The inhalation of natural nanoparticles (NPs) emitted from volcanic activity may be a risk to human health. However, the literature rarely reports the fate and response of NPs once in contact with lung fluids. In this work, we studied the particle size distribution of ashfall from Popocatépetl volcano, Mexico. The collected ashes (n = 5) were analyzed with scanning electron microscopy (SEM) to obtain the elemental composition and morphology, and to determine the size of the ash particles using ParticleMetric software (PMS). The PMS reported most of the ash to have submicrometric size (<1 μm) and an average equivalent circle of 2.72 μm. Moreover, to our knowledge, this study investigated for the first time the behavior of ash NPs at different times (0 to 24 h) while in contact with in vitro lung fluid, Gamble Solution (GS) and Artificial Lysosomal Fluid (ALF) using dynamic light scattering (DLS). We found a large variability in the hydrodynamic diameter, with values less than 1 nm and greater than 5 μm. Furthermore, aggregation and disaggregation processes were recognized in GS and ALF, respectively. The results of this study increase the knowledge of the interaction between NPs and lung fluids, particularly within the alveolar macrophage region.

β-carotene (β-C) is a hydrophobic compound, easily degradable by light and oxygen and with low solubility, limiting its applications. β-cyclodextrin (β-CD) can encapsulate β-C, protecting it from degradation and maintaining its bioactivity. Therefore, this research aimed to characterize and determine the antioxidant and erythroprotective activity of β-C/β-CD inclusion complexes. The co-precipitation technique was used to elaborate β-C/β-CD in a 40:60 ratio, obtaining a high yield (94.10%), an entrapment efficiency of 82.47%, and a loading efficiency of 11.92%. The moisture of β-C/β-CD was 2.93%. β-C release increased over the time of 216 h (80.8%, 92.8%, and 97.4% at 8 °C, 25 °C, and 37 °C, respectively). A UV–visible analysis confirmed the presence of β-carotene in the inclusion complex, indicating successful encapsulation without significant structural changes. According to the adsorption–desorption isotherms, the complexes showed a type II isotherm. The FT-IR and Raman spectroscopy confirmed the formation of the inclusion complex, which interacted by hydrogen bonds, hydrophobic interactions, or van der Waals forces. The DSC showed an endothermic peak at 118 °C in the β-C/β:CD. The TGA revealed reduced water loss in the β-carotene/β-cyclodextrin complex, indicating limited water binding due to encapsulation. The microscopic surface morphologies observed by the SEM of β-C/β-CD were irregular-shaped clumps in the surface with a particle average size of 8.09 µm. The X-ray diffraction showed a crystalline structure of the complex. The zeta potential determination indicated a negative charge (−23 and −32 mV). The ABTS, DPPH, and FRAP demonstrated the antioxidant activity of β-C/β:CD (34.09%, 21.73%, and 8.85. mM ET/g, respectively), similar to pure β-C (34.64%, 22.63%, and 9.12 μM ET/g, respectively). The complexes showed an erythroprotective effect inhibiting hemolysis (64.09%). Therefore, with these characteristics, β-CD is a good encapsulant for β-C, and this complex could be applied in the food and pharmaceutical industries.

Nanodiamonds have been studied for several biomedical applications due to their inherent biocompatibility and low cytotoxicity. Recent investigations have shown perspectives in using fluorescent nanodiamonds as nanothermometers because of their optical properties’ dependence on temperature. Easy and accurate localized temperature sensing is essential in a wide variety of scientific fields. Our work demonstrated how the fluorescence spectrum of high-pressure high-temperature fluorescent nanodiamonds of three different sizes: 35 nm, 70 nm and 100 nm, changes with temperature within an important biological temperature range (25 °C to 60 °C). Taking advantage of this phenomenon, we obtained nanothermic scales (NS) from the zero phonon lines (ZPL) of the NV⁰ and NV⁻ colour centres. In particular, the 100 nm-sized features the more intense fluorescence spectra whose linear dependence with temperature achieved 0.98 R² data representation values for both NV⁰ and NV⁻. This model predicts temperature for all used nanodiamonds with sensitivities ranging from 5.73% °C⁻¹ to 6.994% °C⁻¹ (NV⁰) and from 4.14% °C⁻¹ to 6.475% °C⁻¹ (NV⁻). Furthermore, the non-cytotoxic interaction with HeLa cells tested in our study enables the potential use of fluorescence nanodiamonds to measure temperatures in similar nano and microcellular aqueous environments with a simple spectroscopic setup.

