Revealing Roles of High-Electronegativity Fluorine Atoms in Boosting Redox Potential of Layered Sodium Cathodes.

The development of high-energy-density cathode materials is regarded as the ultimate goal of alkali metal-ion batteries energy storage. However, the strategy of regulating specific capacity is limited by the theoretical capacity, and meanwhile focusing on improving capacity will lead to structural destructions. Herein, a novel perspective is proposed that tuning the electronic band structure by introducing highly electronegative fluoride atoms in NaxTMO2-yFy (0 < x < 1, 0 < y < 2) model compounds to improve redox potential for developing high-energy-density layered oxides. Highly electronegative fluoride atoms is introduced into P2-type Na0.67Fe0.5Mn0.5O2 (NFM), and the thus fluoride NFM (F-NFM) cathode achieved high redox potential (3.0 V) and high energy density (446 Wh kg-1). Proved by structural characterizations, fluorine atoms are successfully incorporated into oxygen sites in NFM lattice. Ultraviolet photoelectron spectroscopy is applied to quantitatively analyze the improved redox potential of F-NFM, which is achieved by the decreased valence band energy in electronic band structure due to the strongly electrophilic fluoride ions. Moreover, fluoride atoms can stabilize the local environment of NFM and improve its redox potential. The work provides a perspective to improve redox potential by tuning the electronic band structure in layered oxides and developing high-energy-density alkali metal-ion batteries.

Deciphering the SAM- and Metal-Dependent Mechanism of O-Methyltransferases in Cystargolide and Belactosin Biosynthesis: A Structure-Activity Relationship Study.

Cystargolides and belactosins are natural products with a distinct dipeptide structure and an electrophilic ß-lactone warhead. They are known to inhibit proteases such as the proteasome or caseinolytic protease P, highlighting their potential in treating cancers and neurodegenerative diseases. Recent genetic analyses have shown homology between the biosynthetic pathways of the two inhibitors. Here, we characterize the O-methyltransferases BelI and CysG, which catalyze the initial step of ß-lactone formation. Employing techniques such as crystallography, computational analysis, mutagenesis, and activity assays, we identified a His-His-Asp (HHD) motif in the active sites of the two enzymes, which is crucial for binding a catalytically active calcium ion. Our findings thus elucidate a conserved divalent metal-dependent mechanism in both biosynthetic pathways that distinguishes BelI and CysG from previously characterized O-methyltransferases.

Enhanced degradation of phenolic pollutants by a novel cold-adapted laccase from Peribacillus simplex.

Laccase (EC 1.10.3.2), as eco-friendly biocatalysts, holds immense potential for sustainable applications across various environmental and industrial sectors. Despite the growing interest, the exploration of cold-adapted laccases, especially their unique properties and applicability, remains limited. In this study, we have isolated, cloned, expressed, and purified a novel laccase from Peribacillus simplex (GenBank: PP430751), which was derived from permafrost layer. The recombinant laccase (PsLac) exhibited optimal activity at 30 °C and a pH optimum of 3.5. Remarkably, PsLac exhibited remarkable stability in the presence of organic solvents, with its enzyme activity increasing by 20 % after being incubated in a 30 % trichloromethane solution for 12 h, compared to its initial activity. Furthermore, the enzyme preserved 100 % of its activity after undergoing eight freeze-thaw cycles. Notably, the catalytic center of PsLac contains Zn2+ instead of the typically observed Cu2+ found in other laccases, and metal-ion substitution experiments raised the catalytic efficiency to 3-fold when Zn2+ was replaced with Fe2+. Additionally, PsLac has demonstrated a proficient ability to degrade phenolic pollutants, such as hydroquinone, even at a low temperature of 16 °C, positioning it as a promising candidate for environmental bioremediation and contributing to cleaner production processes.

Recent Development of Fluoroquinolone Derivatives as Anticancer Agents.

Cancer is the second leading cause of death in the world following cardiovascular disease. Its treatment, including radiation therapy and surgical removal of the tumour, is based on pharmacotherapy, which prompts a constant search for new and more effective drugs. There are high costs associated with designing, synthesising, and marketing new substances. Drug repositioning is an attractive solution. Fluoroquinolones make up a group of synthetic antibiotics with a broad spectrum of activity in bacterial diseases. Moreover, those compounds are of particular interest to researchers as a result of reports of their antiproliferative effects on the cells of the most lethal cancers. This article presents the current progress in the development of new fluoroquinolone derivatives with potential anticancer and cytotoxic activity, as well as structure-activity relationships, along with possible directions for further development.

