Boon and bane of metal ions in medicine

A multi-technique approach to enlighten the role of metal coordination in calcitermin antiviral properties

In this work we presented how the use of suitable electroanalytical, thermodynamic and spectroscopic methods combined with proper experimental conditions can provide comprehensive information on the interaction between metal ions and peptides in solution, as a successful strategy for studying biological systems. Our candidate peptide is calcitermin, an effective metal chelator with significant anti-Candida and antibacterial activity in the presence of divalent metals. While the bioinorganic chemistry of calcitermin with zinc and copper is quite well described in the literature, no data about nickel complexes are available; we therefore deepened calcitermin ability to form nickel complexes by different analytical techniques, including potentiometry, ultraviolet-visible absorption spectrophotometry, circular dichroism and high-resolution mass spectrometry. Moreover, for the first time we have investigated the antiviral activity of calcitermin and its metal complexes towards Herpes simplex type 1. Despite the nickel-associated slow kinetics, which requires specific experimental precautions, calcitermin forms stable complexes with this cation at different pH conditions. Both the apopeptide and its metal complexes show a random coil secondary structure, which is often characteristic of viral cellular adhesion inhibition. This research highlights that calcitermin and its metal complexes can interfere with viral infections, particularly HSV-1, most likely by altering cell membrane permeability.

Metal-Organic Frameworks: Unlocking New Frontiers in Cardiovascular Diagnosis and Therapy

Cardiovascular disease (CVD) is one of the most critical diseases which is the predominant cause of death in the world. Early screening and diagnosis of the disease and effective treatment after diagnosis play an important role in the patient's recovery. Metal-organic frameworks (MOFs), a kind of hybrid ordered micro or meso-porous materials, constructed by metal nodes or clusters with organic ligands, due to their special features like high porosity and specific surface area, open metal sites, or ligand tunability, are widely used in various areas including gas storage, catalysis, sensors, biomedicine. Recently, advances in MOFs are bringing new developments and opportunities for the healthcare industry including the theranostic of CVD. In this review, the applications of MOFs are illustrated in the diagnosis and therapy of CVD, including biomarker detection, imaging, drug delivery systems, therapeutic gas delivery platforms, and nanomedicine. Also, the toxicity and biocompatibility of MOFs are discussed. By providing a comprehensive summary of the role played by MOFs in the diagnosis and treatment of CVDs, it is hoped to promote the future applications of MOFs in disease theranostics, especially in CVDs.

Advances in Sonodynamic Therapy: Focus on Ferroptosis

Ferroptosis is a nonapoptotic form of cell death discovered in 2012. Noninvasive treatments regulating ferroptosis are important for a wide range of diseases. Among the noninvasive treatments, sonodynamic therapy (SDT) has become promising due to its strong tissue penetration and few side effects. In recent years, targeted drug delivery platforms constructed on the basis of SDT have provided an efficient delivery mode for the regulation of ferroptosis. Based on the latest research reports, this Perspective introduces the basic mechanism of SDT and the influencing factors of therapeutic effects, elucidates the significance of ferroptosis-targeted SDT, and summarizes the recent studies on ferroptosis-targeted SDT through different pathways. We also present innovative studies of composite ultrasound-responsive drug delivery platforms. Finally, a brief summary and outlook based on current ferroptosis-targeted SDT are presented.

Nanomedicine's shining armor: understanding and leveraging the metal-phenolic networks

Metal-phenolic networks (MPNs), which comprise supramolecular amorphous networks formed by interlinking polyphenols with metal ions, garner escalating interest within the realm of nanomedicine. Presently, a comprehensive synthesis of the cumulative research advancements and utilizations of MPNs in nanomedicine remains absent. Thus, this review endeavors to firstly delineate the characteristic polyphenols, metal ions, and their intricate interaction modalities within MPNs. Subsequently, it elucidates the merits and demerits of diverse synthesis methodologies employed for MPNs, alongside exploring their potential functional attributes. Furthermore, it consolidates the diverse applications of MPNs across various nanomedical domains encompassing tumor therapy, antimicrobial interventions, medical imaging, among others. Moreover, a meticulous exposition of the journey of MPNs from their ingress into the human body to eventual excretion is provided. Lastly, the persistent challenges and promising avenues pertaining to MPNs are delineated. Hence, this review offering a comprehensive exposition on the current advancements of MPNs in nanomedicine, consequently offering indirect insights into their potential clinical implementation.

Controlled release of bioactive copper (I) acylthiourea complexes through immobilization onto electrospun PCL/lignin nanofibers

This study presents the first development of Cu (I) acylthiourea complexes (C1-C5) incorporated polycaprolactone/lignin (PCL/Lig) electrospun nanofiber composites (PCL/Lig@Cu(I)). Electrospinning conditions and mass ratios of PCL and lignin were optimized, followed by the incorporation of varying concentrations of Cu(I) complexes. Structural, morphological, and thermal properties were characterized using SEM, TEM, FT-IR, XRD, TGA and WCA analyses. Mechanical properties, release behavior and antibacterial activity were also assessed. Results confirmed the successful incorporation of Cu-complex into PCL/Lignin nanofiber composites. The PCL/Lig@Cu(I) composite membranes exhibited excellent thermal stability. After incorporating Cu complex into PCL/Lig membranes, the hydrophobicity was found to be enhanced by approximately 5 %. The PCL/Lig@C4 exhibited a stable and continuous release of Cu-complex until the initial 12 h, but after that there was a decrease in the release by 21.27, 26.07 and 24.41 % was observed for the samples PCL/Lig@C4-1%, 2 % and 3 % respectively. To our delight, the PCL/Lig@C4-1% showed a very controlled and steady release of bioactive Cu(I)-complex for a very long period of time (20 days). Overall, our study demonstrates the feasibility of using acylthiourea Cu (I) complexes (C1-C5) immobilized PCL/Lig nanofiber composites for biomedical applications requiring controlled release and antibacterial activity.

