Rational Lithium Salt Molecule Tuning for Fast Charging/Discharging Lithium Metal Battery.

The electrolytes for lithium metal batteries (LMBs) are plagued by a low Li+ transference number (T+) of conventional lithium salts and inability to form a stable solid electrolyte interphase (SEI). Here, we synthesized a self-folded lithium salt, lithium 2-[2-(2-methoxy ethoxy)ethoxy]ethanesulfonyl(trifluoromethanesulfonyl) imide (LiETFSI), and comparatively studied with its structure analogue, lithium 1,1,1-trifluoro-N-[2-[2-(2-methoxyethoxy)ethoxy)]ethyl]methanesulfonamide (LiFEA). The special anion chemistry imparts the following new characteristics: i) In both LiFEA and LiETFSI, the ethylene oxide moiety efficiently captures Li+, resulting in a self-folded structure and high T+ around 0.8. ii) For LiFEA, a Li-N bond (2.069 Å) is revealed by single crystal X-ray diffraction, indicating that the FEA anion possesses a high donor number (DN) and thus an intensive interphase "self-cleaning" function for an ultra-thin and compact SEI. iii) Starting from LiFEA, an electron-withdrawing sulfone group is introduced near the N atom. The distance of Li-N is tuned from 2.069 Šin LiFEA to 4.367 Šin LiETFSI. This alteration enhances ionic separation, achieves a more balanced DN, and tunes the self-cleaning intensity for a reinforced SEI. Consequently, the fast charging/discharging capability of LMBs is progressively improved. This rationally tuned anion chemistry reshapes the interactions among Li+, anions, and solvents, presenting new prospects for advanced LMBs.

Chemotherapy-Enabled Colorectal Cancer Immunotherapy of Self-Delivery Nano-PROTACs by Inhibiting Tumor Glycolysis and Avoiding Adaptive Immune Resistance.

The chemo-regulation abilities of chemotherapeutic medications are appealing to address the low immunogenicity, immunosuppressive lactate microenvironment, and adaptive immune resistance of colorectal cancer. In this work, the proteolysis targeting chimera (PROTAC) of BRD4 (dBET57) is found to downregulate colorectal cancer glycolysis through the transcription inhibition of c-Myc, which also inhibits the expression of programmed death ligand 1 (PD-L1) to reverse immune evasion and avoid adaptive immune resistance. Based on this, self-delivery nano-PROTACs (designated as DdLD NPs) are further fabricated by the self-assembly of doxorubicin (DOX) and dBET57 with the assistance of DSPE-PEG2000. DdLD NPs can improve the stability, intracellular delivery, and tumor targeting accumulation of DOX and dBET57. Meanwhile, the chemotherapeutic effect of DdLD NPs can efficiently destroy colorectal cancer cells to trigger a robust immunogenic cell death (ICD). More importantly, the chemo-regulation effects of DdLD NPs can inhibit colorectal cancer glycolysis to reduce the lactate production, and downregulate the PD-L1 expression through BRD4 degradation. Taking advantages of the chemotherapy and chemo-regulation ability, DdLD NPs systemically activated the antitumor immunity to suppress the primary and metastatic colorectal cancer progression without inducing any systemic side effects. Such self-delivery nano-PROTACs may provide a new insight for chemotherapy-enabled tumor immunotherapy.

Competitive fitness and homologous recombination of SARS-CoV-2 variants of concern.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continue to emerge and cocirculate in humans and wild animals. The factors driving the emergence and replacement of novel variants and recombinants remain incompletely understood. Herein, we comprehensively characterized the competitive fitness of SARS-CoV-2 wild type (WT) and three variants of concern (VOCs), Alpha, Beta and Delta, by coinfection and serial passaging assays in different susceptible cells. Deep sequencing analyses revealed cell-specific competitive fitness: the Beta variant showed enhanced replication fitness during serial passage in Caco-2 cells, whereas the WT and Alpha variant showed elevated fitness in Vero E6 cells. Interestingly, a high level of neutralizing antibody sped up competition and completely reshaped the fitness advantages of different variants. More importantly, single clone purification identified a significant proportion of homologous recombinants that emerged during the passage history, and immune pressure reduced the frequency of recombination. Interestingly, a recombination hot region located between nucleotide sites 22,995 and 28,866 of the viral genomes could be identified in most of the detected recombinants. Our study not only profiled the variable competitive fitness of SARS-CoV-2 under different conditions, but also provided direct experimental evidence of homologous recombination between SARS-CoV-2 viruses, as well as a model for investigating SARS-CoV-2 recombination.

