Multi-Targeted Peptide-Modified Gold Nanoclusters for Treating Solid Tumors in the Liver

Cascade nanozymes based on glucose oxidase modified gold nanoclusters for enhanced synergistic cancer therapy via activated autophagy and apoptosis

Although cascade strategy based on starvation therapy and nanozymes synergistic therapy has shown its unique advantages in tumor treatment, the relatively large size of integrated nanoplatform and protective autophagy greatly reduces the therapeutic effects. Herein, we report an ultra-small cascade nanozyme for enhanced synergistic cancer therapy by using glucose oxidase (GOx) capped gold nanoclusters (AuNCs@GOx). The constructed AuNCs@GOx integrates starvation therapy, chemo-dynamic therapy (CDT) and autophagy modulation, which realizes efficient tumor treatment. GOx converts glucose into gluconic acid and H2O2, followed by the transformation from H2O2 to high-toxic ·OH via peroxidase mimic AuNCs. Notably, AuNCs@GOx activate autophagy via inhibiting the PI3K/AKT/mTOR signaling pathway and activating AMPK/mTOR/ULK1 signaling pathway in Hela cells, thereby synergizing with mitochondrial apoptosis to induce tumor cell death. In vitro experiments using multiple cancer cell lines (SKOV-3, MCF-7, HT-29, Hela and 4 T1) and normal cells (GES-1 and 293 T) demonstrates that AuNCs@GOx could specifically and significantly suppress the cancer cells growth without damaging the normal cells. Furthermore, AuNCs@GOx could effectively inhibit 4 T1 tumor growth with good biocompatibility in vivo. Overall, the introduction of AuNCs@GOx into tumor cells realizes effective cascade treatment of tumor, which induces enhanced CDT and starvation therapy through activating autophagy-mediated death pathway and inducing apoptosis.

Inhibition of Post-Surgical Tumor Recurrence by 3-Bromopyruvate-Conjugated Gold Nanoclusters via MAPK and PI3K-Akt Pathways

The multitargeted strategy demonstrates significant potential in modern medical treatment, enhancing efficacy and reducing the risk of drug resistance. The rational combination design of nanomaterials and small molecules expands the new prospects of multitargeted therapies. Here, we have covalently linked ligands of atomic gold nanoclusters with 3-bromopyruvate and strategically designed a multitargeted approach to prevent postsurgical melanoma recurrence by activating the mitogen-activated protein kinase pathway and downregulating the phosphatidylinositol 3-kinase pathway. In vitro and in vivo validations confirm safety and outstanding efficacy, with recurrence rates reduced to 0% in completely resected mouse tumor models from 100%. The surface ligand modifiability of gold nanoclusters enables the precise engineering of nanodrugs with a molecule-like structure, providing a novel template that aligns with the clinical translation criteria set by the FDA. These findings identify an effective multitargeted strategy to develop structurally well-defined gold nanocluster-modified drug molecules in preventing postsurgical tumor recurrence.

Surface engineering of NIR-II luminescent gold nanoclusters for brain glioma-targeted imaging

Ultrasmall gold nanoclusters (AuNCs) with photoluminescence in the second near-infrared region (NIR-II) have emerged as promising probes for in vivo biomedical applications. However, it remains a challenge to utilize NIR-II-emitting AuNCs for imaging brain glioblastoma (GBM), which is highly lethal and hard to diagnose in time. Herein, we have presented systematic investigations on the brain delivery and GBM targeting efficacies of NIR-II-emitting AuNCs protected by different ligands. We first synthesized four types of AuNCs with surface coatings of small thiolated ligands and proteins, and then studied their in vitro penetration capability into the blood-brain barrier (BBB) and in vivo GBM targeting performances. It was found that the BBB permeability of AuNCs determined by the in vitro transwell model was not evidently affected by the surface ligands. Significantly, AuNCs protected by albumin exhibited notably extended blood circulation and less skull binding compared to those protected by small ligands, enabling superior in vivo brain GBM-targeted NIR-II PL imaging. We also modified the albumin-AuNCs with targeting peptides to improve in vivo imaging contrast. Additionally, AuNCs had negligible toxic effects on major organs as well as brain tissues and neurons, corroborating their good biocompatibility. This study examined the surface engineering of NIR-II luminescent AuNCs for brain GBM targeting, which may offer insights into the future design of AuNCs for bioapplications.