Synthesis of Novel [{(2-Amino-5-Nitro-N-[(E)-Thiophen-2-yl-Methylidene]Aniline-κ3N1:N4:S)(Sulphato-κ2O1:O3)}Zinc(II)] Complex with Physico-Chemical and Biological Perspective Exploration: A Combined Experimental and Computational Studies

A novel metal complex was synthesized using freshly prepared 2-Amino-5-nitro-N-[(E)-thiophen-2-yl-methylidene]aniline ligand with Zn (II) sulphate heptahydrate in a 1:1 molar ratio. The ligand and the complex were characterized using different spectroscopic techniques, and the complex was assigned a distorted square pyramidal geometry. Additionally, DNA binding assays and antibacterial activity were used to assess the biological perspectives for the synthesized complex, including the ligand and complex which was further confirmed by molecular docking. Fluorescence Spectroscopy, viscosity measurement, and adsorption measurement were used to investigate the interaction of the Zn (II) complex with CT-DNA. A comparative in vitro antibacterial activity study against Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis, and Staphylococcus aureus strains were studied with free ligand and Zn (II) metal complex. The stable geometry of the complex was additionally established through computational simulation utilizing density functional theory, which was followed by the calculation of several electronic properties. The ADMET characteristics of the complex and ligand were also assessed using ADMET analysis. The in-silico ADMET properties pointed to a significant drug-likeness feature in the synthesized compounds, based on the Lipinski criteria.

Exploring Thermal Stability, Vibrational Properties, and Biological Assessments of Dichloro(l-histidine)copper(II): A Combined Theoretical and Experimental Study

Dichloro(l-histidine)copper(II) crystal ([Cu(l-His)Cl2] complex) was obtained by the slow evaporation method and characterized concerning its thermal stability, phase transformations, and electronic and vibrational properties. X-ray diffraction (XRPD) confirmed that this complex crystallizes with an orthorhombic structure (P212121 space group). Thermal analyses (TG and DTA) demonstrate stability from ambient temperature up to 460 K, followed by a phase transition from the orthorhombic structure to the amorphous form around 465 K, as confirmed by temperature-dependent XRPD studies. The active modes in Fourier transform infrared (FT-IR) and Raman spectroscopy spectra were suitably assigned via density functional theory (DFT) calculations. Additionally, Hirshfeld surface analysis uncovered the prominence of Cl···H, O···H, and H···H interactions as the primary intermolecular forces within the crystal structure. The antimicrobial activity of the [Cu(l-His)Cl2] complex was investigated, demonstrating significant efficacy against Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Pseudomonas aeruginosa), and fungi (Candida albicans). The minimum inhibitory concentration and cell viability tests showed that the complex inhibits the growth of S. aureus bacteria at a concentration of 1.5 μM without causing damage to the human cell line. The pharmacokinetic parameters corroborate the other tested parameters and highlight the [Cu(l-His)Cl2] complex as a promising alternative for future clinical trials and medicinal applications. The alignment of the pharmacokinetic parameters with other tested criteria highlights the potential of the [Cu(l-His)Cl2] complex as a promising candidate for future clinical studies.

Strategies for the development of metalloimmunotherapies

Metal ions play crucial roles in the regulation of immune pathways. In fact, metallodrugs have a long record of accomplishment as effective treatments for a wide range of diseases. Here we argue that the modulation of interactions of metal ions with molecules and cells involved in the immune system forms the basis of a new class of immunotherapies. By examining how metal ions modulate the innate and adaptive immune systems, as well as host-microbiota interactions, we discuss strategies for the development of such metalloimmunotherapies for the treatment of cancer and other immune-related diseases.

Metals in Cancer Research: Beyond Platinum Metallodrugs

The discovery of the medicinal properties of platinum complexes has fueled the design and synthesis of new anticancer metallodrugs endowed with unique modes of action (MoA). Among the various families of experimental antiproliferative agents, organometallics have emerged as ideal platforms to control the compounds' reactivity and stability in a physiological environment. This is advantageous to efficiently deliver novel prodrug activation strategies, as well as to design metallodrugs acting only via noncovalent interactions with their pharmacological targets. Noteworthy, another justification for the advance of organometallic compounds for therapy stems from their ability to catalyze bioorthogonal reactions in cancer cells. When not yet ideal as drug leads, such compounds can be used as selective chemical tools that benefit from the advantages of catalytic amplification to either label the target of interest (e.g., proteins) or boost the output of biochemical signals. Examples of metallodrugs for the so-called "catalysis in cells" are considered in this Outlook together with other organometallic drug candidates. The selected case studies are discussed in the frame of more general challenges in the field of medicinal inorganic chemistry.

Organic-inorganic composite hydrogels: compositions, properties, and applications in regenerative medicine

Hydrogels, formed from crosslinked hydrophilic macromolecules, provide a three-dimensional microenvironment that mimics the extracellular matrix. They served as scaffold materials in regenerative medicine with an ever-growing demand. However, hydrogels composed of only organic components may not fully meet the performance and functionalization requirements for various tissue defects. Composite hydrogels, containing inorganic components, have attracted tremendous attention due to their unique compositions and properties. Rigid inorganic particles, rods, fibers, etc., can form organic-inorganic composite hydrogels through physical interaction and chemical bonding with polymer chains, which can not only adjust strength and modulus, but also act as carriers of bioactive components, enhancing the properties and biological functions of the composite hydrogels. Notably, incorporating environmental or stimulus-responsive inorganic particles imparts smartness to hydrogels, hence providing a flexible diagnostic platform for in vitro cell culture and in vivo tissue regeneration. In this review, we discuss and compare a set of materials currently used for developing organic-inorganic composite hydrogels, including the modification strategies for organic and inorganic components and their unique contributions to regenerative medicine. Specific emphasis is placed on the interactions between the organic or inorganic components and the biological functions introduced by the inorganic components. The advantages of these composite hydrogels indicate their potential to offer adaptable and intelligent therapeutic solutions for diverse tissue repair demands within the realm of regenerative medicine.

