Table 2.
Relevant biomedical applications of THz technology and related conclusions
| Techniques | Detected Compounds | Results | References | |
|---|---|---|---|---|
| THz time-domain spectroscopy (THz-TDS) | Amino acids and peptides | Glycine, alanine and their peptides | The vibrational band of poly-glycine was found at a frequency of 1.37 THz | Yamamoto et al.30 |
| Nucleic acids | DNA | Recording the far-infrared (0.5–4.0 THz) dielectric function of the four nucleobases and corresponding nucleosides forming the building blocks of deoxyribose nucleic acid (DNA) | Fischer et al.31 | |
| Sequences of oligonucleotides | The four oligonucleotides(HQ-411, HQ-418, HQ-419, and HQ-420)exhibited distinguishably different absorption behaviors over a frequency range of 0.2–2.6 THz | Tang et al.32 | ||
| RNA | The single-stranded RNA polymers poly-A and poly-C showed significant differences in both absorption and refractive index in the frequency range of 0.1–3 THz | Fischer et al.33 | ||
| Proteins | TRPM8 protein | It is the first study of the glycosylated state of proteins from the perspective of molecular structure and cellular functional expression using THz spectroscopy | Mernea et al.34 | |
| Immunoglobin (IgG) protein | Determination of the effects of two antibodies on the dielectric properties of a polar liquid from 0.1 to 1.3 THz | Sun et al.35 | ||
| Six kinds of protein rn21, rn22, rn28, n42, n43 and n53 | A label-free method to acquire the quantitative distribution of different kinds of proteins using THz-TDS was presented | Han et al.36 | ||
| Lipids | Myelin | It demonstrated differences in the optical properties of myelin-deficient and normal brains in the THz band | Zou et al.37 | |
| Tissues | Fresh porcine muscle, fresh porcine adipose tissue and skin | Measurement of the optical properties from 0.1 to 1.6 THz for muscle, adipose tissue, and skin | Wilmink et al.38 | |
| Human dehydrated normal and cancerous gastric tissues | THz characteristic spectra of gastric cancer tissues were observed at 0.2–0.5 THz and 1–1.5 THz | Hou et al.39 | ||
| Human brain tissues from Alzheimer’s disease patients | It showed differences between healthy and diseased tissues | Png et al.40 | ||
| Brain tissues from AD mice | It was the first time to detect optical molecular torsional modes due to tryptophan difference between AD and normal mouse models using THz technique | Shi et al.41 | ||
| Human shin | THz features of the palm, ventral (inner) and dorsal (outer) forearm in the 0.1–2 THz spectral region were collected | Echchgadda et al.42 | ||
| Pharmaceuticals | Aspirin and aspirin precursors | The reduction of the spreading of the drug compounds of aspirin and its precursors was found by THz-TDS | Laman et al.43 | |
| Tablet release properties | THz-TDS technology allowed fast (1 s) direct measurement of porosity of different types of tablets | Bawuah et al.44 | ||
| THz pulsed imaging (TPI) and THz imaging | Tissues | Laboratory rats | TPI allowed non-invasive and accurate differentiation of tissue types | Huang et al.45 |
| Basal cell carcinoma and melanoma | Tumors exhibited high absorption areas in both pulsed THz imaging (0.2–0.5 THz integrated) | Berry et al.46 | ||
| Proteins | Immunoglobulin G (IgG) and ferritin molecules | It was the first demonstration of THz near-field imaging of a single IgG molecule | Yang et al.47 | |
| Pharmaceuticals | Comparation of the efficacy of different TDD methods | THz imaging technique for quantitative evaluation of different transdermal application methods was feasible and potential | Wang et al.48 | |
| Tablet and coating integrity and performance | THz radiation can extract information on the internal coating configuration of a table | Fitzgerald et al.49 | ||
| Cancers | Skin cancer | THz pulse imaging can distinguish basal cell carcinoma from normal tissue | Woodward et al.50 Pickwell et al.51 Wallace et al.52 | |
| Breast cancer | TPI can distinguish breast cancerous tissue from normal tissue | Vohra et al.53 Bowman et al.6 | ||
| Oral cancer | THz imaging can distinguish well between cancerous areas and surrounding tissues in the oral region | Sim et al.54,55 | ||
| Brain cancer | THz imaging can determine the boundaries of malignant regions using animal brain tumor models | Oh et al.56 | ||
| THz-based metallic mesh (electromagnetic surface waves in the THz region) | Nucleic acids | Single-stranded and double-stranded of DNA | A metallic mesh-based THz method clearly revealed the difference in optical properties between single- and double-stranded DNA molecules on the basis of refractive index | Hasebe et al.57 |
| THz photo-mixing spectrometer | Nucleic acids | DNA | A strong signal around 0.72 THz and a weak signal around 0.4 THz were detected in the aqueous DNA solution | Zhang et al.58 |
| THz freeze out spectroscopy (TFOS) | Proteins | Protein-ligand binding | TFOS can be used to identify protein-ligand binding in solution | Chen et al.59 |
| All-metal THz metamaterial biosensor | Proteins | Bovine serum albumin | THz biosensor based on all-metal metamaterials can detect proteins well | Wang et al.60 |