Intratumoral self-assembly of renal-clearable gold nanoparticles as precise photothermal nanomedicine for liver tumor therapy

Noninvasive photothermal therapy (PTT) for cancer with photothermal agents (PTAs) has recently achieved success in both preclinical and clinical trials. However, traditional PTAs tend to nonspecifically accumulate in normal liver tissue, hampering their use in PTT of liver tumors. By taking advantage of extremely low liver accumulation from ultrasmall renal-clearable gold nanoparticles (AuNPs), we report a biosafe therapeutic PTT strategy to treat liver tumors precisely through the intratumoral self-assembly of renal-clearable AuNPs at the tumor site via host-guest interactions. After active tumor targeting from the host AuNPs functionalized with both cyclo (Arg-Gly-Asp-d-Phe-Cys) and cyclodextrin, the guest AuNPs functionalized with both pH-responsive doxorubicin and adamantane are designed to precisely trigger intratumoral self-assembly, enhancing both PTT and chemotherapy toward the liver tumor microenvironment. This smart design principle generates a precise therapeutic action toward liver tumors without causing any noticeable heating effect or damage to the surrounding normal liver tissue.

Glutathione: a naturally occurring tripeptide for functional metal nanomaterials

Glutathione (GSH), a naturally occurring tripeptide, plays an important role as an intracellular antioxidant in the physiological microenvironment and participates in redox balance, detoxification, and cellular and disease regulation. The unique structural features of GSH, including the reductive thiol and multiple coordination sites (carboxyl and amino group), make it a significant molecule not only in the physiological context but also as a ligand in the development of functional metal nanomaterials. In this context, GSH's role as a protective ligand and reducing agent in surface etching and ligand exchange reactions has been explored at the molecular level, expanding the diversity of GSH-protected metal nanomaterials. With photoluminescence (PL) as one of its most intriguing properties, investigations into GSH's influence on PL properties emphasize its multifaceted coordination capabilities in surface coating, charge transfer from electron-rich functional groups, chirality arising from its unique structure, and available conjugation sites. Moreover, the biocompatibility of GSH, combined with the synergistic effect of metal components, renders GSH-protected nanomaterials an "Inseparable Duo" highly suited for applications in bio-sensing, bio-imaging via PL radiative decay and anti-cancer bio-therapies through photothermal therapy, photodynamic therapy, and radiotherapy. By exploring the multifaceted roles of GSH, this Perspective aims to highlight pathways including the encouragement of deeper synthetic exploration, innovative design at the bio-nano interface, and expanded nanobiomedical applications.

Photothermal Miniemulsion Polymerization by Amphiphilic Gold Nanoclusters

Gold nanoclusters (AuNCs), which are approximately 2 nm in size, exhibit distinctive photophysical and catalytic properties, but their performance is often compromised by environmental factors. To mitigate these challenges, attempts have been made to incorporate AuNCs into polymer matrices to enhance their stability. Miniemulsion polymerization has proven to be an effective method for fabricating organic-inorganic composites. Here, we present a facile photothermal-assisted method for miniemulsion polymerization utilizing AuNCs, which serve as co-stabilizers of the emulsion and photothermal conversion agents. By grafting tryptamine onto hydrophilic AuNCs, the amphiphilic AuNCs were spontaneously adsorbed at the styrene/water interfaces, resulting in stable nanoemulsions. Taking advantage of the photothermal properties of surface-bounded AuNCs, rapid polymerization of styrene within the nanoemulsion was successfully initiated by external laser irradiation. The prepared nanocomposites inherited the photothermal activity of AuNCs and exhibited good photothermal stability and repeatability. This approach not only facilitates remote control of chemical reactions, but also optimizes the distribution of AuNCs within the final polymer matrix, thereby enabling the efficient synthesis of nanocomposites while exploiting the unique photofunctionality of AuNCs.

