Advancements in manganese complex-based MRI agents: Innovations, design strategies, and future directions

This review focuses on the advancements in manganese (Mn) complex-based magnetic resonance imaging (MRI) agents for imaging different diseases. Here we emphasize the unique redox properties of Mn to deliver innovative MRI contrast agents, including small molecules, nanoparticles (NPs), metal-organic frameworks (MOFs), and polymer hybrids. Aspects of their rational design have been discussed, including size dependence, morphology tuning, surface property enhancement, etc., while also discussing the existing challenges and potential solutions. The present work will inspire and motivate scientists to emphasize MRI-guided applications and bring clinical success in the coming years.

Te4+ and Er3+ doped ZrO2 nanoparticles with enhanced photocatalytic, antibacterial activity and dielectric properties: A next generation of multifunctional material

Amid rising water contamination from industrial sources, tackling toxic dyes and pathogens is critical. Photocatalysis offers a cost-effective and eco-friendly solution to this pressing challenges. Herein, we synthesized Te4+ and Er3+ doped ZrO2 photocatalysts through hydrothermal method and investigated their efficacy in degrading Congo red (CR) and pathogens under visible light. XRD and Raman Spectroscopy confirm monoclinic and tetragonal mixed-phases without any impurities. Doping-induced defects, reduced crystalline diameter, high surface area, modified bandgap (2.95 eV), photoluminescence quenching, coupled with interfacial polarization, contribute to EZO's excellent dielectric response (1.149 × 106), for achieving remarkable photocatalytic activity, verified by photoelectrochemical measurements, LC-MS and phytotoxicity analysis. Under optimal conditions, EZO achieves 99% CR degradation within 100 min (TOC 79.9%), surpassing ZO (77%) and TZO (84%). Catalyst dosages, dye concentrations, and solution pH effect on EZO's photocatalytic performance are systematically assessed. Scavenging experiment emphasized the pivotal role of · OH in CR degradation with 96.4% efficiency after 4 cycles, affirming its remarkable stability. Moreover, EZO demonstrates ROS-mediated antibacterial activity against E. faecalis and E. coli bacteria under visible light, achieving >97% and >94% inhibition rate with an inhibition zone > 3 mm. Hence, the nanoparticle's dual action offers a practical solution for treating contaminated wastewater, ensuring safe irrigation.

Sonochemically synthesized black phosphorus nanoparticles: a promising candidate for piezocatalytic antibacterial activity with enhanced dielectric properties

The drawbacks inherent to traditional antibacterial therapies, coupled with the escalating prevalence of multi-drug resistant (MDR) microorganisms, have prompted the imperative need for novel antibacterial strategies. Accordingly, the emerging field of piezocatalysis in semiconductors harnesses mechanical stress to drive chemical reactions by utilizing piezo-generated free charge carriers, presenting a promising technology. To the best of our knowledge, this study is the first to provide a comprehensive overview of the eradication of pathogenic S. aureus bacteria using few-layer black phosphorus (SCBP) piezo catalyst under mechanical stimuli, along with the exploration of temperature dependent dielectric properties. The synthesis of the piezo catalysts involved a one-step cost-effective sonochemical method, and its structural, morphological, elemental, optical, and overall polarization properties were thoroughly characterized and compared with the traditional method-derived product (TABP). The synthesis-introduced defects, reduced crystalline diameters, modified bandgap (1.76 eV), nanoparticle aggregation, photoluminescence quenching, along with interfacial polarization, synergistically contribute to SCBP's exceptional dielectric response (4.596 × 107 @40 Hz), which in turn enhanced the piezocatalytic activity. When subjected to soft ultrasound stimulation at 15 kHz, the piezo catalyst SCBP demonstrated significant ROS-mediated antibacterial activity, resulting in a ∼94.7% mortality rate within 40 minutes. The impact of this study extends to cost-effective energy storage devices and advances in antibacterial therapy, opening new dimensions in both fields.

