Graphene-Based and Surface-Enhanced Raman Spectroscopy for Monitoring the Physio-Chemical Response of Thermophilic Bacterial Spores to Low Temperatures Exposure

Abstract

Monitoring the spore life cycle is one of the main issues in several fields including environmental control, sustainable ecosystems, food security, and healthcare systems. In this framework, the study of the living organism resistance to extreme conditions like those mimicking space environments is particularly interesting. The assessment of the local change of the pH level can be extremely useful for this purpose. An optical physiometer method based on the Raman response of the graphene, which is able to locally sense pH of a fluid on a micrometric scale, has been recently proposed. Due to the presence of π -bonds at the surface, the electronic doping of graphene is determined by the external conditions and can be electrochemically controlled or altered by the contact with an acid or alkaline fluid. The doping level affects the vibrational energies of the graphene that can be monitored by conventional Raman spectroscopy. In addition, Surface-Enhanced Raman Spectroscopy (SERS) can give direct information on the biochemical changes occurring in spore components. In this work, we propose the joint use of Graphene-Based Raman Spectroscopy (GbRS) and SERS for the monitoring of the response of spores to exposure to low temperatures down to 100 K. The spores of the thermophilic bacterium Parageobacillus thermantarcticus isolated from an active volcano of Antarctica (Mt. Melbourne) were investigated. These spores are particularly resistant to several stressing stimuli and able to adapt to extreme conditions like low temperatures, UV irradiation, and γ -rays exposure. The results obtained showed that the joint use of GbRS and SERS represents a valuable tool for monitoring the physio-chemical response of bacterial spores upon exposure to stressing stimuli.

A turn-on fluorescent Zn(ii) metal–organic framework sensor for quantitative anthrax biomarker detection

“…Therefore, it is feasible to indirectly detect Bacillus anthracis by quantification of the DPA content. Several chemical and biological techniques have been applied for the real-time and exact identification of trance DPA, 4 such as surface enhanced Raman spectroscopy (SERS), 5 polymerase chain reaction (PCR), 6 direct apparent fluorescence filtration (DEFT), 7 aerobic plate counting (APC), UV spectrophotometry and other methods. However, most of these methods suffer from complicated preprocessing and tedious operations, are time-consuming and require expensive instruments.…”

Genomic Analysis Provides New Insights Into Biotechnological and Industrial Potential of Parageobacillus thermantarcticus M1

“…Several experiments were carried out either in space or in laboratories, by simulating the extreme environmental parameters that are typical of space and exoplanets, such as irradiation with UV and γ-rays, desiccation, low temperature values, etc. ( Di Donato et al, 2018b ; Romano et al, 2018 , 2022 ; Camerlingo et al, 2020 ). P. thermantarcticus viable cells and its spores were found to survive in a space simulated environment, which in turn lead to a new scenario called as the Panspermia theory that states that life on Earth could have originated from bacterial species from other places transported by solar pressure.…”

Rapid Detection Method for Pathogenic Candida Captured by Magnetic Nanoparticles and Identified Using SERS via AgNPs+

“…Moreover, the SERS spectrometer is stable with low maintenance costs, and the operation is simple. 12,13 In this study, we tested the zeta potential of Candida and found that the surfaces of C. albicans, C. tropicalis, and C. krusei were all negatively charged. Thus, we selected AgNPs + as the SERS-enhanced substrate.…”

“…Moreover, the SERS spectrometer is stable with low maintenance costs, and the operation is simple. 12 , 13 …”