Near-infrared Properties Research Articles

Understanding Macrophage Interaction with Antimony-Doped Tin Oxide Plasmonic Nanoparticles.

Antimony-doped tin oxide nanoparticles (ATO NPs) have emerged as a promising tool in biomedical applications, namely robust photothermal effects upon near-infrared (NIR) light exposure, enabling controlled thermal dynamics to induce spatial cell death. This study investigated the interplay between ATO NPs and macrophages, understanding cellular uptake and cytokine release. ATO NPs demonstrated biocompatibility with no impact on macrophage viability and cytokine secretion. These findings highlight the potential of ATO NPs for inducing targeted cell death in cancer treatments, leveraging their feasibility, unique NIR properties, and safe interactions with immune cells. ATO NPs offer a transformative platform with significant potential for future biomedical applications by combining photothermal capabilities and biocompatibility.

A NIR iridium(III) complex-based luminescence probe for imaging mitochondria pyruvate dehydrogenase kinase 1 in triple-negative breast cancer cells

The aberrant expression of mitochondrial pyruvate dehydrogenase kinase 1 (PDK1) is highly associated with tumorigenesis and metastasis of triple-negative breast cancer (TNBC). However, because of the dearth of highly sensitive and targetable probes for PDK1, the precise imaging of mitochondrial PDK1 in TNBC cells remains challenging. We herein describe the first near-infrared (NIR) luminescence probe for visualizing PDK1 in TNBC living cells through conjugating a PDK1 inhibitor, dichloroacetic acid (DCA), to an iridium(III) complexes. This probe retains not only the favorable optical characteristics of iridium(III) complexes, but also the specific binding ability of DCA for PDK1. The probe can sensitively and specifically detect mitochondria PDK1 in TNBC cells, as verified by cellular thermal shift assay (CETSA), knockdown and selectivity experiments. Moreover, complex 1 has the capability for imaging TNBC spheroids and zebrafish models with good imaging contrast and penetration, presumably benefiting from its PDK1 target ability and NIR property. Importantly, the probe shows negligible luminescence in normal cell lines with low expression of PDK1, demonstrating its ability to discriminate TNBC cells from normal cells. This probe, which acts through the interplay of both low oxygen diffusion and a rigid microenvironment upon binding to PDK1, could provide mechanistic insights into the biological roles of PDK1 in TNBC and support the development of PDK1-based TNBC diagnostic probes in vivo.

1991T-like Supernovae* *This paper includes data gathered with the 6.5 m Magellan telescopes at Las Campanas Observatory, Chile.

Understanding the nature of the luminous 1991T-like supernovae (SNe) is of great importance to SN cosmology as they are likely to have been more common in the early Universe. In this paper, we explore the observational properties of 1991T-like SNe to study their relationship to other luminous, slow-declining Type Ia supernovae (SNe Ia). From the spectroscopic and photometric criteria defined in Phillips et al., we identify 17 1991T-like SNe from the literature. Combining these objects with 10 1991T-like SNe from the Carnegie Supernova Project-II, the spectra, light curves, and colors of these events, along with their host galaxy properties, are examined in detail. We conclude that 1991T-like SNe are closely related in essentially all of their UV, optical, and near-infrared properties—as well as their host galaxy parameters—to the slow-declining subset of Branch core-normal SNe and to the intermediate 1999aa-like events, forming a continuum of luminous SNe Ia. The overriding difference between these three subgroups appears to be the extent to which 56Ni mixes into the ejecta, producing the premaximum spectra dominated by Fe iii absorption, the broader UV light curves, and the higher luminosities that characterize the 1991T-like events. Nevertheless, the association of 1991T-like SNe with the rare Type Ia circumstellar material SNe would seem to run counter to this hypothesis, in which case 1991T-like events may form a separate subclass of SNe Ia, possibly arising from single-degenerate progenitor systems.

