Mining activities in Chile generate massive amounts of tailings, creating significant environmental risks due to heavy metal contamination. Phytoremediation offers an eco-friendly solution, yet studies on native Chilean species are scarce. This study evaluates the effects of ethylenediamine tetraacetic acid (EDTA) and nanoscale zero-valent iron (nZVI) on the potential of the native Cistanthe grandiflora for the phytoremediation of copper mine tailings. A six-month pot experiment was conducted with four treatments: EDTA 300 mg·kg⁻¹, EDTA 600 mg·kg⁻¹, nZVI 500 mg·kg⁻¹, and a control group without additions. The results indicate that Cistanthe grandiflora primarily acts as a phytostabilizer, accumulating higher metal concentrations in roots than in aerial parts. The application of EDTA significantly enhanced the Bioconcentration Factor for Cu, Ni, Pb, and Mo, increasing BCF values from 0.5 to 1.0 or more in several cases. Specifically, a lower dose of EDTA (300 mg·kg⁻¹) successfully increased the Translocation Factor (TF) of cadmium to 1.3, suggesting a potential for phytoextraction for this element. Conversely, nZVI application showed a limited impact, slightly improving the Translocation factor for copper and chromium but without exceeding unity. These findings demonstrate that Cistanthe grandiflora, assisted by EDTA, is a promising candidate for the phytostabilization of heavy metals in mine tailings.

The corrosion of metallic biomaterials under physiological conditions remains a critical challenge due to the risk of ion release affecting biocompatibility. In this study, the time-dependent electrochemical behavior of a poly(vinyl alcohol) (PVA)/chitosan biopolymer coating applied to biomedical-grade steel was evaluated to assess its protective performance. The coating was prepared via dip-coating using a 9.9:0.1 PVA/chitosan formulation and characterized by FTIR and Raman spectroscopy to confirm intermolecular interactions and film formation. Electrochemical impedance spectroscopy was employed over 216 h of immersion in Hanks’ Balanced Salt Solution to monitor coating degradation and corrosion mechanisms. The coated system exhibited a significant increase in the low-frequency impedance modulus from approximately 1200–1400 to 5000–6000 Ω·cm², indicating enhanced barrier properties and interfacial stability compared to uncoated steel. Equivalent circuit analysis revealed a transition from a predominantly capacitive, barrier-controlled response at early immersion stages to diffusion-influenced behavior at longer exposure times, associated with electrolyte penetration and interfacial processes. Overall, the PVA/chitosan coating effectively delays corrosion reactions and maintains high impedance under simulated physiological conditions, demonstrating its potential as a protective and biocompatible surface modification for metallic biomedical applications.

This work describes an efficient and environmentally friendly method for the synthesis of silver-based nanostructures through a green route using Aloe vera extract as a reducing agent, silver nitrate (AgNO₃) as a precursor, and polyvinylpyrrolidone (PVP, 10 kDa molecular weight) as a stabilizing agent. The formation of these structures was supported by UV–Vis spectroscopy, where a surface plasmon resonance (SPR) band was observed between 425 and 460 nm. Scanning electron microscopy revealed predominantly spherical features in the 300–500 nm range; however, the distinction between primary nanoparticles and aggregates cannot be conclusively established from SEM alone. EDX analysis indicated a silver content of 59.96 wt%. Antibacterial assays performed in Z8 medium demonstrated a reduction in cyanobacterial growth with increasing dosage, with complete inhibition observed at ≥20 $\mu$L (nominal MIC = 1.77 mg mL⁻¹, based on precursor estimation). Total dissolved solids and absorbance measurements exhibited a decreasing trend with increasing concentration (effect size = 0.87, $p<0.001$), supporting an inhibitory effect under the tested conditions. These findings suggest potential antibacterial activity. However, this study should be considered exploratory, and further work is required to elucidate the underlying mechanisms.