In this contribution, the synthesis of fluorescent carbon quantum dots (CQDs) by laser fragmentation is reported. To achieve it, an initial suspension of carbon glassy microparticles in polyethylene glycol 200 is irradiated using two different experimental setups, a batch and a flow jet configuration. While the batch configuration is the standard irradiation setup, the flow jet configuration is less extended and it is proposed an implementation with common laboratory material. Besides, this system ensures an improved control over the fluence and the energy delivered to the target, increasing CQDs fabrication rate by 15%. The fluorescence of the generated nanoparticles is measured obtaining an increase of the quantum yield of one order of magnitude. The achieved fluorescence together with their easy cell internalization permits their use as fluorophore. To prove it, the flow jet synthesized CQDs are used for fluorescent imaging of healthy and cancerous human cells. The required incubation time is only 10 minutes and no centrifugation or any other extra processing of the sample is needed. In addition, the fluorescence photostability is measured to be of more than 2 hours in an in vitro application, proving the viability of the generated CQDs even for labeling in applications where long image acquisition times are required.
Recently we developed a new method of spherical submicron particle production by pulsed laser irradiation of primary small irregular nanoparticles suspended in liquid. For the first time we demonstrated that the nanoparticles can not only reduce their sizes under the pulse laser irradiation, but can grow essentially. To control the particle formation process, the mechanism of particle interaction with laser pulse has to be understood. Particle heating-melting-evaporation model was successfully applied to clarify this mechanism.
The fabrication of a designed arrangement of matter at the nano-scale level is a central goal of contemporary engineering endeavours. Silver nanoparticles synthesized by a laser ablation method in pure water are able to produce the aggregates, agglomerates and crystals due to condensed matter physics and chemistry. The stability of agglomerates and crystals is variable, depending on the composition of ensembles dominated by Ag2O and Ag respectively. The paper will present some fascinating nanostructures, such as films and vesicles.