Near-infrared Research Articles

Ce3+ and Cr3+ co-activated ultra-wide visible-NIR garnet phosphor for phosphor-converted light emitting diode

In the past decade, the near-infrared (NIR) phosphor-converted light emitting diode (pc-LED) and NIR phosphors has made considerable progress. However, for the field of non-destructive testing, ultra-wide Vis-NIR pc-LED light source can detect a wider range of components compared to NIR pc-LED. Therefore, the development of high-performance ultra-wide Vis-NIR phosphors is quite necessary. Based on the CaLu2Mg2Si3O12 (CLMSO):Cr3+ with excellent performance, this article proposes the introduction of activator Ce3+ into CLMSO:Cr3+ phosphor, which significantly increase the emission band-width. Co-doped phosphor exhibit excellent thermal stability (maintain 75 % room temperature intensity @ 150 °C). The Vis-NIR light output power can reached 64.4 mW @ 100 mA and 60.9 mW@ 100 mA for pc-LED fabricated with CLMSO:0.01Ce3+, 0.001Cr3+ and CLMSO:0.01Ce3+, 0.002Cr3+ with the electricity to Vis-NIR conversion efficiency reached 30.5 %@10 mA and 29.5 % @10 mA, respectively. The CLMSO: Ce3+, Cr3+ phosphor is expected to become the new generation light sources for miniaturized spectrometer.

Classification of industrial tapioca starch hydrolysis products based on their Brix and dextrose equivalent values using near-infrared spectroscopy.

Industrial starch hydrolysis allows the production of syrups with varying functionality depending on their Brix value and dextrose equivalent (DE). As the current methods for evaluating these products are labor-intensive and time-consuming, the objective of this study was to investigate the potential of near-infrared (NIR) spectroscopy for classifying the different tapioca starch hydrolysis products. NIR spectra of samples of seven products (n = 410) were recorded in transflectance mode in the 12 000-4000 cm-1 range. Next, orthogonal partial least squares (OPLS) regression models were built to predict the Brix and DE values of the different samples. To classify the different starch hydrolysis products, support vector machines (SVM) were trained using either the raw spectra or latent variables (LVs) obtained from the OPLS models. The best classification accuracy was obtained by the SVM classifier based on the LVs from the OPLS model for DE prediction, resulting in 95% correct classification over all classes. These results show the potential of NIR spectroscopy for classifying tapioca starch hydrolysis products with respect to their functional properties related to the Brix and DE values. © 2024 Society of Chemical Industry.

Pyrrole-substituted difluoroboron β-diketonate dyes: Facile synthesis and multi-state optical properties

Difluoroboron β-diketonate complexes (BF2bdks) are classic fluorescent molecules that have been applied in luminescent materials, oxygen and mechanical sensors, and most investigations concentrate on BF2bdks with varying aromatic groups without heteroatoms. In this work, a new molecular platform BF2bdks with heterocycle-substituted is prepared in one pot, and six unsymmetric π-expanded BF2bdks are synthesized via condensation reaction. B-1∼6 exhibit comparable fluorescence properties in solution, aggregated and solid states. B-3 (683 nm, Φf = 13.1 %) and B-5 (700 nm, Φf = 2.1 %) show near infra-red (NIR) emission with moderate fluorescence intensity in solution state. Solid emission of B, B-1-3 and B-5 are detected with fluorescence quantum yield from 12.8 % to 25.6 %, and B-2, B-3 and B-5 show AIE phenomenon in aggregated state. The results are supported by crystal analysis and DFT calculation in some extent. In a word, this work enriches the heterocycle-substituted BF2bdks system. B-3 and B-5 with moderate intensity NIR emission in solution, aggregated and solid states at the same time, providing a simple preparation method for multi-states luminescent dyes.