Asymmetric Trihalogenated Aromatic Lithium Salt Induced Lithium Halide Rich Interface for Stable Cycling of All-Solid-State Lithium Batteries.

Solid polymer electrolytes (SPEs) are the key components for all-solid-state lithium metal batteries with high energy density and intrinsic safety. However, the low lithium ion transference number (t+) of a conventional SPE and its unstable electrolyte/electrode interface cannot guarantee long-term stable operation. Herein, asymmetric trihalogenated aromatic lithium salts, i.e., lithium (3,4,5-trifluorobenzenesulfonyl)(trifluoromethanesulfonyl)imide (LiFFF) and lithium (4-bromo-3,5-difluorobenzenesulfonyl)(trifluoromethanesulfonyl)imide (LiFBF), are synthesized for polymer electrolytes. They exhibit higher t+ values and better compatibility with Li metal than conventional lithium bis(trifluoromethanesulfonyl) imide (LiTFSI). Due to the trihalogenated aromatic anions, LiFFF- and LiFBF-based electrolytes are prone to generate an LiF- and LiBr-rich solid electrolyte interphase (SEI), therefore increasing the stability of the solid electrolyte/anode interface. Particularly, LiFBF could induce a LiF/LiBr hybrid SEI, where LiF shows a high Young's modulus and high surface energy for homogenizing Li ion flux and LiBr exhibits an extremely low Li ion diffusion barrier in the SEI layer. As a result, the Li/Li symmetric cells could remain stable for more than 1200 h without a short circuit and the LiFePO4/Li batteries showed superb electrochemical performance over 1200 cycles at 1 C. This work provides valuable insights from the perspective of lithium salt molecular structures for high-performance all-solid-state lithium metal batteries.

A single amino acid substitution in the capsid protein of Zika virus contributes to a neurovirulent phenotype.

Increasing evidence shows the African lineage Zika virus (ZIKV) displays a more severe neurovirulence compared to the Asian ZIKV. However, viral determinants and the underlying mechanisms of enhanced virulence phenotype remain largely unknown. Herein, we identify a panel of amino acid substitutions that are unique to the African lineage of ZIKVs compared to the Asian lineage by phylogenetic analysis and sequence alignment. We then utilize reverse genetic technology to generate recombinant ZIKVs incorporating these lineage-specific substitutions based on an infectious cDNA clone of Asian ZIKV. Through in vitro characterization, we discover a mutant virus with a lysine to arginine substitution at position 101 of capsid (C) protein (termed K101R) displays a larger plaque phenotype, and replicates more efficiently in various cell lines. Moreover, K101R replicates more efficiently in mouse brains and induces stronger inflammatory responses than the wild type (WT) virus in neonatal mice. Finally, a combined analysis reveals the K101R substitution promotes the production of mature C protein without affecting its binding to viral RNA. Our study identifies the role of K101R substitution in the C protein in contributing to the enhanced virulent phenotype of the African lineage ZIKV, which expands our understanding of the complexity of ZIKV proteins.

Tuning and Balancing the Donor Number of Lithium Salts and Solvents for High-Performance Li Metal Anode.

The low reversibility of Li deposition/stripping in conventional carbonate electrolytes hinders the development of lithium metal batteries. Herein, we proposed a combination of solvents with a moderate donor number (DN) and LiNO3 as the sole salt, which has rarely been attempted due to its low solubility or dissociation degree in common solvents. It is found that the DN value of solvents is highly correlated to the reversibility of Li deposition behavior when LiNO3 is applied as the sole salt. The combination of LiNO3 and solvents with moderate DN behaves like a quasi-concentrated electrolyte even at a common or moderate concentration, while neither the solvents with poor solubility and low dissociation for LiNO3 (which usually corresponds to a low DN) nor the solvents with high dissociation for LiNO3 (which usually corresponds to an overly high DN) can achieve a high reversibility for low conductivity or excessive solvent decomposition. As a result, a Coulombic efficiency as high as 99.6% for Li deposition/stripping is achieved with the optimized combination. We believe this work will give a better understanding of the role of anions and solvents in the regulation of the solvation structure, and DN can be utilized as an important guideline to sieve suitable solvents for LiNO3 as the main salt to exhibit intriguing properties beyond traditional cognition.