Near-infrared fluorescent probe for selective and sensitive detection of glutathione based on thioctic acid-functionalized Ag/Au NCs-assisted by ferric ion

Accurate determination of glutathione (GSH) levels in biological fluids and food supplements is paramount. To address this need, we developed a near-infrared (NIR) fluorescent probe with high sensitivity and selectivity for GSH detection. This probe comprises thioctic acid-functionalized silver and gold nanoclusters (ThA@Ag/Au NCs), emitting red light at 720 nm upon excitation at 310 nm. In the presence of Fe3+ ions, which form complexes with ThA, the fluorescence of ThA@Ag/Au NCs is quenched due to aggregation. However, upon addition of GSH, a potent chelator for Fe3+, the fluorescence of the probe is restored, leading to enhanced emission. Under optimized conditions, the fluorescence response (F/F°) exhibits a linear relationship with increasing GSH concentration within the range of 0.03–95 µM, achieving a limit of detection (LOD) of 9.0 nM. This designed scheme demonstrates excellent selectivity, sensitivity, and accuracy for GSH detection. Furthermore, the NIR fluorescent probe effectively estimated GSH levels in various matrices, including capsules, serum, urine, and saliva samples, yielding recoveries % ranging from 97.2 % to 103.2 %, with RSD % below 4.34 %. Due to its NIR properties, this fluorescent probe holds promise for diagnosing various diseases and potential in vivo applications.

Near‐infrared aggregation‐induced emission materials: Bibliometric analysis and their application in biomedical field

AbstractAggregation‐induced emission (AIE) is an intriguing photophysical phenomenon, where specific materials exhibit a remarkable surge in luminescence when brought together in non‐ideal solvents or within a solid matrix. Since the concept of AIE was first introduced in 2001, numerous advanced applications have been gradually explored across various domains, including optics, electronics, energy, and the life sciences. Of particular note is the growing interest in the application of AIE systems with near‐infrared (NIR) emissive feature in the field of biomedicine, encompassing detection, imaging, and therapeutic interventions. Notably, bibliometric analysis serves as a valuable tool to provide researchers with a comprehensive understanding of research achievements and developmental trends in specific fields, which is crucial for academic research. Herein, we present a general bibliometric overview spanning two decades of NIR‐AIE development. With the assistance of core scientific databases and various bibliometric software tools, we conducted a systematic analysis of annual publications and citations, the most influential countries/regions, leading authors, journals, and institutions, as well as the hot topics related to NIR applications and forward‐looking predictions. Furthermore, the application of AIE with NIR properties in the biomedical field is also systematically reviewed.

An indole–based near–infrared fluorescent “Turn–On” probe for H2O2: Selective detection and ultrasensitive imaging of zebrafish gallbladder

Fluorescent probes play essential roles in medical imaging, where the researchers can select one of many molecules to use to help monitor the status of living systems under investigation. To date, a few scaffolds that allow the in vivo detection of H2O2 are available only. Herein, we provide a highly sensitive and selective near-infrared fluorescent probe that detects H2O2 based on the ICT sensing mechanism. We report the first indole–incorporated fluorescent probe Indo–H2O2 that allows H2O2 detection with a LOD of 25.2 nM featuring a boronate group conjugated to an indole scaffold; the boronate cleaves upon reaction with H2O2. A 5-membered malononitrile derivative was incorporated; Indo–H2O2 has near-infrared (NIR) properties and the reaction time is low (∼25 min) compared to other related probes. Indo–H2O2 was successfully employed in both endogenous and exogenous imaging trials of H2O2 in living cells. Indo–H2O2 also allows the real-time monitoring of H2O2in vivo. It preferentially accesses the gallbladder of zebrafish. Our findings support Indo–H2O2 as a highly sensitive fluorescent NIR probe for detecting H2O2, and an idea to incorporate a central indole unit in future fluorescent probe designs.