"Antibacterial properties of nine indium(III) complexes of substituted pyrazoles/pyrazolate and the structural and solution characterization of the mer- and trans‑indium(III) complexes of 4-Me-pzH"

Two indium(III) complexes of formula mer-[InIIICl3(4-Me-pzH)3] and trans-[InIIICl2(4-Me-pzH)4]Cl·(4-Me-pzH)2·(H2O) were isolated from the same reaction mixture and crystallographically characterized. The two complexes exist in dynamic equilibrium and their dynamic behavior was probed by variable temperature 1H NMR spectroscopy in the 202 to 296 K range. Powder X-ray diffraction of the batch confirmed existence of both complexes in a 1:2 ratio. Antibacterial properties of both new complexes, in addition to seven other previously published indium(III) complexes, were investigated against three Gram-positive and four Gram-negative pathogenic bacterial strains. The results showed potential for the development of indium(III)-based antipseudomonal and antituberculosis drugs, with mer-[InCl3(4-Ph-pzH)3] being especially effective.

Spatiotemporal Modulated Scaffold for Endogenous Bone Regeneration via Harnessing Sequentially Released Guiding Signals

The design of a scaffold that can regulate the sequential differentiation of bone marrow mesenchymal stromal cells (BMSCs) according to the endochondral ossification (ECO) mechanism is highly desirable for effective bone regeneration. In this study, we successfully fabricated a dual-networked composite hydrogel composed of gelatin and hyaluronic acid (termed GCDH-M), which can sequentially release chondroitin sulfate (CS) and magnesium/silicon (Mg/Si) ions to provide spatiotemporal guidance for chondrogenesis, angiogenesis, and osteogenesis. The fast release of CS is from the GCDH hydrogel, and the sustained releases of Mg/Si ions are from poly(lactide-co-glycolide) microspheres embedded in the hydrogel. There is a difference in the release rates between CS and ions, resulting in the ability for the fast release of CS and sustained release of ions. The dual networks between the modified gelatin and hyaluronic acid via covalent bonding and host-guest interactions render the hydrogel with some dynamic feature to meet the differentiation development of BMSCs laden inside the hydrogel, i.e., transforming into a chondrogenic phenotype, further to a hypertrophic phenotype and eventually to an osteogenic phenotype. As evidenced by the results of in vitro and in vivo evaluations, this GCDH-M composite hydrogel was proved to be able to create an optimal microenvironment for embedded BMSCs responding to the sequential guiding signals, which aligns with the rhythm of the ECO process and ultimately boosts bone regeneration. The promising outcome achieved with this innovative hydrogel system sheds light on novel scaffold design targeting bone tissue engineering.

Design and Development of Inexpensive Paper-Based Chemosensors for Detection of Divalent Copper

Simple, portable, and low-cost paper-based sensors are alternative devices that have the potential to replace high-cost sensing technologies. The compatibility of the paper base biosensors for both chemical and biochemical accentuates its feasibility for application in clinical diagnosis, environmental monitoring, and food quality monitoring. High concentration of copper in blood serum and urine is associated with diseases like liver diseases, carcinomas, acute and chronic infections, rheumatoid arthritis, etc. Detection of copper concentration can give an early sign of Alzheimer disease. Apart from that genetic Wilson's disease can be detected by evaluating the concentration of copper in the urine. In view of the above advantages, a novel and the highly sensitive paper-based sensor has been designed for the selective detection of Cu2+ ions. The fast and highly sensitive chemiresistive multi-dye system sensor can detect Cu2+ ions selectively in as low as 2.23 ppm concentration. Least interference has been observed for counter ion in the detection of Cu2+. Copper chloride, nitrate, and acetate were used to validate the detection process. This assay provides a very high selectivity of Cu2+ ion over other metal cations such as Na+, Mg2+, Ca2+, etc. The easy preparation and high stability of dye solutions, easy functionalization of the paper-based sensors, high selectivity over other cations, low interference of counter anion, and significantly low detection limit of 2.23 ppm make it an effective Cu2+ ion sensor for real-time application in near future.

GelMA-based bioactive hydrogel scaffolds with multiple bone defect repair functions: therapeutic strategies and recent advances

Currently, the clinical treatment of critical bone defects attributed to various causes remains a great challenge, and repairing these defects with synthetic bone substitutes is the most common strategy. In general, tissue engineering materials that mimic the structural, mechanical and biological properties of natural bone have been extensively applied to fill bone defects and promote in situ bone regeneration. Hydrogels with extracellular matrix (ECM)-like properties are common tissue engineering materials, among which methacrylate-based gelatin (GelMA) hydrogels are widely used because of their tunable mechanical properties, excellent photocrosslinking capability and good biocompatibility. Owing to their lack of osteogenic activity, however, GelMA hydrogels are combined with other types of materials with osteogenic activities to improve the osteogenic capability of the current composites. There are three main aspects to consider when enhancing the bone regenerative performance of composite materials: osteoconductivity, vascularization and osteoinduction. Bioceramics, bioglass, biomimetic scaffolds, inorganic ions, bionic periosteum, growth factors and two-dimensional (2D) nanomaterials have been applied in various combinations to achieve enhanced osteogenic and bone regeneration activities. Three-dimensional (3D)-bioprinted scaffolds are a popular research topic in bone tissue engineering (BTE), and printed and customized scaffolds are suitable for restoring large irregular bone defects due to their shape and structural tunability, enhanced mechanical properties, and good biocompatibility. Herein, the recent progress in research on GelMA-based composite hydrogel scaffolds as multifunctional platforms for restoring critical bone defects in plastic or orthopedic clinics is systematically reviewed and summarized. These strategies pave the way for the design of biomimetic bone substitutes for effective bone reconstruction with good biosafety. This review provides novel insights into the development and current trends of research on GelMA-based hydrogels as effective bone tissue engineering (BTE) scaffolds for correcting bone defects, and these contents are summarized and emphasized from various perspectives (osteoconductivity, vascularization, osteoinduction and 3D-bioprinting). In addition, advantages and deficiencies of GelMA-based bone substitutes used for bone regeneration are put forward, and corresponding improvement measures are presented prior to their clinical application in near future (created with BioRender.com).

