Advances with Lipid-Based Nanosystems for siRNA Delivery to Breast Cancers

Breast cancer is the most frequently diagnosed cancer among women. Breast cancer is also the key reason for worldwide cancer-related deaths among women. The application of small interfering RNA (siRNA)-based drugs to combat breast cancer requires effective gene silencing in tumor cells. To overcome the challenges of drug delivery to tumors, various nanosystems for siRNA delivery, including lipid-based nanoparticles that protect siRNA from degradation for delivery to cancer cells have been developed. These nanosystems have shown great potential for efficient and targeted siRNA delivery to breast cancer cells. Lipid-based nanosystems remain promising as siRNA drug delivery carriers for effective and safe cancer therapy including breast cancer. Lipid nanoparticles (LNPs) encapsulating siRNA enable efficient and specific silencing of oncogenes in breast tumors. This review discusses a variety of lipid-based nanosystems including cationic lipids, sterols, phospholipids, PEG-lipid conjugates, ionizable liposomes, exosomes for effective siRNA drug delivery to breast tumors, and the clinical translation of lipid-based siRNA nanosystems for solid tumors.

Advances in Targeted Therapy of Breast Cancer with Antibody-Drug Conjugate

Antibody-drug conjugates (ADCs) are a potential and promising therapy for a wide variety of cancers, including breast cancer. ADC-based drugs represent a rapidly growing field of breast cancer therapy. Various ADC drug therapies have progressed over the past decade and have generated diverse opportunities for designing of state-of-the-art ADCs. Clinical progress with ADCs for the targeted therapy of breast cancer have shown promise. Off-target toxicities and drug resistance to ADC-based therapy have hampered effective therapy development due to the intracellular mechanism of action and limited antigen expression on breast tumors. However, innovative non-internalizing ADCs targeting the tumor microenvironment (TME) component and extracellular payload delivery mechanisms have led to reduced drug resistance and enhanced ADC effectiveness. Novel ADC drugs may deliver potent cytotoxic agents to breast tumor cells with reduced off-target effects, which may overcome difficulties related to delivery efficiency and enhance the therapeutic efficacy of cytotoxic cancer drugs for breast cancer therapy. This review discusses the development of ADC-based targeted breast cancer therapy and the clinical translation of ADC drugs for breast cancer treatment.

Recent Advances with Precision Medicine Treatment for Breast Cancer including Triple-Negative Sub-Type

Breast cancer is a heterogeneous disease with different molecular subtypes. Breast cancer is the second leading cause of mortality in woman due to rapid metastasis and disease recurrence. Precision medicine remains an essential source to lower the off-target toxicities of chemotherapeutic agents and maximize the patient benefits. This is a crucial approach for a more effective treatment and prevention of disease. Precision-medicine methods are based on the selection of suitable biomarkers to envision the effectiveness of targeted therapy in a specific group of patients. Several druggable mutations have been identified in breast cancer patients. Current improvements in omics technologies have focused on more precise strategies for precision therapy. The development of next-generation sequencing technologies has raised hopes for precision-medicine treatment strategies in breast cancer (BC) and triple-negative breast cancer (TNBC). Targeted therapies utilizing immune checkpoint inhibitors (ICIs), epidermal growth factor receptor inhibitor (EGFRi), poly(ADP-ribose) polymerase inhibitor (PARPi), antibody-drug conjugates (ADCs), oncolytic viruses (OVs), glucose transporter-1 inhibitor (GLUT1i), and targeting signaling pathways are potential treatment approaches for BC and TNBC. This review emphasizes the recent progress made with the precision-medicine therapy of metastatic breast cancer and TNBC.

Mechanisms of Resistance and Current Treatment Options for Glioblastoma Multiforme (GBM)

Glioblastoma multiforme (GBM) is a highly aggressive form of brain cancer that is difficult to treat due to its resistance to both radiation and chemotherapy. This resistance is largely due to the unique biology of GBM cells, which can evade the effects of conventional treatments through mechanisms such as increased resistance to cell death and rapid regeneration of cancerous cells. Additionally, the blood–brain barrier makes it difficult for chemotherapy drugs to reach GBM cells, leading to reduced effectiveness. Despite these challenges, there are several treatment options available for GBM. The standard of care for newly diagnosed GBM patients involves surgical resection followed by concurrent chemoradiotherapy and adjuvant chemotherapy. Emerging treatments include immunotherapy, such as checkpoint inhibitors, and targeted therapies, such as bevacizumab, that attempt to attack specific vulnerabilities in GBM cells. Another promising approach is the use of tumor-treating fields, a type of electric field therapy that has been shown to slow the growth of GBM cells. Clinical trials are ongoing to evaluate the safety and efficacy of these and other innovative treatments for GBM, intending to improve with outcomes for patients.

