Abstract
ObjectivesTerahertz (THz)‐based imaging techniques hold great potential for biological and biomedical applications, which nevertheless are hampered by the low spatial resolution of conventional THz imaging systems. In this work, we report a high‐performance photoconductive antenna microprobe‐based near‐field THz time‐domain spectroscopy scanning microscope.Materials and methodsA single watermelon pulp cell was prepared on a clean quartz slide and covered by a thin polyethylene film. The high performance near‐field THz microscope was developed based on a coherent THz time‐domain spectroscopy system coupled with a photoconductive antenna microprobe. The sample was imaged in transmission mode.ResultsWe demonstrate the direct imaging of the morphology of single watermelon pulp cells in the natural dehydration process with our near‐field THz microscope.ConclusionsGiven the label‐free and non‐destructive nature of THz detection techniques, our near‐field microscopy‐based single‐cell imaging approach sheds new light on studying biological samples with THz.
Highlights
Terahertz (THz) radiation refers to the frequency band ranging from 0.1 to 10 THz in the electromagnetic spectrum, corresponding to wavelengths from 3 mm to 30 μm.[1,2] Recently, THz imaging of biological samples has attracted fast-growing interest among the scientists in biology-related fields worldwide due to its unique characteristics such as being highly sensitive to the structure of biomolecules, non-destructive to biological samples and without the requirement of staining or labelling the samples.[3,4] For example, THz imaging can provide much more chemical information of a biological sample but has much less ionization damage to the sample than X-ray microscopy imaging.[5]
In order to image individual cells, we newly developed a high-performance (Sections 1-3 in Supporting Information) photoconductive antenna microprobe (PCAM)-based near-field THz time-domain spectroscopy (THz-TDS) scanning system which allows us to collect a full THz waveform in 0.17 seconds with a signal-to-noise ratio of ~50 dB, a signal dynamic range of ~50 dB and a calibrated spatial resolution of ~3 μm that is approximately 1-2 orders higher than that of conventional THz imaging systems
A cartoon showing the structure of the watermelon pulp cell (Figure 4) was sketched to help interpret the phenomena observed during the cell drying process
Summary
Terahertz (THz) radiation refers to the frequency band ranging from 0.1 to 10 THz in the electromagnetic spectrum, corresponding to wavelengths from 3 mm to 30 μm.[1,2] Recently, THz imaging of biological samples has attracted fast-growing interest among the scientists in biology-related fields worldwide due to its unique characteristics such as being highly sensitive to the structure of biomolecules, non-destructive to biological samples and without the requirement of staining or labelling the samples.[3,4] For example, THz imaging can provide much more chemical information of a biological sample but has much less ionization damage to the sample than X-ray microscopy imaging.[5]. Tissue slices from the lung and breast of patients, and from mouse brain have been successfully investigated using THz imaging techniques, and the diseased regions were unambiguously distinguished from the normal regions for the examined samples.[8,9,10] One more example, water content and distribution in plant tissues have been successfully investigated using THz imaging techniques.[11,12] These pioneering studies have manifested the great potential of the application of THz imaging techniques in biological fields such as biomedical detection and plant physiology
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
