Terahertz three-dimensional monitoring of nanoparticle-assisted laser tissue soldering

Abstract

In view of minimally-invasive clinical interventions, laser tissue soldering assisted by plasmonic nanoparticles is emerging as an appealing concept in surgical medicine, holding the promise of surgeries without sutures. Rigorous monitoring of the plasmonically-heated solder and the underlying tissue is crucial for optimizing the soldering bonding strength and minimizing the photothermal damage. To this end, we propose a non-invasive, non-contact, and non-ionizing modality for monitoring nanoparticle-assisted laser-tissue interaction and visualizing the localized photothermal damage, by taking advantage of the unique sensitivity of terahertz radiation to the hydration level of biological tissue. We demonstrate that terahertz radiation can be employed as a versatile tool to reveal the thermally-affected evolution in tissue, and to quantitatively characterize the photothermal damage induced by nanoparticle-assisted laser tissue soldering in three dimensions. Our approach can be easily extended and applied across a broad range of clinical applications involving laser-tissue interaction, such as laser ablation and photothermal therapies.

Autofluorescence guided welding of heart tissue by laser pulse bursts at 1550 nm

“…Histological analysis confirmed our assumption: no severe damage to the cells along the welded cut was observed. The fluorescence spectroscopy presented a valuable objective endpoint determination of the welding process, which played an important role in the high degree of reproducibility of the welding, similar to [53]. We attribute the occurrence of minor damage of small areas at the beginning and end of the weld to the fact that the laser beam was delayed a little bit longer in these places while reversing welding direction.…”

Optically activated and interrogated plasmonic hydrogels for applications in wound healing

“…Signs of thermal damage were minimal and always confined within about 100 μm of the weld spots [46]. The possibility to monitor the extent of thermal damage by optical methods as terahertz radiation [102] may be added in future implementations as a means to enhance the safety of the procedure. Altogether, our results are consistent with our previous work [14,15,43].…”

Time‐Domain Integration of Broadband Terahertz Pulses in a Tapered Two‐Wire Waveguide

“…Terahertz (THz) technology has been witnessing a massive growth over the past decades. [ 1–4 ] Indeed, THz radiation—electromagnetic waves with a spectral content conventionally falling in the 0.1 × 10 12 to 10 × 10 12 Hz range [ 5 ] —has been proven useful in many scientific and technology fields, spanning from time‐domain spectroscopy [ 6–8 ] through biomedical imaging [ 9–12 ] and quality control, [ 13,14 ] to telecommunications. [ 15–17 ] Specifically, the rapidly increasing demand for higher bandwidths and data rates in wireless communication systems has inspired several groups worldwide to employ THz waves as a means to transmit and receive information.…”