Near-infrared signature of hydrothermal opal: a case study of Icelandic silica sinters

Abstract. Silica minerals constitute a main target to assess the origin of life or the possibility of its emergence. On Earth, ancient hydrothermal silica deposits have preserved the oldest forms of life. Beyond Earth, such silica-rich hydrothermal systems have been observed on Mars by orbital near-infrared (NIR) remote sensing and in situ rover exploration. This work investigates the variations of texture and NIR properties of opal with temperature, within a single geological context of hot springs. Silica sinters have been sampled in Icelandic hot-spring fields, in the Reykholt region, and at the Hveravellir site, with water temperature ranging from 14 to 101 ∘C. Variations in the NIR spectral features (concavity ratio criteria, CRC) vary with fluid temperature, lithofacies, and microtexture. Only high-temperature samples display high CRC values (CRC5200>0.85), but low CRC values (CRC5200 < 0.75) are measured for any temperature. Hence, temperature is not the only parameter controlling spectral properties of opal. Several other parameters such as the hydrodynamic context, the microbial activity, silica micro-textures, and porosity may also affect silica precipitation, the incorporation and speciation of water in it, and thus its NIR signature. The observations suggest a limitation in the use of NIR spectral features for the interpretation of the geological context of fossil opal on Earth or Mars: only opal with high CRC values can be inferred as being formed by hydrothermal activity. Low CRC values can be attributed to either low-temperature hydrothermal activity (< 50–60 ∘C) or to continental weathering.

Development of a multifunctional platform for near-infrared imaging and targeted radionuclide therapy for tumors

Biotin receptor (BR) is overexpressed in several human tumor cell lines and has become an important biomarker for tumor diagnosis and treatment. Therefore, much attention has been attracted in the field of developing BR-targeting agents. In clinical practice, a multifunctional platform that can be used for both diagnosis and treatment is much desirable. In this study, to improve diagnostic and therapeutic efficacy of BR-positive tumors, we developed a multifunctional platform RT-H2 to combine with the cyanine scaffold for near infrared (NIR) imaging and the radioisotope 131I for targeted radionuclide therapy (TRT). In vitro experiments showed that RT-H2 possessed favorable NIR properties and could selectively accumulate in BR-positive HeLa cells. In vivo NIR imaging of HeLa tumor-bearing mice exhibited high accumulation and long retention time (72 h) of RT-H2 in the tumor. Furthermore, RT-H2 was also employed as a carrier to develop 131I-labeled TRT agent due to its favorable properties in vivo. The radiolabeling conditions were optimized and the optimal conditions determined to be 1.2 equiv of Idogen, reaction time 4 min and room temperature, yielding the radiotracer [131I]I-RT-H2 with the radiochemical purity (RCP) of > 95% after a simple purification by a C18 column. In vitro cell experiments indicated that [131I]I-RT-H2 could specifically target Hela cells and displayed dose-dependent antitumor effect. In vivo experiments demonstrated that [131I]I-RT-H2 obviously inhibited the tumor proliferation in HeLa tumor-bearing mice within 4 weeks. All these results indicate that RT-H2 has the potential to serve as a multifunctional platform for tumor diagnosis and treatment.

A Switchable Near‐Infrared‐Absorbing Dye Based on Redox‐Bistable Benzitetraazaporphyrin

AbstractActivatable near‐infrared (NIR) dyes responsive to external stimuli are used in medical and other applications. Here, we describe the design and synthesis of bench‐stable 18π‐ and 20π‐electron benzitetraazaporphyrins (BzTAPs) possessing redox‐switchable NIR properties. X‐Ray, NMR, and UV/Visible‐NIR analyses revealed that 20π‐electron BzTAP 1 exhibits NIR absorption and antiaromaticity with a paratropic ring‐current, while 18π‐electron BzTAP 2 shows weakly aromatic character with NIR inertness. Notably, the NIR‐silent BzTAP 2 was readily converted to the NIR‐active BzTAP 1 in the presence of mild reducing agents such as amine. The intense NIR absorption band of BzTAP 1 is in sharp contrast to the very weak absorption bands of previously reported antiaromatic porphyrinoids. Molecular orbital analysis revealed that symmetry‐lowering perturbation of the 20π‐electron porphyrinoid skeleton enables the HOMO–LUMO transition of 1 to be electric‐dipole‐allowed. BzTAPs are expected to be useful for constructing activatable NIR probes working in reductive environments.