Approaches to Improve EPR-Based Drug Delivery for Cancer Therapy and Diagnosis

The innovative development of nanomedicine has promised effective treatment options compared to the standard therapeutics for cancer therapy. However, the efficiency of EPR-targeted nanodrugs is not always pleasing as it is strongly prejudiced by the heterogeneity of the enhanced permeability and retention effect (EPR). Targeting the dynamics of the EPR effect and improvement of the therapeutic effects of nanotherapeutics by using EPR enhancers is a vital approach to developing cancer therapy. Inadequate data on the efficacy of EPR in humans hampers the clinical translation of cancer drugs. Molecular targeting, physical amendment, or physiological renovation of the tumor microenvironment (TME) are crucial approaches for improving the EPR effect. Advanced imaging technologies for the visualization of EPR-induced nanomedicine distribution in tumors, and the use of better animal models, are necessary to enhance the EPR effect. This review discusses strategies to enhance EPR effect-based drug delivery approaches for cancer therapy and imaging technologies for the diagnosis of EPR effects. The effort of studying the EPR effect is beneficial, as some of the advanced nanomedicine-based EPR-enhancing approaches are currently undergoing clinical trials, which may be helpful to improve EPR-induced drug delivery and translation to clinics.

Biopolymer-Based Nanosystems for siRNA Drug Delivery to Solid Tumors including Breast Cancer

Nanobiopolymers such as chitosan, gelatin, hyaluronic acid, polyglutamic acid, lipids, peptides, exosomes, etc., delivery systems have prospects to help overwhelmed physiological difficulties allied with the delivery of siRNA drugs to solid tumors, including breast cancer cells. Nanobiopolymers have favorable stimuli-responsive properties and therefore can be utilized to improve siRNA delivery platforms to undruggable MDR metastatic cancer cells. These biopolymeric siRNA drugs can shield drugs from pH degradation, extracellular trafficking, and nontargeted binding sites and are consequently suitable for drug internalization in a controlled-release fashion. In this review, the utilization of numerous biopolymeric compounds such as siRNA drug delivery systems for MDR solid tumors, including breast cancers, will be discussed.

Recent Development in Metallic Nanoparticles for Breast Cancer Therapy and Diagnosis

Metal-based nanoparticles are very promising for their applications in cancer diagnosis, drug delivery and therapy. Breast cancer is the major reason of death in woman especially in developed countries including EU and USA. Due to the heterogeneity of cancer cells, nanoparticles are effective as therapeutics and diagnostics. Anti-cancer therapy of breast tumors is challenging because of highly metastatic progression of the disease to brain, bone, lung, and liver. Magnetic nanoparticles are crucial for metastatic breast cancer detection and protection. This review comprehensively discusses the application of nanomaterials as breast cancer therapy, therapeutics, and diagnostics.

Advances with metal oxide-based nanoparticles as MDR metastatic breast cancer therapeutics and diagnostics

Metal oxide nanoparticles have attracted increased attention due to their emerging applications in cancer detection and therapy. This study envisioned to highlight the great potential of metal oxide NPs due to their interesting properties including high payload, response to magnetic field, affluence of surface modification to overcome biological barriers, and biocompatibility. Mammogram, ultrasound, X-ray computed tomography (CT), MRI, positron emission tomography (PET), optical or fluorescence imaging are used for breast imaging. Drug-loaded metal oxide nanoparticle delivered to the breast cancer cells leads to higher drug uptake. Thus, enhanced the cytotoxicity to target cells compared to free drug. The drug loaded metal oxide nanoparticle formulations hold great promise to enhance efficacy of breast cancer therapy including multidrug resistant (MDR) and metastatic breast cancers. Various metal oxides including magnetic metal oxides and magnetosomes are of current interests to explore cancer drug delivery and diagnostic efficacy especially for metastatic breast cancer. Metal oxide-based nanocarrier formulations are promising for their usage in drug delivery and release to breast cancer cells, cancer diagnosis and their clinical translations.

Biomarker targeted therapy approaches for TNBC using metal oxide-based NPs are highly effective and promising.

Recent Advances in Synthesis and Applications of Single-Atom Catalysts for Rechargeable Batteries

The rapid development of flexible and wearable optoelectronic devices, demanding the superior, reliable, and ultra-long cycling energy storage systems. But poor performances of electrode materials used in energy devices are main obstacles. Recently, single-atom catalysts (SACs) are considered as emerging and potential candidates as electrode materials for battery devices. Herein, we have discussed the recent methods for the fabrication of SACs for rechargeable metal-air batteries, metal-CO₂ batteries, metal-sulfur batteries, and other batteries, following the recent advances in assembling and performance of these batteries by using SACs as electrode materials. The role of SACs to solve the bottle-neck problems of these energy storage devices and future perspectives are also discussed.