Zika virus targets human trophoblast stem cells and prevents syncytialization in placental trophoblast organoids.

Zika virus (ZIKV) infection during pregnancy threatens pregnancy and fetal health. However, the infectivity and pathological effects of ZIKV on placental trophoblast progenitor cells in early human embryos remain largely unknown. Here, using human trophoblast stem cells (hTSCs), we demonstrated that hTSCs were permissive to ZIKV infection, and resistance to ZIKV increased with hTSC differentiation. Combining gene knockout and transcriptome analysis, we demonstrated that the intrinsic expression of AXL and TIM-1, and the absence of potent interferon (IFN)-stimulated genes (ISGs) and IFNs contributed to the high sensitivity of hTSCs to ZIKV. Furthermore, using our newly developed hTSC-derived trophoblast organoid (hTSC-organoid), we demonstrated that ZIKV infection disrupted the structure of mature hTSC-organoids and inhibited syncytialization. Single-cell RNA sequencing (scRNA-seq) further demonstrated that ZIKV infection of hTSC-organoids disrupted the stemness of hTSCs and the proliferation of cytotrophoblast cells (CTBs) and probably led to a preeclampsia (PE) phenotype. Overall, our results clearly demonstrate that hTSCs represent the major target cells of ZIKV, and a reduced syncytialization may result from ZIKV infection of early developing placenta. These findings deepen our understanding of the characteristics and consequences of ZIKV infection of hTSCs in early human embryos.

Supramolecular Polymer Ion Conductor with Weakened Li Ion Solvation Enables Room Temperature All-Solid-State Lithium Metal Batteries.

Improved durability, enhanced interfacial stability, and room temperature applicability are desirable properties for all-solid-state lithium metal batteries (ASSLMBs), yet these desired properties are rarely achieved simultaneously. Here, in this work, it is noticed that the huge resistance at Li metal/electrolyte interface dominantly impeded the normal cycling of ASSLMBs especially at around room temperature (<30 °C). Accordingly, a supramolecular polymer ion conductor (SPC) with "weak solvation" of Li+ was prepared. Benefiting from the halogen-bonding interaction between the electron-deficient iodine atom (on 1,4-diiodotetrafluorobenzene) and electron-rich oxygen atoms (on ethylene oxide), the O-Li+ coordination was significantly weakened. Therefore, the SPC achieves rapid Li+ transport with high Li+ transference number, and importantly, derives a unique Li2 O-rich SEI with low interfacial resistance on lithium metal surface, therefore enabling stable cycling of ASSLMBs even down to 10 °C. This work is a new exploration of halogen-bonding chemistry in solid polymer electrolyte and highlights the importance of "weak solvation" of Li+ in the solid-state electrolyte for room temperature ASSLMBs.

PA-E18G substitution in influenza A virus confers resistance to ZX-7101, a cap-dependent endonuclease inhibitor.

Cap-dependent endonuclease (CEN) in the polymerase acidic protein (PA) of influenza A virus (IAV) represents a promising drug target due to its critical role in viral gene transcription. The CEN inhibitor, baloxavir marboxil (BXM), was approved in Japan and the US in 2018 and several other countries subsequently. Along with the clinical use of BXM, the emergence and spread of IAV variants with reduced susceptibility to BXM have aroused serious concern. Herein, we comprehensively characterized the in vitro and in vivo antiviral activities of ZX-7101A, an analogue of BXM. The active form of prodrug ZX-7101 showed broad-spectrum antiviral potency against various IAV subtypes, including pH1N1, H3N2, H7N9 and H9N2, in MDCK cells, and the 50% effective concentration (EC50) was calculated to nanomole level and comparable to that of baloxavir acid (BXA), the active form of BXM. Furthermore, in vivo assays showed that administration of ZX-7101A conferred significant protection against lethal pH1N1 challenge in mice, with reduced viral RNA loads and alleviated pulmonary damage. Importantly, serial passaging of H1N1 virus in MDCK cells under selection pressure of ZX-7101 led to a resistant variant at the 15th passage. Reverse genetic and sequencing analysis demonstrated that a single E18G substitution in the PA subunit contributed to the reduced susceptibility to both ZX-7101 and BXA. Taken together, our results not only characterized a new CEN inhibitor of IAV but also identified a novel amino acid substitution responsible for CEN inhibitor resistance, which provides critical clues for future drug development and drug resistance surveillance.

A pangolin-origin SARS-CoV-2-related coronavirus: infectivity, pathogenicity, and cross-protection by preexisting immunity.