Effective assessment of lanthanide ion delivery into live cells by paramagnetic NMR spectroscopy

We report an effective assessment of lanthanide ion (Ln3+) delivery into live cells by paramagnetic NMR spectroscopy. Free Ln3+ ions are toxic to live cells resulting in a gradual leakage of target proteins to the extracellular media. The citrate-Ln3+ complex is an efficient and mild reagent over the free Ln3+ form for live cell delivery.

Cobalt-Doped Bioactive Glasses for Biomedical Applications: A Review

Improving angiogenesis is the key to the success of most regenerative medicine approaches. However, how and to which extent this may be performed is still a challenge. In this regard, cobalt (Co)-doped bioactive glasses show promise being able to combine the traditional bioactivity of these materials (especially bone-bonding and osteo-stimulatory properties) with the pro-angiogenic effect associated with the release of cobalt. Although the use and local delivery of Co²⁺ ions into the body have raised some concerns about the possible toxic effects on living cells and tissues, important biological improvements have been highlighted both in vitro and in vivo. This review aims at providing a comprehensive overview of Co-releasing glasses, which find biomedical applications as various products, including micro- and nanoparticles, composites in combination with biocompatible polymers, fibers and porous scaffolds. Therapeutic applications in the field of bone repair, wound healing and cancer treatment are discussed in the light of existing experimental evidence along with the open issues ahead.

Metallo-antiviral aspirants: Answer to the upcoming virusoutbreak

In light of the current SARS-CoV-2 outbreak, about one million research papers (articles, reviews, communications, etc.) were published in the last one and a half years. It was also noticed that in the past few years; infectious diseases, mainly those of viral origin, burdened the public health systems worldwide. The current wave of the Covid-19 pandemic has unmasked critical demand for compounds that can be swiftly mobilized for the treatment of re-emerging or emerging viral infections. With the potential chemical and structural characteristics of organic motifs, the coordination compounds might be a promising and flexible option for drug development. Their therapeutic consequence may be tuned by varying metal nature and its oxidation number, ligands characteristics, and stereochemistry of the species formed. The emerging successes of cisplatin in cancer chemotherapy inspire researchers to make new efforts for studying metallodrugs as antivirals. Metal-based compounds have immense therapeutic potential in terms of structural diversity and possible mechanisms of action; therefore, they might offer an excellent opportunity to achieve new antivirals. This review is an attempt to summarize the current status of antiviral therapies against SARS-CoV-2 from the available literature sources, discuss the specific challenges and solutions in the development of metal-based antivirals, and also talk about the possibility to accelerate discovery efforts in this direction.

Molecular Mechanisms Underlying Neuroinflammation Elicited by Occupational Injuries and Toxicants

Occupational injuries and toxicant exposures lead to the development of neuroinflammation by activating distinct mechanistic signaling cascades that ultimately culminate in the disruption of neuronal function leading to neurological and neurodegenerative disorders. The entry of toxicants into the brain causes the subsequent activation of glial cells, a response known as 'reactive gliosis'. Reactive glial cells secrete a wide variety of signaling molecules in response to neuronal perturbations and thus play a crucial role in the progression and regulation of central nervous system (CNS) injury. In parallel, the roles of protein phosphorylation and cell signaling in eliciting neuroinflammation are evolving. However, there is limited understanding of the molecular underpinnings associated with toxicant- or occupational injury-mediated neuroinflammation, gliosis, and neurological outcomes. The activation of signaling molecules has biological significance, including the promotion or inhibition of disease mechanisms. Nevertheless, the regulatory mechanisms of synergism or antagonism among intracellular signaling pathways remain elusive. This review highlights the research focusing on the direct interaction between the immune system and the toxicant- or occupational injury-induced gliosis. Specifically, the role of occupational injuries, e.g., trips, slips, and falls resulting in traumatic brain injury, and occupational toxicants, e.g., volatile organic compounds, metals, and nanoparticles/nanomaterials in the development of neuroinflammation and neurological or neurodegenerative diseases are highlighted. Further, this review recapitulates the recent advancement related to the characterization of the molecular mechanisms comprising protein phosphorylation and cell signaling, culminating in neuroinflammation.

The Localized Ionic Microenvironment in Bone Modelling/Remodelling: A Potential Guide for the Design of Biomaterials for Bone Tissue Engineering

Bone is capable of adjusting size, shape, and quality to maintain its strength, toughness, and stiffness and to meet different needs of the body through continuous remodeling. The balance of bone homeostasis is orchestrated by interactions among different types of cells (mainly osteoblasts and osteoclasts), extracellular matrix, the surrounding biological milieus, and waste products from cell metabolisms. Inorganic ions liberated into the localized microenvironment during bone matrix degradation not only form apatite crystals as components or enter blood circulation to meet other bodily needs but also alter cellular activities as molecular modulators. The osteoinductive potential of inorganic motifs of bone has been gradually understood since the last century. Still, few have considered the naturally generated ionic microenvironment's biological roles in bone remodeling. It is believed that a better understanding of the naturally balanced ionic microenvironment during bone remodeling can facilitate future biomaterial design for bone tissue engineering in terms of the modulatory roles of the ionic environment in the regenerative process.