Neutrophils as an emerging therapeutic target and tool for cancer therapy

Activation of neutrophils is necessary for the protection of the host against microbial infection. This property can be used as mode of therapy for cancer treatment. Neutrophils have conflicting dual functions in cancer as either a tumor promoter or inhibitor. Neutrophil-based drug delivery has achieved increased attention in pre-clinical models. This review addresses in detail the different neutrophil constituents, the conflicting function of neutrophils and activation of the neutrophil as an important target of therapy for cancer treatment, and use of neutrophils or neutrophil membrane-derived vesicles as vehicles for drug delivery and targeting.

Photocatalytic performance, anti-bacterial activities and 3-chlorophenol sensor fabrication using MnAl2O4·ZnAl2O4 nanomaterials

A MnAl₂O₄·ZnAl₂O₄ nanomaterial was synthesized by co-precipitation and characterized by XRD, SEM, EDS, TEM, AFM, FTIR, PL, CV and EIS. The photocatalytic activity of the nanocomposite against MV dye and its MDR anti-bacterial functions were studied. The nanocomposite shows excellent photocatalytic as well as anti-bacterial activity. A MnAl₂O₄·ZnAl₂O₄ nanomaterial/Nafion/GCE electrode was fabricated and implemented as the working electrode of a 3-CP sensor. The sensor exhibited good sensitivity, with the lowest detection limit, fast response time, large linear dynamic range (LDR), and long-term stability in the chemical environment. The estimated sensitivity is 70.07 μA mM^-1 cm^-2. The LDR, limit of detection (LOD), and limit of quantification (LOQ) are 0.1 nM to 0.01 M, 0.0014 ± 0.0001 nM, and 0.004 nM, respectively. The MnAl₂O₄·ZnAl₂O₄ nanomaterial/Nafion/GCE is a promising fabricated sensor probe for the selective detection of 3-CP for the environmental safety and healthcare fields on a large scale.

Recent Advances in Tumor Targeting via EPR Effect for Cancer Treatment

Cancer causes the second-highest rate of death world-wide. A major shortcoming inherent in most of anticancer drugs is their lack of tumor selectivity. Nanodrugs for cancer therapy administered intravenously escape renal clearance, are unable to penetrate through tight endothelial junctions of normal blood vessels and remain at a high level in plasma. Over time, the concentration of nanodrugs builds up in tumors due to the EPR effect, reaching several times higher than that of plasma due to the lack of lymphatic drainage. This review will address in detail the progress and prospects of tumor-targeting via EPR effect for cancer therapy.

Advances in siRNA delivery strategies for the treatment of MDR cancer

RNA interference (RNAi) represents a promising therapeutic method that uses siRNA for cancer treatment. Although the RNAi technique has been increasingly used for clinical trials, systemic siRNA delivery into targeted cells is still challenging. The barriers impeding siRNA therapeutics delivery and impacting the treatment outcome must overcome with negligible systemic toxicity for a desirable and successful delivery of siRNA to MDR cancer cells. Nano delivery strategies have been investigated for nanocarrier functionalization, cancer immunotherapy and cancer targeting. Lipid nanoparticles (LNPs), dynamic polyconjugates (DPC™), GalNAc-siRNA conjugates, exosome and RBC systems have shown potential for efficient delivery of siRNA to cancer cells. Delivery of siRNA to tumor cells, immune cells to regulate T cell functions for immunotherapy are promising approaches.

Photocatalytic, anti-bacterial performance and development of 2,4-diaminophenylhydrazine chemical sensor probe based on ternary doped Ag·SrSnO3 nanorods

Ag·SrSnO₃ NRs is an excellent photocatalyst, kills both Gram positive and Gram negative bacteria. The 2,4-DAPHyd sensor fabricated by layered Ag·SrSnO₃ NRs onto GCE shows high sensitivity (7.5854 μA μM⁻¹ cm⁻²); LDR, 0.1 nM~0.01 mM & LOD, 96.13 ± 4.81 pM.

Photocatalysis, photoinduced enhanced anti-bacterial functions and development of a selective m-tolyl hydrazine sensor based on mixed Ag·NiMn2O4 nanomaterials