Reconfigurable Optical Sensor for Metal-Ion-Mediated Label-Free Recognition of Different Biomolecular Targets.

Reconfiguration of chemical sensors, intended as the capacity of the sensor to adapt to novel operational scenarios, e.g., new target analytes, is potentially game changing and would enable rapid and cost-effective reaction to dynamic changes occurring at healthcare, environmental, and industrial levels. Yet, it is still a challenge, and rare examples of sensor reconfiguration have been reported to date. Here, we report on a reconfigurable label-free optical sensor leveraging the versatile immobilization of metal ions through a chelating agent on a nanostructured porous silica (PSiO2) optical transducer for the detection of different biomolecules. First, we show the reversible grafting of different metal ions on the PSiO2 surface, namely, Ni2+, Cu2+, Zn2+, and Fe3+, which can mediate the interaction with different biomolecules and be switched under mild conditions. Then, we demonstrate reconfiguration of the sensor at two levels: 1) switching of the metal ions on the PSiO2 surface from Cu2+ to Zn2+ and testing the ability of Cu2+-functionalized and Zn2+-reconfigured devices for the sensing of the dipeptide carnosine (CAR), leveraging the well-known chelating ability of CAR toward divalent metal ions; and 2) reconfiguration of the Cu2+-functionalized PSiO2 sensor for a different target analyte, namely, the nucleotide adenosine triphosphate (ATP), switching Cu2+ with Fe3+ ions to exploit the interaction with ATP through phosphate groups. The Cu2+-functionalized and Zn2+-reconfigured sensors show effective sensing performance in CAR detection, also evaluated in tissue samples from murine brain, and so does the Fe3+-reconfigured sensor toward ATP, thus demonstrating effective reconfiguration of the sensor with the proposed surface chemistry.

Ultrasensitive detection platform for Staphylococcus aureus based on DNAzyme tandem blocking CRISPR/Cas12a system.

Detection methods based on CRISPR/Cas12a have been widely developed in the application of pathogenic microorganisms to guarantee food safety and public health. For sensitive detection, the CRISPR-based strategies are often in tandem with amplification methods. However, that may increase the detection time and the process may introduce nucleic acid contamination resulting in non-specific amplification. Herein, we established a sensitive S. aureus detection strategy based on the CRISPR/Cas12a system combined with DNAzyme. The activity of Cas12a is blocked by extending the spacer of crRNA (bcrRNA) and can be reactivated by Mn2+. NH2-modified S. aureus-specific aptamer was loaded on the surface of Fe3O4 MNPs (apt-Fe3O4 MNPs) and MnO2 NPs (apt-MnO2 NPs) by EDC/NHS chemistry. The S. aureus was captured to form apt-Fe3O4 MNPs/S. aureus/apt-MnO2 NPs complex and then MnO2 NPs were etched to release Mn2+ to activate DNAzyme. The active DNAzyme can cleave the hairpin structure in bcrRNA to recover the activity of the CRISPR/Cas system. By initiating the whole detection process by generating Mn2+ through nanoparticle etching, we established a rapid detection assay without nucleic acid extraction and amplification process. The proposed strategy has been applied in the ultrasensitive quantitative detection of S. aureus and has shown good performance with an LOD of 5 CFU/mL in 29 min. Besides, the proposed method can potentially be applied to other targets by simply changing the recognition element and has the prospect of developing a universal detection strategy.

First principles theoretical of designing Sandwich-like Metallic BP4 Monolayer as Anode for Alkali Metal-ion Batteries.

Phosphorene has been widely used as anode material for batteries. However, the huge volume change during charging and discharging process, the semiconductor properties, and the high open circuit voltage limit its application. Based on this, by introducing the electron-deficient boron atoms into blue phosphorene, we proposed a P-rich sandwich-like BP4 monolayer by density functional theory calculation and particle swarm optimization. The BP4 monolayer shows good thermodynamic and dynamic stability, as well as chemical stability in O2 atmosphere, mainly due to the strengthened P-P bond of the outer layer by the middle boron atoms adopting sp3 hybridization. According to the band structure, the BP4 monolayer shows metallic property, which is beneficial to electron conductivity. Furthermore, compared with blue phosphorene and black phosphorene, the P-rich BP4 monolayer shows higher theoretical capacity for Li, Na, and K of 1193.90, 1119.28, and 397.97 mA·h·g-1, respectively. The lattice constant of BP4 monolayer increases only 3.73 (Li), 2.52 (Na) after Li/Na fully adsorbed on the anode. More importantly, the wettability of BP4 monolayer in the electrolyte is comparable to that of graphene. These findings show that the stable sandwich-like BP4 monolayer has potential as a lightweight anode material.