The Anti-Leishmania amazonensis and Anti-Leishmania chagasi Action of Copper(II) and Silver(I) 1,10-Phenanthroline-5,6-dione Coordination Compounds

Leishmaniasis is a neglected disease caused by protozoa belonging to the Leishmania genus. Notably, the search for new, promising and potent anti-Leishmania compounds remains a major goal due to the inefficacy of the available drugs used nowadays. In the present work, we evaluated the effects of 1,10-phenanthroline-5,6-dione (phendione) coordinated to silver(I), [Ag(phendione)₂]ClO₄ (Ag-phendione), and copper(II), [Cu(phendione)₃](ClO₄)₂·4H₂O (Cu-phendione), as potential drugs to be used in the chemotherapy against Leishmania amazonensis and Leishmania chagasi. The results showed that promastigotes treated with Ag-phendione and Cu-phendione presented a significant reduction in the proliferation rate. The IC₅₀ values calculated to Ag-phendione and Cu-phendione, respectively, were 7.8 nM and 7.5 nM for L. amazonensis and 24.5 nM and 20.0 nM for L. chagasi. Microscopical analyses revealed several relevant morphological changes in promastigotes, such as a rounding of the cell body and a shortening/loss of the single flagellum. Moreover, the treatment promoted alterations in the unique mitochondrion of these parasites, inducing significant reductions on both metabolic activity and membrane potential parameters. All these cellular perturbations induced the triggering of apoptosis-like death in these parasites, as judged by the (i) increased percentage of annexin-positive/propidium iodide negative cells, (ii) augmentation in the proportion of parasites in the sub-G₀/G₁ phase and (iii) DNA fragmentation. Finally, the test compounds showed potent effects against intracellular amastigotes; contrarily, these molecules were well tolerated by THP-1 macrophages, which resulted in excellent selective index values. Overall, the results highlight new selective and effective drugs against Leishmania species, which are important etiological agents of both cutaneous (L. amazonensis) and visceral (L. chagasi) leishmaniasis in a global perspective.

Ultrasmall iron-quercetin metal natural product nanocomplex with antioxidant and macrophage regulation in rheumatoid arthritis

Oxidative stress, due to the disruption of the balance between reactive oxygen species (ROS) generation and the antioxidant defense system, plays an important role in the pathogenesis of rheumatoid arthritis (RA). Excessive ROS leads to the loss of biological molecules and cellular functions, release of many inflammatory mediators, stimulate the polarization of macrophages, and aggravate the inflammatory response, thus promoting osteoclasts and bone damage. Therefore, foreign antioxidants would effectively treat RA. Herein, ultrasmall iron-quercetin natural coordination nanoparticles (Fe-Qur NCNs) with excellent anti-inflammatory and antioxidant properties were constructed to effectively treat RA. Fe-Qur NCNs obtained by simple mixing retain the inherent ability to remove ROS of quercetin and have a better water-solubility and biocompatibility. In vitro experiments showed that Fe-Qur NCNs could effectively remove excess ROS, avoid cell apoptosis, and inhibit the polarization of inflammatory macrophages by reducing the activation of the nuclear factor-κ-gene binding (NF-κB) pathways. In vivo experiments showed that the swollen joints of mice with rheumatoid arthritis treated with Fe-Qur NCNs significantly improved, with Fe-Qur NCNs largely reducing inflammatory cell infiltration, increasing anti-inflammatory macrophage phenotypes, and thus inhibiting osteoclasts, which led to bone erosion. This study demonstrated that the new metal-natural coordination nanoparticles could be an effective therapeutic agent for the prevention of RA and other diseases associated with oxidative stress.

New Derivatives of 5-((1-Methyl-Pyrrol-2-yl) Methyl)-4-(Naphthalen-1-yl)-1,2,4-Triazoline-3-Thione and Its Coordination Compounds with Anticancer Activity

A new ligand 5-((1-methyl-pyrrol-2-yl) methyl)-4-(naphthalen-1-yl)-1,2,4-triazoline-3-thione (C15) and its metal complexes with formulae: Mn(C15)Cl₂MeOH (1), Fe(C15)Cl₂MeOH (2), Ni(C15)Cl₂MeOH (3), Cu(C15)₂Cl₂ (4) and Zn(C15)₄Cl₂ (5) have been synthesized. The C15 ligand and complexes were characterized by NMR, elemental analysis, FT-IR, EPR, magnetic and TGA studies. The anticancer activities of the organic ligand (C15) and complexes (1–5) were evaluated against human colon adenocarcinoma (HT29) and human lung (A549) cancer cell lines. The complex (1) exhibited potential activity at concentration of 794.37 μM (A549) and 654.31 μM (HT29) in both cancer cells. The complex (3) showed significant activity against the HT29 cancer cell line with an IC₅₀ value of 1064.05 μM. This article highlights some of the metals that have become important in the development of new coordination complexes and the treatment of cancer. Additionally, for C15, the toxicity was predicted by ADMET analysis and molecular docking.

Diastereomeric Separation of Chiral fac-Tricarbonyl(iminopyridine) Rhenium(I) Complexes and Their Cytotoxicity Studies: Approach toward an Action Mechanism against Glioblastoma

A series of new (tricarbonyl)rhenium(I) complexes were synthesized using chiral bidentate ligands (+)/(-)-iminopyridines (L_R/L_S). The reaction yielded a mixture of mononuclear Re(I) diastereoisomers, formulated as fac-[Br(CO)₃Re_(S/R)L_(S/R)]. Each single diastereoisomer was isolated and fully characterized. X-ray crystallography and circular dichroism spectra verified their enantiomeric nature. The cytotoxicity of each complex was evaluated against six cancer cell lines. The effect of the two complexes on viability, proliferation, and migration was analyzed on glioblastoma cell lines (U251 and LN229). Changes in the expression of histones, apoptotic, and key signaling proteins, as well as alterations in DNA structure, were also observed. These experiments showed that the chirality associated with both metal and ligand has a strong influence on cytotoxicity.

