The search for sensitive and rapid analytical techniques for the determination of natural antioxidants is an area in constant growth due, among other aspects, to the complexity of plant matrices. In this study, silver nanoparticles prepared with the aqueous extract of Mimosa albida leaves were used to assess their polyphenolic content and antioxidant capacity. Silver nanoparticles were characterized by different techniques. As a result, nanoparticles of 6.5 ± 3.1 nm were obtained. The total phenolic content in the extract was 1320.4 ± 17.6 mg of gallic acid equivalents GAE· 100 g⁻¹ and in the nanoparticles 257.3 ± 5.1 mg GAE· 100 g⁻¹. From the phenolic profile analyzed by ultra high-performance liquid chromatography (UPLC) with a diode-array detector (DAD), the presence of apigenin and luteolin in the plant extract is postulated. The antioxidant capacity measured by oxygen radical absorbance capacity ORAC-fluorescein assay was 86917 ± 6287 and 7563 ± 967 µmol ET g⁻¹ in the extract and nanoparticles respectively. Electrochemical analysis by cyclic voltammetry (CV) confirmed the effective reduction capacity of the Mimosa albida leaves extract to reduce Ag ions to AgNPs and differential pulse voltammetry (DPV) suggested the presence of two main reducing agents in the extract. From this study, it was concluded that the aqueous extract of Mimosa albida contains reducing agents capable of synthesizing silver nanoparticles, which can be used in the phytochemical industry.

Research on nanomaterial exposure-related health risks is still quite limited; this includes standardizing methods for measuring metals in living organisms. Thus, this study validated an atomic absorption spectrophotometry method to determine fertility and bioaccumulated iron content in Drosophila melanogaster flies after feeding them magnetite nanoparticles (Fe₃O₄NPs) dosed in a culture medium (100, 250, 500, and 1000 mg kg⁻¹). Some NPs were also coated with chitosan to compare iron assimilation. Considering both accuracy and precision, results showed the method was optimal for concentrations greater than 20 mg L⁻¹. Recovery values were considered optimum within the 95–105% range. Regarding fertility, offspring for each coated and non-coated NPs concentration decreased in relation to the control group. Flies exposed to 100 mg L⁻¹ of coated NPs presented the lowest fertility level and highest bioaccumulation factor. Despite an association between iron bioaccumulation and NPs concentration, the 500 mg L⁻¹ dose of coated and non-coated NPs showed similar iron concentrations to those of the control group. Thus, Drosophila flies’ fertility decreased after NPs exposure, while iron bioaccumulation was related to NPs concentration and coating. We determined this method can overcome sample limitations and biological matrix-associated heterogeneity, thus allowing for bioaccumulated iron detection regardless of exposure to coated or non-coated magnetite NPs, meaning this protocol could be applicable with any type of iron NPs.

Among emerging pollutants, endocrine disruptors such as estradiol are of most concern. Conventional water treatment technologies are not capable of removing this compound from water. This study aims to assess a method that combines physicochemical and biological strategies to eliminate estradiol even when there are other compounds present in the water matrix. Na-montmorillonite, Ca-montmorillonite and zeolite were used to remove estradiol in a medium with sulfamethoxazole, triclosan, and nicotine using a Plackett–Burman experimental design; each treatment was followed by biological filtration with Daphnia magna. Results showed between 40 to 92% estradiol adsorption in clays; no other compounds present in the mixture were adsorbed. The most significant factors for estradiol adsorption were the presence of nicotine and triclosan which favored the adsorption, the use of Ca-montmorillonite, Zeolite, and time did not favor the adsorption of estradiol. After the physicochemical treatment, Daphnia magna was able to remove between 0–93% of the remaining estradiol. The combination of adsorption and biological filtration in optimal conditions allowed the removal of 98% of the initial estradiol concentration.

Chicken feathers are a poultry by-product rich in keratin, a recalcitrant protein whose valorization requires efficient solubilization. This study evaluated gamma irradiation as a pretreatment for enhancing the enzymatic susceptibility and extraction of keratin from chicken feather powder (CFP). In vitro pepsin digestibility increased significantly from approximately 31% in non-irradiated CFP to 48% after irradiation at 25 kGy (p < 0.05), a 54% relative increase. Four solubilization methods were compared, and an alkaline–bisulfite system containing 1.78% NaOH and 0.5% NaHSO₃ was selected based on protein recovery, reproducibility, and responsiveness to irradiation. Response surface methodology identified extraction conditions of 75 °C for 2 h at a liquid-to-solid ratio of 30:1. Irradiation increased the soluble protein recovery from approximately 72% in the control to over 90% at 20 kGy, although no significant improvement occurred beyond 15 kGy. The hydrolysates consisted predominantly of low-molecular-weight material (30 kDa fractions. Overall, gamma irradiation increased the enzymatic susceptibility and extractability of feather keratin and influenced the hydrolysate characteristics, supporting further evaluation of these fractions for antimicrobial and other value-added applications.

Heavy metals such as lead (Pb) and mercury (Hg) pose a threat to ecosystems due to their toxicity, persistence, and bioaccumulation. Their direct detection is limited by low concentrations and high environmental variability, highlighting the value of bioindicators as a tool for indirect and continuous monitoring. This study reviewed the use of bees, fish, birds, and bats as biomonitors of Pb and Hg in Latin America. Research reporting concentrations in biological matrices (muscle, liver, blood, and feathers) was compiled, analyzed using instrumental techniques such as AAS, ICP-MS, ICP-OES, and HPLC-MS. The results reveal levels exceeding international standards and the absence of regulation for specific tissues. It was concluded that these species are effective bioindicators and that legislative expansion is necessary to strengthen environmental and public health management.