Silkworm-derived carbon nano rods (swCNR) for detection of bismuth ions (Bi3+) in aquatic medium and their antiradical properties.

The extensive utilization of bismuth and its derivatives in many industries, such as chemical, semiconductor, pharmaceutical, and cosmetics, leads to their accumulation in wastewater, posing a risk to both human health and the environment. Carbon nanorods (CNR) are fluorescent nanoparticles with an ability to detect various analytes as sensing probes. This study focuses on the production, structure, and chemical composition characterization of silkworm-derived CNR (swCNR) and their ability to detect bismuth ions (Bi3+) and inhibit radicals. The optimum wavelength for exciting the fluorescence of swCNR was 370 nm, and the resulting emission peak was observed at 436 nm. The prepared swCNR showed static fluorescence quenching mechanism-based sensing of Bi3+ ions with a limit of detection of 175 nM and two linear ranges from 0.5 to 5 µM (R2 = 0.9997) and 10-50 µM (R2 = 0.9995). The swCNR demonstrated high selectivity in detecting Bi3+ ions in the spiked river water samples, thus establishing the swCNR's role as a nano fluorescence probe designed for the selective detection of Bi3+ ions among other metal ions. Favorable results for the antiradical ability of swCNR were obtained against hydroxyl, 2,2 diphenyl-1 picrylhydrazyl, and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radicals with scavenging percentages of 15, 32, and 90, respectively. The possible applications of swCNR in the environmental and antioxidant sectors are proposed in this study.

Investigation of the Potential of Repurposing Medium-Density Fiberboard Waste as an Adsorbent for Heavy Metal Ion Removal.

Medium-density fiberboard (MDF) waste generation has increased steadily over the past decades, and therefore, the investigation of novel methods to recycle this waste is very important. The potential of repurposing MDF waste as an adsorbent for the treatment of Cd(II), Cu(II), Pb(II), and Zn(II) ions in water was investigated using MDF offcuts. The highest adsorption potential in single-metal ion solution systems was observed for Pb(II) ions. The experimental data of Pb(II) ions fit well with the Freundlich isotherm and pseudo-second-order kinetic models. Complexation and electrostatic interactions were identified as the adsorption mechanisms. The adsorption behavior of multi-metal ion adsorption systems was investigated by introducing Cd(II) ions as a competitive metal ion. The presence of the Cd(II) ions reduced the adsorption potential of Pb(II) ions, yet the preference for the Pb(II) ions remained. Regeneration studies were performed by using 0.1 M HCl as a regeneration agent for both systems. Even though a significant amount of adsorbed metal ions were recovered, the adsorption potential of the MDF was reduced in the subsequent adsorption cycles. Based on these results, MDF fines have the potential to be used as an economical adsorbent for remediation of wastewater containing heavy metal ions.

Engineering two-component systems for advanced biosensing: From architecture to applications in biotechnology.

Two-component systems (TCSs) are prevalent signaling pathways in bacteria. These systems mediate phosphotransfer between histidine kinase and a response regulator, facilitating responses to diverse physical, chemical, and biological stimuli. Advancements in synthetic and structural biology have repurposed TCSs for applications in monitoring heavy metals, disease-associated biomarkers, and the production of bioproducts. However, the utility of many TCS biosensors is hindered by undesired performance due to the lack of effective engineering methods. Here, we briefly discuss the architectures and regulatory mechanisms of TCSs. We also summarize the recent advancements in TCS engineering by experimental or computational-based methods to fine-tune the biosensor functional parameters, such as response curve and specificity. Engineered TCSs have great potential in the medical, environmental, and biorefinery fields, demonstrating a crucial role in a wide area of biotechnology.

A Tip-Based Workflow for Sensitive IMAC-Based Low Nanogram Level Phosphoproteomics.

