Cotton is the most widely used natural fiber for textiles; however, the capacity of cotton fibers to absorb large amounts of moisture, retain oxygen, and have a high specific surface area makes them more prone to microbial contamination, becoming an appropriate medium for the growth of bacteria and fungi. In recent years, the incorporation of silver nanoparticles in textile products has been widely used due to their broad-spectrum antibacterial activity and low toxicity towards mammalian cells. The aim of the current study is to continue the assessment of our developed nanocomposite and evaluate the antibacterial and antifungal activity of the nanocomposite based on silver nanoparticles and carboxymethyl chitosan (AgNPs-CMC) against Escherichia coli, Staphylococcus aureus, and Candida albicans, evaluated by the well diffusion method. The antibacterial activity against E. coli and S. aureus was also evaluated by the qualitative method of inhibition zone and the quantitative method of colony counting. Likewise, the antifungal activity of the functionalized fabric against Candida albicans and Aspergillus niger was determined by the inhibition zone method and the antifungal activity method GBT 24346-2009, respectively. The functionalized fabric showed 100% antibacterial activity against E. coli and S. aureus and good antifungal activity against C. albicans and A. niger. Our results indicate that the functionalized fabric could be used in garments for hospital use to reduce nosocomial infections.

In the present investigation, an ethanolic fraction (EF) of Lepechinia meyenii (salvia) was prepared and fractionated by gradient column chromatography, and the main secondary metabolites present in the EF were identified by HPLC-MS. Silver nanoparticles (AgNPs) were synthesized and conjugated with the EF of Lepechinia meyenii (salvia). The AgNPs synthesis was optimized using Plackett-Burman design and response surface methodology (RSM), considering the following independent variables: stirring speed, synthesis pH, synthesis time, synthesis temperature and EF volume. The AgNPs synthesized under the optimized conditions were characterized by UV visible spectroscopy (UV-VIS), Fourier Transform Infrared Spectroscopy (FT-IR), Dynamic Light Scattering (DLS) and Scanning Transmission Electron Microscopy (STEM). The antibacterial activity of the AgNPs against Staphylococcus aureus (ATCC^® 25923) was evaluated. The following flavonoids were identified: rosmarinic acid, diosmin and hesperetin-7-O-rutinoside. The optimized conditions for the synthesis of nanoparticles were pH 9.45, temperature 49.8 °C, volume of ethanolic fraction 152.6 µL and a reaction time of 213.2 min. The obtained AgNPs exhibited an average size of 43.71 nm and a resonance plasmon of 410–420 nm. Using FT-IR spectroscopy, the disappearance of the peaks between 626.50 and 1379.54 cm⁻¹ was evident with the AgNPs, which would indicate the participation of these functional groups in the synthesis and protection of the nanoparticles. A hydrodynamic size of 47.6 nm was obtained by DLS, while a size of 40–60 nm was determined by STEM. The synthesized AgNPs conjugated with the EF showed a higher antibacterial activity than the EF alone. These results demonstrate that the AgNPs synthesized under optimized conditions conjugated with the EF of the Lepechinia meyenii (salvia) presented an increased antibacterial activity.

In the last decade, the green synthesis of nanoparticles has had a prominent role in scientific research for industrial and biomedical applications. In this current study, silver nitrate (AgNO₃) was reduced and stabilized with an aqueous extract of Thelypteris glandulosolanosa (Raqui-raqui), forming silver nanoparticles (AgNPs-RR). UV-vis spectrophotometry, dynamic light scattering (DLS), and scanning transmission electron microscopy (STEM) were utilized to analyze the structures of AgNPs-RR. The results from this analysis showed a characteristic peak at 420 nm and a mean hydrodynamic size equal to 39.16 nm, while the STEM revealed a size distribution of 6.64–51.00 nm with an average diameter of 31.45 nm. Cellular cytotoxicity assays using MCF-7 (ATCC^® HTB-22™, mammary gland breast), A549 (ATCC^® CCL-185, lung epithelial carcinoma), and L929 (ATCC^® CCL-1, subcutaneous connective tissue of Mus musculus) demonstrated over 42.70% of MCF-7, 59.24% of A549, and 8.80% of L929 cells had cell death after 48 h showing that this nanoparticle is more selective to disrupt neoplastic than non-cancerous cells and may be further developed into an effective strategy for breast and lung cancer treatment. These results demonstrate that the nanoparticle surfaces developed are complex, have lower contact angles, and have excellent scratch and wear resistance.

Cancer is one of the leading causes of mortality worldwide, with breast and colon cancers being among the most common neoplasms in men and women, respectively. Despite significant advancements in treatment, there is a pressing need to enhance specificity and reduce systemic side effects. Importantly, a distinctive feature of cancer cells is their acidic extracellular environment, which profoundly influences cancer progression. In this study, we evaluated the anticancer activity of a pH-sensitive nanocomposite based on silver nanoparticles and pegylated carboxymethyl chitosan (AgNPs-CMC-PEG) in breast cancer (MCF-7) and colon cancer (HCT 116) cell lines. To achieve this, we synthesized and characterized the nanocomposite using UV-Vis spectroscopy, Dynamic Light Scattering (DLS), Fourier-Transform Infrared Spectroscopy (FT-IR), and Scanning Electron Microscopy (STEM-in-SEM). Furthermore, we assessed cytotoxic effects, apoptosis, and reactive oxygen species (ROS) generation using MTT, DAPI, and H2DCFDA assays. Additionally, we analyzed the expression of DNA methyltransferases (DNMT3a) and histone acetyltransferases (MYST4, GCN5) at the mRNA level using RT-qPCR, along with the acetylation and methylation of H3K9ac and H3K9me2 through Western blot analysis. The synthesized nanocomposite demonstrated an average hydrodynamic diameter of approximately 175.4 nm. In contrast, STEM-in-SEM analyses revealed well-dispersed nanoparticles with an average core size of about 14 nm. Additionally, Fourier-transform infrared (FTIR) spectroscopy verified the successful surface functionalization of the nanocomposite with polyethylene glycol (PEG), indicating effective conjugation and structural stability. The nanocomposite exhibited a pH and concentration dependent cytotoxic effect, with enhanced activity observed at an acidic pH 6.5 and at concentrations of 150 µg/ml, 75 µg/ml, and 37.5 µg/ml for both cell lines. Notably, the nanocomposite preferentially induced apoptosis accompanied by ROS generation. Moreover, expression analysis revealed a decrease in H3K9me2 and H3K9ac in both cell lines, with a more pronounced effect in MCF-7 at an acidic pH. Furthermore, the expression of DNMT3a at the mRNA level significantly decreased, particularly at acidic pH. Regarding histone acetyltransferases, GCN5 expression decreased in the HCT 116 line, while MYST4 expression increased in the MCF-7 line. These findings demonstrate that the AgNPs-CMC-PEG nanocomposite has therapeutic potential as a pH-responsive nanocomposite, capable of inducing significant cytotoxic effects and altering epigenetic markers, particularly under the acidic conditions of the tumor microenvironment. Overall, this study highlights the advantages of utilizing pH-sensitive materials in cancer therapy, paving the way for more effective and targeted treatment strategies.