Heteroatom number-dependent cluster frameworks in structurally comparable Pd-Au nanoclusters

Investigating the impact of heteroatom alloying extents on regulating the cluster structures is crucial for the fabrication of cluster-based nanomaterials with customized properties. Herein, two structurally comparable PdxAu12 (x = 1, 2) nanoclusters with a uniform surface environment but completely distinct kernel configurations were controllably synthesized and structurally determined. The single Pd-alloyed Pd1Au12 nanocluster retained an icosahedral metal framework, while the Pd2Au12 nanocluster with two Pd heteroatoms exhibited a unique toroidal configuration. The additional Pd heteroatom not only led to significant changes in the cluster frameworks but also profoundly affected their electrocatalytic CO2 reduction performance. The Pd1Au12 nanocluster demonstrated enhanced catalytic performance, exhibiting a higher current density, a lower onset potential, and greater CO faradaic efficiency compared to the Pd2Au12 nanocluster. This work offers new insights into the customization of the structures and properties of gold nanoclusters by regulating the doping degree of Pd heteroatoms.

Ligand-Targeted Ag9 Cluster Self-Cascade Antioxidants for Enhanced Reactive Oxygen Species Clearance in the Treatment of Inflammatory Bowel Disease

Atomically precise metal nanoclusters (MNCs) with flexible peripheral ligands provide selective channels and unique electronic structures to the rigid metal core, showing great application potential in many fields such as biomimetic nanozymes. In this study, we developed cost-effective, low-toxicity, and water-soluble MNC based self-cascade antioxidants for enhanced reactive oxygen species clearance. Compared to Ag nanoparticles, the Ag9 NCs with a monovalent Ag core coordinated by nonmetallic S and O show superior superoxide dismutase-like (inhibition 86.7%) and catalase-like (Km = 20.37 mM, Vmax = 3.13 × 10-3 mM s-1) activities. Interestingly, the -COOH groups on the ligands endow Ag9 NCs with a -42.5 mV negative surface charge, enhancing the targeting to inflammatory cells. Additionally, Ag9 NCs' remarkable therapeutic effects have been confirmed in cell cultures and an inflammatory bowel disease (IBD) model. Thus, this study proposes a novel cluster-based nanozyme that utilizes ligands for targeting and monovalent metal cores for catalysis, demonstrating significant therapeutic potential for IBD treatment.

Core-Satellite Nanoassembly Overcomes Spatial Heterogeneity of Dendric Cell Distribution in Pancreatic Tumors for Effective Chemoimmunotherapy

Pancreatic cancer therapies such as chemotherapy and immunotherapy are hindered by the dense extracellular matrix known as physical barriers, leading to heterogeneity impeding the effective penetration of chemotherapeutic agents and activation of antitumor immune responses. To address this challenge, we developed a hybrid nanoassembly with a distinct core-satellite-like heterostructure, PLAF@P/T-PD, which is responsive to both internal pH/redox and external ultrasound stimulations. This heterostructural nanoassembly features a polymersome core encapsulating an ultrasound contrast agent perfluoropentane and a chemotherapeutic agent Taxol (PLAF@P/T) electrostatically coated with satellite-like polyplexes carrying an immune agonist dsDNA (PD), which brings about synergistic functions inside the pancreatic tumor. The PLAF@P/T core functions as an enhancer for intratumor delivery through size enlargement and charge conversion in response to reactive oxygen species (ROS) and low pH, which triggers polyplex release and enables ultrasound-assisted tumor-penetrating Taxol delivery. Meanwhile, the released cationic polyplexes function as nucleic nanomedicine preferentially engulfed by peripheral dendritic cells (DCs) for immune modulation. Animal studies in mouse orthotopic pancreatic tumor model demonstrated exceptional therapeutic efficacy against both primary and metastatic tumors, which underlines the potential of this heterostructural nanoplatform for overcoming the therapeutic challenges associated with the heterogeneous physical barrier hindering intratumor drug delivery in pancreatic cancer treatment.