Analyzing the phosphoproteome at nanoscale poses a significant challenge, mainly due to the substantial sample loss from nonspecific surface adsorption during the enrichment of low stoichiometric phosphopeptides. Here, we describe a tandem tip-based phosphoproteomics sample preparation method capable of sequential sample cleanup and enrichment without the need for additional sample transfer, thereby minimizing sample loss. Integration of this method to our recently developed SOP (surfactant-assisted one-pot sample preparation) and iBASIL (improved boosting to amplify signal with isobaric labeling) approaches creates a streamlined workflow, enabling sensitive, high-throughput nanoscale phosphoproteomics measurements.

Application of catalytic technology based on the piezoelectric effect in wastewater purification.

The demands of human life and industrial activities result in a significant influx of toxic contaminants into aquatic ecosystems. In particular, organic pollutants such as antibiotics and dye molecules, bacteria, and heavy metal ions are represented, posing a severe risk to the health and continued existence of living organisms. The method of removing pollutants from water bodies by utilizing the principle of the piezoelectric effect in combination with chemical catalytic processes is superior to other wastewater purification technologies because it can collect water energy, mechanical energy, etc. to achieve cleanliness and high removal efficiency. Herein, we briefly introduced the piezoelectric mechanisms and then reviewed the latest advances in the design and synthesis of piezoelectric materials, followed by a summary of applications based on the principle of piezoelectric effect to degrade pollutants in water for wastewater purification. Moreover, water purification technologies incorporating the piezoelectric effect, including piezoelectric effect-assisted membrane filtration, activation of persulfate, and battery electrocatalysis are elaborated. Finally, future challenges and research directions for the piezoelectric effect are proposed.

Rubik's cube PBA frameworks for optimizing the electrochemical performance in alkali metal-ion batteries.

PBA frameworks have stood out among metal-organic frameworks because of their easy preparation, excellent stability, porous structures, and rich redox properties. Unfortunately, their non-ideal conductivity and significant volume expansion during cycling prevent more widespread application in alkali-metal-ion (Li+, Na+, and K+) batteries. By changing the type and molar ratio of metal ions, Rubik's PBA frameworks with infinite structural variations were obtained in this study, just like the Rubik's cube undergoes infinite changes during the rotation. X-ray adsorption fine structure measurements have documented the existence and determined the coordination environment of the metal ions in the Rubik's PBA framework. Benefiting from the more stable Rubik's cube structures with diverse composition, enhanced conductivity, and greater adsorption capacity, the obtained Rubik's cubes CoM-PBA anodes, especially CoZn-PBA deliver the enhanced cycling and rate performance in all the alkali-metal-ion batteries. The findings are supported by density functional theory calculations. Ex-situ X-ray photoelectron spectroscopy, and in-situ X-ray diffraction measurements were undertaken to explore the storage mechanism of CoZn-PBA anodes. Our results further demonstrate that the Rubik's cube PBA framework-based materials could be widely applied in the field of alkali-metal-ion batteries.

Effect of diastereoisomeric composition on the chromatographic retention of phosphorothioated oligonucleotides using three different liquid chromatography systems.

To increase understanding of the interactions and effects of the diastereoisomeric character of phosphorothioate (PS) oligonucleotides on chromatographic retention, three chromatographic methods [in-series reversed phase-strong anion exchange (RP-SAX), ion pair-reversed phase and metal ion complexation chromatography (MICC)] were applied to the characterization of stereo-enriched compounds. Chromatographic systems are widely available, amenable to routine applications, and simple to deploy in comparison to more advanced instrumentation (e.g., 31P NMR) and procedures (e.g., enzymatic digestion). Analogous diastereoisomeric distribution profiles were obtained by RP-SAX and IP-RP based on their common mechanism of separation involving the combination of hydrophobic and electrostatic interactions. Similar linear relationships between retention time (tR) and the numbers of stereo random, Rp, and Sp PS linkages were obtained with both methods. Sp-enriched diastereoisomers were retained longer than stereo random and Rp-enriched diastereoisomers. MICC produced much broader diastereoisomeric peak distributions than the other two methods due to its more complicated nature of interaction. Average mass spectra showed a smaller number of Ag ions (1-7) complex with early eluting diastereoisomers than with later eluting diastereoisomers (which complex between 6-12 Ag ions). A higher late-to-early peak UV area ratio was obtained for a sample containing 10 Sp linkages vs one containing 10 Rp linkages pointing to the tendency of the Sp diastereoisomers for increased interactions which could be explained by structures with more open or stretched configurations. Consideration of the peak shapes of the MICC distributions led to comparable hierarchical cluster analysis (HCA) classification to that produced by the IP-RP method, indicating a good orthogonality between the two methods. Preliminary analysis of the data using partial least squares showed that it should be possible to determine the diastereoisomeric composition of PS oligonucleotides from chromatographic data following appropriate data training.