β-carotene (β-C) is a hydrophobic compound, easily degradable by light and oxygen, with low solubility limiting its applications. β-cyclodextrin (β-CD) can encapsulate β-C, protecting it from degradation and maintaining its bioactivity. Therefore, this research aimed to characterize and determine the antioxidant and erythroprotective activity of β-C/β-CD inclusion complexes. The co-precipitation technique was used to elaborate the β-C/β-CD in a 40:60 ratio, obtaining a high yield (94.10%), an entrapment efficiency of 82.47%, and a loading efficiency of 11.92%. The moisture of β-C/β-CD was 2.93%. β-C release increased over 168 h (80% and 93% at 8 °C and 25 °C, respectively). According to adsorption-desorption isotherms, complexes showed a type II isotherm. FT-IR and Raman confirmed the formation of the inclusion complex interacting by hydrogen bonds, hydrophobic interactions, or Van der Waals forces. DSC showed an endothermic peak at 118 °C in β-C/β:CD. The microscopic surface morphologies observed by SEM of β-C/β-CD were irregular-shaped clumps in the surface with a particle average size of 8.09 µm. X-ray Diffraction showed a crystalline structure of the complex. Zeta potential determination indicated a negative charge (−23 and −32 mV). ABTS, DPPH, and FRAP demonstrated the antioxidant activity of β-C/β:CD (8.63%, 6.35%, and 1.57-mM ET/g) similar to pure β-C (8.21%, 5.99%, and 1.26 mM ET/g). The complexes showed an erythroprotective effect inhibiting hemolysis (32.57%). Therefore, with these characteristics, β-CD is a good encapsulant for β-C where this complex could be applied in food and pharmaceutical industries.

Radiotherapy is widely used as a treatment for patients with breast cancer (BC). In vitro irradiation of BC cells provides a strategy to investigate early cellular and molecular events induced by ionizing radiation. Characterizing structural and membrane responses may identify biomarkers of radiosensitivity, improving understanding of treatment effects and enabling patient specific optimization. In this work, Raman spectroscopy and atomic force microscopy (AFM) were applied in vitro to investigate mechanisms relevant to BC radiotherapy. Breast cancer cell line MD Anderson-Metastatic Breast-231 (MDA-MB-231) was exposed to doses of 2, 4, and 10 Gy. Non-irradiated BC cells were used as control samples. Samples were incubated at 37 °C, 5% carbon dioxide (CO₂), and analyzed at 0, 24, and 48 h post-irradiation using AFM and Raman spectroscopy to detect morphological and biochemical changes. Raman spectroscopy showed significantly increased intensities at 1250, 1455, and 1670 cm⁻¹ at 24 h, followed by decreases at 48 h (4–10 Gy). Atomic force microscopy showed reduced membrane roughness at 0 h from 34.0 ± 3.4 nm in controls to 23.6 ± 2.9 nm at 10 Gy, and from 39.50 ± 6.05 nm to 26.86 ± 5.44 nm at 48 h. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed reduced viability at 48 h: 84.0% (2 Gy), 81.5% (4 Gy), and 80.3% (10 Gy). Raman spectroscopy and AFM demonstrate the capability to detect early radiation-induced chemical and surface alterations, suggesting potential utility for identifying biomarkers of radiotherapeutic response in breast cancer cells.