Metal-phenolic-network-coated gold nanoclusters for enhanced photothermal/chemodynamic/immunogenic cancer therapy

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, characterised by a short survival period, high malignancy, strong invasiveness, and high rates of recurrence and metastasis. Due to its unique molecular phenotype, TNBC is insensitive to endocrine therapy or molecular targeted therapy. The conventional treatment approach involves systemic chemotherapy for overall management; however, adjuvant chemotherapy after surgery has shown poor efficacy as residual lesions can easily lead to tumour recurrence. Therefore, there is an urgent need to find more effective treatment strategies. Herein, we designed a gold nanocluster coated with a metal-phenol formaldehyde network structure (AuNCs@PDA-Mn) for tumour Photothermal therapy and chemodynamic therapy (PTT and CDT), which induces systemic immune responses to suppress tumour metastasis. Experimental results show that after continuous irradiation for 10 min under an 808 nm laser (1.0W/cm2), AuNCs@PDA-Mn not only exhibits better tumour inhibition both in vitro and in vivo but also triggers stronger immune effects systemically. Therefore, this combined PTT and CDT treatment approach has great potential and provides a clinically relevant and valuable option for triple-negative breast cancer.

Ultrasmall metal nanoclusters as efficient luminescent probes for bioimaging

Ultrasmall metal nanoclusters (NCs, <2 nm) have emerged as a novel class of luminescent probes due to their atomically precise size and tailored physicochemical properties. The rapid advancements in the design and utilization of metal NC-based luminescent probes are facilitated by the atomic-level manipulation of metal NCs. This review article explores (i) the engineering of metal NCs' functions for bioimaging applications, and (ii) the diverse uses of metal NCs in bioimaging. We begin by presenting an overview of the engineering functions of metal NCs as luminescent probes for bioimaging applications, highlighting key strategies for enhancing NCs' luminescence, biocompatibility and targeting capabilities towards biological specimens. Our discussion then centers on the bioimaging applications of metal NCs in subcellular organelles, individual cells, tissues, and entire organs. Finally, we offer a perspective on the challenges and potential developments in the future use of metal NCs for bioimaging applications.

Inflection of Resistive Switching Behavior in Atomically Precise Silver Cluster-Assembled Materials

Bottom-up design of electronic materials based on nanometer-sized building blocks requires precise control over their self-assembly process. Atomically precise metal nanoclusters (NCs) are the well-characterized building blocks for crafting tunable nanomaterials. Here, a solution-processed assembly of a newly synthesized molecular silver nanocluster (0 D Ag12-NC) into a 1D nanocluster chain (1 D Ag12-CAM) is mediated by 4,4'-bipyridine linker Both 0 D Ag12-NC and 1 D Ag12-CAM consist of Ag12 core that adopts the cuboctahedron geometry protected by organic ligands. The resistive switching devices are fabricated in a sandwich-like structure of ITO (Indium tin oxide)/X/Ag (where X is either 0 D Ag12-NC or 1 D Ag12-CAM). The device based on 1 D Ag12-CAM exhibited excellent resistive switching behaviour, enduring up to 1000 cycles and boasting a fivefold higher Ion/Ioff ratio compared to the device based on the molecular 0 D Ag12-NC nanocluster. Furthermore, the device based on 1 D Ag12-CAM demonstrated negative differential resistance (NDR) phenomena, achieving a peak-to-valley ratio of 2.34 with a switching efficiency of 23 Ns. This work highlights the importance of interconnecting molecular nanoclusters into 1D nanocluster chains for fine-tuning resistive memory properties in futuristic electronic appliances.

Organotropic Engineering of Luminescent Gold Nanoclusters for In Vivo Imaging of Lung Orthotopic Tumors

Gold nanoclusters (AuNCs) are emerging as promising functional probes for bioapplications. However, because of rapid renal clearance, it is a challenge to tailor their biofate and improve their disease-targeting ability in vivo. Herein, we report an efficient strategy to tailor their organotropic actions by rationally designing AuNC assemblies. The nanocluster assembly is established based on the moderate electrostatic interaction or strong coordination between AuNCs, enabled by solely chitosan (CS) or the coadded chelating metal ions (e.g., Gd3+). We show that AuNCs-CS is rapidly excreted into urine, while further coordination of Gd3+ confers assemblies with liver and lung accumulation capabilities, dependent on Gd3+ contents. The organotropic actions are unraveled to result from their tunable stability in vivo and binding capability to cells/proteins. We also demonstrate that lung-targeting assemblies can enable specific NIR-II luminescence imaging of lung orthotopic tumors, which cannot be realized by employing discrete AuNCs. We anticipate that these findings will offer insights into the design principles of metal nanocluster probes and related bioapplications.