A Switchable Near-Infrared-Absorbing Dye Based on Redox-Bistable Benzitetraazaporphyrin.

Activatable near-infrared (NIR) dyes responsive to external stimuli are used in medical and other applications. Here, we describe the design and synthesis of bench-stable 18π- and 20π-electron benzitetraazaporphyrins (BzTAPs) possessing redox-switchable NIR properties. X-Ray, NMR, and UV/Visible-NIR analyses revealed that 20π-electron BzTAP 1 exhibits NIR absorption and antiaromaticity with a paratropic ring-current, while 18π-electron BzTAP 2 shows weakly aromatic character with NIR inertness. Notably, the NIR-silent BzTAP 2 was readily converted to the NIR-active BzTAP 1 in the presence of mild reducing agents such as amine. The intense NIR absorption band of BzTAP 1 is in sharp contrast to the very weak absorption bands of previously reported antiaromatic porphyrinoids. Molecular orbital analysis revealed that symmetry-lowering perturbation of the 20π-electron porphyrinoid skeleton enables the HOMO-LUMO transition of 1 to be electric-dipole-allowed. BzTAPs are expected to be useful for constructing activatable NIR probes working in reductive environments.

Image Decomposition Technique Based on Near-Infrared Transmission.

One way to diagnose a disease is to examine pictures of tissue thought to be affected by the disease. Near-infrared properties are subdivided into nonionizing, noninvasive, and nonradiative properties. Near-infrared also has selectivity properties for the objects it passes through. With this selectivity, the resulting attenuation coefficient value will differ depending on the type of material or wavelength. By measuring the output and input intensity values, as well as the attenuation coefficient, the thickness of a material can be measured. The thickness value can then be used to display a reconstructed image. In this study, the object studied was a phantom consisting of silicon rubber, margarine, and gelatin. The results showed that margarine materials could be decomposed from other ingredients with a wavelength of 980 nm.

Optimizing Broadband Near-Infrared Emission in Bi/Sn-Doped Aluminosilicate Glass by Modulating Glass Composition.

The Bi/Sn-doped aluminosilicate glass samples were prepared using a melting–quenching method and their near-infrared (NIR) emission properties were studied. An ultra-broadband NIR emission ranging from 950 nm to 1600 nm was observed in all samples under 480 nm excitation, which covered the whole fiber low-loss window. The NIR emission spectrum showed that the maximum emission peak was about 1206 nm and the full width at half maximum (FWHM) was about 220 nm. Furthermore, the NIR emission intensity strongly depends on the composition of the glass, which can be optimized by modulating the glass composition. The Bi0 and Bi+ ions were the NIR luminescence source of the glass samples in this paper. The Bi/Sn-doped aluminosilicate glass has the potential to become a new type of core fiber material and to be applied to optical fiber amplifiers (OFAs), based on its excellent performance in ultra-broadband NIR emission.

Revealing the vibronic coupling effects in the size-dependent optical properties of cycloparaphenylene dications

We explain the visible and near-infrared optical properties of low-lying singlet excited states (S and S) of [5]-, [7]- and [9]cycloparaphenylene dications (CPPs). A narrow energy gap (<150 cm) separates these states at the Franck–Condon point of the individual molecule. The energy gap increases upon increasing the molecular size. Consequently, [5]CPP possesses highly overlapping S and S absorption bands. The overlap between these bands decreases and the resulting composite spectrum appears broader, particularly for [9]CPP. Theoretical spectra generated using quantum wavepacket calculations within the linear vibronic coupling approach match well with the experiment. Our findings reveal near-degenerate S and S minima, highlighting the relevance of both these states while assigning experimental fluorescence emission properties of CPPs.

