Near-infrared Illumination Research Articles

Chiral CuxCoyS Nanoparticles under Magnetic Field and NIR Light to Eliminate Senescent Cells

AbstractIn the present study, chiral CuxCoyS nanoparticles (NPs) were developed to selectively induce apoptosis of senescent cells using both an alternating magnetic field (AMF) and near infrared (NIR) photon illumination. The chiral effects on living cells were investigated, and d‐CuxCoyS NPs showed about 2.5 times higher of internalized ability than l‐NPs. By modifying beta 2 macroglobulin (MG), senescent cells were effectively eliminated by d‐CuxCoyS NPs without damaging the activities of normal cells under AMF and photon illumination. Compared to the individual application of NIR illumination and AMF, their synergistic effect induced the production of caspase‐3 with a much shorter treatment time and higher efficiency due to the more serious photon‐induced cellular redox and mechanical damage of cellular skeleton. Moreover, the developed strategy was successfully used to remove senescent cells in vivo. This study developed a controllable way of regulating cell activities using chiral NPs, which will provide a valuable way for treating diseases and promoting health.

Toward understanding and optimizing Au-hyperdoped Si infrared photodetectors

Au-hyperdoped Si absorbs near-infrared (NIR) light and recent efforts have successfully produced Si-based NIR photodetectors based on this property but with low detection efficiencies. Here, we investigate the differences between the optical and photocurrent properties of Au-hyperdoped Si. Although defects introduced during fabrication of these materials may not exhibit significant optical absorption, we show that they can produce a measurable photocurrent under NIR illumination. Our results indicate that the optimal efficiency of impurity-hyperdoped Si materials is yet to be achieved and we discuss these opportunities in light of our results. This work thus represents a step forward in demonstrating the viability of using impurity-hyperdoped Si materials for NIR photodetection.

Near infrared-driven photoelectrochemical water splitting: Review and future prospects

Photoelectrochemical (PEC) water splitting supplies an environmentally friendly, sustainable approach to generating renewable hydrogen fuels. Oxides semiconductors, e.g. TiO2, BiVO4, and Fe2O3, have been widely developed as photoelectrodes to demonstrate the utility in PEC systems. Even though significant effort has been made to increase the PEC efficiency, these materials are still far from practical applications. The main issue of metal oxides is the wide bandgap energy that hinders effective photons harvesting from sunlight. In solar spectrum, over 40% of the energy is located in the near-infrared (NIR) region. Developing sophisticated PEC systems that can be driven by NIR illumination is therefore essential. This review gives a concise overview on PEC systems based on the use of NIR-driven photoelectrodes. Promising candidates as efficient yet practical NIR-responsive photoelectrodes are suggested and discussed. Future outlooks on the advancement of PEC water splitting are also proposed.

Photochemical Activity of Black Phosphorus for Near‐Infrared Light Controlled In Situ Biomineralization

The photochemical activity of black phosphorus (BP) in near‐infrared (NIR) light controlled in situ biomineralization is investigated. Owing to the excellent NIR absorption, irradiation with NIR light not only promotes degradation of BP into PO4 3−, but also enhances the chemical activity to accelerate the reaction between PO4 3− and Ca2+ and promote in situ biomineralization. Mineralization of hydrogels is demonstrated by the preparation of BP incorporated hydrogel (BP@Hydrogel) which delivers greatly improved biomineralization performance under NIR illumination. The biomineralization process which can be controlled by modulating the light irradiation time and location has a high potential in controlling the mechanical properties and osteoinductive ability in tissue engineering. This study also provides insights into the degradation, photochemical activity, and new biological/biomedical applications of BP.

A Magnetically Navigated Microcannula for Subretinal Injections.

Retinal disorders, including age-related macular degeneration, are leading causes of vision loss worldwide. New treatments, such as gene therapies and stem cell regeneration, require therapeutics to be introduced to the subretinal space due to poor diffusion to the active component of the retina. Subretinal injections are a difficult and risky surgical procedure and have been suggested as a candidate for robot-assisted surgery. We propose a different actuation paradigm to existing robotic approaches using remote magnetic navigation to control a flexible microcannula. A flexible cannula allows for high dexterity and considerable safety advantages over rigid tools, while maintaining the benefits of micrometer precision, hand tremor removal, and telemanipulation. The position of the cannula is tracked in real-time using near-infrared tip illumination, allowing for semi-automatic placement of the cannula and an intuitive user interface. Using this tool, we successfully performed several subretinal injections in ex-vivo porcine eyes under both microscope and optical coherence tomography visualization.