Chiral Amphiphilic Au23 Cluster and Its Specific Recognition to Remote Di-amines

The atomic precision of metal nanoclusters and variability of surface ligands pave the way for their rational design and functionalization, whereas the property strengthening in multiple ways has been long challenging. Herein, improved amphiphilicity, chirality, thermostability, and strong CPL (circularly polarized luminescence) properties have been accomplished by facile ligand exchange of [Au23(CHT)16]- with HCapt (HCHT and HCapt denote cyclohexanethiol and captopril). In addition, the obtained chiral [Au23(SR)16]- (short for [Au23(CHT)16-x(Capt)x]-) clusters show specific binding affinity to remote-diamines (such as arginine and single/double strand DNA), originating from the hydrogen bonding and Van der Waals interaction among the surface Capt ligands and the di-amine groups.

When Metal Nanoclusters Meet Smart Synthesis

Atomically precise metal nanoclusters (MNCs) represent a fascinating class of ultrasmall nanoparticles with molecule-like properties, bridging conventional metal-ligand complexes and nanocrystals. Despite their potential for various applications, synthesis challenges such as a precise understanding of varied synthetic parameters and property-driven synthesis persist, hindering their full exploitation and wider application. Incorporating smart synthesis methodologies, including a closed-loop framework of automation, data interpretation, and feedback from AI, offers promising solutions to address these challenges. In this perspective, we summarize the closed-loop smart synthesis that has been demonstrated in various nanomaterials and explore the research frontiers of smart synthesis for MNCs. Moreover, the perspectives on the inherent challenges and opportunities of smart synthesis for MNCs are discussed, aiming to provide insights and directions for future advancements in this emerging field of AI for Science, while the integration of deep learning algorithms stands to substantially enrich research in smart synthesis by offering enhanced predictive capabilities, optimization strategies, and control mechanisms, thereby extending the potential of MNC synthesis.

Induction of Non-Canonical Ferroptosis by Targeting Clusters Suppresses Glioblastoma

Glioblastoma multiforme (GBM) is the most aggressive brain tumor. There is a pressing need to develop novel treatment strategies due to the poor targeting effect of current therapeutics. Here, a gold cluster coated with optimized GBM-targeting peptide is engineered, namely NA. NA can efficiently target GBM both in vitro and in vivo. Interestingly, the uptake of NA significantly sensitizes GBM cells to ferroptosis, a form of programmed cell death that can bypass the tumor resistance to apoptosis. This effect is exerted through regulating the HO-1-dependent iron ion metabolism, which is the non-canonical pathway of ferroptosis. The combined treatment of a ferroptosis inducer and NA profoundly inhibited tumor growth in both the GBM spheroid model and a syngeneic mouse model with enhanced ferroptosis levels and excellent biosafety. Importantly, the infiltration of tumoricidal lymphocytes is also significantly increased within tumor. Therefore, NA presents a potential novel nanomaterial-based strategy for GBM treatment.

Near-Infrared Laser-Switching DNA Phase Separation Nanoinducer for Glioma Therapy

DNA phase separation participates in chromatin packing for the modulation of gene transcription, but the induction of DNA phase separation in living cells for disease treatment faces huge challenges. Herein, we construct a Ru(II)-polypyridyl-loaded upconversion nanoplatform (denoted as UCSNs-R) to achieve the manipulation of DNA phase separation and production of abundant singlet oxygen (1O2) for efficient treatment of gliomas. The utilization of the UCSN not only facilitates high loading of Ru(II)-polypyridyl complexes (RuC) but also promotes the conversion of near-infrared (NIR) laser to ultraviolet light for efficient 1O2 generation. The released RuC exhibit DNA "light-switch" behavior and high DNA binding affinity that induce phase separation of DNA in living cells, thus resulting in DNA damage and suppressing tumor-cell growth. In vivo investigation demonstrates the high capability of UCSNs-R in inhibiting tumor proliferation under NIR laser illumination. This work represents a paradigm for designing a DNA phase separation nanoinducer through integration of the UCSN with Ru(II)-polypyridyl-based complexes for efficient therapy of gliomas.