In this work, a tri-metal based nanocomposite was synthesized and characterized. A detailed investigation of the photocatalytic dye degradation efficiency of the nanocomposite under visible light showed promising results in a wide pH range, both acidic and basic medium. Studies on anti-bacterial activity against seven pathogenic bacteria, including both Gram positive and Gram negative species, were conducted in the presence and absence of light and compared with the standard antibiotic gentamicin. The minimum inhibitory concentration (MIC) values of Ag·NiMn₂O₄ against multidrug-resistant (MDR) pathogens ranged from 0.008 to 0.65 μg μL^-1, while the minimum bactericidal concentration (MBC) was found to be 0.0016 μg μL^-1. The nanomaterial, Ag·NiMn₂O₄ was deposited onto the surface of a glassy carbon electrode (GCE; 0.0316 cm²) as a thin film to fabricate the chemical sensor probe. The proposed sensor showed linear current (vs. concentration) response to m-THyd (m-tolyl hydrazine) from 1.0 pM to 0.01 mM, which is denoted as the linear dynamic range (LDR). The estimated sensitivity and detection limit of the m-THyd sensor were found to be 47.275 μA μM^-1 cm^-2 and 0.97 ± 0.05 pM, respectively. As a potential sensor, it is reliable due to its good reproducibility, rapid response, higher sensitivity, working stability for long duration and efficiency in the analysis of real environmental samples.

siRNA based drug design, quality, delivery and clinical translation

Gene silencing by RNA interference represents a promising therapeutic approach. The development of carriers, e.g., polymers, lipids, peptides, antibodies, aptamers, small molecules, exosome and red blood cells, is crucial for the systemic delivery of siRNA. Cell-specific targeting ligands in the nano-carriers can improve the pharmacokinetics, biodistribution, and selectivity of siRNA therapeutics. The safety, effectiveness, quality and prosperity of production and manufacturing are important considerations for selecting the appropriate siRNA carriers. Efficacy of systemic delivery of siRNA requires considerations of trafficking through the blood, off-target effects, innate immune response and endosomal escape avoiding lysosomal degradation for entering into RNAi process. Multifunctional nanocarriers with stimuli-responsive properties such as pH, magnetic and photo-sensitive segments can enhance the efficacy of siRNA delivery. The improved preclinical characterization of suitable siRNA drugs, good laboratory practice, that reduce the differences between in vitro and in vivo results may increase the success of siRNA drugs in clinical settings.

Monoclonal Antibody 2C5-Modified Mixed Dendrimer Micelles for Tumor-Targeted Codelivery of Chemotherapeutics and siRNA

Targeted delivery of chemotherapeutics to tumors has the potential to reach a high dose at the tumor while minimizing systemic exposure. Incorporation of antibody within a micellar platform represents a drug delivery system for tumor-targeted delivery of antitumor agents. Such modified immunomicelles can result in an increased accumulation of antitumor agents and enhanced cytotoxicity toward cancer cells. Here, mixed dendrimer micelles (MDM) composed of PEG_2k-DOPE-conjugated generation 4 polyamidoamine dendrimer G4-PAMAM-PEG_2k-DOPE and PEG_5k-DOPE were coloaded with doxorubicin and siMDR-1. This formulation was further modified with monoclonal antibodies 2C5 with nucleosome-restricted specificity that effectively recognized cancer cells via the cell-surface-bound nucleosomes. Micelles with attached 2C5 antibodies significantly enhanced cellular association and tumor killing in both monolayer and spheroid tumor models as well as in vivo in experimental animals compared to the nontargeted formulations.

Enhanced visible light-mediated photocatalysis, antibacterial functions and fabrication of a 3-chlorophenol sensor based on ternary Ag2O·SrO·CaO

A novel multi-metal oxide nanocomposite, Ag₂O·SrO·CaO, was synthesized by a facile co-precipitation method followed by calcinations. The synthesized nanocomposite was characterized by XRD, FESEM, EDS, TEM, FTIR spectroscopy and photoluminescence (PL) spectroscopy. The composite showed enhanced photocatalytic activity under visible light irradiation and excellent anti-bacterial performance against both Gram-positive and Gram-negative bacteria. Here, the synthesized Ag₂O·SrO·CaO nanomaterials were deposited on a glassy carbon electrode (GCE) in the form of a thin film to fabricate the desired electrochemical sensor and subjected to I–V analysis of 3-chlorophenol (3-CP) in a phosphate buffer solution (PBS). A calibration curve was plotted from the linear relation of current versus concentration and used to calculate the sensitivity (8.9684 μA μM⁻¹ cm⁻²), linear dynamic range (LDR, 0.1 nM to 0.01 mM) and lower limit of detection (DL, 97.12 ± 4.86 pM). The analytical parameters of the sensor such as response time, reproducibility and long-term stability in the detection of 3-CP were reliable. Finally, it was used to analyze real samples collected from various environmental sources and found to be acceptable.

The electrochemical detection mechanism of 3-CP in PBS buffer using the heterostructure nanocomposite Ag₂O·SrO·CaO. The proposed electrochemical reaction is supposed as C₆OH₅Cl + 11H₂O → 6CO₂ + 27H⁺ + Cl⁻ + 26e⁻.