Robust Iris Presentation Attack Detection Fusing 2D and 3D Information

Diversity and unpredictability of artifacts potentially presented to an iris sensor calls for presentation attack detection methods that are agnostic to specificity of presentation attack instruments. This article proposes a method that combines two-dimensional and three-dimensional properties of the observed iris to address the problem of spoof detection in case when some properties of artifacts are unknown. The 2D (textural) iris features are extracted by a state-of-the-art method employing Binary Statistical Image Features (BSIF) and an ensemble of classifiers is used to deliver 2D modality-related decision. The 3D (shape) iris features are reconstructed by a photometric stereo method from only two images captured under near-infrared illumination placed at two different angles, as in many current commercial iris recognition sensors. The map of normal vectors is used to assess the convexity of the observed iris surface. The combination of these two approaches has been applied to detect whether a subject is wearing a textured contact lens to disguise their identity. Extensive experiments with NDCLD'15 dataset, and a newly collected NDIris3D dataset show that the proposed method is highly robust under various open-set testing scenarios, and that it outperforms all available open-source iris PAD methods tested in identical scenarios. The source code and the newly prepared benchmark are made available along with this article.

An Integrated Enhancement Solution for 24-Hour Colorful Imaging

The current industry practice for 24-hour outdoor imaging is to use a silicon camera supplemented with near-infrared (NIR) illumination. This will result in color images with poor contrast at daytime and absence of chrominance at nighttime. For this dilemma, all existing solutions try to capture RGB and NIR images separately. However, they need additional hardware support and suffer from various drawbacks, including short service life, high price, specific usage scenario, etc. In this paper, we propose a novel and integrated enhancement solution that produces clear color images, whether at abundant sunlight daytime or extremely low-light nighttime. Our key idea is to separate the VIS and NIR information from mixed signals, and enhance the VIS signal adaptively with the NIR signal as assistance. To this end, we build an optical system to collect a new VIS-NIR-MIX dataset and present a physically meaningful image processing algorithm based on CNN. Extensive experiments show outstanding results, which demonstrate the effectiveness of our solution.

Bolometric Effect Enhanced Ultrafast Graphene Based Do-It-Yourself Wearable Respiration Sensor for Personal Healthcare Monitoring

The report demonstrates the Near Infrared (NIR) illuminated enhanced breath sensor utilizing direct writing of solvent free graphene pencil on biodegradable cellulose paper to monitor different respiration patterns and rate for non-invasive personal healthcare monitoring. Various breath patterns such as deep, slow and fast breathing were tested and interestingly the fabricated sensor was able to distinguish the pattern based on the frequency and the amplitude of current peaks obtained. Also, the fabricated sensor was able to identify the hydration level of the individual where in 25–35 % decrement in the sensor current value was observed when the measurements were performed after consuming water. To enhance the desorption process of water molecules, breath sensing was performed under NIR illumination where the photo response was bolometric in nature which results in the faster desorption process due to the heat generated. The fall time observed under NIR illumination was 1.32sec and without NIR illumination was 2.01 sec suggesting a 34% improvement in the performance of the fabricated sensor. The change in the current under human breath exhalation is due to the electron transfer process and swelling of the graphene sheets. Detailed conduction mechanism of graphene under NIR illumination is presented suggesting the combination of both bolometric nature and direct photoconductivity with the former predominantly affecting the conductivity. The successful demonstration of such low-cost, do it yourself wearable enhanced respiration sensor is a major step ahead in the non-invasive personal healthcare monitoring and hold potential for commercialization.

Upconversion Nonlinear Structured Illumination Microscopy.

Video-rate super-resolution imaging through biological tissue can visualize and track biomolecule interplays and transportations inside cellular organisms. Structured illumination microscopy allows for wide-field super resolution observation of biological samples but is limited by the strong extinction of light by biological tissues, which restricts the imaging depth and degrades its imaging resolution. Here we report a photon upconversion scheme using lanthanide-doped nanoparticles for wide-field super-resolution imaging through the biological transparent window, featured by near-infrared and low-irradiance nonlinear structured illumination. We demonstrate that the 976 nm excitation and 800 nm upconverted emission can mitigate the aberration. We found that the nonlinear response of upconversion emissions from single nanoparticles can effectively generate the required high spatial frequency components in the Fourier domain. These strategies lead to a new modality in microscopy with a resolution below 131 nm, 1/7th of the excitation wavelength, and an imaging rate of 1 Hz.

