Electronic charge transport phenomena directed smart fabrication of Metal-Semiconductor based electronic junction device by a supramolecular Mn(II)-Metallogel

Mechanically Flexible Self-Healing Mg(II)-Metallogel: Approach of Triggering the ROS-Induced Apoptosis in Human Breast Cancer Cells

A self-assembly-directed thixotropic metallohydrogel (i.e., Mg-Tetrakis) of Mg(II)-metal salt and N,N,N',N'-tetrakis(2-hydroxy-ethyl)ethylenediamine (i.e., Tetrakis) was successfully achieved. The organic chemical component N,N,N',N'-tetrakis(2-hydroxy-ethyl)ethylenediamine was used as a low-molecular-weight gelator, and water was employed as the gel-forming solvent. The fabricated supramolecular metallohydrogel promisingly depicted viscoelastic and mechanoelastic behaviors, which are interpreted through various rheological parameters. The thixotropic behavior of the metallohydrogel is also well characterized through this rheological study. Field emission scanning electron microscopy microstructural analyses were performed to visualize the morphological arrangements of the metallohydrogel. The anticancer properties of the synthesized metallogels are investigated through this work. The cytotoxic potential of the metallohydrogel on the MCF-7 breast cancer cell line is critically examined. Reducing the growth of breast cancer cell line MCF-7 through the treatment of gel on the colony formation assay has been explored through the work. The antimigratory potential of the metallohydrogel on the MCF-7 cell was also scrutinized. The anticancer effect of the fabricated metallohydrogel is inspected through various assay formation strategies, like wound healing assay, tumor spheroid inhibition assay, nuclear fragmentation assay, and so on. Quantitative reactive oxygen species analysis of the cancer cells by treatment with the metallohydrogel was also conducted through this study. The mechanistic apoptosis study was executed by studying the expression of various apoptotic markers like BAX, BCL2, PUMA, and NOXA.

Comparative outcomes of the voltage-dependent current density, charge transportation and rectification ratio of electronic devices fabricated using mechanically flexible supramolecular networks

In this study, we report the synthetic method of two distinct supramolecular metallogels, namely Mn-BDA and Cd-BDA, using Mn(II) acetate tetrahydrate, Cd(II) acetate dihydrate and butane-1,4-dicarboxylic acid (BDA). DMF, a polar aprotic solvent, was immobilized in both metallogel-networks for their synthesis. The metallogelation of Mn-BDA was successfully attained through the instant mixing of a Mn(II)-source and BDA in DMF solvent media. By applying ultrasonication, a Cd-BDA metallogel was prepared. The stoichiometry of gel-forming components concerning metal salts and the LMWG are accountable to obtain respective stable metallogels. Rheological parameters such as storage modulus (G') and loss modulus (G'') explored the mechanical flexibility of the synthesized metallogels through amplitude and angular frequency sweep experiments. Both the metallogels possess significant mechanical stability, which was determined by monitoring diverse gel-to-sol transition shear strain values (γ%). Distinctive morphological visualizations of both of these metallogels (i.e., Mn-BDA and Cd-BDA) were made via field emission scanning electron microscopic (FESEM) studies, demonstrating a fibrous inter-connected network with a hierarchical self-assembled arrangement for Mn(II)-based metallogels and a typical stacked-flake-like association with hierarchical motifs for Cd(II)-based metallogels. EDAX elemental mapping substantiated the presence of metallogel-forming agents such as individual metal acetate salts, BDA acting as a low-molecular weight gelator, and gel-immobilized solvents such as DMF. Furthermore, Fourier transform infrared spectroscopy and ESI-mass spectroscopy were performed for both these supramolecular metallogels. FT-IR spectroscopic and ESI-mass spectroscopic results clearly substantiate the possible non-covalent supramolecular interactions among basic molecular repeating moieties, i.e., butane-1,4-dicarboxylic acid (the low-molecular weight gelator), individual metal salts and gel-immobilized polar aprotic solvent DMF for the construction of distinct stable supramolecular metallogel-systems. The semiconducting property of the fabricated metallogels was investigated. Two Schottky diodes (SDs) composed of ITO/Cd-BDA/Al and ITO/Mn-BDA/Al in a sandwich pattern with Al serving as the metal electrode were fabricated. Both these metallogel-based devices effectively offer significant semiconducting diode features with non-linear J-V characteristics. The non-ohmic conduction protocol of the fabricated metallogel-based devices was explored. Mn-BDA and Cd-BDA metallogel-based fabricated devices have rectification ratios of 6.67 and 23.50, respectively. The gel-based diode performances were examined by observing the voltage-dependent current density, charge transportation and rectification ratio.

Stimuli-responsive and self-healing supramolecular Zn(II)-guanosine metal-organic gel for Schottky barrier diode application

Spontaneous formation of a supramolecular metal-organic hydrogel using unsubstituted guanosine as a ligand and Zn2+ ions is reported. Guanosine, in the presence of NaOH, self-assembled into a stable G-quadruplex structure, which underwent crosslinking through Zn2+ ions to afford a stable hydrogel. The gel has been characterized using several spectroscopic as well as microscopic studies. The hydrogel demonstrated excellent stimuli responsiveness towards various chemicals and pH. Furthermore, the gel exhibited intrinsic thixotropic behavior and showed self-healing and injectable properties. The optical properties of the Zn-guanosine metallo-hydrogel suggested a semiconducting nature of the gel, which has been exploited for fabricating a thin film device based on a Schottky diode interface between metal and a semiconductor. The fabricated device shows excellent charge transport characteristics and linear rectifying behavior. The findings are likely to pave the way for newer research in the area of soft electronic devices fabricated using materials synthesized by employing simple biomolecules.

