The presence of plastic particles in oceans has been recognized as a major environmental concern. The decrease in particle size increases their ability to directly interact with biota, with particles in the nanometer size range (nanoplastics—NPs) displaying a higher ability to penetrate biological membranes, which increases with the decrease in particle size. This study aimed to evaluate the role of life stages in the effects of poly(methyl)methacrylate (PMMA) NPs on the polychaete Hediste diversicolor, a key species in the marine food web and nutrient cycle. Thus, behavioral (burrowing activity in clean and spiked sediment) and biochemical endpoints (neurotransmission, energy reserves, antioxidant defenses, and oxidative damage) were assessed in juvenile and adult organisms after 10 days of exposure to spiked sediment (between 0.5 and 128 mg PMMA NPs/Kg sediment). Overall, the results show that H. diversicolor is sensitive to the presence of PMMA NPs. In juveniles, exposed organisms took longer to burrow in sediment, with significant differences from the controls being observed at all tested concentrations when the test was performed with clean sediment, whereas in PMMA NP-spiked sediment, effects were only found at the concentrations 8, 32, and 128 mg PMMA NPs/Kg sediment. Adults displayed lower sensitivity, with differences to controls being found, for both sediment types, at 8, 32, and 128 mg PMMA NPs/Kg sediment. In terms of Acetylcholinesterase, used as a marker of effects on neurotransmission, juveniles and adults displayed opposite trends, with exposed juveniles displaying increased activity (suggesting apoptosis), whereas in adults, overall decreased activity was found. Energy-related parameters revealed a generally similar pattern (increase in exposed organisms) and higher sensitivity in juveniles (significant effects even at the lower concentrations). NPs also demonstrated the ability to increase antioxidant defenses (higher in juveniles), with oxidative damage only being found in terms of protein carbonylation (all tested NPs conditions) in juveniles. Overall, the data reveal the potential of PMMA NPs to affect behavior and induce toxic effects in H. diversicolor, with greater effects in juveniles.

Biopolymeric nanoparticles (NPs) have gained significant attention in several areas as an alternative to synthetic polymeric NPs due to growing environmental and immunological concerns. Among the most promising biopolymers is poly(lactic acid) (PLA), with a reported high degree of biocompatibility and biodegradability. In this work, PLA NPs were synthesized according to a controlled gelation process using a combination of single-emulsion and nanoprecipitation methods. This study evaluated the influence of several experimental parameters for accurate control of the PLA NPs’ size distribution and aggregation. Tip sonication (as the stirring method), a PLA concentration of 10 mg/mL, a PVA concentration of 2.5 mg/mL, and low-molecular-weight PLA (Mw = 5000) were established as the best experimental conditions to obtain monodisperse PLA NPs. After gelification process optimization, flutamide (FLU) was used as a model drug to evaluate the encapsulation capability of the PLA NPs. The results showed an encapsulation efficiency of 44% for this cytostatic compound. Furthermore, preliminary cell viability tests showed that the FLU@PLA NPs allowed cell viabilities above 90% up to a concentration of 20 mg/L. The comprehensive findings showcase that the PLA NPs fabricated using this straightforward gelification method hold promise for encapsulating cytostatic compounds, offering a novel avenue for precise drug delivery in cancer therapy.

Selenium nanoparticles (SeNPs) are increasingly used in aquaculture and related sectors, raising concerns about their release and potential impact on aquatic organisms, especially during early life stages. This study assessed the acute toxicity of chemically synthesized surfactant-stabilized, non-functionalized SeNPs with a hydrodynamic diameter of 52.7 ± 0.2 nm (DLS) and a primary size of 67 ± 11 nm (SEM) in three freshwater species representing different trophic levels and standardized ecotoxicological test systems: Daphnia magna neonates (48 h), Danio rerio embryos and larvae (96 and 120 h), and Xenopus laevis tadpoles (96 h). Survival and developmental endpoints were quantified, and a log-logistic benchmark dose (BMD) approach was applied to quantal concentration-response data, using the lower 95% confidence limit of the BMD at 10% extra risk (BMDL₁₀) as the point of departure. BMDL₁₀ values varied by more than three orders of magnitude, from 9.3 mg L^-1 total Se for D. magna to 0.007 mg L^-1 total Se for X. laevis, with D. rerio showing intermediate effect thresholds and toxicity increasing with exposure duration. X. laevis tadpoles showed the lowest effect thresholds, with BMDL₁₀ values approximately 1329-fold lower than those of D. magna. The EC₅₀ or LC₅₀ to BMDL₁₀ ratios (1.8-3.6) demonstrated that median effect metrics may underestimate hazard at low-effect levels relevant for environmental protection. Using the most sensitive BMDL₁₀ and applying a conservative assessment factor of 1000, a provisional freshwater predicted no-effect concentration of 7 ng L^-1 total Se was derived for screening-level risk assessment. Overall, these findings support the application of BMD-based approaches in nanomaterial ecotoxicology and identify amphibian larval test systems and growth-related endpoints as sensitive components for environmental hazard screening of SeNPs. However, the observed cross-test differences in effect thresholds should be interpreted cautiously because the assays were conducted under species-specific standardized exposure conditions that differed in developmental stage, exposure duration, feeding regime, and exposure pathways. Consequently, the present study provides a comparison of standardized acute toxicity test systems rather than a strict stage-equivalent assessment of intrinsic species sensitivity.