Light‐Induced Chiral Iron Copper Selenide Nanoparticles Prevent β‐Amyloidopathy In Vivo

The accumulation and deposition of β-amyloid (Aβ) plaques in the brain is considered a potential pathogenic mechanism underlying Alzheimer's disease (AD). Chiral l/d-Fex Cuy Se nanoparticles (NPs) were fabricated that interfer with the self-assembly of Aβ42 monomers and trigger the Aβ42 fibrils in dense structures to become looser monomers under 808 nm near-infrared (NIR) illumination. d-Fex Cuy Se NPs have a much higher affinity for Aβ42 fibrils than l-Fex Cuy Se NPs and chiral Cu2-x Se NPs. The chiral Fex Cuy Se NPs also generate more reactive oxygen species (ROS) than chiral Cu2-x Se NPs under NIR-light irradiation. In living MN9D cells, d-NPs attenuate the adhesion of Aβ42 to membranes and neuron loss after NIR treatment within 10 min without the photothermal effect. In-vivo experiments showed that d-Fex Cuy Se NPs provide an efficient protection against neuronal damage induced by the deposition of Aβ42 and alleviate symptoms in a mouse model of AD, leading to the recovery of cognitive competence.

MUTE-SIM: multiphoton up-conversion time-encoded structured illumination microscopy

Multiphoton microscopy (MPM) plays important role in biological imaging for its low scattering nature, yet it typically requires high illumination intensity. Although time-stretch of the ultrashort pulse can achieve ultrahigh speed scanning and deep penetration, the near-infrared illumination yields a compromised resolution because of its long wavelength. Here, by combining structured illumination with up-conversion materials, a multiphoton up-conversion time-encoded structured illumination microscopy (MUTE-SIM) with the scanning rate of 50 MHz is developed, which overcomes the limitation on the resolution. The resolution limit of near-infrared light is surpassed by a factor of 223.3% with low illumination intensity. This imaging strategy provides an ultrafast, low intensity, super-resolution MPM approach imaging, which has great potential in deep-tissue with high spatial resolution.

Light-Mediated Shape Transformation of a Self-Rolling Nanocomposite Hydrogel Tube.

Self-rolling of a planar hydrogel sheet represents an advanced approach for fabricating a tubular construct, which is of significant interest in biomedicine. However, the self-rolling tube is usually lacking in remote controllability and requires a relatively tedious fabrication procedure. Herein, we present an easy and controllable approach for fabricating self-rolling tubes that can respond to both magnetic field and light. With the introduction of magnetic nanorods in a hydrogel precursor, a strain gradient is created across the thickness of the formed hydrogel sheet during the photopolymerization process. After the removal of the strain constraint, the nanocomposite sheet rolls up spontaneously. The self-rolling scenario of the sheet can be tuned by varying the sheet geometry and the magnetic nanorod concentration in the hydrogel precursor. The nanocomposite hydrogel tube translates in the presence of a magnetic field and produces heat upon a near-infrared (NIR) light illumination by virtue of the magnetic and photo-thermal properties of the magnetic nanorods. The self-rolling tube either opens up or expands its diameter under NIR light irradiation depending on the number of rolls in the tube. With the use of a thermo-responsive hydrogel material, we demonstrate the magnetically guided motion of the chemical-bearing nanocomposite hydrogel tube and its controlled chemical release through its light-mediated deformation. The approach reported herein is expected to be applicable to other self-rolling polymer-based dry materials, and the nanocomposite hydrogel tube presented in this work may find potential applications in soft robot and controlled release of drug.

A Genome-Editing Nanomachine Constructed with a Clustered Regularly Interspaced Short Palindromic Repeats System and Activated by Near-Infrared Illumination.

The RNA-guided CRISPR/Cas9 system is a powerful genome-editing technology with broad applications. Improving delivery efficiency and controllable activity of the CRISPR/Cas9 system is an area of intense research. We report the design, construction, and application of a CRISPR/Cas9 nanomachine (LACM), activated by a near-infrared (NIR) laser, which enables efficient delivery of single-guide RNA (sgRNA) into living cells and achieves controlled release of the sgRNA for the CRISPR/Cas9 activity. The LACM was constructed using a gold nanorod (AuNR) as a carrier that was decorated with dozens of protector DNAs stably hybridizing with the target binding domain of sgRNA. The DNA assembly on the AuNR protected the sgRNA. Irradiation with a NIR laser generated heat on the AuNR, resulting in controlled release of sgRNA, which guided the CRISPR/Cas9 genome editing. Successful editing of the EGFP and EMX1 genes in A549 and HEK293T cells, as well as knocking down of the PLK1 gene to induce apoptosis of the target cells, highlights the promising potential of the LACM for diverse applications.

Self-Powered Visible-Invisible Multiband Detection and Imaging Achieved Using High-Performance 2D MoTe2/MoS2 Semivertical Heterojunction Photodiodes.