Piezodynamic Eradication of Both Gram-Positive and Gram-Negative Bacteria by Using a Nanoparticle Embedded Polymeric Membrane

Nowadays, bacterial infection is regarded as a serious threat to humankind, which needs to be taken care of. The emergence of antibiotic resistance and multidrug resistance (MDR) is rendering this situation more troublesome. However, several alternative treatment regimens have aided such diseases quite well in the recent past, among which dynamic antibacterial therapies combat this situation quite well. Among various dynamic therapies, piezodynamic therapy is a very recent avenue, in which mechanical stimuli have been exploited to treat bacterial infections. Herein, piezo-active bismuth ferrite-loaded poly(vinylidene fluoride-co-hexafluoropropylene) polymer has been utilized to eradicate gram-positive bacteria (E. faecalis) and gram-negative bacteria (E. coli). The sample has been designed in a free-standing membrane form, which, under soft ultrasound (~10 kHz), generates reactive radicals to ablate bacteria. Initially, the structure and morphology of the membrane have been substantiated by using X-ray diffraction and scanning electron microscopy methods; besides, Fourier transform infrared spectrum of the sample depicts a tremendously high value of polarizability and further confirms the piezo-activity of the membrane. More than 99% of E. coli and E. faecalis have been successfully eradicated within 30 min of ultrasound. Moreover, the solid-state structure and hydrophobic nature of the membrane help us to reuse it in a cyclic manner, which is possibly reported herein for the very first time. This novel membrane could be deployed in healthcare systems and pigment industries and could be exploited as a self-cleaning material.

Nanomaterials as multimodal photothermal agents (PTAs) against 'Superbugs'

Superbugs, also known as multidrug-resistant bacteria, have become a lethal and persistent threat due to their unresponsiveness toward conventional antibiotics. The main reason for this is that superbugs can rapidly mutate and restrict any foreign drug/molecule in their vicinity. Herein, nanomaterial-mediated therapies have set their path and shown burgeoning efficiency toward the ablation of superbugs. Notably, treatment modalities like photothermal therapy (PTT) have shown prominence in killing multidrug-resistant bacteria with their ability to generate local heat shock-mediated hyperthermia in such species. However, photothermal treatment has some serious limitations, such as high cost, complexity, and even toxicity to some extent. Hence, it is important to resolve such shortcomings of PTTs as they provide substantial tissue penetration. This is why multimodal PTTs have emerged and taken over this domain of research for the past few years. In this work, we have summarized and critically reviewed such exceptional works of recent times and provided a perspective to enhance their efficiencies. Profoundly, we discuss the design rationales of some novel photothermal agents (PTAs) and shed light on their mechanisms. Finally, challenges for PTT-derived multimodal therapy are presented, and capable synergistic bactericidal prospects are anticipated.

Thermoelectric, Electrochemical, & Dielectric Properties of Four ZnO Nanostructures

In this work, we investigated the thermoelectric, electrochemical, and dielectric properties of four different ZnO morphologies, namely nanoribbons, nanorods, nanoparticles, and nanoshuttles. Temperature-dependent Seebeck coefficients were observed using thermoelectric measurements, which confirmed that all synthesized ZnO nanostructures are n-type semiconductors. The Van der Pauw method was applied to measure electrical conductivity, which was also used to calculate the thermal activation energy. Electrochemical properties were analyzed by cyclic voltammetry techniques under five different optical filters. Electrical conductivity of ZnO morphologies showed an increasing trend with increasing temperature. The highest electrical conductivity (1097.60 Ω−1 m−1) and electronic thermal conductivity (1.16×10−4 W/mK) were obtained for ZnO nanorods at 425 K, whereas ZnO nanoshuttles carried the lowest electrical conductivity (1.10 × 10−4 Ω−1 m−1) and electronic thermal conductivity (8.72 × 10−7 W/mK) at 325 K. ZnO nanorods obtained the maximum Power factor value in all temperature ranges. All nanostructures showed electro-catalytic performance with different optical filters. From impedance spectroscopy analysis, ZnO nanorods showed the highest dielectric constant at high frequencies (>1 MHz) at 2.02 ± 0.06, while ZnO nanoshuttles gave the highest dielectric constant at low frequencies (<100 Hz) at 9.69 ± 0.05. These results indicate that ZnO nanorods have the most favorable thermoelectric, electrochemical, and dielectric properties compared to all other ZnO morphologies.

