Investigation of Laser-Induced Periodic Surface Structures Using Synthetic Optical Holography

In this paper, the investigation of laser-induced periodic surface structures (LIPSSs) on a polycrystalline diamond substrate using synthetic optical holography (SOH) is demonstrated. While many techniques for LIPSS detection operate with sample contact and/or require preparation or processing of the sample, this novel technique operates entirely non-invasively without any processing of or contact with the LIPSS sample at all. The setup provides holographic amplitude and phase images of the investigated sample with confocally enhanced and diffraction-limited lateral resolution, as well as three-dimensional surface topography images of the periodic structures via phase reconstruction with one single-layer scan only

High-throughput analysis of microalgae cell wall permeability in biotechnological production settings

Microalgae represent a promising resource for nature-derived compounds in different fields of interest. The rigid microalgae cell wall (composed of a polysaccharide and glycoprotein matrix) provides the cells with a formidable defence against harsh environments, but typically poses a major bottleneck for efficient product extraction, and hence sustainable process setups. The aim of this study was to evaluate the applicability of a high-throughput screening method for microalgae cell wall permeability, based on flow cytometry and titration against the exposure time in proceeding fixation steps. A panel of comparative trials were carried out on Chlorella vulgaris cultures to visualize changes in wall permeability via different fixation and staining techniques (methanol treatment and microwaving). Different intracellular targets were addressed (lipid storage vesicles and DNA) to define the optimal strategy with regard to information content on wall configuration and overall robustness. The tests were carried out for different growth conditions (photoautotrophic and heterotrophic cultures) and process states.The main results showed that both dies efficiently reached their intracellular target depending on fixation conditions, with minimal non-specific staining. Both assay formats yielded valuable, but non-redundant information on the current wall permeability. As expected, analyses targeted to DNA content proved to be more stable over culture time than those directed to lipid depositories, which can subjected to dynamic changes in response to growth conditions.The future perspectives will be to implement the flow cytometric assays as a real-time monitoring tool to exert control over product extraction efficiency in different microalgae strains and biotechnological production settings

Investigation of laser-induced periodic surface structures using synthetic optical holography

In this paper, the investigation of laser-induced periodic surface structures (LIPSSs) on a polycrystalline diamond substrate using synthetic optical holography (SOH) is demonstrated. While many techniques for LIPSS detection operate with sample contact and/or require preparation or processing of the sample, this novel technique operates entirely non-invasively without any processing of or contact with the LIPSS sample at all. The setup provides holographic amplitude and phase images of the investigated sample with confocally enhanced and diffraction-limited lateral resolution, as well as three-dimensional surface topography images of the periodic structures via phase reconstruction with one single-layer scan only