Two-dimensional(2D) van der Waals (vdW) heterostructures herald new opportunities for conducting fundamental studies of new physical/chemical phenomena and developing diverse nanodevice applications. In particular, vdW heterojunction p-n diodes exhibit great potential as high-performance photodetectors, which play a key role in many optoelectronic applications. Here, we report on 2D MoTe2/MoS2 multilayer semivertical vdW heterojunction p-n diodes and their optoelectronic application in self-powered visible-invisible multiband detection and imaging. Our MoTe2/MoS2 p-n diode exhibits an excellent electrical performance with an ideality factor of less than 1.5 and a high rectification (ON/OFF) ratio of more than 104. In addition, the photodiode exhibits broad spectral photodetection capability over the range from violet (405 nm) to near-infrared (1310 nm) wavelengths and a remarkable linear dynamic range of 130 dB within an optical power density range of 10-5 to 1 W/cm2 in the photovoltaic mode. Together with these favorable static photoresponses and electrical behaviors, very fast photo- and electrical switching behaviors are clearly observed with negligible changes at modulation frequencies greater than 100 kHz. In particular, inspired by the photoswitching results for periodic red (638 nm) and near-infrared (1310 nm) illumination at 100 kHz, we successfully demonstrate a prototype self-powered visible-invisible multiband image sensor based on the MoTe2/MoS2 p-n photodiode as a pixel. Our findings can pave the way for more advanced developments in optoelectronic systems based on 2D vdW heterostructures.

Infrared Illumination and Subcutaneous Venous Network: Can it be of Help for the Study of CEAP C1 Limbs?

The subcutaneous venous network (SVN) is difficult to see with the naked eye. Near infrared illumination (NIr-I) claims to improve this. The aims of this observational study were to investigate whether there are differences between the different methods; to quantify the length and diameter of SVNs; and to confirm if they differ between C0A and C1 CEAP limbs. In total, 4 796 images, half of them from the visible spectrum (VS) and the other half from the nearninfrared spectrum (NIrS), belonging to 109 females (C0A: n=50; C1 CEAP: n=59) were used to establish the morphological characteristics of the SVN by visual analysis. With Photoshop CS4, SVN diameters and lengths were obtained by digital analysis of 3 052 images, once the images of whole extremities were excluded. On NIr-I, the diameters, trajectories, and colouration of SVNs of C1 limbs appeared more irregular than SVNs of C0A limbs. Compared with the VS images, NIr-I allowed visualisation of a greater length of the SVN in both groups (p<.010). This capacity varied from 2.6±0.9 times (C1) to 16.2±11.9 (C0A). While the SVN length seen in the VS images from C1 limbs was greater than observed in C0A limbs (p<.001), differences between NIr-I images only existed in the lateral part of the lower leg (p=.016). With NIr-I, the median diameter of the C1 CEAP SVN veins was 5.8mm (interquartile range [IQR] 4.3-7.5mm), while the median diameter in C0A SVN limbs was 2.6mm (IQR 2.0-3.6mm) (p<.001). The NIr-I reveals the characteristics of the SVN better than the naked eye. Further studies are required to determine the significance of the changes in the SVN in C0A and C1 limbs, and the factors causing them.

Growth of SiGeSn Thin Films Using Simplified PECVD Reactor towards NIR Sensor Devices

SiGeSn is a promising group IV semiconducting alloy to advance the field of silicon photonics. The bandgap of the alloy can be tuned by varying its’ Si and Sn concentrations for developing devices in the near infrared (NIR) range. The growth of the material using a cost-effective process is still challenging due to various obstacles. In this work, a simplified in-house assembled plasma enhanced chemical vapor deposition (PECVD) reactor was used to deposit SiGeSn films. Plasma allows for the use of commercially available precursors (GeH4, Si2H6 and SnCl4) while providing high dissociation and deposition growth rates. Polycrystalline films were deposited at susceptor temperatures in the range of 350 °C–450 °C to study the effect of process temperature on the Sn segregation and Sn incorporation in the films. Selective area growth (SAG) of SiGeSn films was also achieved by depositing films on patterned silicon substrates. The composition of the films was characterized by Rutherford Back Scattering while the structural and optical properties of the films were analyzed using X-ray diffraction and Raman spectroscopy. Selectively grown films were fabricated into basic test photodiodes and evaluated for electrical performance under NIR illumination.

Construction of a near-infrared responsive upconversion nanoplatform against hypoxic tumors via NO-enhanced photodynamic therapy.

