Colloidal synthesis of ternary AgFeS2 nanocrystals and their transformation to Ag2S-Fe7S8 heterodimers

Photothermal Ferrotherapy - Induced Immunogenic Cell Death via Iron-Based Ternary Chalcogenide Nanoparticles Against Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is highly malignant and prone to recurrence and metastasis. Patients with TNBC have limited therapeutic options, often resulting in poor prognosis. Some new treatments for TNBC have been considered in the past decade, such as immunotherapy, photothermal therapy (PTT), and ferroptosis therapy, that allow the rapid and minimally invasive ablation of cancer. However, a multifunctional nanodrug system with more potent efficacy for TNBC is still needed. The use of iron-based ternary chalcogenide nanoparticles (NPs), namely AgFeS2, is reported, which synergistically combines photothermal therapy, ferrotherapy, and immunotherapy in one system for the treatment of TNBC. AgFeS2 possesses excellent photothermal conversion performance for tumor near-infrared (NIR) phototherapy. Upon photoirradiation, these NPs generate heat, accelerate the release of iron ions, and effectively catalyze the Fenton reaction, resulting in cell apoptosis and ferroptosis. Additionally, AgFeS2 promotes the release of tumor-specific antigens and triggers an immune response via immunogenic cell death (ICD), thereby providing unique synergistic mechanisms for cancer therapy. The present study demonstrates the great potential of iron-based ternary chalcogenide as a new therapeutic platform for a combination of photothermal therapy, ferrotherapy, and immunotherapy for the suppression of TNBC.

Magnetic Nanoparticle Composites: Synergistic Effects and Applications

Composite materials are made from two or more constituent materials with distinct physical or chemical properties that, when combined, produce a material with characteristics which are at least to some degree different from its individual components. Nanocomposite materials are composed of different materials of which at least one has nanoscale dimensions. Common types of nanocomposites consist of a combination of two different elements, with a nanoparticle that is linked to, or surrounded by, another organic or inorganic material, for example in a core-shell or heterostructure configuration. A general family of nanoparticle composites concerns the coating of a nanoscale material by a polymer, SiO2 or carbon. Other materials, such as graphene or graphene oxide (GO), are used as supports forming composites when nanoscale materials are deposited onto them. In this Review we focus on magnetic nanocomposites, describing their synthetic methods, physical properties and applications. Several types of nanocomposites are presented, according to their composition, morphology or surface functionalization. Their applications are largely due to the synergistic effects that appear thanks to the co-existence of two different materials and to their interface, resulting in properties often better than those of their single-phase components. Applications discussed concern magnetically separable catalysts, water treatment, diagnostics-sensing and biomedicine.

Structure, electronic and optical properties of chalcopyrite-type nano-clusters XFeY2 (X=Cu, Ag, Au; Y=S, Se, Te): a density functional theory study

Iron-based chalcopyrite materials have diverse applications in solar cells, spintronic, thermoelectric devices, LEDs and medical sciences. In this report we have studied structure, electronic and optical properties of chalcopyrite-type nano-cluster XFeY2 (X=Cu, Ag, Au; Y=S, Se, Te) systematically by using Density Functional Theory (DFT). Our computed HOMO-LUMO energy gap of XFeY2 is in the range of 1.568–3.982 eV, which endorses its potential application in optoelectronic devices and solar cells. The result shows that chalcopyrite-type material AuFeS2 having a star-type structure with point group C2v and sextet spin multiplicity, is the most stable cluster with HOMO-LUMO energy gap of 3.982 eV. The optical properties viz. optical electronegativity, refractive index, dielectric constant, IR and Raman activity of these nano-clusters are also investigated. The result exhibits that HOMO-LUMO energy gap of XFeY2 along with optical electronegativity and vibrational frequency decreases from S to Se to Te, whereas refractive index and dielectric constant increases in the reverse order.

