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Thermoresponsive polymers incorporated with photo-absorbing agents have been widely utilized for controlled drug delivery using light as an external stimulus. However, previously developed thermoresponsive drug carriers have disadvantages such as low biocompatibility and implantation failure. In the present study, gold nanorods (GNRs)-encapsulated poly(N-vinyl caprolactam) (PVCL) (GNR-PVCL) microparticles were synthesized by the stop-flow lithography (SFL) method. The SFL method enabled the fabrication of near-infrared (NIR) light-responsive GNR-PVCL microparticles of uniform size, which can allow localized injection. Doxorubicin (DOX) was encapsulated into GNR-PVCL microparticles to achieve NIR light-responsive anticancer therapy. DOX-loaded GNR-PVCL (DOX-GNR-PVCL) microparticles exhibited NIR light-triggered drug release due to the photothermal effect of GNRs, which increases the local temperature above the volume phase transition temperature of GNR-PVCL microparticles. In addition, DOX-GNR-PVCL exhibited controlled DOX release in response to the periodic irradiation of NIR light. Moreover, we demonstrated the efficient intracellular release of DOX upon NIR light exposure, and thus, NIR light-responsive anticancer activity. This study demonstrates that DOX-GNR-PVCL microparticles have significant potential as implantable drug carriers enabling NIR light-triggered drug release.

The solar spectral converters mainly involve the energy transfer between two codoped ions. Here, we report a series of Ce3+, Cr3+, Ln3+ (Ln = Yb, Nd, Er) tridoped Gd3Sc2Ga3O12 (GSGO) phosphors with improved absorption and increasing near infrared (NIR) emission. We observed the multiple energy transfer behaviors of Cr3+→Ln3+, Ce3+→Ln3+, Ce3+→Cr3+, and Ce3+→Cr3+→Ln3+ in GSGO matrix. When Ce3+ is introduced into the GSGO:Cr3+,Ln3+ phosphors, the energy transfer of Ce3+→Cr3+→Ln3+ has been realized by utilizing the energy transfer bridge of the Cr3+ ion. Consequently, GSGO:Ce3+,Cr3+,Ln3+ can absorb almost all ultraviolet and visible (UV–Vis) light and produce strong NIR light thanks to the synergistic effect of Ce3+→Cr3+→Ln3+, improving the photovoltaic conversion efficiency of c-Si solar cells. Our results show that the prepared GSGO:Ce3+,Cr3+,Ln3+ have the potential application in the solar spectral material for c-Si solar cells. Meanwhile, the strategy of multiple energy transfers gives a new way to design the spectral conversion materials with wider absorption for c-Si solar cells.

Both of carbon dioxide (CO2) and near-infrared (NIR) light as triggers for non-invasive remotely control are attracting wide attentions due to their good biocompatibility and easy operation. Here, CO2/NIR light dual controlled nanoparticles are proposed to remotely regulate the unzipping of dsDNA by using imidazole functionalized conjugated polymer nanoparticles (imidazole-CPNs). The dsDNA successfully coats on the shell of imidazole-CPNs to form imidazole-CPNs/dsDNA assembly due to intensively electrostatic interaction triggered by CO2. Furthermore, the unzipping process of dsDNA is remotely controlled by NIR light based on the photothermal effect, and it can be readily monitored by the fluorescence intensity of ethidium bromide (EB) and CD spectra of dsDNA. Thus, dual stimulation responsive imidazole-CPNs effectively control dsDNA unzipping under CO2 stimulus and NIR light, promising a new direction in the biological applications of DNA, such as the treatments of diseases caused by gene duplication abnormality.

Owing to the structural controllability, pore modification and unique semiconductor property of metal-organic frameworks (MOFs), the investigation on MOFs as efficient photocatalysts for hydrogen production from water splitting under UV, visible or even NIR light irradiation have made great progress. In this review, we systematically summarized the recent advances of MOFs-based photocatalysts for hydrogen production from water, and divided them into three categories: MOFs, MOFs composites and MOFs-derived photocatalysts. The high hydrogen production efficiency and possible hydrogen production mechanism of MOFs-based photocatalysts were analyzed in detail. A brief perspective was given to achieve high effective and stable MOFs-based materials for photolysis of water, providing suggestions to explore new and efficient MOFs-based photocatalysts.