Engineering of phytic acid-coated Prussian nanoparticles for combined Nitric oxide and Low-Temperature photothermal therapy of osteosarcoma

The overall survival rate for osteosarcoma (OS) has not shown any improvement over the past three decades, highlighting the persistent challenge in diagnosing and treating this disease. Nitric oxide (NO) plays a crucial role in some forms of tumor therapy. However, achieving precise and targeted release of NO remains an obstacle in anti-tumor treatment. Given this circumstance, the utilization of near infrared (NIR) laser-induced photothermal effect offers promising potential for controlled delivery of NO. In this study, we have successfully developed a therapeutic nanoparticle, PB@SNP-PA, by loading NO donor sodium nitroprusside (SNP) into Prussian blue (PB) and coating it with phytic acid (PA) for bone targeting, achieving controlled release of NO and enhancing the anti-tumor effect under NIR laser. Moreover, PB@SNP-PA significantly impairs the mitochondria of OS cells, alleviate heat tolerance induced by heat shock proteins, and mediate apoptosis as a potential anticancer mechanism. By utilizing the bisphosphonate-adsorption property of phytic acid, we have achieved bone targeting for PB@SNP-PA, which exhibits significant intra-tumoral enrichment and remarkable anti-tumor effects in vivo by inhibiting bone dissolution. These findings suggest that PB@SNP-PA functions as a unique platform for controlled NO release, proposing a novel approach for combined anti-tumor therapy involving photothermal and gas therapies.

Surface and Atmospheric Heating Responses to Spectrally Resolved Albedo of Frozen and Liquid Water Surfaces

AbstractMultiple Earth system models (ESMs) discretize surface albedo into two semi‐broadbands comprising the UV/visible and near‐infrared (NIR) wavelengths. Here, we use an offline single‐column radiative transfer model to investigate the radiative effects of spectrally resolving the surface albedo. We use the Snow, Ice, and Aerosol Radiative model, extended to simulate liquid water, to calculate snow, ice, and liquid water albedo. We flux‐weight the hyperspectral albedo into the coarser spectral bands used by the atmospheric shortwave radiative transfer model. We establish representative atmospheric profiles for the three surface types and compare their shortwave fluxes and atmospheric warming rates with the spectrally resolved albedo to those calculated with the semi‐broadband approximation. Spectrally resolved surface albedo over snow and ice reduces atmospheric warming by darkening the albedo of NIR bands, correcting the too‐strong surface absorption in visible bands, and too‐weak surface absorption in shortwave infrared bands caused by the semi‐broadband approximation. We explore the effects on surface and atmospheric warming rates of varying solar zenith angle, cloud cover, relative humidity, and snow grain/air bubble radii. The semi‐broadband albedo biases can exceed 10% and 2% for the surface and atmospheric net flux respectively, being particularly strong under conditions which alter the distributions of surface insolation (i.e., cloud cover or increased atmospheric water vapor). These results show that transmitting a higher resolution spectral radiation field between the atmosphere and surface reduces biases in surface absorption and atmospheric heating present in ESMs that currently use the semi‐broadband approximation.

Preclinical evaluation of AGTR1-Targeting molecular probe for colorectal cancer imaging in orthotopic and liver metastasis mouse models

Despite advancements in colorectal cancer (CRC) treatment, the prognosis remains unfavorable for patients with distant liver metastasis. Fluorescence molecular imaging with specific probes is increasingly used to guide CRC surgical resection in real-time and treatment planning. Here, we demonstrate the targeted imaging capacity of an MPA-PEG4-N3-Ang II probe labeled with near-infrared (NIR) fluorescent dye targeting the angiotensin II (Ang II) type 1 receptor (AGTR1) that is significantly upregulated in CRC. MPA-PEG4-N3-Ang II was highly selective and specific to in vitro tumor cells and in vivo tumors in a mouse CRC xenograft model. The favorable ex vivo imaging and in vivo biodistribution of MPA-PEG4-N3-Ang II afforded tumor-specific accumulation with low background and >10 contrast tumor-to-colorectal values in multiple subcutaneous CRC models at 8 h following injection. Biodistribution analysis confirmed the probe's high uptake in HT29 and HCT116 orthotopic and liver metastatic models of CRC with signal-to-noise ratio (SNR) values of tumor-to-colorectal and -liver fluorescence of 5.8 ± 0.6, 5.3 ± 0.7, and 2.7 ± 0.5, 2.6 ± 0.5, respectively, enabling high-contrast intraoperative tumor visualization for surgical navigation. Given its rapid tumor targeting, precise tumor boundary delineation, durable tumor retention and docking study, MPA-PEG4-N3-Ang II is a promising high-contrast imaging agent for the clinical detection of CRC.

