RESUMO
In this work we present biological effects of silver nanoparticles (AgNPs) synthesized by picosecond laser ablation of silver in deionized water. We examined induction of chromosomal aberrations, lymphocyte micronuclei, appearance and recovery of double strand breaks (DSBs) of DNA, cell proliferation potential, concentration of lipid peroxidation products and insulin-like growth factor 1 (ILGF-1). We found that AgNPs sized from 3 nm to 8 nm induce cell cytostasis, which is accompanied with its clastogenic action on DNA, while AgNPs, sized 2 nm behaves contrary stimulating cell proliferation by enhancing ILGF-1 concentration.
Assuntos
Proliferação de Células/efeitos dos fármacos , Linfócitos/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Tamanho da Partícula , Prata/toxicidade , Aberrações Cromossômicas/efeitos dos fármacos , Humanos , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Linfócitos/citologia , Linfócitos/metabolismo , Masculino , Testes para Micronúcleos , Mutagênicos/toxicidade , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Spatially resolved, time-integrated optical emission spectroscopy was applied for investigation of copper plasma produced by a nanosecond infrared (IR) transversely excited atmospheric (TEA) CO2 laser, operating at 10.6 µm. The effect of surrounding air pressure, in the pressure range 0.1 to 1013 mbar, on plasma formation and its characteristics was investigated. A linear dependence of intensity threshold for plasma formation on logarithm of air pressure was found. Lowering of the air pressure reduces the extent of gas breakdown, enabling better laser-target coupling and thus increases ablation. Optimum air pressure for target plasma formation was 0.1 mbar. Under that pressure, the induced plasma consisted of two clearly distinguished and spatially separated regions. The maximum intensity of emission, with sharp and well-resolved spectral lines and negligibly low background emission, was obtained from a plasma zone 8 mm from the target surface. The estimated excitation temperature in this zone was around 7000 K. The favorable signal to background ratio obtained in this plasma region indicates possible analytical application of TEA CO2 laser produced copper plasma. Detection limits of trace elements present in the Cu sample were on the order of 10 ppm (parts per million). Time-resolved measurements of spatially selected plasma zones were used to find a correlation between the observed spatial position and time delay.
