Explore the vast range of titles available.

Hybrid nanomaterials have been extensively investigated because of the possibility of obtaining multiple functions in one stable entity. The magnetite nanoparticles (Fe 3 O 4 NPs) present unique superparamagnetic properties that enable their application in various fields. Silver nanoparticles (Ag NPs) also stand out in biomedical applications, especially as antitumorigenic and antibacterial agent. The combination of Fe 3 O 4 NPs and Ag NPs in one hybrid nanostructure (Fe 3 O 4 @Ag NPs) represents a promising strategy for targeted biomedical applications. Fe 3 O 4 @Ag NPs can be synthesized through a green route using natural reagents, as both reducing and capping agent, minimizing the nanomaterial toxicity. In this work, Fe 3 O 4 @Ag NPs were synthesized via a green route, and green tea extract was used as the reducing agent of silver ions and capping agent of the obtained Fe 3 O 4 @Ag NPs. The nanoparticles were characterized by several techniques confirming the formation of a hybrid composite consisting of 87.1% of Fe 3 O 4 and 12.9% of Ag, with spherical shape and an average size of 25 nm. The cytotoxicity of Fe 3 O 4 @Ag NPs was verified against both tumoral and non-tumoral cell lines, demonstrating selective cytotoxicity against tumoral cell line, suggesting a biocompatibility of these nanoparticles. Thus, superparamagnetic hybrid Fe 3 O 4 @Ag NPs might find important biomedical applications with targeted antitumorigenic properties. Graphic Abstract

Nitric oxide (NO) is involved in physiological processes, including vasodilatation, wound healing and antibacterial activities. As NO is a free radical, designing drugs to generate therapeutic amounts of NO in controlled spatial and time manners is still a challenge. In this study, the NO donor S-nitrosoglutathione (GSNO) was incorporated into the thermoresponsive Pluronic F-127 (PL)-chitosan (CS) hydrogel, with an easy and economically feasible methodology. CS is a polysaccharide with known antimicrobial properties. Scanning electron microscopy, rheology and differential scanning calorimetry techniques were used for hydrogel characterization. The results demonstrated that the hydrogel has a smooth surface, thermoresponsive behavior and good mechanical stability. The kinetics of NO release and GSNO diffusion from GSNO-containing PL/CS hydrogel demonstrated a sustained NO/GSNO release, in concentrations suitable for biomedical applications. The GSNO-PL/CS hydrogel demonstrated a concentration-dependent toxicity to Vero cells, and antimicrobial activity to Pseudomonas aeruginosa (minimum inhibitory concentration and minimum bactericidal concentration values of 0.5 µg·mL−1 of hydrogel, which corresponds to 1 mmol·L−1 of GSNO). Interestingly, the concentration range in which the NO-releasing hydrogel demonstrated an antibacterial effect was not found to be toxic to the Vero mammalian cell. Thus, the GSNO-PL/CS hydrogel is a suitable biomaterial for topical NO delivery applications.

Tissue engineering for spinal cord injury (SCI) remains a complex and challenging task. Biomaterial scaffolds have been suggested as a potential solution for supporting cell survival and differentiation at the injury site. However, different biomaterials display multiple properties that significantly impact neural tissue at a cellular level. Here, we evaluated the behavior of different cell lines seeded on chitosan (CHI), poly (ε-caprolactone) (PCL), and poly (L-lactic acid) (PLLA) scaffolds. We demonstrated that the surface properties of a material play a crucial role in cell morphology and differentiation. While the direct contact of a polymer with the cells did not cause cytotoxicity or inhibit the spread of neural progenitor cells derived from neurospheres (NPCdn), neonatal rat spinal cord cells (SCC) and NPCdn only attached and matured on PCL and PLLA surfaces. Scanning electron microscopy and computational analysis suggested that cells attached to the material’s surface emerged into distinct morphological populations. Flow cytometry revealed a higher differentiation of neural progenitor cells derived from human induced pluripotent stem cells (hiPSC-NPC) into glial cells on all biomaterials. Immunofluorescence assays demonstrated that PCL and PLLA guided neuronal differentiation and network development in SCC. Our data emphasize the importance of selecting appropriate biomaterials for tissue engineering in SCI treatment.