Virus spillover remains a major challenge to public health. A panel of SARS-CoV-2-related coronaviruses have been identified in pangolins, while the infectivity and pathogenicity of these pangolin-origin coronaviruses (pCoV) in humans remain largely unknown. Herein, we comprehensively characterized the infectivity and pathogenicity of a recent pCoV isolate (pCoV-GD01) in human cells and human tracheal epithelium organoids and established animal models in comparison with SARS-CoV-2. pCoV-GD01 showed similar infectivity to SARS-CoV-2 in human cells and organoids. Remarkably, intranasal inoculation of pCoV-GD01 caused severe lung pathological damage in hACE2 mice and could transmit among cocaged hamsters. Interestingly, in vitro neutralization assays and animal heterologous challenge experiments demonstrated that preexisting immunity induced by SARS-CoV-2 infection or vaccination was sufficient to provide at least partial cross-protection against pCoV-GD01 challenge. Our results provide direct evidence supporting pCoV-GD01 as a potential human pathogen and highlight the potential spillover risk.

Web Resources for SARS-CoV-2 Genomic Database, Annotation, Analysis and Variant Tracking.

The SARS-CoV-2 genomic data continue to grow, providing valuable information for researchers and public health officials. Genomic analysis of these data sheds light on the transmission and evolution of the virus. To aid in SARS-CoV-2 genomic analysis, many web resources have been developed to store, collate, analyze, and visualize the genomic data. This review summarizes web resources used for the SARS-CoV-2 genomic epidemiology, covering data management and sharing, genomic annotation, analysis, and variant tracking. The challenges and further expectations for these web resources are also discussed. Finally, we highlight the importance and need for continued development and improvement of related web resources to effectively track the spread and understand the evolution of the virus.

Holey Ti3C2 MXene-Derived Anode Enables Boosted Kinetics in Lithium-Ion Capacitors.

Lithium-ion capacitors (LICs) attract enormous attention because of the urgent demands for high power and energy density devices. However, the intrinsic imbalance between anodes and cathodes with different charge-storage mechanisms blocks the further improvement in energy and power density. MXenes, novel two-dimensional materials with metallic conductivity, accordion-like structure, and regulable interlayer spacing, are widely employed in electrochemical energy storage devices. Herein, we propose a holey Ti3C2 MXene-derived composite (pTi3C2/C) with enhanced kinetics for LICs. This strategy effectively decreases the surface groups (-F and -O) and generates expanded interplanar spacing. The in-plane pores of Ti3C2Tx lead to increased active sites and accelerated lithium-ion diffusion kinetics. Benefiting from the expanded interplanar spacing and accelerated lithium-ion diffusion, the pTi3C2/C as an anode implements excellent electrochemical property (capacity retention about 80% after 2000 cycles). Furthermore, the LIC fabricated with a pTi3C2/C anode and an activated carbon cathode displays a maximum energy density of 110 Wh kg-1 and a considerable energy density of 71 Wh kg-1 at 4673 W kg-1. This work provides an effective strategy to achieve high antioxidant capability and boosted electrochemical properties, which represents a new exploration of structural design and tuneable surface chemistry for MXene in LICs.

Characterization and phylogenetic analysis of a neurovirulent Zika virus isolated from Cambodia in 2019.

The geographic range of Zika virus (ZIKV) has expanded from Asia to the Americas, leading to the 2015-2016 pandemic with enhanced neurovirulence. At present, ZIKV is continuously circulating in many Southeast Asian countries. Unfortunately, the persistent evolution of ZIKV in Southeast Asia and its influence on the biological characteristics of the virus remain incompletely understood. In this study, the in vitro and in vivo properties of a new ZIKV isolate obtained from Cambodia in 2019 (CAM/2019) were characterized and compared with those of the Cambodian strain (CAM/2010). Compared with CAM/2010, the CAM/2019 virus showed similar plaque morphology and growth curves in cell cultures and induced comparable viremia and organ viral loads profiles in both BALB/c and A129 (IFNAR1-/- ) mice upon intraperitoneal (i.p.) inoculation. Remarkably, the CAM/2019 virus exhibited enhanced neurovirulence in neonatal mice compared with CAM/2010, with a 74-fold reduction in the 50% lethal dose (LD50 ). Consistently, CAM/2019 produced higher viral loads in the brains of BALB/c neonatal mice than CAM/2010 did. Sequence alignment showed that the CAM/2019 virus has acquired 12 amino acid substitutions, several of which were found to be associated with neurovirulence. In particular, the CAM/2019 virus shared an A1204T substitution in NS2A with the Thai isolate SI-BKK02 that was isolated from a microcephaly case. Taken together, our results indicate that a ZIKV strain isolated with specific mutations has emerged in Cambodia, highlighting the need for extensive molecular and disease surveillance in Cambodia and other Asian countries.

