Scientists for a day. Students in PaGES 3 observe molecular vibrations and gold nanoparticles in the laboratories of the Elettra synchrotron.
28 February - 14 March 2018, Friuli Venezia Giulia - Italy

PaGES3 students in the Infrared Laboratory at Elettra

Theory is fundamental to understand the principles of science. However, science itself would not be such without practical experiments. This is why PaGES 3 project placed at the core of its activities a full day per school, in the laboratories at the Elettra synchrotron, to allow participants to have a better understanding of formulas and theorems, through the direct manipulation of the tools and substances used by professional researchers during their experiments. In particular, with the support of PhD students and professional scientists at the CERIC facility in Trieste, students had a closer look at the Infrared Laboratory led by Lisa Vaccari and to the techniques used in the NanoInnovation Lab led by Loredana Casalis.

Infrared spectroscopy is a powerful tool to analyze molecular vibration. These vibrations generate an infrared absorption spectrum, which depends on the type of vibrating molecule. Moreover, the percentage of absorption is related to the concentration of the molecule: the higher the concentration of the analyte, the more intense is the peak in the spectrum. After a brief introductory lecture about these principles, students analyzed the different lipids pure or mixed prepared in the NanoInnovation Laboratory with the technique of infrared Attenuated Total Reflection spectroscopy. With the help of a database, the students acquired and analyzed the pure lipids (DOPC and Sfingomielina), recognizing the spectra and the distinctive molecular vibrations. Then, the spectra of two mixed lipids were acquired (one mix with double concentration of DOPC) and from the position of the peaks and the absorption intensities, they recognized the two mixes. This simple experiment allowed giving a first overview of the infrared technique and its data analysis.

The second part of the visit focused on a range of research topics in the field of nanotechnology. In the last few years, functionalized gold nanoparticles (AuNPs) with controlled geometrical and optical properties are the subject of intensive studies in biomedical diagnostics and therapies. In order to study such features, students carried out colorimetric assays of various AuNP colloidal suspensions (i.e. 10 nm, 20 nm and 40 nm). Moreover, they investigated how the aggregation state of AuNPs induces a macroscopic colorimetric variation depending on the added solution (i.e. salt, sugar and albumin). In the perspective to develop a newer diagnostic/therapeutic method, AuNPs have been DNA-conjugated and characterized via colorimetric assay.

After this experience, students will learn how to analyze the data collected during the experiments, and to write a scientific article from the results obtained.

The training material is available here