Facing the challenge of biosample imaging by FTIR with a synchrotron radiation source

FTIR synchrotron radiation microspectroscopy is a powerful molecular probe of biological samples at cellular resolution. Here it is discussed how an optimized combination of IR instrumentation (FPA detectors) and SR optical systems could reach the expected advantages of a SR-based system

Facing the challenge of biosample imaging by FTIR with a synchrotron radiation source

Fourier-transform infrared (FTIR) synchrotron radiation (SR) microspectroscopy is a powerful molecular probe of biological samples at cellular resolution (10 microm). As the brilliance of SR is 100-1000 times higher than that of a conventional Globar source, FTIR microscopes are now available in almost all advanced SR facilities around the world. However, in spite of this superior performance, the expected advances in IR SR microscopy have not yet been realised, particularly with regard to bio-analytical studies of single cells and soft tissues. In recent decades solid-state array detectors have revolutionized the fields of molecular spectroscopy and chemical imaging, and now new IR focal plane array detectors implemented at ultra-bright SR facilities will extend the performance and overcome the existing limitations, possibly allowing IR SR instrumentation to achieve the highest sensitivity and resolution of molecular imaging. The impact of IR imaging on large tissue area and the complexity of the analysis are discussed. In view of the high brilliance of SR sources, a comparison of published microscope images is given. Finally, it is briefly outlined how an optimized combination of IR instrumentation and SR optical systems could reach the expected advantages of a SR-based FTIR imaging system

Proximity array device: a novel photon detector working in long wavelengths

We present here an innovative photon detector based on the proximity junction array device (PAD) working at long wavelengths. We show that the vortex dynamics in PAD undergoes a transition from a Mott insulator to a vortex metal state by application of an external magnetic field. The PAD also evidences a Josephson I-V characteristic with the external field dependent tunneling current. At high applied currents, we observe a dissipative regime in which the vortex dynamics is dominated by the quasi-particle contribution from the normal metal. The PAD has a relatively high photo-response even at frequencies below the expected characteristic frequency while, its superconducting properties such as the order parameter and the Josephson characteristic frequency can be modulated via external fields to widen the detection band. This device represents a promising and reliable candidate for new high-sensitivity long-wavelength detectors. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Transcriptional modulations induced by proton irradiation in mice skin in function of adsorbed dose and distance

Hadron therapy by proton beams represents an advanced anti-cancer strategy due to its highly localized dose deposition allowing a greater sparing of normal tissue and/or organs at risk compared to photon/electron radiotherapy. However, it is not clear to what extent non-targeted effects such as transcriptional modulations produced along the beamline may diffuse and impact the surrounding tissue. In this work, we analyze the transcriptome of proton-irradiated mouse skin and choose two biomarker genes to trace their modulation at different distances from the beam's target and at different doses and times from irradiation to understand to what extent and how far it may propagate, using RNA-Seq and quantitative RT-PCR. In parallel, assessment of lipids alteration is performed by FTIR spectroscopy as a measure of tissue damage. Despite the observed high individual variability of expression, we can show evidence of transcriptional modulation of two biomarker genes at considerable distance from the beam's target where a simulation system predicts a significantly lower adsorbed dose. The results are compatible with a model involving diffusion of transcripts or regulatory molecules from high dose irradiated cells to distant tissue's portions adsorbing a much lower fraction of radiation

OPTICAL PERFORMANCES OF SINBAD, THE INFRARED BEAMLINE AT DAFNE

SINBAD (Synchrotron Infrared Beamline At DANE) is the first Italian synchrotron radiation beamline operating in the infrared range. It collects the radiation emitted by DANE, an electron–positron collider designed to work at 0.51 GeV with a beam current I1 A. The actual performances of the beamline, in terms of brilliance gain with respect to blackbodies and polarization properties, are presented and discussed. Finally, the stability of the SINBAD source, a critical issue for Fourier-transform infrared spectroscopy, is discussed

Spectroscopic evidence of the radioresistance of Chroococcidiopsis biosignatures: A combined Raman, FT-IR and THz-TDs spectroscopy study

In the last decades, Mars has been widely studied with on-site missions and observations, showing a planet that could have hosted life in the past. For this reason, the recent and future space missions on the red planet will search for traces of past and, possibly, present life. As a basis for these missions, Space Agencies, such as the European Space Agency, have conducted many experiments on living organisms, studying their behavior in extraterrestrial conditions, learning to recognize their biosignatures with techniques remotely controllable such as Raman spectroscopy. Among these organisms, the radioresistant cyanobacterium Chroococcidiopsis was irradiated during the STARLIFE campaign with strong radiative insults. In this article we have investigated this cyanobacterium using Raman spectroscopy and extended the characterization of its biosignatures and its response to the radiative stress to the mid- Infrared and Terahertz spectral region using the Fourier Transform InfraRed (FT-IR) and Terahertz Time Domain spectroscopy (THz- TDs), which demonstrates the compatibility and suitability of these techniques for future space missions