Changes in endemic patterns of respiratory syncytial virus infection in pediatric patients under the pressure of nonpharmaceutical interventions for COVID-19 in Beijing, China.

A series of nonpharmaceutical interventions (NPIs) was launched in Beijing, China, on January 24, 2020, to control coronavirus disease 2019. To reveal the roles of NPIs on the respiratory syncytial virus (RSV), respiratory specimens collected from children with acute respiratory tract infection between July 2017 and Dec 2021 in Beijing were screened by capillary electrophoresis-based multiplex PCR (CEMP) assay. Specimens positive for RSV were subjected to a polymerase chain reaction (PCR) and genotyped by G gene sequencing and phylogenetic analysis using iqtree v1.6.12. The parallel and fixed (paraFix) mutations were analyzed with the R package sitePath. Clinical data were compared using SPSS 22.0 software. Before NPIs launched, each RSV endemic season started from October/November to February/March of the next year in Beijing. After that, the RSV positive rate abruptly dropped from 31.93% in January to 4.39% in February 2020; then, a dormant state with RSV positive rates ≤1% from March to September, a nearly dormant state in October (2.85%) and November (2.98%) and a delayed endemic season in 2020, and abnormal RSV positive rates remaining at approximately 10% in summer until September 2021 were detected. Finally, an endemic RSV season returned in October 2021. There was a game between Subtypes A and B, and RSV-A replaced RSV-B in July 2021 to become the dominant subtype. Six RSV-A and eight RSV-B paraFix mutations were identified on G. The percentage of severe pneumonia patients decreased to 40.51% after NPIs launched. NPIs launched in Beijing seriously interfered with the endemic season of RSV.

covSampler: A subsampling method with balanced genetic diversity for large-scale SARS-CoV-2 genome data sets.

Phylogenetic analysis has been widely used to describe, display, and infer the evolutionary patterns of viruses. The unprecedented accumulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes has provided valuable materials for the real-time study of SARS-CoV-2 evolution. However, the large number of SARS-CoV-2 genome sequences also poses great challenges for data analysis. Several methods for subsampling these large data sets have been introduced. However, current methods mainly focus on the spatiotemporal distribution of genomes without considering their genetic diversity, which might lead to post-subsampling bias. In this study, a subsampling method named covSampler was developed for the subsampling of SARS-CoV-2 genomes with consideration of both their spatiotemporal distribution and their genetic diversity. First, covSampler clusters all genomes according to their spatiotemporal distribution and genetic variation into groups that we call divergent pathways. Then, based on these divergent pathways, two kinds of subsampling strategies, representative subsampling and comprehensive subsampling, were provided with adjustable parameters to meet different users' requirements. Our performance and validation tests indicate that covSampler is efficient and stable, with an abundance of options for user customization. Overall, our work has developed an easy-to-use tool and a webserver (https://www.covsampler.net) for the subsampling of SARS-CoV-2 genome sequences.

A Catechol-Meter Based on Conventional Personal Glucose Meter for Portable Detection of Tyrosinase and Sodium Benzoate.

In this study, the personal glucose meter (PGM) was first used as a fast and user-friendly meter for analyzing catechol (CA) based on the reduction of the mediator K3[Fe(CN)6] to K4[Fe(CN)6] in the glucose test strip. Then, an easy, low-cost, and convenient PGM-based method for detecting tyrosinase (TYR) activity and sodium benzoate (SBA) was developed on the basis of the TYR-catalyzed reaction. In this method, CA is oxidized to form o-benzoquinone by TYR, thereby reducing the residual amount of CA and the PGM readout. On the other hand, SBA can inhibit the oxidation of CA catalyzed by TYR and increase the residual amount of CA after the enzymatic reaction. Therefore, the activity of TYR is proportional to the difference in the PGM readout of CA, and the concentration of SBA is positively correlated with the residual amount of CA. After the relevant experimental conditions were systematically optimized, the proposed PGM-based method for the detection of TYR and SBA was successfully validated. The liner ranges are 1.0-103.3 U/mL and 6.25-1000 ppm, and the quantification limits are 1.0 U/mL and 6.25 ppm for TYR and SBA, respectively. Moreover, the spiked recovery tests in normal human serum and carbonate beverages (i.e., Cola, Sprite, and Fanta) were performed, and the recoveries (91.6-106.8%) further confirm the applicability of the PGM-based method in real sample analysis.

sitePath: a visual tool to identify polymorphism clades and help find fixed and parallel mutations.