Soft chemistry of metastable metal chalcogenide nanomaterials

The metastable nature of metal chalcogenide nanomaterials (MCNs) provides us with fresh perspectives and plentiful grounds in the search of new strategies for physicochemical tuning. In the past decade, numerous efforts have been devoted to synthesizing and modifying diverse emerging MCNs based on their "soft chemistry", that is, gently regulating the composition, structure, phase, and interface while not entirely disrupting the original features. This tutorial review focuses on design principles based on the metastability of MCNs, such as ion mobility and vacancy, thermal and structural instability, chemical reactivity, and phase transition, together with corresponding soft chemical approaches, including ion-exchange, catalytic growth, segregation or coupling, template grafting or transformation, and crystal-phase engineering, and summarizes recent advances in their preparation and modification. Finally, prospects for the future development of soft chemistry-directed synthetic guidelines and metastable metal chalcogenide-derived nanomaterials are proposed and highlighted.

AgFeS2 nanoparticles as a novel photothermal platform for effective artery stenosis therapy

Ternary I-III-VI2 semiconductors usually have narrow band gaps and large absorption coefficients arising from the unique characteristics of their outer-d valence electrons, which are intimately connected with the photothermal conversion properties. AgFeS2 is known as one such material that has the potential to absorb near-infrared light. In this work, we utilized density functional theory (DFT) calculations to evaluate the electronic structure and optical absorption properties of AgFeS2. Strong absorptions were predicted over a wide Vis-NIR region due to the localized 3d electron of Fe atoms, which agree quite well with the UV-Vis-NIR spectra measured by experiment. The as-prepared AgFeS2 nanoparticles were then modified with mPEG-DSPE, an efficient photothermal agent for artery stenosis therapy. Its photothermal conversion effect has been systematically studied, indicating the potential for causing the hyperthermia of macrophages, an essential part of the artery inflammation response. More importantly, both in vitro cell experiments and in vivo mouse-model studies show that the induction of hyperthermia in artery stenosis by using AgFeS2 nanoparticles is safe and effective when injected at a very low concentration. This study provides a novel photothermal platform derived from the inheritability of bandgap structure and also promotes the process of artery inflammation and stenosis therapy.

Modulated Triple-Material Nano-Heterostructures: Where Gold Influenced the Chemical Activity of Silver in Nanocrystals

For efficient charge separations, multimaterial hetero-nanostructures are being extensively studied as photocatalysts. While materials with one heterojunction are widely established, the chemistry of formation of multijunction heterostructures is not explored. This needs a more sophisticated approach and modulations. To achieve these, a generic multistep seed mediated growth following controlled ion diffusion and ion exchange is reported which successfully leads to triple-material hetero-nanostructures with bimetallic-binary alloy-binary/ternary semiconductors arrangements. Ag2 S nanocrystals are used as primary seeds for obtaining AuAg-AuAgS bimetallic-binary alloyed metal-semiconductor heterostructures via partial reduction of Ag(I) using Au(III) ions. These are again explored as secondary seeds for obtaining a series of triple-materials heterostructures, AuAg-AuAgS-CdS (or ZnS or AgInS2 ), with introduction of different divalent and trivalent ions. Chemistry of each step of the gold ion-induced changes in the rate of diffusion and/or ion exchanges are investigated and the formation mechanism for these nearly monodisperse triple material heterostructures are proposed. Reactions without gold are also performed, and the change in the reaction chemistry and growth mechanism in presence of Au is also discussed.

Phase segregation enabled scandium fluoride–lanthanide fluoride Janus nanoparticles

A phase-segregation based protocol enables the fabrication of a series of scandium fluoride–lanthanide fluoride Janus particles.

