Layered Double Hydroxides as Slow-Release Fertilizer Compounds for the Micronutrient Molybdenum

Molybdenum (Mo) is an essential plant micronutrient. Despite low plant Mo requirements, deficiencies are not uncommon and soluble Mo fertilizers are often applied. However, soluble Mo may result in poor Mo use efficiency due to strong sorption (acid weathered soils) or leaching (lighter-textured soils). Here, ZnAl layered double hydroxides (LDHs), loaded with molybdate (MoO₄), were examined for their potential as slow-release Mo compounds. Chloride-exchanged LDHs with varying Zn/Al ratios (2, 3, and 4) were exchanged with MoO₄. Zn₂Al LDH indicated MoO₄ intercalation, whereas Zn₃Al and Zn₄Al LDHs bound MoO₄ merely on edge sites. Short-term Mo-LDH incubation identified sulfate, carbonate, and phosphate as the most competitive anions for MoO₄ exchange. Long-term Mo-LDH incubation in simulated pH-neutral soil solutions demonstrated slow Mo release from Zn₂Al LDH (half-life of 35 h), with a total Mo desorption of up to 85%. For Zn₃Al and Zn₄Al LDHs, Mo desorption was limited to <20%. Finally, several macronutrient fertilizers were tested as possible carriers for Mo-LDH fertilizer compounds.

Zinc phosphate nanoparticles: A review on physical, chemical, and biological synthesis and their applications

Nanotechnology is considered one of the emerging fields of science that has influenced diverse applications, including food, biomedicine, and cosmetics. The production and usage of materials with nanoscale dimensions like nanoparticles are attractive parts of nanotechnology. Among different nanoparticles, zinc phosphate nanoparticles have attracted attention due to their biocompatibility, biosafety, non-toxicity, and environmental compatibility. These nanoparticles could be employed in various applications like anticorrosion, antibacterial, dental cement, glass ceramics, tissue engineering, and drug delivery. A variety of physical, chemical, and green synthesis methods have been used to synthesize zinc phosphate nanoparticles. All these methods have some limitations along with certain advantages. Chemical approaches may cause health risks and environmental problems due to the toxicity of hazardous chemicals used in these techniques. Moreover, physical methods require high amounts of energy as well as expensive instruments. However, biological methods are free of chemical contaminants and eco-friendly. This review is aimed to explore different methods for the synthesis of zinc phosphate nanoparticles, including physical, chemical, and more recently, biological approaches (using various sources such as plants, algae, and microorganisms). Also, it summarizes the practicable applications of zinc phosphate nanoparticles as anticorrosion pigment, dental cement, and drug delivery agents.

Biomimetically crystallized protease resistant zinc phosphate decorated with gold atomic clusters for bioimaging

Biomimetically crystallized zinc phosphate nanoparticles act as host to protein fragment-stabilized Au nanoclusters for efficient bioimaging.

Lipid-enveloped zinc phosphate hybrid nanoparticles for codelivery of H-2K(b) and H-2D(b)-restricted antigenic peptides and monophosphoryl lipid A to induce antitumor immunity against melanoma

Nanoimmunotherapy, the application of nanotechnology for sustained and targeted delivery of antigens to dendritic cells (DCs), has attracted much attention in stimulating antigen-specific immune response for antitumor therapy. In order to in situ deliver antigens to DCs for efficient antigen presentation and subsequent induction of strong cytotoxic T lymphocytes (CTL) response, here we developed a multi-peptide (TRP2180-188 and HGP10025-33) and toll-like receptor 4 agonist (monophosphoryl lipid A) codelivery system based on lipid-coated zinc phosphate hybrid nanoparticles (LZnP NPs). This delivery system equips with the chelating property of zinc to realize the high encapsulation efficiency with antigenic peptides and the influence on immune system with adjuvant-like feature. The combination of H-2K(b) and H-2D(b)-restricted peptides could provide multiple epitopes as the target of specific MHC alleles, making tumor more difficult to escape from the surveillance of immune system. The formulated LZnP nano-vaccine with the size of 30nm and outer leaflet lipid exhibited antitumor immunity as the secretion of cytokines in vitro and increased CD8(+) T cell response from IFN-γ ELISPOT analysis ex vivo. The antitumor effects were further evidenced from the prophylactic, therapeutic and metastatic melanoma tumor models compared with free antigens and single peptide-loaded nano-vaccines. These results validate the benefit of LZnP-based vaccine for antitumor immunity and indicate that co-delivery of tumor antigens along with adjuvant may be an optimized strategy for tumor immunotherapy.

Co3(OH)2(HPO4)2 as a novel photocatalyst for O2 evolution under visible-light irradiation

Co₃(OH)₂(HPO₄)₂ was proved to be a novel visible-light-driven photocatalyst for O₂ evolution due to the unique characteristics of Co²⁺ octahedra.

A designed synthesis of multifunctional Fe3O4@carbon/zinc phosphate nanoparticles for simultaneous imaging and synergic chemo-photothermal cancer therapy

A simple method is developed to synthesize Fe₃O₄@C/ZnP NPs for simultaneous MRI and synergic chemo-photothermal therapy.