An integrated platform for decoding hydrophilic peptide fingerprints of hepatocellular carcinoma using artificial intelligence and two-dimensional nanosheets

Hydrophilic peptides (HPs) play a critical role in the pathogenesis of hepatocellular carcinoma (HCC). However, the comprehensive and in-depth high-throughput analysis of specific changes in HPs associated with HCC remains unrealized, due to the complex nature of biological fluids and the challenges of mining complex patterns in large data sets. The clinical diagnosis of HCC still lacks a non-destructive and accurate classification method, given the limited specificity of widely used biomarkers. To address these challenges, we have established a multifunctional platform that integrates artificial intelligence computation, hydrophilic interaction extraction of HPs, and MALDI-MS testing. This platform aims to achieve highly sensitive HP fingerprinting for accurate diagnosis of HCC. The method not only facilitates efficient detection of HPs, but also achieves a remarkable 100.00% diagnostic accuracy for HCC in a test cohort, supported by machine learning algorithms. By constructing a panel of HPs with 10 characteristic features, we achieved 98% accuracy in the test cohort for rapid diagnosis and identified 62 HPs deeply involved in pathways related to liver diseases. This integrated strategy provides new research directions for future biomarker studies as well as early diagnosis and individualized treatment of HCC.

Polyhedral {Ag12} and {Ag16} Clusters: Synthesis, Structural Characterization and Third-Order Nonlinear Optical Properties

Two polyhedral silver-thiolate clusters, [S@Ag16(Tab)10(MeCN)8](PF6)14 (Ag16) and [Ag12(Tab)6(DMF)12](PF6)12 (Ag12), were synthesized by using electroneutral Tab species as protective ligands (Tab=4-(trimethylammonio)benzenethiolate, DMF=N,N-dimethylformamide, MeCN=acetonitrile). Ag16 has a decahedral shape composed of eight pentagon {Ag5} units and two square {Ag4} units. The structure of Ag12 is a cuboctahedron, a classical Archimedean structure composed of six triangular faces and eight square faces. The former configuration is discovered in silver-thiolate cluster for the first time, possibly benefited from the more flexible coordination between the Tab ligand and Ag+ facilitated by the electropositive -N(CH3)3 + substituent group. Third-order nonlinear optical studies show that both clusters in DMF exhibit reverse saturate absorption response under the irradiation of 532 nm laser.

Heteroatom Doping Promoted Ultrabright and Ultrastable Photoluminescence of Water-Soluble Au/Ag Nanoclusters for Visual and Efficient Drug Delivery to Cancer Cells

Photoluminescence (PL) metal nanoclusters (NCs) have attracted extensive attention due to their excellent physicochemical properties, good biocompatibility, and broad application prospects. However, developing water-soluble PL metal NCs with a high quantum yield (QY) and high stability for visual drug delivery remains a great challenge. Herein, we have synthesized ultrabright l-Arg-ATT-Au/Ag NCs (Au/Ag NCs) with a PL QY as high as 73% and excellent photostability by heteroatom doping and surface rigidization in aqueous solution. The as-prepared Au/Ag NCs can maintain a high QY of over 61% in a wide pH range and various ionic environments as well as a respectable resistance to photobleaching. The results from structure characterization and steady-state and time-resolved spectroscopic analysis reveal that Ag doping into Au NCs not only effectively modifies the electronic structure and photostability but also significantly regulates the interfacial dynamics of the excited states and enhances the PL QY of Au/Ag NCs. Studies in vitro indicate Au/Ag NCs have a high loading capacity and pH-triggered release ability of doxorubicin (DOX) that can be visualized from the quenching and recovery of PL intensity and lifetime. Imaging-guided experiments in cancer cells show that DOX of Au/Ag NCs-DOX agents can be efficiently delivered and released in the nucleus with preferential accumulation in the nucleolus, facilitating deep insight into the drug action sites and pharmacological mechanisms. Moreover, the evaluation of anticancer activity in vivo reveals an outstanding suppression rate of 90.2% for mice tumors. These findings demonstrate Au/Ag NCs to be a superior platform for bioimaging and visual drug delivery in biomedical applications.