Suberic Acid-Based Supramolecular Metallogels of Ni(II), Zn(II), and Cd(II) for Anti-Pathogenic Activity and Semiconducting Diode Fabrication

The importance of three synthesized metallogels of suberic acid distinctly with nickel, zinc, and cadmium acetate salts has been uncovered. For the creation of these soft materials, N,N'-dimethyl formamide was utilized as a source of the trapped solvent. The synthesized metallogels display intriguing viscoelasticity, and the interpretation of experimental parameters obtained from rheological results advocates the gel behavior. Microstructural analysis combined with energy-dispersive X-ray confirms the occurrence of individual gel-developing constituents as observed in different hierarchical microstructural patterns. Significant variations in microstructural arrangements with diverse extent of supramolecular non-covalent patterns inside gel networks were perceived through field emission scanning electron microscopy, atomic force microscopy, and transmission electron microscopy analyses. Fourier transform infrared and electrospray ionization-mass spectral analyses and powder X-ray diffraction analysis of metallogel samples of different gel-establishing ingredients help to investigate the possible supramolecular interactions dictating the metallogel scaffolds. Thermogravimetric analysis of xerogel samples was collected from the synthesized metallogels to understand the thermal stability. These gel materials were characterized by their potential antibacterial efficiency. The potency of metallogels against selective Gram-positive and Gram-negative bacteria was visualized via a spectrophotometer. Human pathogens like Klebsiella pneumoniae (MTCC 109), Salmonella typhi (MTCC 733), Vibrio parahaemolyticus, Bacillus cereus (MTCC 1272), Lactobacillus fermentum (NCDO 955), and Staphylococcus aureus (MTCC 96) are employed in this study. Apart from the biological significance, our metallogels demonstrate as incredible diode performance of fabricated semiconducting systems, which exhibit a considerable amount of non-linearity demonstrating a non-ohmic conduction mechanism at room temperature in dark conditions. Device fabrication was achieved from these metallogels employing the sandwich model with indium tin oxide-coated glass substrates/metallogel/Al structure.

A croconate-directed supramolecular self-healable Cd(II)-metallogel with dispersed 2D-nanosheets of hexagonal boron nitride: a comparative outcome of the charge-transport phenomena and non-linear rectifying behaviour of semiconducting diodes

The use of croconic acid disodium salt (CADS) as an organic gelator with Cd(II) salt to obtain an efficient soft-scaffold supramolecular self-healable metallogel (Cd-CADS) in N,N-dimethyl formamide (DMF) media was investigated following an ultrasonication technique. The experimentally scrutinized rheological values of the fabricated metallogel not only revealed the visco-elastic property and mechanical stiffness, but also exposed the self-healable behaviour of the gel material. Two-dimensional (2D) nanosheets of hexagonal boron nitride (h-BN) were incorporated within the gel network to obtain a 2D nanosheet dispersed metallogel of Cd(II) croconate (h-BN@Cd-CADS). The microstructural investigations of the original gel network and hexagonal boron nitride (h-BN) 2D nanosheet dispersed gel-network were performed through field emission scanning electron microscopy (FESEM) and established the interconnecting rod-like fibrous type morphological patterns and inter-connected hexagonal type rod-shaped architecture pattern, respectively. High resolution transmission electron microscopy (HRTEM) was used to visualize the morphological distinction of the Cd-CADS metallogel with the h-BN 2D nanosheets. The infrared spectral (FT-IR) outputs helped to identify the formation pathway to construct the semi-solid self-healing flexible metallogel and h-BN 2D nanosheet dispersed metallogel nanocomposite, respectively. Fascinating electronic-charge transportation was revealed in the as-fabricated Cd-CADS and h-BN@Cd-CADS metallogel-based devices. Furthermore, h-BN 2D-nanosheet-directed modulation of the non-linear rectifying feature of the supramolecular Cd-CADS-metallogel was observed, with the h-BN@Cd-CADS metallogel showing a greater rectifying property, implying that it has a higher conductivity compared to the Cd-CADS metallogel.

Strategic fabrication of efficient photo-responsive semiconductor electronic diode-devices by Bovine Serum Albumin protein-based Cu(II)-metallohydrogel scaffolds

Bovine Serum Albumin protein-based two fascinating functional self-healing Cu(II) metallohydrogel scaffolds (MD1 and MD2) have been studied for the development of metal-semiconductor junction based Schottky diode device. Multiple metal-semiconductor (MS) junction devices, offering the sandwich-like configuration of Indium tin oxide (ITO)/ metallogel/Aluminium (Al), have been made-up to investigate the electrical properties of the synthesized metallohydrogel materials. Optical characterizations including optical band gap measurement have been carried out using Tauc's equation for both the metallohydrogels. The current-voltage (I-V) characteristics of just made-up devices are studied under irradiation and non- irradiation conditions to explore the electrical features through investigating the charge transport phenomenon. The electrical conductivity gets estimated as 3.13 × 10^-5 S.m^-1 and 2.69 × 10^-5 S.m^-1 for MD1 and MD2 under dark condition, and 11.06 × 10^-5 S.m^-1 and 5.99 × 10^-5 S.m^-1 for MD1 and MD2, respectively, in photo-irradiation. The measured optical and electrical properties of MD1 and MD2 metallohydrogels are thoroughly investigated and the data indicates that MD1 and MD2 metallohyrogels are semiconducting in nature with excellent photo-responsive behaviour. Moreover, the representative I - V characteristic of the MD1 and MD2 metallohydrogels at both irradiation and non-irradiation conditions represents the nonlinear rectifying behaviour, a typical signature for Schottky diode (SD).