A Discotic Mesogenic near-infrared absorbing dye and its application in photo-responsive liquid crystal elastomers

Near-infrared (NIR) light-responsive liquid crystal elastomers (LCEs) doped with organic small-molecule photothermal agents have garnered scientific attention. However, the challenge remains in designing and synthesizing mesogenic photothermal dyes with absorption wavelengths greater than 800 nm. In this research, we design a novel discotic mesogenic NIR absorbing dye, namely the nickel bis(dithiolene) complex YHD868, and prepare NIR-responsive LCE/YHD868 composite films. The discotic mesogenic molecule YHD868 possesses a columnar hexagonal mesophase and exhibits intense NIR absorption at 868 nm, with a photothermal conversion efficiency of about 27 % and a molar extinction coefficient of approximately 30000 M−1·cm−1. Due to the strong NIR absorption of YHD868, combined with its excellent photothermal stability, the LCE/YHD868 composite films exhibit remarkable photoresponse and mechanical properties. Even at a low doping concentration of 0.2 wt%, the composite film can achieve a tensile strength of 9.8 MPa and an elongation at break of 165 %. Under 880 nm NIR irradiation (3.3 W·cm−2), the film can complete reversible photo-induced shrinking deformation in just 2 s, with a shrinkage ratio of about 64 %. This work offers a new approach for the development of photo-responsive smart soft materials.

Mapping burned areas in Thailand using Sentinel-2 imagery and OBIA techniques

Monitoring burned areas in Thailand and other tropical countries during the post-harvest season is becoming increasingly important. High-resolution remote sensing data from Sentinel-2 satellites, which have a short revisit time, is ideal for accurately and efficiently mapping burned regions. However, automating the mapping of agriculture residual on a national scale is challenging due to the volume of information and level of detail involved. In this study, a Sentinel-2A Level-1C Multispectral Instrument image (MSI) from February 27, 2018 was combined with object-based image analysis (OBIA) algorithms to identify burned areas in Mae Chaem, Chom Thong, Hod, Mae Sariang, and Mae La Noi Districts in Chiang Mai, Thailand. OBIA techniques were used to classify forest, agricultural, water bodies, newly burned, and old burned regions. The segmentation scale parameter value of 50 was obtained using only the original Sentinel-2A band in red, green, blue, near infrared (NIR), and Normalized Difference Vegetation Index (NDVI). The accuracy of the produced maps was assessed using an existing burned area dataset, and the burned area identified through OBIA was found to be 85.2% accurate compared to 500 random burned points from the dataset. These results suggest that the combination of OBIA and Sentinel-2A with a 10 m spatial resolution is very effective and promising for the process of burned area mapping.

Strengthening Near‐Infrared Photon Harvesting in Semi‐Transparent All‐Polymer Solar Cells through the Synergy of Fluorination on the Selenide Monomer Backbone

AbstractAll‐polymer solar cells (all‐PSCs) offer promising potential for large‐scale manufacturing due to their remarkable mechanical and thermal stability. However, the limited capacity of polymer acceptors for near‐infrared (NIR) photon harvesting has impeded their progress in semi‐transparent (ST) all‐PSCs. Here, the study develops a pair of new NIR polymer acceptors, named PYSeF‐T and PYSe2F‐T, with mono‐/di‐fluorinated end groups capped to the selenide monomer backbone, respectively. Owing to the stronger intermolecular interaction and intramolecular charge transfer effect of the di‐fluorinated end groups with the selenide backbone, PYSe2F‐T exhibits a stronger crystallinity and a more bathochromic absorption to 1000 nm. When blended with the donor, PM6, the PY2SeF‐T‐based all‐PSC demonstrates a higher efficiency of 16.73% with a remarkable short‐circuit current (JSC) of 27.7 mA cm−2, which is the highest JSC for all‐PSCs. Based on these, the ST device based on PM6:PYSe2F‐T demonstrates a superior efficiency of 12.52% with an average visible transmittance of 26.2% and a light utilization efficiency of 3.28%, outperforming the mono‐fluorinated counterpart. The work provides an in‐depth understanding of the above synergistic effects to develop NIR polymer acceptors and establishes a solid foundation for future investigations into large‐area and flexible ST all‐PSCs.