Stryphnodendron adstringens (Martius) Coville is a medicinal plant described as having pharmacological properties as anti-inflammatory and antimicrobial activities. Silver chloride nanoparticles (AgCl-NPs) have shown great potential for biomedical applications with efficient antimicrobial properties. Here, we report the photosynthesis of AgCl-NPs using plant extract from S. adstringens ( Sa AgCl-NPs) and their cytotoxic and antimicrobial activities. We photosynthesized Sa AgCl-NPs nearly spherical with low heterogeneity in size and enveloped by an organic material layer responsible for colloidal stability. Sa AgCl-NPs was non-cytotoxic against mammalian VERO cells; however, Sa AgCl-NPs presented remarkable antifungal activity against the pathogenic yeast Cryptococcus neoformans (MIC 80 of 0.32 µg/mL) the causative agent of human cryptococcosis. Notable antibacterial activity was observed against Gram-negative bacteria Pseudomonas aeruginosa (MIC 80 of 2.56 µg/mL) e Serratia marcescens (MIC 80 of 20.48 µg/mL) both microorganisms associated with a variety of human infections, in particular pneumonia. In contrast, Gram-positive bacteria Staphylococcus aureus and Staphylococcus epidermidis , microorganisms that cause pathologies as skin infections, were less susceptible to the Sa AgCl-NPs both with MIC 80 of 40.93 µg/mL. Thus, Sa AgCl-NPs represents an organic–inorganic hybrid nanomaterial with very low cytotoxicity against mammalian cells and high antimicrobial efficiency against pathogenic microorganisms and may be explored as an alternative to antimicrobial drugs.

The 40 amino acid residues peptide MciZ ( M other C ell I nhibitor of Fts Z ) represents a promising antibacterial agent as it is an effective inhibitor of bacterial cell division, Z-ring formation and localization. However, its efficacy is limited to Gram-positive bacteria as MciZ is unable to penetrate into Gram-negative organisms. In this study, we report the synthesis of plasmonic silver chloride nanoparticles stabilized by MciZ (NP/MciZ). NP/MciZ were synthesized using a fast and green route under blue light irradiation. Electron microscopy showed that NP/MciZ were enveloped by a peptide layer responsible for colloidal stability. X-ray diffraction analysis showed that silver chloride nanoparticles were crystalline in nature with small proportion of metallic silver. NP/MciZ showed a dose-dependent cytotoxicity against mammalian VERO cells. However, NP/MciZ exhibited remarkable antibacterial activity against Gram-positive bacterium B. megaterium comparable to MciZ. Furthermore, NP/MciZ showed similar antimicrobial activity against the Gram-negative bacterium E. coli and the yeast C. albicans . The photochemically-generated NP/MciZ presented here is a new organic–inorganic hybrid nanomaterial and has potential for biomedical or other applications.

Zero-valent iron nanoparticles (ZVI NPs) have been employed in environmental and biomedical applications. These nanoparticles are used in the remediation of soil and water contaminated with heavy metals, and ZVI NPs can be used in the biomedical sector, as drug delivery system due to the large surface area-to-volume ratio. However, their toxicity should be better investigated. In this study, green tea extract was used to synthesize ZVI NPs. The green tea-synthesized nanoparticles (GT-ZVI NPs) were characterized by dynamic light scattering (DLS), X-ray diffraction, Fourier transform infrared spectroscopy and atomic force microscopy. DLS analysis revealed that the nanoparticles have average hydrodynamic size of 104 nm. The results indicated the presence of organic matter derived from green tea extract on the surface of GT-ZVI NPs. The average size of the nanoparticles at solid state was found to be 32 nm. The cytotoxicity of GT-ZVI NPs (1–150 µg/mL) was determined on tumoral (human chondrosarcoma line, SW1353 cells) and non-tumoral (Vero fibroblast cell line) by quantitative cell viability analysis and cell morphological evaluation. GT-ZVI NPs exerted more cytotoxic effect on tumoral line compared to non-tumoral cell line. The viability of SW1353 cells was higher than 75% upon incubation with GT-ZVI NPs, at concentrations in the range of 1–60 µg/mL. At nanoparticle concentrations of 100 and 150 µg/mL, the viability of SW1353 cells decreased 69 and 62%, respectively. These results indicate that these nanoparticles might find important applications in cancer treatment with less toxicity to normal cells. Graphic abstract