Thiol-Functionalized Adsorbents through Atomic Layer Deposition and Vapor-Phase Silanization for Heavy Metal Ion Removal.

The removal of toxic heavy metal ions from water resources is crucial for environmental protection and public health. In this study, we address this challenge by developing a surface functionalization technique for the selective adsorption of these contaminants. Our approach involves atomic layer deposition (ALD) followed by vapor-phase silanization of porous substrates. We utilized porous silica gel powder (∼100 µm particles, 89 m2/g surface area, ∼30 nm pores) as an initial substrate. This powder was first coated with ∼0.5 nm ALD Al2O3, followed by vapor-phase grafting of a thiol-functional silane. The modified powder, particularly in acidic conditions (pH = 4), showed high selectivity in adsorbing Cd(II), As(V), Pb(II), Hg(II), and Cu(II) heavy metal ions in mixed ion solutions over common benign ions (e.g., Na, K, Ca, and Mg). Langmuir adsorption isotherms and breakthrough adsorption studies were conducted to assess heavy metal binding affinity and revealed the order of Cd(II) < Pb(II) < Cu(II) < As(V) < Hg(II), with a significantly higher affinity for As(V) and Hg(II) ions. Time-dependent uptake studies demonstrated rapid removal of heavy metal ions from aqueous environments, with Hg(II) exhibiting the fastest adsorption kinetics on thiol-modified surfaces. These findings highlight the potential of ALD and vapor-phase silanization to create effective adsorbents for the targeted removal of hazardous contaminants from water.

Improving Aqueous Zinc Ion Batteries with Alkali Metal Ions.

Aqueous zinc (Zn) ion batteries have received broad attention recently. However, their practical application is limited by severe Zn dendrite growth and the hydrogen evolution reaction. In this study, three alkali metal ions (Li+, Na+, and K+) are added in ZnSO4 electrolytes, which are subjected to electrochemical measurements and molecular dynamics simulations. The studies show that since K+ has the highest mobility and self-diffusion coefficient among the four ions (Li+, Na+, K+, and Zn2+), it enables K+ to preferentially approach a zinc dendrite at an earlier time, driven by a negative electric field during a cathodic process. The electric double layer, with K+ around the negatively charged Zn dendrite, inhibits dendrite growth and mitigates the hydrogen evolution reaction on the Zn anode. Under this kinetic effect, the Zn-Zn symmetric cell with K+ exhibits a long cycling stability of 1000 h at 1 mA·cm-2 of 1 mAh·cm-2 and 190 h at 30 mA·cm-2 of 2 mAh·cm-2. Such a kinetic effect is also observed with additives Na+ and Li+, though less profound than that of K+.

Metal copper and silver revealed potent antimicrobial activity for treating Caenorhabditis elegans infected with carbapenemase-producing Klebsiella pneumonia.

OBJECTIVES: The increasing issue of bacterial resistance, coupled with inadequate progress in developing new antibiotics, necessitates exploring alternative treatments. Antibacterial biomaterials, such as silver and copper, possess advantageous properties such as heat resistance, durability, continuity, and safety. Particularly, they can effectively eliminate pathogenic bacteria while preserving cellular integrity, emphasizing the necessity of identifying optimal metal ion concentrations for practical application. Caenorhabditis elegans (C. elegans) can serve as a noteworthy model in this context. This study employed a C. elegans infection model to assess the efficacy of antibacterial metal ions. METHODS: Hematoxylin-eosin (HE) staining and inductively coupled plasma mass spectrometry (ICP-MS) assay were utilized to determine the toxic levels of metal ions in mice. Additionally, RNA sequencing (RNA-seq) and assessment of reactive oxygen species (ROS) production in the C. elegans model were conducted to elucidate the mechanisms underlying metal ion toxicity. RESULTS: Silver ion concentrations ranging from 10-6 to 10-7 M and copper ion concentrations ranging from 10-4 to 10-5 M exhibited antimicrobial properties without eliciting cytotoxic effects. Analysis of the transcriptome data derived from mRNA isolated from C. elegans indicated that CRKP infection activated the FoxO signaling pathway, potentially leading to ROS accumulation and C. elegans demise. CONCLUSIONS: In conclusion, C. elegans serves as a comprehensive infection model for assessing antibacterial metal ions.