Protein-based nanoparticles (NPs) are attracting increasing attention as sustainable platforms for advanced biomedical applications. However, achieving high encapsulation efficiencies without compromising nanoparticle stability and biocompatibility remains a key challenge for these bio-based delivery systems. In this context, bovine serum albumin (BSA) NPs crosslinked with genipin were developed as green and biocompatible nanocarriers with tunable physicochemical properties. The synthesis conditions were systematically optimized by varying reaction time, temperature, and the BSA:genipin ratio, with 24 h at room temperature and a 10:1 ratio yielding the most suitable NPs in terms of formation and colloidal stability. The optimized BSA NPs were then used to encapsulate sertraline and 5-fluorouracil, achieving encapsulation efficiencies of 82% and 40%, respectively. These results highlight the ability of this nanoplatform to incorporate bioactive compounds with distinct physicochemical characteristics, with the sertraline-loaded NPs showing particularly high loading efficiency for an albumin-based system. In vitro assays performed on normal prostate epithelial cells (PNT-2) and prostate cancer cells (22Rv1) showed that the BSA NPs modulated drug-induced cytotoxicity relative to free drugs, indicating a formulation-dependent biological response. These findings highlight the potential of genipin-crosslinked BSA NPs as a versatile and sustainable platform for drug delivery in cancer therapy.

Nanoplastics (NPs) pose a significant environmental threat due to their small sizes, widespread distribution, and bioavailability, enabling interactions with marine organisms from pelagic to benthic species. In this study, the effects of 10 days of exposure to waterborne poly(methyl)methacrylate (PMMA) NPs were evaluated in the crab Carcinus maenas by assessing behavioral and biochemical endpoints (in gills, hepatopancreas, muscle, and hemolymph). Behavioral assessments using an open field test revealed that exposure to PMMA NPs resulted in an increase in distance walked (from 73.662 ± 17.137 cm in control to 248.560 ± 25.462 cm in the highest PMMA NPs concentration) and in random movement patterns. Muscle acetylcholinesterase (AChE) activity decreased from 10.83 ± 0.73 to 6.75 ± 0.45 nmol/min/mg of protein with PMMA NPs concentration increase, which, combined with behavioral responses, suggests neurological incapacities. In the gills and hepatopancreas, defense and detoxification mechanisms were activated, with a significant increase in superoxide dismutase (SOD) activity (at 20 µg/L in gills and 80 µg/L in hepatopancreas) and glutathione S-transferases (GSTs) activity (all PMMA NPs concentrations in gills and 20 and 320 µg/L in hepatopancreas). Despite these activations, oxidative damage was observed, with a significant increase in protein carbonylation (PC) levels (20, 80, and 320 µg/L in gills and 5, 20, and 80 µg/L in hepatopancreas) and lipid peroxidation (LPO) (80 and 320 µg/L in gills and 80 µg/L in hepatopancreas). Effects on hemolymph followed a pattern similar to those reported for gills and hepatopancreas. An increase in SOD hemolymph activity was observed in organisms exposed to 5 and 80 µg/L, and GSTs activity increased in crabs exposed to 80 µg/L. Oxidative damage in hemolymph was only detected through LPO at 5 and 320 µg/L. Overall, this study showed that PMMA NPs induce biochemical alterations and damage in different tissues of C. maenas and affect its behavior with potential impacts at a population level.