• Journal of Korean Neurosurgical Society
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• v.65 no.4
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• pp.572-581
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• 2022

Objective : Compared to microscopes, exoscopes have advantages in field-depth, ergonomics, and educational value. Exoscopes are especially well-poised for adaptation into fluorescence-guided surgery (FGS) due to their excitation source, light path, and image processing capabilities. We evaluated the feasibility of near-infrared FGS using a 3-dimensional (3D), 4 K exoscope with near-infrared fluorescence imaging capability. We then compared it to the most sensitive, commercially-available near-infrared exoscope system (3D and 960 p). In-vitro and intraoperative comparisons were performed. Methods : Serial dilutions of indocyanine-green (1-2000 ㎍/mL) were imaged with the 3D, 4 K Olympus Orbeye (system 1) and the 3D, 960 p VisionSense Iridium (system 2). Near-infrared sensitivity was calculated using signal-to-background ratios (SBRs). In addition, three patients with brain tumors were administered indocyanine-green and imaged with system 1, with two also imaged with system 2 for comparison. Results : Systems 1 and 2 detected near-infrared fluorescence from indocyanine green concentrations of >250 ㎍/L and >31.3 ㎍/L, respectively. Intraoperatively, system 1 visualized strong near-infrared fluorescence from two, strongly gadolinium-enhancing meningiomas (SBR=2.4, 1.7). The high-resolution, bright images were sufficient for the surgeon to appreciate the underlying anatomy in the near-infrared mode. However, system 1 was not able to visualize fluorescence from a weakly-enhancing intraparenchymal metastasis. In contrast, system 2 successfully visualized both the meningioma and the metastasis but lacked high resolution stereopsis. Conclusion : Three-dimensional exoscope systems provide an alternative visualization platform for both standard microsurgery and near-infrared fluorescent guided surgery. However, when tumor fluorescence is weak (i.e., low fluorophore uptake, deep tumors), highly sensitive near-infrared visualization systems may be required.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.17-27
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• 2022

Fluorescence imaging is widely used to image cells or small animals due to its high temporal and spatial resolution. Because conventional fluorescence imaging uses visible light, the penetration depth of light within the tissue is low, phototoxicity may occur due to visible light, and the detection sensitivity is lowered due to interference by background autofluorescence. In order to overcome this limitation, long-wavelength light should be used, and fluorescence imaging using near-infrared-I (NIR-I) in the region of 700~900 nm has been developed. To further improve imaging quality, researchers are interested in using a longer wavelength light, near-infrared-II (NIR-II) ranging from 1000 to 1700 nm. In the NIR-II region, light scattering is further minimized, and the penetration depth of light in the tissue is improved up to about 10 mm, and autofluorescence of the tissue is reduced, enabling high sensitivity and resolution fluorescence imaging. In this review, among various NIR-II fluorescence imaging probes, inorganic nanoparticle-based probes with excellent photostability and easily tunable emission wavelength were described, focusing on single-walled carbon nanotubes, quantum dots, and lanthanide nanoparticles.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2937-2941
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• 2013

Fluorescence imaging is considered as one of the most powerful techniques for monitoring biomolecule activities in living systems. Near-infrared (NIR) light is advantageous for minimum photodamage, deep tissue penetration, and minimum background autofluorescence interference. Herein, we have developed a new NIR fluorescent dye, namely, RB-1, based on the Rhodamine B scaffold. RB-1 exhibits excellent photophysical properties including large absorption extinction coefficients, high fluorescence quantum yields, and high photostability. In particular, RB-1 displays both absorption and emission in the NIR region of the "biological window" (650-900 nm) for imaging in biological samples. RB-1 shows absorption maximum at 614 nm (500-725 nm) and emission maximum at 712 nm (650-825 nm) in ethanol, which is superior to those of traditional rhodamine B in the selected spectral region. Furthermore, applications of RB-1 for fluorescence imaging in living cells and small animals were investigated using confocal fluorescence microscopy and in vivo imaging system with a high signal-to-noise ratio (SNR = 10.1).

• Journal of Chest Surgery
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• v.52 no.4
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• pp.205-220
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• 2019

Near-infrared (NIR) fluorescence imaging provides a safe and cost-efficient method for immediate data acquisition and visualization of tissues, with technical advantages including minimal autofluorescence, reduced photon absorption, and low scattering in tissue. In this review, we introduce recent advances in NIR fluorescence imaging systems for thoracic surgery that improve the identification of vital tissues and facilitate the resection of tumorous tissues. When coupled with appropriate NIR fluorophores, NIR fluorescence imaging may transform current intraoperative thoracic surgery methods by enhancing the precision of surgical procedures and augmenting postoperative outcomes through improvements in diagnostic accuracy and reductions in the remission rate.

• Journal of Biosystems Engineering
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• v.35 no.2
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• pp.124-131
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• 2010

Chlorophyll fluorescence has been researched for assessing fruit post-harvest quality and condition. The objective of this preliminary research was to investigate the potential of fluorescence spectroscopy for measuring apple fruit quality. Ultraviolet (UV) and blue light was used as an excitation source for inducing fluorescence in apples. Fluorescence spectra were measured from 'Golden Delicious' (GD) and 'Red Delicious' (RD) apples using a visible/near-infrared spectrometer after one, three, and five minutes of continuous UV/blue light illumination. Standard destructive tests were performed to measure fruit firmness, skin and flesh color, soluble solids and acid content from the apples. Calibration models for each of the three illumination time periods were developed to predict fruit quality indexes. The results showed that fluorescence emission decreased steadily during the first three minutes of UV/blue light illumination and was stable within five minutes. The differences were minimal in the model prediction results based on fluorescence data at one, three or five minutes of illumination. Overall, better predictions were obtained for apple skin chroma and hue and flesh hue with values for the correlation coefficient of validation between 0.80 and 0.90 for both GD and RD. Relatively poor predictions were obtained for fruit firmness, soluble solids content, titrational acid, and flesh chroma. This research has demonstrated that fluorescence spectroscopy is potentially useful for assessing selected quality attributes of apple fruit and further research is needed to improve fluorescence measurements so that better predictions of fruit quality can be achieved.

