RESUMEN
Colloidal metal nanoparticles dispersions are commonly used to create functional printed electronic devices and they typically require time-, energy- and equipment-consuming post-treatments to improve their electrical and mechanical properties. Traditional methods, e.g. thermal, UV/IR, and microwave treatments, limit the substrate options and may require expensive equipment, not available in all the laboratories. Moreover, these processes also cause the collapse of the film (nano)pores and interstices, limiting or impeding its nanostructuration. Finding a simple approach to obtain complex nanostructured materials with minimal post-treatments remains a challenge. In this study, a new sintering method for gold nanoparticle inks that called as "click sintering" has been reported. The method uses a catalytic reaction to enhance and tune the nanostructuration of the film while sintering the metallic nanoparticles, without requiring any cumbersome post-treatment. This results in a conductive and electroactive nanoporous thin film, whose properties can be tuned by the conditions of the reaction, i.e., concentration of the reagent and time. Therefore, this study presents a novel and innovative one-step approach to simultaneously sinter gold nanoparticles films and create functional nanostructures, directly and easily, introducing a new concept of real-time treatment with possible applications in the fields of flexible electronics, biosensing, energy, and catalysis.
RESUMEN
Silver nanoparticles (SNPs) are widely used in nanomedicine and consuming products with potential risk to human health. While considerable work was carried out on the molecular, biochemical, and physiological alterations induced by these particles, little is known of the ultrastructural pathological alterations that might be induced by nanosilver materials. The aim of the present work is to investigate the hepatocyte ultrastructural alterations that might be induced by SNP exposure. Male rats were subjected to a daily single dose (2 mg/kg) of SNPs (15-35 nm diameter) for 21 days. Liver biopsies from all rats under study were processed for transmission electron microscopy examination. The following hepatic ultrastructural alterations were demonstrated: mitochondria swelling and crystolysis, endoplasmic reticulum disruption, cytoplasmic vacuolization, lipid droplets accumulation, glycogen depletion, karyopyknosis, apoptosis, sinusoidal dilatation, Kupffer cells activation, and myelin figures formation. The current findings may indicate that SNPs can induce hepatocyte organelles alteration, leading to cellular damage that may affect the function of the liver. These findings might indicate that SNPs potentially trigger heptocyte ultrastructural alterations that may affect the function of the liver with potential risk on human health in relation to numerous applications of these particles. More work is needed to elucidate probable ultrastructural alterations in the vital organs that might result from nanosilver toxicity.
Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Hepatocitos/ultraestructura , Hígado/ultraestructura , Nanopartículas del Metal/toxicidad , Plata/toxicidad , Animales , Biopsia , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Enfermedad Hepática Inducida por Sustancias y Drogas/metabolismo , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Microscopía Electrónica de Transmisión , Orgánulos/efectos de los fármacos , Orgánulos/ultraestructura , Ratas Wistar , Medición de RiesgoRESUMEN
This paper describes the preparation of gallium-68 (68Ga) isotope labeled porous zirconia (ZrO2) nanoparticle (NP) platform of nearly 100nm diameter and its first pharmacokinetic and biodistribution evaluation accomplished with a microPET/CT (µPet/CT) imaging system. Objectives of the investigations were to provide a nanoparticle platform which can be suitable for specific delivery of various therapeutic drugs using surface attached specific molecules as triggering agents, and at the same time, suitable for positron emission tomography (PET) tracing of the prospective drug delivery process. Radiolabeling was accomplished using DOTA bifunctional chelator. DOTA was successfully adsorbed onto the surface of nanoparticles, while the 68Ga-radiolabeling method proved to be simple and effective. In the course of biodistribution studies, the 68Ga-labeled DOTA-ZrNPs showed proper radiolabeling stability in their original suspension and in blood serum. µPet/CT imaging studies confirmed a RES-biodistribution profile indicating stable nano-sized labeled particles in vivo. Results proved that the new method offers the opportunity to examine further specifically targeted and drug payload carrier variants of zirconia NP systems using PET/CT imaging.
Asunto(s)
Radioisótopos de Galio/química , Nanopartículas/química , Radiofármacos/química , Radiofármacos/metabolismo , Circonio/química , Quelantes/química , Quelantes/metabolismo , Sistemas de Liberación de Medicamentos/métodos , Radioisótopos de Galio/metabolismo , Nanopartículas/metabolismo , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Tomografía de Emisión de Positrones/métodos , Distribución Tisular/efectos de los fármacos , Circonio/metabolismoRESUMEN
Abstract To examine gold nanoparticle reprotoxicity, bovine spermatozoa were challenged with ligand-free or oligonucleotide-conjugated gold nanoparticles synthesized purely without any surfactants by laser ablation. Sperm motility declined at nanoparticle mass dose of 10 µg/ml (corresponding to â¼14 000 nanoparticles per sperm cell) regardless of surface modification. Sperm morphology and viability remained unimpaired at all concentrations. Transmission electron microscopy showed an modification dependant attachment of nanoparticles to the cell membrane of spermatozoa, but provided no evidence for nanoparticle entrance into sperm cells. A molecular examination revealed a reduction of free thiol residues on the cell membrane after nanoparticle exposure, which could explain the decrease in sperm motility. Sperm fertilising ability decreased after exposure to 10 µg/ml of ligand-free nanoparticles indicating that agglomerated ligand-free nanoparticles interfere with membrane properties necessary for fertilisation. In conclusion, nanoparticles may impair key sperm functions solely by interacting with the sperm surface membrane.
Asunto(s)
Oro/química , Nanopartículas del Metal/toxicidad , Espermatozoides/efectos de los fármacos , Adsorción , Animales , Bovinos , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , MasculinoRESUMEN
Intended exposure to gold and silver nanoparticles has increased exponentially over the last decade and will continue to rise due to their use in biomedical applications. In particular, reprotoxicological aspects of these particles still need to be addressed so that the potential impacts of this development on human health can be reliably estimated. Therefore, in this study the toxicity of gold and silver nanoparticles on mammalian preimplantation development was assessed by injecting nanoparticles into one blastomere of murine 2 cell-embryos, while the sister blastomere served as an internal control. After treatment, embryos were cultured and embryo development up to the blastocyst stage was assessed. Development rates did not differ between microinjected and control groups (gold nanoparticles: 67.3%, silver nanoparticles: 61.5%, sham: 66.2%, handling control: 79.4%). Real-time PCR analysis of six developmentally important genes (BAX, BCL2L2, TP53, OCT4, NANOG, DNMT3A) did not reveal an influence on gene expression in blastocysts. Contrary to silver nanoparticles, exposure to comparable Ag(+)-ion concentrations resulted in an immediate arrest of embryo development. In conclusion, the results do not indicate any detrimental effect of colloidal gold or silver nanoparticles on the development of murine embryos.