Spirooxazine-Based Dual-Sensing Probe for Colorimetric Detection of Cu2+ and Fe3+ and Its Application in Drinking Water and Rice Quality Monitoring

A spirooxazine derivative, PheSPO (3,3-dimethyl-1-phenethylspiro[indoline-2,3'-naphtho[2,1-b][1,4]oxazine]), as a dual-sensing probe for Cu²⁺ and Fe³⁺ was synthesized, and its structure was confirmed by ¹H NMR, ¹³C NMR, HRMS, and single-crystal X-ray diffraction. The results reveal that the PheSPO probe is selective to both Cu²⁺ and Fe³⁺ through distinct colorimetric responses in acetonitrile. The sensing performance of PheSPO toward Cu²⁺ was investigated, and upon addition of Cu²⁺, an instant change in color from colorless to bright yellow with a strong absorption band at 467 nm was observed. Due to a dual-sensing behavior, PheSPO also exhibits a unique response toward Fe³⁺ that can be discovered from a color change from colorless to red at an absorption wavelength of 514 nm. Based on spectroscopic analyses and density functional theory calculations, the 1:1 stoichiometric complexation of PheSPO with the targeted metal ions was proposed and the binding constants of 1.95 × 10³ M^-1 for Cu²⁺ and 1.29 × 10³ M^-1 for Fe³⁺ were obtained. In addition, the detection limits of PheSPO for Cu²⁺ and Fe³⁺ were 0.94 and 2.01 μM, respectively. To verify its applicability in real samples, PheSPO was further explored for quantitative determination of both Cu²⁺ and Fe³⁺ in spiked drinking water. The results showed that the recoveries of Cu²⁺ and Fe³⁺ examined using the PheSPO probe were found comparable to those obtained from atomic absorption spectroscopy. Moreover, the PheSPO strip test was developed, and its utilization for qualitative detection of Fe³⁺ in real rice samples was demonstrated.

Ceramic Nanofiber Materials for Wound Healing and Bone Regeneration: A Brief Review

Ceramic nanofibers have been shown to be a new horizon of research in the biomedical area, due to their differentiated morphology, nanoroughness, nanotopography, wettability, bioactivity, and chemical functionalization properties. Therefore, considering the impact caused by the use of these nanofibers, and the fact that there are still limited data available in the literature addressing the ceramic nanofiber application in regenerative medicine, this review article aims to gather the state-of-the-art research concerning these materials, for potential use as a biomaterial for wound healing and bone regeneration, and to analyze their characteristics when considering their application.

Metal Ion-Directed Functional Metal-Phenolic Materials

Metal ions are ubiquitous in nature and play significant roles in assembling functional materials in fields spanning chemistry, biology, and materials science. Metal-phenolic materials are assembled from phenolic components in the presence of metal ions through the formation of metal-organic complexes. Alkali, alkali-earth, transition, and noble metal ions as well as metalloids interacting with phenolic building blocks have been widely exploited to generate diverse hybrid materials. Despite extensive studies on the synthesis of metal-phenolic materials, a comprehensive summary of how metal ions guide the assembly of phenolic compounds is lacking. A fundamental understanding of the roles of metal ions in metal-phenolic materials engineering will facilitate the assembly of materials with specific and functional properties. In this review, we focus on the diversity and function of metal ions in metal-phenolic material engineering and emerging applications. Specifically, we discuss the range of underlying interactions, including (i) cation-π, (ii) coordination, (iii) redox, and (iv) dynamic covalent interactions, and highlight the wide range of material properties resulting from these interactions. Applications (e.g., biological, catalytic, and environmental) and perspectives of metal-phenolic materials are also highlighted.

A Comprehensive Review of Computation-Based Metal-Binding Prediction Approaches at the Residue Level

Clear evidence has shown that metal ions strongly connect and delicately tune the dynamic homeostasis in living bodies. They have been proved to be associated with protein structure, stability, regulation, and function. Even small changes in the concentration of metal ions can shift their effects from natural beneficial functions to harmful. This leads to degenerative diseases, malignant tumors, and cancers. Accurate characterizations and predictions of metalloproteins at the residue level promise informative clues to the investigation of intrinsic mechanisms of protein-metal ion interactions. Compared to biophysical or biochemical wet-lab technologies, computational methods provide open web interfaces of high-resolution databases and high-throughput predictors for efficient investigation of metal-binding residues. This review surveys and details 18 public databases of metal-protein binding. We collect a comprehensive set of 44 computation-based methods and classify them into four categories, namely, learning-, docking-, template-, and meta-based methods. We analyze the benchmark datasets, assessment criteria, feature construction, and algorithms. We also compare several methods on two benchmark testing datasets and include a discussion about currently publicly available predictive tools. Finally, we summarize the challenges and underlying limitations of the current studies and propose several prospective directions concerning the future development of the related databases and methods.

Recent progress in small-molecule fluorescent probes for endoplasmic reticulum imaging in biological systems

Endoplasmic reticulum (ER) is an indispensable organelle in eukaryotic cells involved in protein synthesis and processing, as well as calcium storage and release. Therefore, maintaining the quality of ER is of great importance for cellular homeostasis. Aberrant fluctuations of bioactive species in the ER will result in homeostasis disequilibrium and further cause ER stress, which has evolved to contribute to the pathogenesis of various diseases. Therefore, the real-time monitoring of various bioactive species in the ER is of high priority to ascertain the mysterious roles of ER, which will contribute to unveiling the corresponding mechanism of organism disturbances. Recently, fluorescence imaging has emerged as a robust technique for the direct visualization of molecular events due to its outstanding sensitivity, high temporal-spatial resolution and noninvasive nature. In this review, we comprehensively summarize the recent progress in design strategies, bioimaging applications, potential directions and challenges of ER-targetable small-molecular fluorescent probes.