• Structural Monitoring and Maintenance
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• v.9 no.3
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• pp.259-270
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• 2022

This study explores the use of the recently developed "strain-sensing smart skin" (S⁴) method for noncontact strain measurements on cement-based samples. S⁴ sensors are single-wall carbon nanotubes dilutely embedded in thin polymer films. Strains transmitted to the nanotubes cause systematic shifts in their near-infrared fluorescence spectra, which are analyzed to deduce local strain values. It is found that with cement-based materials, this method is hampered by spectral interference from structured near-infrared cement luminescence. However, application of an opaque blocking layer between the specimen surface and the nanotube sensing film enables interference-free strain measurements. Tests were performed on cement, mortar, and concrete specimens with such modified S⁴ coatings. When specimens were subjected to uniaxial compressive stress, the spectral peak separations varied linearly and predictably with induced strain. These results demonstrate that S⁴ is a promising emerging technology for measuring strains down to ca. 30 𝜇𝜀 in concrete structures.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.2
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• pp.59-64
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• 2019

In this paper, we introduced a near-infrared multi-channel fluorescence imaging system and analyzed the effects of measurements variables such as exposure time, working distance and intensity of excitation light. Fluorescence signal is increased as exposure time becomes longer, excitation light intensity increases or working distance becomes smaller. Furthermore, the proper composition of optical filters and precise packaging of the imaging modules prevent the increase of background signal. Thus, we confirmed an increase in SBR. Based on the result of this research, we proposed a method to use a multi-channel fluorescence imaging system.

• YAKHAK HOEJI
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• v.46 no.3
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• pp.161-167
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• 2002

Angelicae gigantis radix is the root of the perennial plant, which belongs to the family Umbelliferae. However, this herbal drug is represented quite different chemical components according to its different genus name, though other herbal drugs (i.e. Leonuri Herba, Xanthii Fructus and so on) show similar constituents on the same name. The root of Angelica gigas containing the coumarin compounds is commonly used in Korea, while Angelica sinensis and Angelica acutiloba including phthalide compounds are used in China and Japan, respectively as Angelicae gigantis radix. In this paper, a nearinfrared spectroscopic method was developed to determine genus name of Angelica spp., especially A. gigas and A. sinensis which are commonly misused in herbal markets. X-ray fluorescence spectrometry and electronic nose have been also applied as nondestructive methods to discriminate A. gigas from A. sinensis according to their specific properties.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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• pp.177-181
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• 2020

Dual-modality imaging strategy using near-infrared fluorescence (FLI) and photoacoustic imaging (PAI) demands a suitable probe to enable dual-modular signal production. Herein, we demonstrate a synthetic protocol of small molecular dye for dual-modular FLI and PAI. A condensation reaction between squaric acid and carboxypentyl benzoindolium, and followed by basic hydrolysis to give the benzoindole derived squaraine (BSQ) dye in 49% yield. Next, the carboxylic acid group of BSQ was further functionalized with N-hydroxysuccinimide or azide group for an efficient conjugation with a targeting biomolecule. BSQ showed a maximum fluorescent emission at around 680 nm and the photoacoustic signal reached a maximum intensity at 680-700 nm. Based on these results, we conclude that BSQ analogs will be useful probes for dual-modular (FLI/PAI) imaging studies in animal models.

• Journal of The Korean Astronomical Society
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• v.29 no.2
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• pp.223-243
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• 1996

We have constructed a line-by-line model of the A-X system of CO in order to analyze the CO bands appearing in the UV spectra of comets. The model includes electronic, rotational, vibrational transitions, excitations by solar UV radiation, and effects of neutral and electron collisions. The major bands of the A-X system occur in the $1200 - 1800{\AA}$ range where the temporal variation of solar irradiation is significant. The solar spectrum in this spectral range shows many emission lines, which cause a significant Swings effect. We derived fluorescence efficiencies of the bands as functions of heliocentric velocity and cometocentric distance using a high resolution spectrum of the sun. We compared our model with a spectrum of comet P/Halley obtained with the IUE, and estimated that the UV Swings effects are less than 20 fluorescence efficiencies for the most bands of the A-X system. We discuss the temporal variation of solar UV irradiation and its effects on the fluorescence efficiencies. The study of the A-X system also requites knowledge of vibrational and rotational fluorescent processes in the infrared and radio regions because the majority of CO molecules in the coma is in the ground rotational states. The solar infrared spectrum near 5 microns, where the fundamental band of CO occurs, contains strong absorption lines of the fundamental band and hot bands of CO and its isotopes. We derived fluorescence efficiencies of the infrared band as functions of heliocentric velocity and cometrocentric distance. The solar absorption lines near 5 microns cause a 20 reduction of the g-factor of the fundamental band at heliocentric velocities close to 0 km/sec. We discuss the effects of neutral and electron collisions on the fluorescence efficiencies of the infrared and UV bands.