Nanoparticle Tracking Analysis (NTA) allows for the simultaneous determination of both size and concentration of nanoparticles in a sample. This study investigates the accuracy of particle size and concentration measurements performed on an LM10 device. For experiments, standard nanoparticles of different sizes composed of two materials with different refractive indices were used. Particle size measurements were found to have a decent degree of accuracy. This fact was verified by the manufacturer-reported particle size—determined by transmission electron microscopy (TEM)—as well as by performed scanning electron microscopy (SEM) measurements. On the other hand, concentration measurements resulted in overestimation of the particle concentration in majority of cases. Thus, our findings confirmed the accuracy of nanoparticle sizing performed by the LM10 instrument and highlighted the overestimation of particle concentration made by this device. In addition, an approach of swift correction of the results of concentration measurements received for samples is suggested in the presented study.

In a series of recently published works, we demonstrated that the plasmon-assisted microscopy of nano-objects (PAMONO) technique can be successfully employed for the sizing and quantification of single viruses, virus-like particles, microvesicles and charged non-biological particles. This approach enables label-free, but specific detection of biological nano-vesicles. Hence, the sensor, which was built up utilizing plasmon-assisted microscopy, possesses relative versatility and it can be used as a platform for cell-based assays. However, one of the challenging tasks for such a sensor was the ability to reach a homogeneous illumination of the whole surface of the gold sensor slide. Moreover, in order to enable the detection of even relatively low concentrations of nano-particles, the focused image area had to be expanded. Both tasks were solved via modifications of previously described PAMONO-sensor set ups. Taken together, our latest findings can help to develop a research and diagnostic platform based on the principles of the surface plasmon resonance (SPR)-assisted microscopy of nano-objects.

At the 1.5-GeV synchrotron light source DELTA operated by TU Dortmund University, intense and ultrashort radiation pulses in the vacuum ultraviolet and terahertz regimes are generated by the interaction of femtosecond laser pulses with electron bunches in an undulator. The resulting periodic modulation of the electron energy is converted into a density modulation in a dispersive section, giving rise to coherent radiation emission at harmonics of the seed wavelength in a second undulator. This process is known as coherent harmonic generation (CHG). This paper describes the experimental setup and concentrates on the spectral aspects of CHG radiation under variation of properties of the seed laser pulse and the dispersive section. CHG spectra at the second harmonic of the 800 nm seed wavelength were recorded using a grating spectrometer equipped with an image-intensified CCD camera. Numerical simulations to model the CHG spectra for different group-delay dispersion and third-order dispersion were carried out, and a convolutional neural network was implemented to predict these parameters from measured CHG spectra. The results show that the tunable laser parameters directly translate into the spectrotemporal properties of the coherently emitted pulses.