A Facile and Universal Method for Preparing Polyethylene Glycol-Metal Hybrid Nanoparticles and Their Application in Tumor Theranostics

Metal ions are of widespread interest owing to their brilliant biomedical functions. However, a simple and universal nanoplatform designed for assembling a range of functional metal ions has not been explored. In this study, a concept of polyethylene glycol (PEG)-mediated transport of metal ions is proposed. 31 types of PEG-metal hybrid nanoparticles (P-MNPs) are successfully synthesized through anionic ring-opening polymerization (ROP), "thiol-ene" click reaction, and subsequent incorporation with multiple metal ions. Compared with other methods, the facile method proposed in this study can provide a feasible approach to design MNPs (mostly <200 nm) containing different metal ions and thus to explore their potential for cancer theranostics. As a proof-of-concept demonstration, four types P-MNPs, i.e., PEG-metal hybrid copper nanoparticles (PEG-Cu NPs), ruthenium nanoparticles (PEG-Ru NPs), and manganese nanoparticles (PEG-Mn NPs) or gadolinium nanoparticles (PEG-Gd NPs), are proven to be tailored for chemodynamic therapy, photothermal therapy, and magnetic resonance imaging of tumors, respectively. Overall, this study provides several metal ions-based nanomaterials with versatile functions for broad applications in cancer theranostics. Furthermore, it offers a promising tool that can be utilized for processing other metal-based nanoparticles and exploring their potential in the biomedical field.

Superlow Dosage of Intrinsically Bioactive Zinc Metal-Organic Frameworks to Modulate Endothelial Cell Morphogenesis and Significantly Rescue Ischemic Disease

Despite long-term efforts for ischemia therapy, proangiogenic drugs hardly satisfy therapy/safety/cost/mass production multiple evaluations and meanwhile with a desire to minimize dosages, thereby clinical applications have been severely hampered. Recently, metal ion-based therapy has emerged as an effective strategy. Herein, intrinsically bioactive Zn metal-organic frameworks (MOFs) were explored by bridging the dual superiorities of proangiogenic Zn²⁺ and facile/cost-effective/scalable MOFs. Zn-MOFs could enhance the morphogenesis of vascular endothelial cells (ECs) via the PI3K/Akt/eNOS pathway. However, high dosage is inevitable and Zn-MOFs suffer from insolubility and low stability, which lead to the bioaccumulation of Zn-MOFs and seriously potential toxicity risks. To alleviate this, it is required to decrease the dosage, but this can be entrapped into the dosage/therapy/safety contradiction and disappointing therapy effect. To address these challenges, the bioavailability of Zn-MOFs is urgent to improve for the minimization of dosage and significant therapy/safety. The mitochondrial respiratory chain is Zn²⁺ active, which inspired us to codecorate EC-targeted and mitochondria-localizing-sequence peptides onto Zn-MOF surfaces. Interestingly, after codecoration, a 100-fold reduced dosage acquired equally powerful vascularization, and the superlow dosage significantly rescued ischemia (4.4 μg kg^-1, about one order of magnitude lower than the published minimal value). Additionally, no obvious muscle injury was found after treatment. Potential toxicity risks were alleviated, benefiting from the superlow dosage. This advanced drug simultaneously satisfied comprehensive evaluations and dosage minimization. This work utilizes engineering thought to rationally design "all-around" bioactive MOFs and is expected to be applied for ischemia treatment.

Bioactive glasses incorporating less-common ions to improve biological and physical properties

Bioactive glasses (BGs) have been a focus of research for over five decades for several biomedical applications. Although their use in bone substitution and bone tissue regeneration has gained important attention, recent developments have also seen the expansion of BG applications to the field of soft tissue engineering. Hard and soft tissue repair therapies can benefit from the biological activity of metallic ions released from BGs. These metallic ions are incorporated in the BG network not only for their biological therapeutic effects but also in many cases for influencing the structure and processability of the glass and to impart extra functional properties. The "classical" elements in silicate BG compositions are silicon (Si), phosphorous (P), calcium (Ca), sodium (Na), and potassium (K). In addition, other well-recognized biologically active ions have been incorporated in BGs to provide osteogenic, angiogenic, anti-inflammatory, and antibacterial effects such as zinc (Zn), magnesium (Mg), silver (Ag), strontium (Sr), gallium (Ga), fluorine (F), iron (Fe), cobalt (Co), boron (B), lithium (Li), titanium (Ti), and copper (Cu). More recently, rare earth and other elements considered less common or, some of them, even "exotic" for biomedical applications, have found room as doping elements in BGs to enhance their biological and physical properties. For example, barium (Ba), bismuth (Bi), chlorine (Cl), chromium (Cr), dysprosium (Dy), europium (Eu), gadolinium (Gd), ytterbium (Yb), thulium (Tm), germanium (Ge), gold (Au), holmium (Ho), iodine (I), lanthanum (La), manganese (Mn), molybdenum (Mo), nickel (Ni), niobium (Nb), nitrogen (N), palladium (Pd), rubidium (Rb), samarium (Sm), selenium (Se), tantalum (Ta), tellurium (Te), terbium (Tb), erbium (Er), tin (Sn), tungsten (W), vanadium (V), yttrium (Y) as well as zirconium (Zr) have been included in BGs. These ions have been found to be particularly interesting for enhancing the biological performance of doped BGs in novel compositions for tissue repair (both hard and soft tissue) and for providing, in some cases, extra functionalities to the BG, for example fluorescence, luminescence, radiation shielding, anti-inflammatory, and antibacterial properties. This review summarizes the influence of incorporating such less-common elements in BGs with focus on tissue engineering applications, usually exploiting the bioactivity of the BG in combination with other functional properties imparted by the presence of the added elements.

Highly sensitive determination of cadmium and lead in whole blood by electrothermal vaporization-atmospheric pressure glow discharge atomic emission spectrometry

In this study, a fast and simple method for highly sensitive detection of Cd and Pb elements based on atmospheric pressure glow discharge atomic emission spectrometry (APGD-AES) coupling with tungsten coil electrothermal vaporization (ETV) was proposed. A small amount of sample (10 μL) was dropped onto the tungsten coil, followed by drying, pyrolysis and vaporization procedures, and then the vaporized analyte was transported to APGD for excitation. The whole procedure took approximately 3 min. Multi-step heating of the ETV unit can separate matrices and solvents from the analyte, providing an advantage in detecting samples with complex matrix. Under the optimal experimental conditions, limits of detection of 0.4 μg L^-1 (4 pg) for cadmium and 1.2 μg L^-1 (12 pg) for lead were obtained, with relative standard deviations of 20 μg L^-1 Cd and 100 μg L^-1 Pb both being <5%. The accuracy of the ETV-APGD-AES system was verified by the determination of heavy metals in whole blood standard sample (GBW(E)090,251) and the practicability of the ETV-APGD-AES system were demonstrated by the determination of heavy metals in human whole blood. The results obtained by this instrument agree well with the standard values and those obtained by ICP-MS.