BACKGROUND: Identifying polymorphism clades on phylogenetic trees could help detect punctual mutations that are associated with viral functions. With visualization tools coloring the tree, it is easy to visually find clades where most sequences have the same polymorphism state. However, with the fast accumulation of viral sequences, a computational tool to automate this process is urgently needed. RESULTS: Here, by implementing a branch-and-bound-like search method, we developed an R package named sitePath to identify polymorphism clades automatically. Based on the identified polymorphism clades, fixed and parallel mutations could be inferred. Furthermore, sitePath also integrated visualization tools to generate figures of the calculated results. In an example with the influenza A virus H3N2 dataset, the detected fixed mutations coincide with antigenic shift mutations. The highly specificity and sensitivity of sitePath in finding fixed mutations were achieved for a range of parameters and different phylogenetic tree inference software. CONCLUSIONS: The result suggests that sitePath can identify polymorphism clades per site. The clustering of sequences on a phylogenetic tree can be used to infer fixed and parallel mutations. High-quality figures of the calculated results could also be generated by sitePath.

A Paper-Based Analytical Device Integrated with Smartphone: Fluorescent and Colorimetric Dual-Mode Detection of ß-Glucosidase Activity.

In this work, indoxyl-glucoside was used as the substrate to develop a cost-effective, paper-based analytical device for the fluorescent and colorimetric dual-mode detection of ß-glucosidase activity through a smartphone. The ß-glucosidase can hydrolyze the colorless substrate indoxyl-glucoside to release indoxyl, which will be self-oxidized to generate green products in the presence of oxygen. Meanwhile, the green products emit bright blue-green fluorescence under ultraviolet-visible light irradiation at 365 nm. Fluorescent or colorimetric images were obtained by a smartphone, and the red-green-blue channels were analyzed by the Adobe Photoshop to quantify the ß-glucosidase activity. Under the optimum conditions, the relative fluorescent and colorimetric signals have a good linear relationship with the activity of ß-glucosidase, in the range of 0.01-1.00 U/mL and 0.25-5.00 U/mL, and the limits of detection are 0.005 U/mL and 0.0668 U/mL, respectively. The activities of ß-glucosidase in a crude almond sample measured by the fluorescent and colorimetric methods were 23.62 ± 0.53 U/mL and 23.86 ± 0.25 U/mL, respectively. In addition, the spiked recoveries of normal human serum and crude almond samples were between 87.5% and 118.0%. In short, the paper-based device, combined with a smartphone, can provide a simple, environmentally friendly, and low-cost method for the fluorescent and colorimetric dual-mode detection of ß-glucosidase activity.

Multicolor colorimetric assay for copper ion detection based on the etching of gold nanorods.

An effective, selective, and multicolor colorimetric assay for Cu2+ detection based on the regulation of peroxidase-like nanozyme-mediated etching of gold nanorods (Au NRs) is proposed. Cu2+-creatinine complex is selected as the nanozyme that exhibits excellent peroxidase-like activity even in the case of low concentration of Cu2+, which can catalyze 3,3,5,5-tetramethylbenzidine (TMB) to produce oxidized TMB (TMB+) in the presence of hydrogen peroxide, and TMB+ is oxidized to generate TMB2+ after adding H+, and the TMB2+ can etch Au NRs. The determination of Cu2+ is achieved based on the blue shift of the longitudinal localized surface plasmon resonance peak of Au NRs. Under the optimal conditions, the developed colorimetric assay exhibits high sensitivity for the detection of Cu2+ (limit of detection is 0.034 µM) with a wide linear range of 0.05-4.0 µM (R2 = 0.987). The solution shows a rainbow-like color in response to the increase of Cu2+ concentration, which can realize the semi-quantitative detection of Cu2+ by naked eyes. In addition, the developed method exhibits excellent selectivity for Cu2+-detection. The established method was used for the determination of Cu2+ in lake water, soil, and normal human serum with satisfactory recovery of spiked samples.