Near-infrared photoimmunotherapy targeting PD-L1: Improved efficacy by preconditioning the tumor microenvironment.

Near-infrared photoimmunotherapy (NIR-PIT) is a new type of cancer therapy that employs antibody-IRDye700DX conjugates (AbPCs) and near-infrared (NIR) light at a wavelength of 689 nm, the excitation wavelength of IR700. Administered intravenously, injected AbPCs bind specifically to cells expressing the target antigen, whereupon NIR light exposure causes rapid, selective killing. This process induces an anticancer T cell response, leading to sustained anticancer host immune response. Programmed cell death ligand-1 (PD-L1) is a major inhibitory immune checkpoint molecule expressed in various cancers. In this study, we first assessed the efficacy of PD-L1-targeted NIR-PIT (αPD-L1-PIT) in immune-competent tumor mouse models. αPD-L1-PIT showed a significant therapeutic effect on the tumor models with high PD-L1 expression. Furthermore, αPD-L1-PIT induced an abscopal effect on distant tumors and long-term immunological memory. In contrast, αPD-L1-PIT was not as effective for tumor models with low PD-L1 expression. To improve the efficacy of PD-L1-targeted NIR-PIT, PEGylated interferon-gamma (IFNγ) was administered with αPD-L1-PIT. The combination therapy improved the treatment efficacy by increasing PD-L1 expression leading to more efficient cell killing by αPD-L1-PIT. Furthermore, the PEGylated IFNγ led to a CD8+ T cell-dominant tumor microenvironment (TME) with an enhanced anticancer T cell response after αPD-L1-PIT. As a result, even so-called cold tumors exhibited complete responses after αPD-L1-PIT. Thus, combination therapy of PEGylated IFNγ and PD-L1-targeted NIR-PIT has the potential to be an important future strategy for cancer immunotherapy.

Polydopamine-Coated Copper-Doped Co3O4 Nanosheets Rich in Oxygen Vacancy on Titanium and Multimodal Synergistic Antibacterial Study.

Medical titanium-based (Ti-based) implants in the human body are prone to infection by pathogenic bacteria, leading to implantation failure. Constructing antibacterial nanocoatings on Ti-based implants is one of the most effective strategies to solve bacterial contamination. However, single antibacterial function was not sufficient to efficiently kill bacteria, and it is necessary to develop multifunctional antibacterial methods. This study modifies medical Ti foils with Cu-doped Co3O4 rich in oxygen vacancies, and improves their biocompatibility by polydopamine (PDA/Cu-Ov-Co3O4). Under near-infrared (NIR) irradiation, nanocoatings can generate •OH and 1O2 due to Cu+ Fenton-like activity and a photodynamic effect of Cu-Ov-Co3O4, and the total reactive oxygen species (ROS) content inside bacteria significantly increases, causing oxidative stress of bacteria. Further experiments prove that the photothermal process enhances the bacterial membrane permeability, allowing the invasion of ROS and metal ions, as well as the protein leakage. Moreover, PDA/Cu-Ov-Co3O4 can downregulate ATP levels and further reduce bacterial metabolic activity after irradiation. This coating exhibits sterilization ability against both Escherichia coli and Staphylococcus aureus with an antibacterial rate of ca. 100%, significantly higher than that of bare medical Ti foils (ca. 0%). Therefore, multifunctional synergistic antibacterial nanocoating will be a promising strategy for preventing bacterial contamination on medical Ti-based implants.

Hyperspectral Imaging and Machine Learning as a Nondestructive Method for Proso Millet Seed Detection and Classification.

Millet is a small-seeded cereal crop with big potential. There are many different cultivars of proso millet (Panicum miliaceum L.) with different characteristics, bringing forth the issue of sorting which are important for growers, processors, and consumers. Current methods of grain cultivar detection and classification are subjective, destructive, and time-consuming. Therefore, there is a need to develop nondestructive methods for sorting the cultivars of proso millet. In this study, the feasibility of using near-infrared (NIR) hyperspectral imaging (900-1700 nm) to discriminate between different cultivars of proso millet seeds was evaluated. A total of 5000 proso millet seeds were randomly obtained and investigated from the ten most popular cultivars in the United States, namely Cerise, Cope, Earlybird, Huntsman, Minco, Plateau, Rise, Snowbird, Sunrise, and Sunup. To reduce the large dimensionality of the hyperspectral imaging, principal component analysis (PCA) was applied, and the first two principal components were used as spectral features for building the classification models because they had the largest variance. The classification performance showed prediction accuracy rates as high as 99% for classifying the different cultivars of proso millet using a Gradient tree boosting ensemble machine learning algorithm. Moreover, the classification was successfully performed using only 15 and 5 selected spectral features (wavelengths), with an accuracy of 98.14% and 97.6%, respectively. The overall results indicate that NIR hyperspectral imaging could be used as a rapid and nondestructive method for the classification of proso millet seeds.

