Terahertz (THz) biophotonics technology: Instrumentation, techniques, and biomedical applications

Abstract

Terahertz (THz) technology has experienced rapid development in the past two decades. Growing numbers of interdisciplinary applications are emerging, including materials science, physics, communications, and security as well as biomedicine. THz biophotonics involves studies applying THz photonic technology in biomedicine, which has attracted attention due to the unique features of THz waves, such as the high sensitivity to water, resonance with biomolecules, favorable spatial resolution, capacity to probe the water–biomolecule interactions, and nonionizing photon energy. Despite the great potential, THz biophotonics is still at an early stage of development. There is a lack of standards for instrumentation, measurement protocols, and data analysis, which makes it difficult to make comparisons among all the work published. In this article, we give a comprehensive review of the key findings that have underpinned research into biomedical applications of THz technology. In particular, we will focus on the advances made in general THz instrumentation and specific THz-based instruments for biomedical applications. We will also discuss the theories describing the interaction between THz light and biomedical samples. We aim to provide an overview of both basic biomedical research as well as pre-clinical and clinical applications under investigation. The paper aims to provide a clear picture of the achievements, challenges, and future perspectives of THz biophotonics.

Terahertz Imaging and Sensing for Healthcare: Current Status and Future Perspectives

“…The acquired information is obtained from the data acquisition card (DAQ), quantized to bits for further image processing [28]. The outstanding features of THz-TDS systems like providing broad bandwidth, picosecond level resolution, field detection ability which comprise of both phase and magnitude information for the spectrum make them useful for various applications [30], [47], [48].…”

“…to characterize tissue complex permittivity which is a reflection of molecular interaction with THz radiation [34], [57]. Effective Medium Theories (EMT) include the Bruggeman model, Maxwell Garnett (MG) and Landau Lifshitz Looyenga (LLL) models [47]. Another models include the Cole Cole models [56], and stratified media theory.…”

Noble classical and quantum approach to model the optical properties of metallic nanoparticles to enhance the sensitivity of optoplasmonic sensors

“…23,24 Enhancement of SPP properties has potential application in nanophotonics, security, super-resolution imaging, and optical biosensors. [25][26][27] Plasmonic-based optical sensors (OPS) have high specicity, sensitivity, small size, and cost-effective advantages over conventional sensors. Their application has been used to measure cancer cell mechanics such as extracellular matrix, nucleoskeleton, and cytoskeleton; applying both the classical and quantum models of SPP properties.…”

Accurate and early prediction of the wound healing outcome of burn injuries using the wavelet Shannon entropy of THz time-domain waveforms

“…27 Over the past two decades, terahertz time-domain spectroscopy (THz-TDS) has emerged as a promising technique for the non-invasive sensing of various biological tissues. 28,29 THz-TDS has been effective in the delineation of breast or skin cancer margins, [30][31][32][33][34][35][36] diagnosis of brain, 37 colon, 38 and gastric 39 tumors, screening the diabetic foot syndrome 40,41 and monitoring the corneal hydration for diagnosing glaucoma. [42][43][44][45][46][47][48][49] In skin assessment applications, THz-TDS has been used for quantifying the hydration changes in the skin.…”