Efficient selective 4-aminophenol sensing and antibacterial activity of ternary Ag2O3·SnO2·Cr2O3 nanoparticles

The electrochemical oxidation of 4-AP based on Ag₂O₃·SnO₂·Cr₂O₃ NPs/binder/GCE sensor.

Enhanced photocatalytic activity and ultra-sensitive benzaldehyde sensing performance of a SnO2·ZnO·TiO2 nanomaterial

The synthesis of a ternary SnO₂·ZnO·TiO₂ nanomaterial (NM) by a simple co-precipitation method and its potential applications as an efficient photocatalyst and chemical sensor have been reported. The synthesized nanomaterial was fully characterized by XRD, SEM, EDS, XPS, FTIR, AFM and photoluminescence studies. This nanomaterial exhibited enhanced efficiency in photo-catalysis of Methyl Violet 6b (MV) dye degradation. The observed photocatalyst efficiency of the SnO₂·ZnO·TiO₂ nanomaterial was 100% under UV light at pH 9. Moreover, it lost around 12% efficiency over five reuses. The PL properties with changing excitation energy were also reported. Glassy carbon electrode (GCE) was modified with the SnO₂·ZnO·TiO₂ nanomaterial by an efficient electrochemical technique to develop a chemical sensor for selective benzaldehyde. Hazardous benzaldehyde was carefully chosen as a target analyte by a selectivity study; it displays a rapid response towards the SnO₂·ZnO·TiO₂/Nafion/GCE sensor probe in electrochemical sensing. It also shows superb sensitivity, an ultra-low detection limit, long-term stability, and very good repeatability and reproducibility. In this study, a linear calibration plot was obtained for 0.1 nM to 1.0 mM aqueous benzaldehyde solutions, with a sensitivity value of 4.35 nA μM⁻¹ cm⁻² and an exceptionally low detection limit (LOD) of 3.2 ± 0.1 pM (S/N = 3). Hence, a chemical sensor modified with SnO₂·ZnO·TiO₂/GCE may be a promising sensor in the determination of toxic chemicals in the environmental and healthcare fields.

Schematic of a GCE fabricated with SnO₂·ZnO·TiO₂ NMs/Nafion/GCE using a conducting Nafion binder and its electrochemical response as a benzaldehyde sensor.

Fabrication of a 2,4-dinitrophenol sensor based on Fe3O4@Ag@Ni nanomaterials and studies on their antibacterial properties

Scheme representing (a) MO coated GCE, (b) theoretical I–V response, (c) observed I–V responses by the MO/Nafion/GCE, and (d) proposed detection mechanism of 2,4-DNP.

Enhanced photocatalytic activity and chemical sensor development based on ternary B2O3·Zn6Al2O9·ZnO nanomaterials for environmental safety

Preparation of ternary B₂O₃·Zn₆Al₂O₉·ZnO nanomaterials by a simple co-precipitation method and their potential application as an efficient photo-catalyst as well as chemical sensor has been reported.

Synthesis, characterization, low temperature solid state PL and photocatalytic activities of Ag₂O·CeO₂·ZnO nanocomposite

A novel multi-metal nanocomposite oxide Ag2O·CeO2·ZnO has been prepared by co-precipitation of their carbonates from aqueous solutions of the metal nitrates following calcinations and annealing 5h at 450°C and 4h at 600°C. Ag2O·CeO2·ZnO has been characterized by XRD, SEM, EDS and PL spectra. According to XRD results the crystallite size of Ag2O·CeO2·ZnO varies in the range of 19-111 nm with an average size of 50 nm, which is in good agreement with SEM results. Elemental analysis was performed by SEM-EDS. Emissions of Ag2O·CeO2·ZnO has been observed in UV (NBE emission), visible and NIR regions at 325 nm excitation by a line of He-Cd laser. Photocatalytic as well as anti-bacterial activities have been studied. The nano composite Ag2O·CeO2·ZnO shows an excellent photocatalytic dye degradation activity.

Photoluminescence, photocatalytic and antibacterial activities of CeO2·CuO·ZnO nanocomposite fabricated by co-precipitation method

A novel tri-metallic oxide nanocomposite CeO2·CuO·ZnO has been synthesized by a simple co-precipitation method. The nanocomposite has been characterized by XRD, SEM, EDS, FTIR and PL spectra. The crystallite size of the CeO2·CuO·ZnO was calculated using XRD data. The crystallite size of the CeO2·CuO·ZnO mixed metal oxide annealed at 600 °C is found to be in range of 15.34-44.81 nm, with an average size of 29.51 nm. Excitation at different wavelengths showed PL in UV and visible regions. It has been found that PL behavior of CeO2·CuO·ZnO is excitation wavelength dependent. This flexible PL property is conflicting to well-known Kasha's rule of excitation wavelength dependence of emission spectrum. The catalyst shows better photo-catalytic dye degradation efficiency in slightly alkaline pH in presence of H2O2. Nanocomposite CeO2·CuO·ZnO was found to be effective against pathogenic bacteria.