Monitoring Enzyme Activity Using Near-Infrared Fluorescent Single-Walled Carbon Nanotubes.

Enzymes serve as pivotal biological catalysts that accelerate essential chemical reactions, thereby influencing a variety of physiological processes. Consequently, the monitoring of enzyme activity and inhibition not only yields crucial insights into health and disease conditions but also forms the basis of research in drug discovery, toxicology, and the understanding of disease mechanisms. In this context, near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWCNTs) have emerged as effective tools for tracking enzyme activity and inhibition through diverse strategies. This perspective explores the physicochemical attributes of SWCNTs that render them well-suited for such monitoring. Additionally, we delve into the various strategies developed so far for successfully monitoring enzyme activity and inhibition, emphasizing the distinctive features of each principle. Furthermore, we contrast the benefits of SWCNT-based NIR probes with conventional gold standards in monitoring enzyme activity. Lastly, we highlight the current challenges faced in this field and suggest potential solutions to propel it forward. This perspective aims to contribute to the ongoing progress in biodiagnostics and seeks to engage the wider community in developing and applying enzymatic assays using SWCNTs.

Control of chemical release in hydrogel microvalve array for localized chemical stimulations

Chemical stimulation is considered as one of the most promising therapeutic solutions for degenerated retina due to its ability to mimic a natural chemical signaling pathway. However, the majority of demonstrated platforms actuate chemicals using bulky external setups. Hence, developing high-resolution chemical release platforms with remote-controlled actuation mechanism is of great interest to the next generation of chemical prosthetics. Moreover, the effectiveness of chemical stimulation depends on several parameters, such as the chemical dosage, pulse duration, and spread radius. Therefore, to engineer the chemical release profile, the actuation mechanism of these localized chemical release platforms needs to be thoroughly studied to facilitate modifications. In this study, we have presented a high-resolution chemical release platform based on a macroporous silicon membrane structure. Chemical release ports defined in the membrane pores can be remotely actuated through thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm) hydrogel with near-infrared (NIR) light. As plasmonic heating elements, gold nanorod (GNR) was incorporated within PNIPAAm hydrogel. The pore size of the hydrogel was tuned by varying tetrahydrofuran content in the hydrogel polymerization solution. We have shown that the chemical release properties through membrane pores can be controlled as required using this approach. This insight can be used to engineer the relevant chemical release parameters, thereby creating an efficient chemical stimulation platform.

Shape Memory Polyurethane Composite With Fast Response to Near-Infrared Light Based on Tannic Acid-Iron and Dynamic Phenol-Carbamate Network.

Intelligent materials derived from green and renewable bio-based materials garner widespread attention recently. Herein, shape memory polyurethane composite (PUTA/Fe) with fast response to near-infrared (NIR) light is successfully prepared by introducing Fe3+ into the tannic acid-based polyurethane (PUTA) matrix through coordination between Fe3+ and tannic acid. The results show that the excellent NIR light response ability is due to the even distribution of Fe3+ filler with good photo-thermal conversion ability. With the increase of Fe3+ content, the NIR light response shape recovery rate of PUTA/Fe composite films is significantly improved, and the shape recovery time is reduced from over 60 s to 40s. In addition, the mechanical properties of PUTA/Fe composite film are also improved. Importantly, owing to the dynamic phenol-carbamate network within the polymer matrix, the PUTA/Fe composite film can reshape its permanent shape through topological rearrangement and show its good NIR light response shape memory performance. Therefore, PUTA/Fe composites with high content of bio-based material (TA content of 15.1-19.4%) demonstrate the shape memory characteristics of fast response to NIR light; so, it will have great potential in the application of new intelligent materials including efficient and environmentally friendly smart photothermal responder.