A cascade nanosystem with "Triple-Linkage" effect for enhanced photothermal and activatable metal ion therapy for hepatocellular carcinoma.

Due to the limitations of single-model tumor therapeutic strategies, multimodal combination therapy have become a more favorable option to enhance efficacy by compensating for its deficiencies. However, in nanomaterial-based multimodal therapeutics for tumors, exploiting synergistic interactions and cascade relationships of materials to achieve more effective treatments is still a great challenge. Based on this, we constructed a nanoplatform with a "triple-linkage" effect by cleverly integrating polydopamine (PDA), silver nanoparticles (AgNPs), and glucose oxidase (GOx) to realize enhanced photothermal therapy (PTT) and activatable metal ion therapy (MIT) for hepatocellular carcinoma (HCC) treatment. First, the non-radiative conversion of PDA under light conditions was enhanced by AgNPs, which directly enhanced the photothermal conversion efficiency of PDA. In addition, GOx reduced the synthesis of cellular heat shock proteins by interfering with cellular energy metabolism, thereby enhancing cellular sensitivity to PTT. On the other hand, H2O2, a by-product of GOx-catalyzed glucose, could be used as an activation source to activate non-toxic AgNPs to release cytotoxic Ag+, achieving activatable Ag+-mediated MIT. In conclusion, this nanosystem achieved efficient PTT and MIT for HCC by exploiting the cascade effect among PDA, AgNPs, and GOx, providing a novel idea for the design of multimodal tumor therapeutic systems with cascade regulation.

Tripeptide-Assisted Gold Nanocluster Formation for Fe3+ and Cu2+ Sensing.

Fluorescent gold nanoclusters (AuNCs) have shown promise as metal ion sensors. Further research into surface ligands is crucial for developing sensors that are both selective and sensitive. Here, we designed simple tripeptides to form fluorescent AuNCs, capitalizing on tyrosine's reduction capability under alkaline conditions. We investigated tyrosine's role in both forming AuNCs and sensing metal ions. Two tripeptides, tyrosine-cysteine-tyrosine (YCY) and serine-cysteine-tyrosine (SCY), were used to form AuNCs. YCY peptides produced AuNCs with blue and red fluorescence, while SCY peptides produced blue-emitting AuNCs. The blue fluorescence of YCY- and SCY-AuNCs was selectively quenched by Fe3+ and Cu2+, whereas red-emitting YCY-AuNC fluorescence remained stable with 13 different metal ions. The number of tyrosine residues influenced the sensor response. DLS measurements revealed different aggregation propensities in the presence of various metal ions, indicating that chelation between the peptide and target ions led to aggregation and fluorescence quenching. Highlighting the innovation of our approach, our study demonstrates the feasibility of the rational design of peptides for the formation of fluorescent AuNCs that serve as highly selective and sensitive surface ligands for metal ion sensing. This method marks an advancement over existing methods due to its dual capability in both synthesizing gold nanoclusters and detecting analytes, specifically Fe3+ and Cu2+.

The Programmable Catalytic Core of 8-17 DNAzymes.

8-17 DNAzymes (8-17, 17E, Mg5, and 17EV1) are in vitro-selected catalytic DNA molecules that are capable of cleaving complementary RNAs. The conserved residues in their similar catalytic cores, together with the metal ions, were suggested to contribute to the catalytic reaction. Based on the contribution of the less conserved residues in the bulge loop residues (W12, A15, A15.0) and the internal stem, new catalytic cores of 8-17 DNAzymes were programmed. The internal stem CTC-GAG seems to be more favorable for the DNAzymes than CCG-GGC, while an extra W12.0 led to a significant loss of activity of DNAzymes, which is contrary to the positive effect of A15.0, by which a new active DNAzyme 17EM was derived. It conducts a faster reaction than 17E. It is most active in the presence of Pb2+, with the metal ion preference of Pb2+ >> Zn2+ > Mn2+ > Ca2+ ≈ Mg2+. In the Pb2+ and Zn2+-mediated reactions of 17EM and 17E, the same Na+- and pH dependence were also observed as what was observed for 17E and other 8-17 DNAzymes. Therefore, 17EM is another member of the 8-17 DNAzymes, and it could be applied as a potential biosensor for RNA and metal ions.