Terahertz Tech Advances Microbial Measurement

Microorganisms play a critical role in all life, and advances in detecting and understanding them have broad implications for medicine, environmental science, and industry. Ding Cao, Guangyou Fang, and Xuequan Chen, from the GBA Branch of Aerospace Information Research Institute, Chinese Academy of Sciences, have contributed to a growing body of work exploring the potential of terahertz technology in microbiology. Their review highlights how terahertz waves, uniquely sensitive to water and molecular motion, offer a non-invasive and label-free method for both studying microbial function and accurately identifying different types of microorganisms. This research represents a significant step towards bridging the gap between terahertz photonics and microbiology, paving the way for new tools and deeper insights into the microbial world.

Tracing THz Impact on Bacterial Gene and Protein Expression

Terahertz (THz) radiation is emerging as a powerful tool for microbiology, demonstrating unique non-thermal effects on microorganisms. Studies reveal that exposing E. coli to a continuous wave of 3. 1THz resulted in an increase in plasmid copy number and red fluorescence protein production. Investigations into transcriptional activity demonstrate significant impacts on processes including abortive initiation and pausing under THz radiation, and analysis of a broadband synchrotron source of 0.

5-18THz revealed cellular responses related to osmotic stress, plasma membrane regulation, and phospholipid biosynthesis. Researchers also examined the extremophilic bacterium Geobacillus icigianus, observing changes in metabolic pathways such as chemotaxis and the synthesis of peptidoglycan and riboflavin following both short-term and long-term THz exposures, primarily attributed to disturbances in the expression of genes related to copper, iron, and zinc homeostasis. Importantly, studies consistently demonstrate that THz radiation, unlike UV radiation or chemical stimulants, does not cause genetic mutations or DNA damage in bacterial cells, as confirmed by Ames tests on five different bacterial strains. Beyond bacteria, investigations on yeast cells showed an increased growth rate specifically at 341GHz, while studies on Archaea revealed alterations in the expression levels of 16 proteins upon THz exposure.

Developing Advanced THz Biosensors and Cellular Engineering

Notably, submillimeter-wave radiation promoted the separation of frustules from diatom algae cell membranes. Scientists are now leveraging these biological effects to create THz-sensitive biosensors, utilizing genetically engineered E. coli to detect metabolic pathways. Transforming E. coli with a plasmid containing the katG gene promoter linked to green fluorescent protein (GFP) resulted in increased GFP expression under THZ radiation, indicating higher expression of hydroperoxidase I and providing a means to study hydrogen peroxide-degrading metabolic pathways. Similar increasing gene expressions were observed using promoters of other sensor genes, including copA, emrR, matA, safA.