Chiral Ligand-Concentration Mediating Asymmetric Transformations of Silver Clusters: NIR-II Circularly Polarized Phosphorescence Lighting.

Near infrared (NIR) emitter with circularly polarized phosphorescence (CPP), known as NIR CPP, has emerged as a key part in the research of cutting-edge luminescent materials. However, it remains a challenge to obtain nanoclusters with NIR CPP activity. Here, we propose an asymmetric transformation approach to efficiently synthesize two pairs of chiral silver nanoclusters (R/S-Ag29 and R/S-Ag16) using an achiral Ag10 nanocluster as starting material in the presence of different concentration chiral inducer (R/S)-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (R/S-BNP). R/S-Ag29, formed in the low-concentration R/S-BNP, exhibits a unique kernel-shell structure consisting of a distorted Ag13 icosahedron and an integrated cage-like organometallic shell with a C3 symmetry, and possesses a superatomic 6-electron configuration (1S2ǀ1P4). By contrast, R/S-Ag16, formed in the high-concentration R/S-BNP, features a sandwich-like pentagram with AgI-pure kernel. Profiting from the hierarchically chiral structures and superatomic kernel-dominated phosphorescence, R/S-Ag29 exhibits infrequent CPP activity in the second near-infrared (975 nm) region, being the first instance of NIR-II CPP observed among CPL metal nanoclusters. This study presents a new approach to reduce the difficulty of de novo synthesis for chiral silver nanomaterials, and facilitates the design of CPP-active superatomic nanoclusters in NIR region.

Chiral Ligand‐Concentration Mediating Asymmetric Transformations of Silver Clusters: NIR‐II Circularly Polarized Phosphorescence Lighting

Near infrared (NIR) emitter with circularly polarized phosphorescence (CPP), known as NIR CPP, has emerged as a key part in the research of cutting‐edge luminescent materials. However, it remains a challenge to obtain nanoclusters with NIR CPP activity. Here, we propose an asymmetric transformation approach to efficiently synthesize two pairs of chiral silver nanoclusters (R/S‐Ag29 and R/S‐Ag16) using an achiral Ag10 nanocluster as starting material in the presence of different concentration chiral inducer (R/S)‐1,1'‐binaphthyl‐2,2'‐diyl hydrogenphosphate (R/S‐BNP). R/S‐Ag29, formed in the low‐concentration R/S‐BNP, exhibits a unique kernel‐shell structure consisting of a distorted Ag13 icosahedron and an integrated cage‐like organometallic shell with a C3 symmetry, and possesses a superatomic 6‐electron configuration (1S2ǀ1P4). By contrast, R/S‐Ag16, formed in the high‐concentration R/S‐BNP, features a sandwich‐like pentagram with AgI‐pure kernel. Profiting from the hierarchically chiral structures and superatomic kernel‐dominated phosphorescence, R/S‐Ag29 exhibits infrequent CPP activity in the second near‐infrared (975 nm) region, being the first instance of NIR‐II CPP observed among CPL metal nanoclusters. This study presents a new approach to reduce the difficulty of de novo synthesis for chiral silver nanomaterials, and facilitates the design of CPP‐active superatomic nanoclusters in NIR region.

Comprehensive High-resolution Chemical Spectroscopy of Barnard’s Star with SPIRou

Determination of fundamental parameters of stars impacts all fields of astrophysics, from galaxy evolution to constraining the internal structure of exoplanets. This paper presents a detailed spectroscopic analysis of Barnard’s star (otherwise known as Gl 699) that compares an exceptionally high-quality (an average signal-to-noise ratio of ∼1000 in the entire domain), high-resolution near-infrared (NIR) spectrum taken with Canada-France-Hawaii Telescope/SPIRou to PHOENIX-ACES stellar atmosphere models. The observed spectrum shows thousands of lines not identified in the models with a similarly large number of lines present in the model but not in the observed data. We also identify several other caveats, such as continuum mismatch, unresolved contamination, and spectral lines significantly shifted from their expected wavelengths; all of these can be a source of bias for the determination of abundance. Out of >104 observed lines in the NIR that could be used for chemical spectroscopy, we identify a short list of a few hundred lines that are reliable. We present a novel method for determining the effective temperature (T eff) and overall metallicity of slowly rotating M dwarfs that uses several groups of lines as opposed to bulk spectral fitting methods. With this method, we infer T eff = 3231 ± 21 K for Barnard's star, consistent with the value of 3238 ± 11 K inferred from the interferometric method. We also provide measurements of the abundance of 15 different elements for Barnard's star, including the abundances of four elements (K, O, Y, Th) never reported before for this star. This work emphasizes the need to improve current atmosphere models to fully exploit the NIR domain for chemical spectroscopy analysis.