Electrophoretic Microplate Protein Identification Based on Gold Staining of Molybdenum Disulfide Hydrogels

Numerous high-performance nanotechnologies have been developed, but their practical applications are largely restricted by the nanomaterials' low stabilities and high operation complexity in aqueous substrates. Herein, we develop a simple and high-reliability hydrogel-based nanotechnology based on the in situ formation of Au nanoparticles in molybdenum disulfide (MoS2)-doped agarose (MoS2/AG) hydrogels for electrophoresis-integrated microplate protein recognition. After the incubation of MoS2/AG hydrogels in HAuCl4 solutions, MoS2 nanosheets spontaneously reduce Au ions, and the hydrogels are remarkably stained with the color of as-synthetic plasmonic Au hybrid nanomaterials (Au staining). Proteins can precisely mediate the morphologies and optical properties of Au/MoS2 heterostructures in the hydrogels. Consequently, Au staining-based protein recognition is exhibited, and hydrogels ensure the comparable stabilities and sensitivities of protein analysis. In comparison to the fluorescence imaging and dye staining, enhanced sensitivity and recognition performances of proteins are implemented by Au staining. In Au staining, exfoliated MoS2 semiconductors directly guide the oriented growth of plasmonic Au nanostructures in the presence of formaldehyde, showing environment-friendly features. The Au-stained hydrogels merge the synthesis and recognition applications of plasmonic Au nanomaterials. Significantly, the one-step incubation of the electrophoretic hydrogels leads to high simplicity of operation, largely challenging those multiple-step Ag staining routes which were performed with high complexity and formaldehyde toxicity. Due to its toxic-free, simple, and sensitive merits, the Au staining integrated with electrophoresis-based separation and microplate-based high-throughput measurements exhibits highly promising and improved practicality of those developing nanotechnologies and largely facilitates in-depth understanding of biological information.

Multidimensional Interactive Cascading Nanochips for Detection of Multiple Liver Diseases via Precise Metabolite Profiling

It is challenging to detect and differentiate multiple diseases with high complexity/similarity from the same organ. Metabolic analysis based on nanomatrix-assisted laser desorption/ionization mass spectrometry (NMALDI-MS) is a promising platform for disease diagnosis, while the enhanced property of its core nanomatrix materials has plenty of room for improvement. Herein, a multidimensional interactive cascade nanochip composed of iron oxide nanoparticles (FeNPs)/MXene/gold nanoparticles (AuNPs), IMG, is reported for serum metabolic profiling to achieve high-throughput detection of multiple liver diseases. MXene serves as a multi-binding site and an electron-hole source for ionization during NMALDI-MS analysis. Introduction of AuNPs with surface plasmon resonance (SPR) properties facilitates surface charge accumulation and rapid energy conversion. FeNPs are integrated into the MXene/Au nanocomposite to sharply reduce the thermal conductivity of the nanochip with negligible heat loss for strong thermally-driven desorption, and construct a multi-interaction proton transport pathway with MXene and AuNPs for strong ionization. Analysis of these enhanced serum fingerprint signals detected from the IMG nanochip through a neural network model results in differentiation of multiple liver diseases via a single pass and revelation of potential metabolic biomarkers. The promising method can rapidly and accurately screen various liver diseases, thus allowing timely treatment of liver diseases.

The roles of templates consisting of amino acids in the synthesis and application of gold nanoclusters

Gold nanoclusters (AuNCs) with low toxicity, high photostability, and facile synthesis have attracted great attention. The ligand is of great significance in stabilizing AuNCs and regulating their properties. Ligands consisting of amino acids (proteins and peptides) are an ideal template for synthesizing applicative AuNCs due to their inherent bioactivity, biocompatibility, and accessibility. In this review, we summarize the correlation of the template consisting of amino acids with the properties of AuNCs by analyzing different peptide sequences. The selection of amino acids can regulate the fluorescence excitation/emission and intensity, size, cell uptake, and light absorption. By analyzing the role played by AuNCs stabilized by proteins and peptides in the application, universal rules and detailed performances of sensors, antibacterial agents, therapeutic reagents, and light absorbers are reviewed. This review can guide the template design and application of AuNCs when selecting proteins and peptides as ligands.