Visible–Near-Infrared Luminescence and Scintillation Properties of Pr-Doped Bi4ge3o12 Single Crystals

Visible–Near-Infrared Luminescence and Scintillation Properties of Pr-Doped Bi4ge3o12 Single Crystals

Rational Design of ICT-Based Fluorescent Probe with AIE and NIR Properties for Hypochlorite Determination

In recent years, the easily synthesized fluorescent probes with good photophysical and sensing properties have attracted widespread attention. Herein, by utilizing the fluorescence regulation effect of electron push-pull effect and the oxidation property of hypochlorite (ClO−) to C=N double bonds, we rationally proposed two intramolecular charge transfer (ICT)-based fluorescent probes with typical aggregation-induced emission (AIE) properties for ClO− detection. The synthesis process of the two probes is very convenient, and both of them can exhibit significant colorimetric and fluorescence changes within 3 min in the presence of ClO−. Moreover, compared with Probe A, the Probe B with near-infrared (NIR) fluorescence centered at 677 nm was successfully applied to ClO− determination in tap water and food samples as well as live cell imaging.

Highly Sunlight Reflective and Infrared Semi-Transparent Nanomesh Textiles.

Radiative cooling in textiles is one of the important factors enabling cooling of the human body for thermal comfort. In particular, under an intense sunlight environment such as that experienced with outdoor exercise and sports activities, high near-infrared (NIR) reflectance to block sunlight energy influx along with high IR transmittance in textiles for substantial thermal emission from the human body would be highly desirable. This investigation demonstrates that a nanoscale geometric control of textile structure alone, instead of complicated introduction of specialty polymer materials and composites, can enable such desirable NIR and IR optical properties in textiles. A diameter-dependent Mie scattering event in fibers and associated optical and thermal behavior were simulated in relation to a nonwoven, nanomesh textile. As an example, a nanomesh structure made of PVDF (polyvinylidene fluoride) electrospun fibers with ∼600 nm average diameter was examined, which exhibited a significant radiative cooling performance with over 90% solar and NIR reflectance to profoundly block the sunlight energy influx as well as ∼50% IR transmittance for human body radiative heat dissipation. An extraordinary cooling effect, as much as 12 °C, was obtained on a simulated skin compared to the normal textile fabric materials. Such a powerful radiative cooling performance together with IR transmitting capability by the nanomesh textile offers a way to efficiently manage sunlight radiation energy to make persons, devices, and transport vehicles cooler and help to save energy in an outdoor sunlight environment as well as indoor conditions.

Fluorescence/photoacoustic imaging-guided nanomaterials for highly efficient cancer theragnostic agent

Imaging modalities combined with a multimodal nanocomposite contrast agent hold great potential for significant contributions in the biomedical field. Among modern imaging techniques, photoacoustic (PA) and fluorescence (FL) imaging gained much attention due to their non-invasive feature and the mutually supportive characteristic in terms of spatial resolution, penetration depth, imaging sensitivity, and speed. In this present study, we synthesized IR783 conjugated chitosan–polypyrrole nanocomposites (IR-CS–PPy NCs) as a theragnostic agent used for FL/PA dual-modal imaging. A customized FL and photoacoustic imaging system was constructed to perform required imaging experiments and create high-contrast images. The proposed nanocomposites were confirmed to have great biosafety, essentially a near-infrared (NIR) absorbance property with enhanced photostability. The in vitro photothermal results indicate the high-efficiency MDA-MB-231 breast cancer cell ablation ability of IR-CS–PPy NCs under 808 nm NIR laser irradiation. The in vivo PTT study revealed the complete destruction of the tumor tissues with IR-CS–PPy NCs without further recurrence. The in vitro and in vivo results suggest that the demonstrated nanocomposites, together with the proposed imaging systems could be an effective theragnostic agent for imaging-guided cancer treatment.