Combination of Chemical and Physical Cancer Therapeutics Developed with Microcapsules Made of κ-Casein and Gold Nanoparticles in the Presence of Drug-Loaded Phase Change Materials.

Tumor heterogeneity requires development of an anticancer system equipped with both chemical and physical therapeutics to eradicate cancer exhibiting drug resistance and clonal evolution into diverse tumor cells. Assortment of various toxic components into one platform without compromising their individual toxic activity remains a formidable task. Herein, a novel drug delivery system (DDS) exerting potent cytotoxicity toward cancer cells was fabricated with gold nanoparticles (AuNPs) coated with an innocuous self-assembly protein of κ-casein (κC). Pickering emulsions of the κC-AuNP conjugates in the presence of chloroform inside led to the κC-AuNP microcapsules being stabilized via robust β-sheet formation between κC molecules located on the single-layered shell made of κC-AuNPs. Phase change material (PCM) comprising a eutectic mixture of lauric acid and myristic acid with the melting point of 43 °C was encapsulated in the presence of a hydrophilic anticancer drug of doxorubicin (Dox), in which the PCM has played multiple functions such as drug-holding matrix and thermoresponsive gating material for drug release. Once liberated with the heat generated by the AuNPs upon a near-infrared (NIR) irradiation at 808 nm, the PCM by itself exhibited not only chemical cytotoxicity but also physical toxic effects such as membrane destabilization of the cells and a possible cellular fixative effect toward cancer cells by the solidified PCM at body temperature. Moreover, the PCM was shown to facilitate the intranuclear localization of Dox. As a result, the DDS comprising κC-AuNP microcapsules containing Dox-loaded PCM was demonstrated to show a powerful anticancer effect upon the NIR irradiation, which unleashed several toxic agents such as Dox, PCM, heat-generating AuNPs, and tissue-immobilizing solidified PCM. Therefore, the κC-AuNP microcapsules would serve as an anticancer system into which diverse chemical and physical therapeutic agents could be combined to effectively remove the heterogeneous and drug resistant cancer cells.

Persistent Luminescence Lifetime-Based Near-Infrared Nanoplatform via Deep Learning for High-Fidelity Biosensing of Hypochlorite.

In light of deep tissue penetration and ultralow background, near-infrared (NIR) persistent luminescence (PersL) bioprobes have become powerful tools for bioapplications. However, the inhomogeneous signal attenuation may significantly limit its application for precise biosensing owing to tissue absorption and scattering. In this work, a PersL lifetime-based nanoplatform via deep learning was proposed for high-fidelity bioimaging and biosensing in vivo. The persistent luminescence imaging network (PLI-Net), which consisted of a 3D-deep convolutional neural network (3D-CNN) and the PersL imaging system, was logically constructed to accurately extract the lifetime feature from the profile of PersL intensity-based decay images. Significantly, the NIR PersL nanomaterials represented by Zn1+xGa2-2xSnxO4: 0.4 % Cr (ZGSO) were precisely adjusted over their lifetime, enabling the PersL lifetime-based imaging with high-contrast signals. Inspired by the adjustable and reliable PersL lifetime imaging of ZGSO NPs, a proof-of-concept PersL nanoplatform was further developed and showed exceptional analytical performance for hypochlorite detection via a luminescence resonance energy transfer process. Remarkably, on the merits of the dependable and anti-interference PersL lifetimes, this PersL lifetime-based nanoprobe provided highly sensitive and accurate imaging of both endogenous and exogenous hypochlorite. This breakthrough opened up a new way for the development of high-fidelity biosensing in complex matrix systems.