How does the chain length of PEG functionalized at the outer surface of mesoporous silica nanoparticles alter the uptake of molecules?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The current work describes the development of new mesoporous silica nanoparticles (MSNs) containing a high content of phenyl groups (hydrophobic species) inside the mesopores and externally functionalized with polyethylene glycol (PEG), a hydrophilic moiety, to provide biocompatibility and colloidal stability. The MSNs were encapsulated with curcumin, a versatile hydrophobic drug for biological use. The ability of silica nanoparticles to optimize the solubility of this biologically-active molecule in water was investigated. Nanoparticles were characterized using C-13 and Si-29 Nuclear Magnetic Resonance (NMR), thermal analysis (TGA and DTA), nitrogen sorption analysis, transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential (PZ). We assessed the curcumin water solubility using the pegylated nanoparticles as well as the influence of the PEG chain length (500 and 2000 Da) and its concentration on the encapsulation process. The results indicate that the higher the PEG chain length the lower the MSN encapsulation capacity for curcumin, possibly due to steric factors. However, all of the nanoparticles largely improved curcumin solubility in water.The current work describes the development of new mesoporous silica nanoparticles (MSNs) containing a high content of phenyl groups (hydrophobic species) inside the mesopores and externally functionalized with polyethylene glycol (PEG), a hydrophilic moie40980608067CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)sem informaçãoWe acknowledge financial support from CAPES, INCT-Inomat, Brazilian Nanotoxicology Network (Cigenanotox) and NanoBioss-SisNANO/MCT

Ecotoxicological Effects Of Carbofuran And Oxidised Multiwalled Carbon Nanotubes On The Freshwater Fish Nile Tilapia: Nanotubes Enhance Pesticide Ecotoxicity.

The interactions of carbon nanotubes with pesticides, such as carbofuran, classical contaminants (e.g., pesticides, polyaromatic hydrocarbons, heavy metals, and dyes) and emerging contaminants, including endocrine disruptors, are critical components of the environmental risks of this important class of carbon-based nanomaterials. In this work, we studied the modulation of acute carbofuran toxicity to the freshwater fish Nile tilapia (Oreochromis niloticus) by nitric acid treated multiwalled carbon nanotubes, termed HNO3-MWCNT. Nitric acid oxidation is a common chemical method employed for the purification, functionalisation and aqueous dispersion of carbon nanotubes. HNO3-MWCNT were not toxic to Nile tilapia at concentrations ranging from 0.1 to 3.0 mg/L for exposure times of up to 96 h. After 24, 48, 72 and 96 h, the LC50 values of carbofuran were 4.0, 3.2, 3.0 and 2.4 mg/mL, respectively. To evaluate the influence of carbofuran-nanotube interactions on ecotoxicity, we exposed the Nile tilapia to different concentrations of carbofuran mixed together with a non-toxic concentration of HNO3-MWCNT (1.0 mg/L). After 24, 48, 72, and 96 h of exposure, the LC50 values of carbofuran plus nanotubes were 3.7, 1.6, 0.7 and 0.5 mg/L, respectively. These results demonstrate that HNO3-MWCNT potentiate the acute toxicity of carbofuran, leading to a more than five-fold increase in the LC50 values. Furthermore, the exposure of Nile tilapia to carbofuran plus nanotubes led to decreases in both oxygen consumption and swimming capacity compared to the control. These findings indicate that carbon nanotubes could act as pesticide carriers affecting fish survival, metabolism and behaviour.111131-

Activated carbon from pyrolysed sugarcane bagasse: silver nanoparticle modification and ecotoxicity assessment

Activated carbon from pyrolysed sugarcane bagasse (ACPB) presented pore size ranges from 1.0 to 3.5 nm, and surface area between 1200 and 1400 m2 g− 1 that is higher than commonly observed to commercial activated carbon. The ACPB material was successfully loaded with of silver nanoparticles with diameter around 35 nm (0.81 wt.%). X-ray photoelectron spectroscopy (XPS) analyses showed that the material surface contains metallic/Ag0 (93.60 wt.%) and ionic/Ag+ states (6.40 wt.%). The adsorption capacity of organic model molecules (i.e. methylene blue and phenol) was very efficient to ACPB and ACPB loaded with silver nanoparticles (ACPB-AgNP), indicating that the material modification with silver nanoparticles has not altered its adsorption capacity. ACPB-AgNP inhibited bacteria growth (Escherichia coli), it is a promising advantage for the use of these materials in wastewater treatment and water purification processes. However, ACPB-AgNP showed environmental risks, with toxic effect to the aquatic organism Hydra attenuata (i.e. LC50 value of 1.94 mg L− 1), and it suppressed root development of Lycopersicum esculentum plant (tomato). Finally, this work draw attention for the environmental implications of activated carbon materials modified with silver nanoparticles565833840CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informaçã

Synthesis and Characterisation of a Graphene Oxide-Gold Nanohybrid for Use as Test Material

This paper reports the synthesis and characterization of a graphene oxide–gold nanohybrid (GO-Au) and evaluates its suitability as a test material, e.g., in nano(eco)toxicological studies. In this study, we synthesised graphene oxide (GO) and used it as a substrate for the growth of nano-Au decorations, via the chemical reduction of gold (III) using sodium citrate. The GO-Au nanohybrid synthesis was successful, producing AuNPs (~17.09 ± 4.6 nm) that were homogenously distributed on the GO sheets. They exhibited reproducible characteristics when characterised using UV-Vis, TGA, TEM, FTIR, AFM, XPS and Raman spectroscopy. The nanohybrid also showed good stability in different environmental media and its physicochemical characteristics did not deteriorate over a period of months. The amount of Au in each of the GO-Au nanohybrid samples was highly comparable, suggesting a potential for use as chemical label. The outcome of this research represents a crucial step forward in the development of a standard protocol for the synthesis of GO-Au nanohybrids. It also paves the way towards a better understanding of the nanotoxicity of GO-Au nanohybrid in biological and environmental systems