Developing methods with a low environmental impact for nanoparticle synthesis remains one of the greatest challenges in nanotechnology. In this context, biomimetic and biological methods have emerged as green chemistry alternatives, and also contribute to our understanding of how nanomaterials interact with cellular molecules. Here, we report a phosphate-dependent biomimetic method to synthesize of cadmium sulphide (CdS) QDs at low temperatures, physiological pH and aerobic conditions, using CdCl₂ and thiols (L-cysteine, glutathione or mercaptosuccinic acid). Inorganic phosphate (Pi) and cellular phosphorylated intermediates such as adenosine monophosphate, glucose-6-phosphate, glycerol-2-phosphate and fructose-1,6-biphosphate, can trigger CdS QDs synthesis. The produced QDs are cubic phase nanocrystals with a tunable fluorescence (450–700 nm), small size (4–12 nm), and are composed of thiols and Pi. In CdS synthesis, the importance of the phosphate is related to its capacity to release H₂S from thiols, a phenomenon associated with its base-properties. Based on the biomimetic method, we developed a Pi-based procedure to synthesize CdS QDs in Escherichia coli. As in the biomimetic procedure, Pi favors QDs-biosynthesis not only by mediating biological generation of H₂S, but also by improving Cd²⁺ cellular uptake. A role for phosphates in the cellular interaction and green synthesis of metal QDs is discussed.

A one-pot green method for aqueous synthesis of fluorescent copper sulphide nanoparticles (NPs) was developed. The reaction was carried out in borax–citrate buffer at physiological pH, 37 °C, aerobic conditions and using Cu (II) and the biological thiol cysteine. NPs exhibit green fluorescence with a peak at 520 nm when excited at 410 nm and an absorbance peak at 410 nm. A size between 8–12 nm was determined by dynamic light scattering and transmission electron microscopy. An interplanar atomic distance of (3.5 ± 0.1) Å and a hexagonal chalcocite crystalline structure (βCh) of Cu₂S NPs were also determined (HR-TEM). Furthermore, FTIR analyses revealed a Cu-S bond and the presence of organic molecules on NPs. Regarding toxicity, fluorescent Cu₂S NPs display high biocompatibility when tested in cell lines and bacterial strains. Electrocatalytic activity of Cu₂S NPs as counter electrodes was evaluated, and the best value of charge transfer resistance (R_ct) was obtained with FTO/Cu₂S (four layers). Consequently, the performance of biomimetic Cu₂S NPs as counter electrodes in photovoltaic devices constructed using different sensitizers (ruthenium dye or CdTe NPs) and electrolytes (S²⁻/S_n²⁻ or I⁻/I³⁻) was successfully checked. Altogether, novel characteristics of copper sulfide NPs such as green, simple, and inexpensive production, spectroscopic properties, high biocompatibility, and particularly their electrochemical performance, validate its use in different biotechnological applications.

Laguna Verde's dome‐shaped structures are distinctive formations within the Central Andes, displaying unique geomicrobiological features. This study represents a pioneering investigation into these structures, assessing their formation, associated taxa, and ecological significance. Through a multifaceted approach that includes chemical analysis of the water body, multiscale characterization of the domes, and analysis of the associated microorganisms, we reveal the complex interplay between geology and biology in this extreme environment. The lake's alkaline waters that are rich in dissolved cations and anions such as chloride, sodium sulfate, and potassium, coupled with its location at the margin of the Antofalla salt flat, fed by alluvial fans and hydrothermal input, provide favorable conditions for mineral precipitation and support for the microorganism's activity. Laguna Verde's dome‐shaped structures are mainly composed of gypsum and halite, displaying an internal heterogeneous mesostructure consisting of three zones: microcrystalline, organic (orange and green layers), and crystalline. The green layer of the organic zone is predominantly composed of Proteobacteria, Bacteroidetes, and Cyanobacteria, while the orange layer is mostly inhabited by Cyanobacteria. The results of the study suggest that oxygenic photosynthesis performed by Cyanobacteria is the main carbon fixation pathway in the microbial community, supported by carbon isotopic ratios of specific biomarkers. This finding highlights the important role played by Cyanobacteria in this ecosystem.

Phosphate and arsenate are very similar compounds, and there is great interest in studying their relationship and their interaction with biological systems. Despite having no apparent biological function, specific genes regulate arsenic interaction with cells and can be located in regions of the genome called arsenic islands, where phosphate metabolism genes are also present. Although they are neighboring genes, the nature of their relationship and how they have been selected is still unknown.In this work, we analyzed the metagenomes of the four microbial ecosystems inhabiting hypersaline lakes of the Argentine Puna and the Atacama salt flat in Chile and have evaluated the presence and abundance of both arsenic and phosphate metabolism genes. The samples analyzed included microbialites, biofilms and microbial mats; all of them established under high arsenic concentrations, high UV radiation and high temperature fluctuation, among others.The results show great differences in the dispersion and abundance of genes related to both phosphate and arsenic metabolism in the analyzed samples. The main difference is given in the Diamante Lake, located in the crater of the Galan volcano characterized by being one of the lakes with the highest arsenic concentration (2.34 mM). Correlating genes abundance with the physicochemical parameters of the lakes studied, our results suggest that arsenic and phosphate metabolism are intricately co-regulated in environmental conditions.