AgFeS2 -Nanowire-Modified BiVO4 Photoanodes for Photoelectrochemical Water Splitting

Photoelectrochemical water splitting is a promising and environmentally friendly route for the conversion of solar energy into hydrogen. However, the efficiency of this energy conversion process is low because of the limited light absorption and rapid bulk recombination of charge carriers. In this study, the combination of a novel ternary sensitizer AgFeS₂ , having a narrow bandgap of 0.9 eV, with a BiVO₄ electrode is presented for the enhancement of the solar-energy-to-hydrogen conversion efficiency. The photoelectrochemical properties of this combined material were investigated and the photocurrent densities of AgFeS₂ -BiVO₄ composite electrodes were greatly enhanced compared with pristine BiVO₄ (15 times higher at 0.6 V vs. Ag/AgCl under AM 1.5G illumination). The enhanced photoelectrochemical properties arise from extended light absorption, fast charge transfer and appropriate energy gap alignment. It was demonstrated that AgFeS₂ nanowires are promising inorganic sensitizers for improving the efficiency of solar water splitting.

Diffusion-Induced Shape Evolution in Multinary Semiconductor Nanostructures

The classical mechanism of crystal growth for architecting different nanomaterials in solution, although widely studied, is mainly restricted to binary semiconductor systems. However, this method is not applicable to multinary nanomaterials, which have multivalent cations possessing different reactivity under identical reaction conditions. Hence, the shape architectures of these nanostructures, which require a more sophisticated approach, remain relatively unexplored compared to those of binary semiconductors. Owing to the importance of the multinary materials, which are emerging as excellent green materials for both light harvesting and light emission, we investigated the diffusion-rate-controlled formation of ternary AgGaSe2 nanostructures and studied their heterostructures with noble metals. Controlling the changes in the rate of diffusion of the Ag ions resulted in the formation of tadpole-shaped AgGaSe2 ternary nanostructures. In situ study by collecting a sequential collection of samples has been carried out, and the conversion of amorphous Ga-selenide to crystalline AgGaSe2 has been monitored. In addition, heterostructures of tadpole AgGaSe2 with noble metals, Au and Pt, were designed, and their photocatalytic behaviors were studied.

Metal Ions Mediated Morphology and Phase Transformation of Chalcogenide Semiconductor: From CuClSe2 Microribbon to CuSe Nanosheet

Foreign ions are of significant importance in controlling and modulating the morphology of semiconductor nanocrystals during the colloidal synthesis process. Herein, we demonstrate the potential of foreign metal ions to simultaneously control the morphology and crystal phase of chalcogenide semiconductors. The results indicate that the introduction of Al(3+) ions can induce the structural transformation from monoclinic CuClSe2 microribbons (MRs) to klockmannite CuSe nanosheets (NSs) and the growth of large-sized CuSe NSs. The as-prepared micrometer-sized CuSe NSs exhibit a high-conducting behavior, long-term durability, and environment stability. The novel properties enable CuSe NSs to open up a bright prospect for printable electrical interconnects and flexible electronic devices.

Alternative synthesis of CuFeSe2 nanocrystals with magnetic and photoelectric properties

Monodisperse CuFeSe2 nanocrystals of high quality have been successfully synthesized for the first time using a hot-solution injection method from the reaction of metallic acetylacetonates with diphenyl diselenide (Ph2Se2) in oleylamine with addition of oleic acid at 255 °C for 90 min. The characterizations of X-ray diffraction, electron microscopy, and compositional analysis reveal that the resulting CuFeSe2 nanocrystals are of tetragonal phase with a stoichiometric composition. The CuFeSe2 nanocrystals exhibit well-defined quasi-cubic shape with an average size of ∼18 nm, and their shape can be tuned from quasi-cubes to quasi-spheres by adjusting the reaction parameters. Magnetic measurement reveals that the as-synthesized CuFeSe2 nanocrystals are ferromagnetic and paramagnetic at 4 and 300 K, respectively. Additionally, the current-voltage (I-V) behavior of the CuFeSe2 nanocrystals suggests that they are promising candidates for application in optoelectronics and solar energy conversion.