Synthesis, structure, PL and photocatalytic activities of La2O2CO3·CeO2·ZnO fabricated by co-precipitation method

A novel tri metallic oxide nanocomposite La2O2CO3·CeO2·ZnO has been synthesized by a simple co-precipitation method. The nanocomposite has been characterized by XRD, SEM, EDS, FTIR and PL spectra. The crystallite size of the La2O2CO3·CeO2·ZnO was calculated using XRD data. The crystallite size of the as synthesized sample varies in the range of 16-30nm and those annealed at 950°C in the range of 26-70nm. Excitation at different wavelengths showed PL in UV and visible regions. It has been found that PL behavior of La2O2CO3·CeO2·ZnO is excitation wavelength dependent. This PL property is conflicting to well-known Kasha's rule of excitation wavelength dependence of emission spectrum. The catalyst shows better photocatalytic dye degradation efficiency in slightly alkaline pH in presence of H2O2.

Synthesis, characterization, PL properties, photocatalytic and antibacterial activities of nano multi-metal oxide NiO⋅CeO2⋅ZnO

A novel multi-metal nanocomposite, NiO⋅CeO2⋅ZnO has been prepared by co-precipitation of their carbonates from aqueous solutions of the metal nitrates following calcination and annealing 5 h at 450°C and 10 h at 950°C. NiO⋅CeO2⋅ZnO has been characterized by XRD, SEM, EDS, IR and PL spectra. The crystallite size of the as-synthesized sample varies in the range of 14-23 nm and those of the annealed sample in the range of 17-50 nm. Emissions of NiO⋅CeO2⋅ZnO have been observed in UV (NBE emission) and visible region at different excitations. Excitation wavelength dependent PL behavior of NiO⋅CeO2⋅ZnO has been observed in acetone at room temperature. This PL property is in disagreement with Kasha's rule of excitation wavelength dependence of emission spectrum. Photocatalytic as well as anti-bacterial activities were studied.

Structure and photoluminescence studies of CeO2·CuAlO2 mixed metal oxide fabricated by co-precipitation method

A novel mixed metal oxide, CeO2·CuAlO2 was fabricated by co-precipitation method in aqueous medium. CeO2·CuAlO2 was characterized by XRD, SEM, EDS, TEM, FTIR and PL spectra. The optical properties of the nanoparticles were studied by photoluminescence (PL) spectra. PL spectra at different excitations were recorded. The composite showed emission in UV, visible and NIR region depending on the excitation wavelength. The special spectral feature observed for this composite is that it showed six emission bands at 364, 409, 434, 448, 465 and 481 nm when excited at 298 nm. The green and red emissions observed at 512 and 669 nm are originated from cubic CeO2 phase when excited at 450 nm. The PL spectra were found to be dependent on excitation wavelength violating Kasha's rule. The X-ray diffraction reveals a cubic CeO2 phase and hexagonal CuAlO2 phase. EDS spectra revealed the presence of cerium (Ce), copper (Cu), aluminum (Al) and oxygen (O) elements. The particle size of the CeO2·CuAlO2 mixed oxide was estimated using Scherrer's formula, which was found to be in the range of 17.2-34.2 nm. The TEM image showed particles are almost uniform size of approximately 15-50 nm with spherical morphology.

Synthesis, structure and excitation wavelength dependent PL properties of novel nanocomposite La2O2CO3·CuO·ZnO

A novel multi-metal nanocomposite, La2O2CO3·CuO·ZnO has been synthesized by co-precipitation method and characterized by XRD, SEM, EDS and PL spectra. XRD showed the presence of La2O2CO3, CuO and ZnO phases with an average particle size of 20 nm. Excitation at different wavelengths showed PL in UV and visible regions. Excitation at 220-270 nm provided UV emissions. Excitations at 298, 324 and 355 nm showed PL in the violet and blue regions. Excitation at 395 and 450 nm provided green and red luminescence, respectively. It has been found that PL behavior of La2O2CO3·CuO·ZnO is excitation wavelength dependent. This PL property is contrary to well-known Kasha's rule of excitation wavelength dependence of emission spectrum. The excitation peaks at 300-325 (broad band), 353, 371, 394, 408 nm were observed when monitored at 450 nm.