Proposed Structural Model for Chiral Au40(SC2H4Ph)24 Nanoclusters

The structural configuration of thiolate-protected gold nanoclusters plays a pivotal role in elucidating the correlation between their structure and properties, comprehending their stability, and guiding experimental synthesis. In this study, utilizing the grand unified model and the ring model, we employed an innovative strategy of fusing triangular Au3 and tetrahedral Au4 elementary blocks by sharing a gold atom to design the gold core, predicting the structure of the Au40(SR)24 nanoclusters. Density functional theory calculations indicate that with the protective ligands simplified to methyl groups the energy of the predicted Au40(SR)24 is 0.45 eV lower than that of the experimentally reported Au40(o-MBT)24 nanoclusters, implying its substantial stability. Furthermore, the calculated UV absorption spectrum and circular dichroism spectrum of predicted Au40(SR)24 are consistent with the experimental results of Au40(SC2H4Ph)24 nanoclusters, suggesting that the predicted structure is a likely candidate for the structure of Au40(SC2H4Ph)24 nanoclusters.

Copper Nanoclusters as Multienzymes Mimic Activities of Oxidase and Ascorbic Acid Oxidase in the Presence of Imidazole

Artificial nanoenzymes based on metal nanoclusters have received great attention for multienzyme activities nowadays. In this work, pepsin-capped copper NCs (Cu-Pep NCs) are used as oxidase, ascorbic acid oxidase (AAO), and peroxidase mimics, and their activities are enhanced by the introduction of imidazole. The oxidase activity increased almost 7.5-fold, while 5-fold and 2-fold increases were observed for the peroxidase and AAO-like activity, respectively. The enhanced radical formation in the presence of imidazole moieties facilitates the enzymatic activity of the Cu-Pep-NCs/Imid system. This work describes the different enzymatic activities of the NCs, paving a new way for artificial nanoenzymes having enhanced activities.

Constructing perfect cubic Ag-Cu alloyed nanoclusters through selective elimination of phosphine ligands

The aspiration of chemists has always been to design and achieve control over nanoparticle morphology at the atomic level. Here, we report a synthesis strategy and crystal structure of a perfect cubic Ag-Cu alloyed nanocluster, [Ag55Cu8I12(S-C6H32,4(CH3)2)24][(PPh4)] (Ag55Cu8I12 for short). The structure of this cluster was determined by single-crystal X-ray diffraction (SCXRD) and further validated by X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP), Energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and 1H and 31P nuclear magnetic resonance (NMR). The surface deviation of the cube was measured to be 0.291 Å, making it the flattest known cube to date.

Biological Interaction and Imaging of Ultrasmall Gold Nanoparticles

The ultrasmall gold nanoparticles (AuNPs), serving as a bridge between small molecules and traditional inorganic nanoparticles, create significant opportunities to address many challenges in the health field. This review discusses the recent advances in the biological interactions and imaging of ultrasmall AuNPs. The challenges and the future development directions of the ultrasmall AuNPs are presented.

Phenylboronic Acid-Modified Gold Nanoclusters as a Nanoantibiotic to Treat Vancomycin-Resistant Enterococcus faecalis-Caused Infections

Vancomycin is one of the last lines of defense against certain drug-resistant bacteria-caused infections. However, the high susceptibility to drug resistance and high toxicity seriously limit the application of vancomycin. Nanoantibiotics provide opportunities to solve these problems. Herein, we present mercaptophenylboronic acid (MBA)-modified gold nanoclusters with well-defined molecular formulas and structure (Au44(MBA)18) and excellent antibacterial activities against various drug-resistant bacteria such as vancomycin-resistant Enterococcus faecalis (VRE). Au44(MBA)18 interacts with bacteria by first attaching to teichoic-acid and destroying the cell wall and subsequently binding to the bacterial DNA. Au44(MBA)18 could be administered via multiple routes and has a high biosafety (500 mg/kg, no ototoxicity), overcoming the two major shortcomings of vancomycin (sole administration route and high ototoxicity). Our study is insightful for curing infections caused by multidrug-resistant bacteria using nanoantibiotics with high biosafety.