A CaO2 @Tannic Acid-FeIII Nanoconjugate for Enhanced Chemodynamic Tumor Therapy

Chemodynamic therapy (CDT) is an effective tumor treatment strategy in which Fe^II reacts with hydrogen peroxide (H₂ O₂ ) in tumor cells to produce highly toxic hydroxyl radical (^. OH) through the Fenton reaction. However, the content of endogenous H₂ O₂ in cells is limited, and the reaction between Fe^III and H₂ O₂ is inefficient, greatly limiting the efficiency of the Fenton reaction and reducing the effectiveness of tumor treatment. Therefore, in this work, we designed and synthesized a new type of nano-system (CaO₂ @TA-Fe^III ) for the enhanced CDT of tumors, in which the polyphenolic compound- tannic acid (TA) and Fe^III formed a TA-Fe nano-coating on the surface of calcium peroxide (CaO₂ ) nanospherical aggregates. When the CaO₂ @TA-Fe^III nanoconjugates reach the tumor site, the CaO₂ contained in the nanoconjugates produces H₂ O₂ after disintegration in tumor cells, and the carried TA rapidly reduces Fe^III to Fe^II , solving the two major shortcomings in CDT of (1) insufficient content of H₂ O₂ in cancer cells, and (2) low catalytic efficiency of the Fenton reaction. Additionally, the ^. OH produced in the Fenton reaction induces oxidative stress for the tumor cells, promoting the occurrence of the "calcium overload" process, and thereby accelerating the death of tumor cells. Experimental results in vitro and in vivo showed that CaO₂ @TA-Fe^III nanoconjugates can effectively kill cancer cells and display an excellent tumor therapeutic effect. We believe that the CaO₂ @TA-Fe^III nanoconjugates are a promising new nano-platform for highly effective tumor treatment.

Highly Sensitive and Selective Spiropyran-Based Sensor for Copper(II) Quantification

The metal-binding capabilities of the spiropyran family of molecular switches have been explored for several purposes from sensing to optical circuits. Metal-selective sensing has been of great interest for applications ranging from environmental assays to industrial quality control, but sensitive metal detection for field-based assays has been elusive. In this work, we demonstrate colorimetric copper sensing at low micromolar levels. Dimethylamine-functionalized spiropyran (SP1) was synthesized and its metal-sensing properties were investigated using UV-vis spectrophotometry. The formation of a metal complex between SP1 and Cu²⁺ was associated with a color change that can be observed by the naked eye as low as ≈6 μM and the limit of detection was found to be 0.11 μM via UV-vis spectrometry. Colorimetric data showed linearity of response in a physiologically relevant range (0-20 μM Cu²⁺) with high selectivity for Cu²⁺ ions over biologically and environmentally relevant metals such as Na⁺, K⁺, Mn²⁺, Ca²⁺, Zn²⁺, Co²⁺, Mg²⁺, Ni²⁺, Fe³⁺, Cd²⁺, and Pb²⁺. Since the color change accompanying SP1-Cu²⁺ complex formation could be detected at low micromolar concentrations, SP1 could be viable for field testing of trace Cu²⁺ ions.

One-pot crystallization of two 1,4-cyclohexanedicarboxylate-based tetranuclear Cu(ii) compounds and their DNA binding affinities

Two new tetranuclear Cu(ii) compounds have been synthesized using flexible linker 1,4-cyclohexanedicarboxylic acid in an one-pot crystallization which exhibit dissimilar affinities to DNA binding.

Bioactive Core-Shell CaF2 Upconversion Nanostructure for Promotion and Visualization of Engineered Bone Reconstruction

Inorganic ion metabolism plays significant roles in various life processes including signal transduction, substance exchange, and cellular constructions. Regulation and monitoring of ion metabolism offer great promise to modulate biological activities and provide insights into related mechanisms. Here, a synergistic nanodepot based on a bioactive core-shell CaF₂ upconversion nanostructure that integrates multiple mineral ions for metabolic regulation was built for the acceleration and monitoring of the biomineralization process. Multiple mineral ions released from the nanodepots can accelerate the growth of inorganic crystals and enhance the production of organic matrixes, synergistically facilitating the regeneration of bone defects in vivo. During the process, such a nanodepot can be constructed to specifically recognize osteoblasts for the monitoring of biomineralization. This nanoprobe represents an efficient strategy to promote and monitor biomineralization-related metabolic activities with applications in fundamental research, disease diagnosis, and regenerative medicine.

2,4-Diketo esters: Crucial intermediates for drug discovery

Convenient structures such as 2,4-diketo esters have been widely used as an effective pattern in medicinal chemistry and pharmacology for drug discovery. 2,4-Diketonate is a common scaffold that can be found in many biologically active and naturally occurring compounds. Also, many 2,4-diketo ester derivatives have been prepared due to their suitable synthesis. These synthetic drugs and natural products have shown numerous interesting biological properties with clinical potential as a cure for the broad specter of diseases. This review aims to highlight the important evidence of 2,4-diketo esters as a privileged scaffold in medicinal chemistry and pharmacology. Herein, numerous aspects of 2,4-diketo esters will be summarized, including synthesis and isolation of their derivatives, development of novel synthetic methodologies, the evaluation of their biological properties as well as the mechanisms of action of the diketo ester derivates. This paperwork is expected to be a comprehensive, trustworthy, and critical review of the 2,4-diketo ester intermediate to the chemistry community.