Synthesis, characterization, and visible–near infrared properties of some perylene‐3,4,9,10‐tetracarboxylic bisimide derivatives

AbstractBACKGROUNDPerylene bisimide pigments are one of the high performance pigment categories that are utilized in near infrared reflective coatings. The relationship between structure and near infrared activity in the perylene pigments has been unknown to date.RESULTSSome of the factors suggested by previous researchers as affecting the near‐infrared (NIR) reflectance of perylene‐bisimide derivatives were investigated in this study and some are validated, while some others are rejected. In the visible region, there are substantial differences between the absorption spectra of the pigments in their solid‐state and dissolved form, indicating that crystallochromic phenomenon present in the pigments. The NIR properties of the synthesized pigments are investigated and the results exhibit an obvious correlation between the imide substitution structure and NIR properties of the pigments. However, a direct relationship cannot be established. Aliphatic substituted PDIs usually exhibit lower reflectance values in comparison to aromatic substituted ones but there are some exceptions in this regard. The results of UV‐visible–NIR reflectance spectra of each pigment were reported in both white and black substrates and, in this regard, the synthesized pigments were classified. All the PDIs fall into the absorbent‐transparent category in the NIR region. Thermogravimetric analysis indicates that all the PDIs have a heat resistance of at least 200 °C.CONCLUSIONThe structure‐NIR reflectance relationship of the five synthesized perylene pigments is evaluated and the results illustrate that the N‐substitution of the imide group can significantly influence the cool activity of the pigments. © 2021 Society of Chemical Industry (SCI).

Facile fabricating of rGO and Au/rGO nanocomposites using Brassica oleracea var. gongylodes biomass for non-invasive approach in cancer therapy

In this study, we report a facile green-synthesis route for the fabrication of reduced graphene oxide (rGO) using biomass of Brassica oleracea var. gongylodes (B. oleracea). In addition, we have attempted to provide a green synthesis approach to prepare Gold nanoparticles (Au NPs) on the surface of rGO by using stem extract of B. oleracea. The synthesized Au/rGO nanocomposite was evaluated using UV–visible and FTIR spectroscopy, XRD, Raman, FE-SEM, EDX, AFM and DLS techniques. The obtained results demonstrated that the synthesized Au NPs on the surface of rGO was spherical with sizes ranging about 12–18 nm. The Au/rGO NC was, also, developed as photo-synthesizer system for the photothermal therapy (PTT) of MCF7 breast cancer cells. The near-infrared (NIR) photothermal properties of Au/rGO NCs was evaluated using a continuous laser at 808 nm with power densities of 1 W.cm−2. Their photothermal efficacy on MCF7 breast cancer cells after optimizing the proper concentration of the NCs were evaluated by MTT assay, Cell cycle and DAPI staining. In addition, the potential of the synthesized Au/rGO NCs on reactive oxygen species generating and antioxidant activity were assessed by DPPH. Au/rGO NCs possess high capacity to light-to-heat conversion for absorption in range NIR light, and it is able to therapeutic effects on MCF7 cells at a low concentration. The maximum amount of cell death is 40.12% which was observed in treatment groups that received a combination of Au/rGO NCs and laser irradiation. The results demonstrate that the nanomaterials synthesized by green approach lead to efficient destruction of cancer cell and might thus serve as an excellent theranostic agent in Photothermal therapy applications.

The hydrothermally synthesis of K3AlF6:Cr3+ NIR phosphor and its performance optimization based on phase control

AbstractPhosphor‐convert (pc) near‐infrared (NIR) LED is the next‐generation smart NIR light sources. Thus, NIR phosphors are quickly developed. The K3Al1−xF6:xCr3+ (KAF:Cr3+) NIR phosphor shows broadband emission from 650 to 900 nm under 430 nm and can be used to fabricate NIR LEDs. In this work, KAF:Cr3+ phosphors were prepared by a hydrothermal method for the first time. Morphologies and NIR properties are tuned by controlling the hydrothermal processes. Different from the cubic KAF:Cr3+ synthesized by a coprecipitation method, KAF:Cr3+ synthesized by the hydrothermal method shows the tetragonal phase. The optimized KAF:3%Cr3+ shows an internal quantum efficiency of about 31.4%. A NIR pc‐LED device was fabricated by integrating the KAF:3%Cr3+ phosphor with a blue LED chip (~450 nm). The output power of NIR light is about 5.5 mW driven at 150 mA.