In Situ-Grown Cdot-Wrapped Boehmite Nanoparticles for Cr(VI) Sensing in Wastewater and a Theoretical Probe for Chromium-Induced Carcinogen Detection

In modern society, massive industrialization escalates environmental degradation by liberating various contaminants into the environment. Hexavalent chromium is a heavy metal that is being discharged from tannery and other industries, resulting in various carcinogenic diseases. This study reports a carbon dot (cdot)-based fluorometric probe for detecting hexavalent chromium in water. This is the very first time that cdots are tailored over the boehmite nanoparticle's surface using an in situ approach. Validation of formation of the nanocomposite has been discussed in detail employing the Rietveld refinement-based X-ray crystallography method. Vibrational spectroscopy and electron microscopy of the sample authenticate the nucleation process and the growth mechanism. The Stern-Volmer approach and time-resolved fluorescence measurements justify the sensitivity of the sensor (∼58 nM), and selectivity is analyzed by exposing the material to different ionic environments. Density functional theory (DFT) is applied herein to analyze the origin of fluorescence and the sensing mechanism of the probe, which shows that photoinduced electron transfer is responsible for the turn-off-based sensing of Cr(VI). The molecular docking simulation is carried out to ensure the binding of cdots to the binding pocket of the glutathione enzyme, which is responsible for treating reactive oxygen species-mediated DNA damage due to elements such as hexavalent chromium. Time-dependent density functional calculations show that the fluorometric probe is capable of detecting Cr(VI) in living cells making it an early stage chromium-mediated carcinogen detector.

Hierarchical γ-alumina: From Pure Phase to Nanocomposites

Recent advances in nanotechnology make it possible to create nanomaterials based on γ-alumina with novel hierarchical structure and physicochemical properties. Hierarchical γ-alumina can be synthesized using chemical or physical methods. The nanostructures based on γ-alumina exhibit unique properties, which are utilized in the design of efficient applications. These superior properties are often due to their hierarchical organizations from the nanosize scale to the macroscopic level. The present review is devoted to the contemporary state of the studies on the methods to produce hierarchical γ-alumina. We tried to summarize herein the literature data on the methods of synthesis of hierarchical γ-AlOOH and γ-Al2O3 with controlled morphology and the application of these methods for the synthesis of hierarchical γ-AlOOH and γ-Al2O3 nanocomposites.

Effects of pH and ions on the morphological evolution of boehmite prepared by hydrothermal treatment of ultrafine Bayer gibbsite

Boehmite morphology depended on the pH and ions of the solution by hydrothermal treatment of gibbsite owing to the difference in nucleation and growth of boehmite from Al³⁺, Al(OH)₄⁻ or the Al(OH)₄⁻Na⁺ ion pair.

Nitrogenous carbon dot decorated natural microcline: an ameliorative dual fluorometric probe for Fe3+ and Cr6+ detection

This work reports a C-dot loaded natural microcline based selective and sensitive dual fluorescent probe for hazardous Fe³⁺ and Cr⁶⁺ detection in water along with its effects in real-life water samples.

Gd(III)-Doped Boehmite Nanoparticle: An Emergent Material for the Fluorescent Sensing of Cr(VI) in Wastewater and Live Cells

This article reports the effect of Gd(III) doping on the structure, microstructure, and optical properties of boehmite nanoparticles. The bright-blue fluorescence along with a long lifetime makes our material an efficient candidate for optical applications. Our material particularly targets and eliminates hexavalent chromium ions (Cr(VI)) from aqueous media, which turns it into a multifunctional fluorescent nanosensor (MFNS). The development of an efficient hexavalent chromium ion (Cr(VI)) sensor to detect and quantify Cr(VI) ions is still a serious issue worldwide. Thus, this work will be very beneficial for various environmental applications. No such work has been reported so far which includes cost-effective and biocompatible boehmite nanoparticles in this field. Detailed synthesis and characterization procedures for the MFNS have been incorporated here. The biocompatibility of the MFNS has also been studied rigorously by performing cell survivability assay (MTT) and cellular morphology assessments. Our extensive research confirmed that the "turn-off" sensing mechanism of this sensor material is based on a collisional quenching model which initiates the photoinduced electron transfer (PET) process. High selectivity and sensitivity (∼1.05 × 10^-5 M) of the MFNS toward hexavalent chromium ions even in real life wastewater samples have been confirmed, which makes this fluorescent probe a potential candidate for new age imaging and sensing technologies.