissociation constant of the Tet-IgG-AuNC-tetanus toxoid complexes was measured to be 2.27 × 10^-8 M. A facile detection approach was developed using a fluorescent Tet-IgG-AuNC-based immunochromatography test strip. By utilizing the high-brightness fluorescent Tet-IgG-AuNCs, this immunosensor showed favorable sensitivity with a detection limit at the level of 0.03 μg/mL. Further results demonstrated that this assay can reliably detect tetanus toxoid and therefore might provide a novel method to replace animal tests for the quantification of tetanus toxicity. Moreover, the antibody-AuNC-based immunochromatography test strip platform serves as a promising candidate to develop new approaches for detecting targeted antigens and biological events of interest.

Amphiphilic Au Nanoclusters Modulated by Magnetic Gemini Surfactants as a Cysteine Chemosensor and an MRI Contrast Agent

Cationic magnetic Gemini surfactants (mag-G-surfs), [C₁₄H₂₉(CH₃)₂N(CH₂)₂N(CH₃)₂C₁₄H₂₉]²⁺·2[XCl₃Br]^- (14-2-14·2X, X = Ce, Gd, or Ho), efficiently induce the aggregation of glutathione-protected Au nanoclusters (NCs) (GSH-Au NCs). These magnetic luminescent aggregates not only possess aggregation-induced emission (AIE) behavior but also display aggregation-induced magnetic enhancement. In particular, 14-2-14·2Ce and 14-2-14·2Gd have a better effect on boosting the luminescence intensity, quantum yield (QY), and luminescence lifetime (τ). The luminescent aggregates of GSH-Au NCs triggered by 14-2-14·2Gd or 14-2-14·2Ho exhibit more favorable paramagnetic behavior. Other Au NCs containing a Au(I)-thiolate complex shell also exhibit the obvious AIE phenomenon after introducing 14-2-14·2Gd, demonstrating the luminescence enhancement effect of mag-G-surfs. The luminescent aggregate 14-2-14·2Ce@GSH-Au NCs can serve as a "light up" fluorometric probe to detect cysteine selectively with the detection limit (DL) of 36 μM, and the magnetic luminescent aggregate 14-2-14·2Gd@GSH-Au NCs has the potential to be a novel contrast agent in T₁-weighted magnetic resonance (MR) imaging due to its satisfactory contrasting ability.

Aggregation-Enhanced Photoluminescence and Photoacoustics of Atomically Precise Gold Nanoclusters in Lipid Nanodiscs (NANO2)

The authors designed a structurally stable nano-in-nano (NANO2) system highly capable of bioimaging via an aggregation-enhanced NIR excited emission and photoacoustic response achieved based on atomically precise gold nanoclusters protected by linear thiolated ligands [Au25(SC n H2n+1)18, n = 4-16] encapsulated in discoidal phospholipid bicelles through a one-pot synthesis. The detailed morphological characterization of NANO2 is conducted using cryogenic transmission electron microscopy, small/wide angle X-ray scattering with the support of molecular dynamics simulations, providing information on the location of Au nanoclusters in NANO2. The photoluminescence observed for NANO2 is 20-60 times more intense than that of the free Au nanoclusters, with both excitation and emission wavelengths in the near-infrared range, and the photoacoustic signal is more than tripled. The authors attribute this newly discovered aggregation-enhanced photoluminescence and photoacoustic signals to the restriction of intramolecular motion of the clusters' ligands. With the advantages of biocompatibility and high cellular uptake, NANO2 is potentially applicable for both in vitro and in vivo imaging, as the authors demonstrate with NIR excited emission from in vitro A549 human lung and the KB human cervical cancer cells.

Responsive hyaluronic acid-gold cluster hybrid nanogel theranostic systems

Tumor microenvironment responsive and self-monitored multimodal synergistic theranostic strategies can significantly improve therapeutic efficacy by overcoming biological barriers. Herein, we report a type of smart fluorescent hyaluronic acid nanogel that can respond to the reducing microenvironment and activate tumor targeting with light-traceable monitoring in cancer therapy. First, the derivative of hyaluronic acid (HA) with a vinyl group and cystamine bisacrylamide were used to synthesize bioreducible HA based nanogels via copolymerization in aqueous medium. Then, multifunctional mHA-gold cluster (mHA-GC) hybrid nanogels were successfully prepared by the in situ reduction of gold salt in the HA nanogels. The HA matrix turns the nanogels into a capsule for effective drug loading with excellent colloidal stability. Interestingly, the reducing tumor microenvironment dramatically enhanced the fluorescence signal of gold clusters in the hybrid nanogels. The highly selective cancer cell uptake and efficient intratumoral accumulation of the hybrid nanogels were demonstrated by fluorescence tracking of these nanogels. Responsive disassembly of the hybrid nanogels and drug release were triggered by excess glutathione presence in cancer cells. Moreover, in vivo and in vitro tumor suppression assays revealed that the doxorubicin-loaded hybrid nanogels exhibited significantly superior tumor cell inhibition abilities compared to free DOX. Overall, the mHA-GC hybrid nanogels emerge as a promising theranostic nanoplatform for the targeted delivery and controlled release of antitumor drugs with light-traceable monitoring in cancer treatment.

Aggregation-Induced Emission of Au/Ag Alloy Nanoclusters for Fluorescence Detection of Inorganic Pyrophosphate and Pyrophosphatase Activity

The development of sensitive and accurate detection of inorganic pyrophosphate (PPi) and pyrophosphatase activity (PPase) is important as they play vital roles in biological systems. However, it is still not satisfactory for most of the analytical methods for PPi and PPase because of their Cu²⁺-dependence and poor accuracy. Although the metal ion triggered aggregation-induced emission (AIE) of metal nanoclusters (NCs) offers a new approach to design a Cu²⁺-free strategy for the accurate determination of PPi and PPase recently, current methods are all focused on utilizing pure metal NCs. Alloy NCs incorporating the advantages of diverse metal usually can achieve improved behaviors in the application, such as enhanced sensitivity and stability. In this work, glutathione stabilized alloy Au/Ag NCs were synthesized via a simple method and used for the fluorescence detection of PPi and PPase based on a Zn²⁺-regulated AIE strategy. The controlled release of Zn²⁺ by PPi and PPase could regulate the AIE of Au/Ag NCs and be employed to response PPi concentration and PPase activity. This method processes simple procedure, high sensitivity and stability, and low toxicity. In addition, we also studied the AIE behaviors of this Au/Ag NCs and offer some fundamental understanding of the AIE properties of water-soluble alloy NCs. This study not only provides a straightforward and new approach for PPi and PPase determination but a basis for further study on the AIE properties of alloy NCs and their application.