NIR and CT luminescence spectra of [Yb(TFN)(S-BINAPO)] and [Yb(HFA)(S-BINAPO)] complexes

The complexes [Yb(TFN)3(S-BINAPO)](TFN=4,4,4-trifluoro-1(2-napthyl)-1,3-butanedione) (complex 1) and [Yb(HFA)3(S-BINAPO)](HFA=hexafluoroacetylacetonate) (complex 2) were synthesized, characterized. The absorption as well as PL spectra have been studied. The complex [Yb(TFN)3(S-BINAPO)] showed narrowed emission peak (half width ∼6 nm) at around 981 nm in addition to several emission peaks in NIR (near infrared) region. The complex [Yb(HFA)3(S-BINAPO)] showed strong emission peak at around 985 nm. The charge transfer luminescence of [Yb(TFN)3(S-BINAPO)] was also observed at 412-463 nm.

Synthesis, characterization and spectroscopic investigations of novel nano multi-metal oxide Co3O4·CeO2·ZnO

A novel multi-metal nanocomposite, Co3O4·CeO2·ZnO has been prepared by co-precipitation of their carbonates from aqueous solutions of the metal nitrates following calcining and annealing 5h at 450°C and 10h at 950°C. Co3O4·CeO2·ZnO has been characterized by XRD, SEM, EDS, IR and PL spectra. The crystallite size of the as-synthesized sample varies in the range of 9-33nm and those of the annealed sample in the range of 19-42nm. Emissions of Co3O4·CeO2·ZnO were observed in UV and visible region at different excitations. Excitation wavelength dependent PL behavior of Co3O4·CeO2·ZnO has been observed in acetone. This PL property is contrary to the well-known Kasha's rule of excitation wavelength dependence of emission spectrum.

X-ray structure and spectroscopy of novel trans-[Ni(L)(NO(3))(2)] and [Ni(L)](ClO(4))(2)·2H(2)O complexes

Ni(L)(NO(3))(2) (complex 1) and [Ni(L)](ClO(4))(2)·2H(2)O (complex 2) [L=3,14-diethyl-2,6,13,17-tetraazatricyclo(16.4.0.0(7,12))docosane] have been prepared and structurally characterized by single-crystal X-ray diffraction at 200K. For these constrained macrocycle complexes, nickel(II) exists in a distorted octahedral environment with the four nitrogen atoms of the macrocyclic ligands and two oxygen atoms from nitrate in axial positions in complex 1. The macrocyclic ligand in complex 1 adopts the most stable trans-III conformation. The Ni-N distances in both the complex 1 (2.094(4)-2.051(4)Å) and complex 2 (2.042(8)-1.996(7)Å), are typical but the axial ligands are coordinating, with NiO bond length, 2.198(3)Å for complex 1. The complex 2 adopts square planner geometry around the Ni(II) with four nitrogen atoms from macrocyclic ligand. The crystals are stabilized in a 3-D network by intra and intermolecular hydrogen bonds that are formed among the secondary nitrogen hydrogen atoms and nitrate in 1, and intermolecular hydrogen bonds are formed by perchlorate and NH groups in 2. The electronic absorption, IR and PL spectral properties are also discussed.

Spectroscopic analysis, DNA binding and antimicrobial activities of metal complexes with phendione and its derivative

A novel ligand (E)-2-styryl-1H-imidazo [4, 5-f] [1, 10] phenanthroline(L) has been synthesized from 1,10-phenanthroline-5,6-dione. Its transition metal complexes, [FeLCl4][L-H] and [CuL2](NO3)2 have also been synthesized. Besides, three mixed ligand lanthanide metal complexes of Phendione and β-diketones have been synthesized, namely [Eu(TFN)3(Phendione)] (TFN = 4,4,4-trifluoro-1(2-napthyl)-1,3-butanedione), [Eu(HFT)3(Phendione)] (HFT = 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione), [Yb(HFA)3(Phendione)] (hfa = hexafluoroacetylacetonate). The synthesized ligands and metal complexes have been characterized by FTIR, UV-Visible spectroscopy and PL spectra. DNA binding activities of the complexes and the ligands have been studied by DNA gel electrophoresis. DNA binding studies showed that Fe complex of the synthesized ligand is more potent DNA binding and damaging agent compare to others under study. The synthesized compounds were also screened for their antimicrobial activities by disc diffusion method against three microbes, namely Escherichia coli, Staphylococcus aureus, Proteus penneri. The lanthanide complexes of phendione showed great antibacterial activities.

3,14-Diethyl-2,13-di-aza-6,17-diazonia-tri-cyclo-[16.4.0.0(7,12)]docosane dichloride tetra-hydrate from synchrotron radiation

The asymmetric unit of title hydrated salt, C₂₂H₄₆N₄²⁺·2Cl⁻·4H₂O, comprises half a centrosymmetric dication, one Cl⁻ anion and two water mol­ecules of crystallization. The structure determination reveals that protonation has occurred at diagonally opposite amine N atoms, and that the dication features intra­molecular N—H⋯N hydrogen bonds. In the crystal, a three-dimensional artchitecture is formed by O—H⋯Cl/N and N—H⋯Cl/O hydrogen bonds.