Photodynamic therapy (PDT) has been extensively used to treat cancer and other malignant diseases because it can offer many unique advantages over other medical treatments such as less invasive, fewer side effects, lower cost, etc. Despite great progress, the efficiency of PDT treatment, as an oxygen-dependent therapy, is still limited by the hypoxic microenvironment in the human tumor region. In this work, we have developed a near-infrared (NIR) activated theranostic nanoplatform based on upconversion nanoparticles (UCNPs), which incorporates PDT photosensitizer (curcumin) and NO donor (Roussin's black salt) in order to overcome hypoxia-associated resistance by reducing cellular respiration with NO presence in the PDT treatment. Our results suggest that the photo-released NO upon NIR illumination can greatly decrease the oxygen consumption rate and hence increase singlet oxygen generation, which ultimately leads to an increased number of cancer cell deaths, especially under hypoxic condition. It is believed that the methodology developed in this study enables to relieve the hypoxia-induced resistance in PDT treatment and also holds great potential for overcoming hypoxia challenges in other oxygen-dependent therapies.

Dual-stimuli responsive nanotheranostics for mild hyperthermia enhanced inhibition of Wnt/β-catenin signaling

Wnt/β-catenin signaling cascade is highly associated with tumorigenesis and progression of various cancers. Targeting Wnt/β-catenin signaling exhibits a promising way for cancer treatment. Herein, dual-stimuli responsive nanotheranostics was synthesized, which was composed of melanin coated magnetic nanoparticles (MMNs) and Wnt signaling inhibitor obatoclax (OBX) for multimodality imaging guided mild hyperthermia-enhanced chemotherapy. The MMNs could be used as contrast agents for magnetic resonance imaging (MRI) and photoacoustic imaging (PAI) guided photothermal therapy. In addition, OBX-loaded MMNs (OBX-MMNs) were specific response to both pH changes and near-infrared (NIR) light illumination, which could trigger OBX release. Most intriguingly, tumor tissue accumulation and cellular internalization of this nanotheranostics could be dramatically enhanced through mild hyperthermia generated by laser-irradiated MMNs. Laser irradiation exhibited efficient chemotherapeutic outcome through enhancing OBX-mediated inhibition of the Wnt/β-catenin signaling. Our results indicated the as-prepared OBX-MMNs hold great potential for MR/PA dual-modal imaging guided mild hyperthermia-enhanced chemotherapy.

Focusing light inside live tissue using reversibly switchable bacterial phytochrome as a genetically encoded photochromic guide star.

Focusing light deep by engineering wavefronts toward guide stars inside scattering media has potential biomedical applications in imaging, manipulation, stimulation, and therapy. However, the lack of endogenous guide stars in biological tissue hinders its translations to in vivo applications. Here, we use a reversibly switchable bacterial phytochrome protein as a genetically encoded photochromic guide star (GePGS) in living tissue to tag photons at targeted locations, achieving light focusing inside the tissue by wavefront shaping. As bacterial phytochrome-based GePGS absorbs light differently upon far-red and near-infrared illumination, a large dynamic absorption contrast can be created to tag photons inside tissue. By modulating the GePGS at a distinctive frequency, we suppressed the competition between GePGS and tissue motions and formed tight foci inside mouse tumors in vivo and acute mouse brain tissue, thus improving light delivery efficiency and specificity. Spectral multiplexing of GePGS proteins with different colors is an attractive possibility.

Effect of Top Channel Thickness in Near Infrared Organic Phototransistors with Conjugated Polymer Gate-Sensing Layers

Here, we report the thickness effect of top channel layers (CLs) on the performance of near infrared (NIR)-detecting organic phototransistors (OPTRs) with conjugated polymer gate-sensing layers (GSLs). Poly(3-hexylthiophene) (P3HT) was employed as a top CL, while poly[{2,5-bis-(2-octyldodecyl)-3,6-bis-(thien-2-yl)-pyrrolo[3,4-c]pyrrole-1,4-diyl}-co-{2,2′-(2,1,3-benzothiadiazole)-5,5′-diyl}] (PODTPPD-BT) was used as a GSL. The thickness of P3HT CLs was varied from 10 to 70 nm. Three different wavelengths of NIR light (λ = 780, 905, and 1000 nm) were introduced and their light intensity was fixed to 0.27 mW cm−2. Results showed that all fabricated devices exhibited typical p-channel transistor behaviors and the highest drain current in the dark was obtained at the P3HT thickness (t) of 50 nm. The NIR illumination test revealed that the NIR photoresponsivity (RC) of GSL-OPTRs could be achieved at t = 50 nm irrespective of the NIR wavelength. The maximum RC of the optimized devices (t = 50 nm) reached ca. 61% at λ = 780 nm and ca. 47% at λ = 1000 nm compared to the theoretical maximum photoresponsivity.