Bis[trans-dichloridobis(propane-1,3-diamine-κ(2)N,N')chromium(III)] tetra-chloridozincate determined using synchrotron radiation

In the title compound, [CrCl(2)(C(3)H(10)N(2))(2)](2)[ZnCl(4)], the Cr(III) atom is coordinated by four N atoms of propane-1,3-diamine (tn) and two Cl atoms in a trans arrangement, displaying a distorted octa-hedral geometry with crystallographic inversion symmetry; the Zn atom in the [ZnCl(4)](2-) anion lies on a -4 axis. The orientations of the two six-membered chelate rings in the complex cation are in an anti chair-chair conformation with respect to each other. The Cr-N bond lengths are 2.087 (6) and 2.097 (6) Å. The Cr-Cl and Zn-Cl bond lengths are 2.3151 (16) and 2.3255 (13) Å, respectively. Weak inter-molecular hydrogen bonds involving the tn NH(2) groups as donors and chloride ligands of the anion and cation as acceptors are observed.

{3,14-Dimethyl-2,6,13,17-tetra-aza-tricyclo-[16.4.0.0]docosane-κN,N',N'',N''')bis-(nitrato-κO)copper(II)

The Cu^II atom in the title compound, [Cu(NO₃)₂(C₂₀H₄₀N₄)], is N,N′,N′′,N′′′-chelated by the macrocyclic ligand: the four N atoms form a square, above and below which are located the O atoms of the nitrate ions. The metal atom exists in a tetra­gonally distorted octa­hedron, on a special position of site symmetry. One of the amino groups is hydrogen bonded to an O atom of the nitrate ion. The other amino group is hydrogen bonded to O atom of an adjacent mol­ecule, generating a supra­molecular dimeric hydrogen-bonded dinuclear aggregate.

3,14-Dimethyl-2,6,13,17-tetra-aza-tricyclo-[16.4.0.0]docosa-ne-(naphthalen-1-yl)methanol (1/2)

In the title co-crystal, C(20)H(40)N(4)·2C(11)H(10)O, the macrocycle is generated by a crystallographic inversion centre. The N atoms show a pyramidal coordination, and the cyclo-hexane ring that is fused to the 14-membered C(10)N(4) ring exists in a chair conformation, whereas the methyl substituent occupies an axial site. The (naphthalen-1-yl)methanol mol-ecule forms an O-H⋯N hydrogen bond to a cyclam N atom. The mean-square-plane passing through the 14-membered ring is approximately coplanar with the naphthalene fused-ring [dihedral angle = 6.6 (1)°].

2,13-Dibenzyl-5,16-diethyl-2,6,13,17-tetra-aza-tricyclo-[16.4.0.0]docosan-2-ium nitrate

One of the tertiary amine atoms has been protonated in the title salt, C₃₆H₅₇N₄⁺·NO₃⁻. The four N atoms of the macrocycle are almost coplanar (r.m.s. deviation = 0.0053 Å), a result correlated with the formation of intra­molecular N—H⋯N and N—H⋯(N,N) hydrogen bonds. With respect to this plane, the benzyl groups lie to either side; a similar arrangement pertains for the cyclo­hexyl rings (each with a chair conformation). Helical supra­molecular chains are evident in the crystal, whereby alternating cations and anions are linked by C—H⋯O inter­actions. The chains are consolidated into supra­molecular arrays in the ab plane via C—H⋯π contacts involving both benzene rings.

Ethylenediammonium bis[bis[N-(2-aminoethyl)glycinato-kappa(3)N,N',O]chromium(III)] tetrachloride dihydrate at 293 and 100 K

The crystal structure of the title compound, (C(2)H(10)N(2))[Cr(C(4)H(9)N(2)O(2))(2)](2)Cl(4) x 2H(2)O, has been determined by single-crystal X-ray diffraction studies at 293 and 100 K. The analyses demonstrated that the crystal consists of ethylenediammonium dications (which lie about inversion centres), bis[N-(2-aminoethyl)glycinato]chromium(III) monocations, Cl(-) anions and hydrate water molecules, in a molecular ratio of 1:2:4:2. The complex cation unit has a slightly distorted octahedrally coordinated Cr atom, with two Cr[bond]O and four Cr[bond]N bonds in the ranges 1.951 (1)-1.953 (1) and 2.054 (1)-2.089 (2) A, respectively, at 293 K. The geometry of the bis[N-(2-aminoethyl)glycinato]chromium(III) moiety was found to be trans,cis,cis with respect to the carboxylate O atom and the primary and secondary amine N atoms. The two analyses, at 293 and 100 K, exhibited no remarkable structural differences, although the colour of the crystals did differ, being red at 293 K and orange at 100 K.