A novel light-responsive nanovalve is facilely prepared on mesoporous silica (mSiO2) coated upconversion nanoparticles (UCNP) through modification of photo-cleavagable pyrenemethyl ester (Py) molecules on its surface. These Py molecules can associate with β-cyclodextrin (β-CD) molecules as gatekeepers to block the mSiO2 pore channels and entrap the loaded drugs. Upon NIR light irradiation, NIR light is upconverted to ultraviolet (UV) and visible (Vis) light by UCNP, and the modified Py molecules are cleaved by the upconverted UV light leading to the detachment of β-CD gatekeepers to trigger drug release. For the fabrication of a monitoring system, β-CD is covalently conjugated with the fluorescein isothiocyanate (FITC) as drug release indicator (FITC-β-CD). The luminescence resonance energy transfer (LRET) from UCNP to Py/FITC-β-CD before drug release results in the quenching of Vis emission of UCNP while the detachment of Py/FITC-β-CD nanovalves after drug release diminishes the LRET between UCNP and FITC-β-CD which recovers the luminescence of UCNP, the change in luminescence provides a potential capability for one to quantitatively monitor the drug release process. in vitro study shows a remarkable killing ability on HeLa cancer cell of this system.

On-fiber micro-structures are favorable platforms for sensing in aqueous environments. Durable in-liquid operation with NIR light transmitted through fused optical microknot fibers defined on adiabatic tapers is presented in straight versus folded configurations. We suggest and demonstrate two schemes for OMF deployment: folded configuration which is intended for remote sensing, and straight configuration on either hydrophilic or hydrophobic substrate, the latter of which is useful in packaged geometries. We study experimentally the OMF preparation methods in folded, straight on glass surface and straight on PDMS surfaces. The persistent detection of NIR light transmission resonances in the presence of volatile liquid capabilities are experimentally demonstrated in the various configurations.

In vivo noninvasively manipulating biological functions by the mediation of biosafe near infrared (NIR) light is becoming increasingly popular. For these applications, upconversion rare-earth nanomaterial holds great promise as a novel photonic element, and has been widely adopted in optogenetics. In this article, an upconversion optogenetic nanosystem that was promised to achieve autophagy up-regulation with spatiotemporal precision was designed. The implantable, wireless, recyclable, less-invasive and biocompatible system worked via two separated parts: blue light-receptor optogenetics-autophagy upregulation plasmids, for protein import; upconversion rods-encapsulated flexible capsule (UCRs-capsule), for converting tissue-penetrative NIR light into local visible blue light. Results validated that this system could achieve up-regulation of autophagy in vitro (in both HeLa and 293T cell lines) and remotely penetrate tissue (∼3.5 mm) in vivo. Since autophagy serves at a central position in intracellular signalling pathways, which is correlative with diverse pathologies, we expect that this method could establish an upconversion material-based autophagy up-regulation strategy for fundamental and clinical applications.

Background Photobiomodulation (PBM) with red and near-infrared light (NIR) –also known as Low-Level Light Therapy–is a low risk, inexpensive treatment–based on non-retinal exposure–under study for several neuropsychiatric conditions. The aim of this paper is to discuss the proposed mechanism of action and to perform a systematic review of pre-clinical and clinical studies on PBM for major depressive disorder (MDD). Methods A search on MEDLINE and EMBASE databases was performed in July 2017. No time or language restrictions were used. Studies with a primary focus on MDD and presenting original data were included (n = 17). References on the mechanisms of action of PBM also included review articles and studies not focused on MDD. Results Red and NIR light penetrate the skull and modulate brain cortex; an indirect effect of red and NIR light, when delivered non-transcranially, is also postulated. The main proposed mechanism for PBM is the enhancement of mitochondrial metabolism after absorption of NIR energy by the cytochrome C oxidase; however, actions on other pathways relevant to MDD are also reported. Studies on animal models indicate a benefit from PBM that is comparable to antidepressant medications. Clinical studies also indicate a significant antidepressant effect and good tolerability. Limitations Clinical studies are heterogeneous for population and treatment parameters, and most lack an appropriate control. Conclusions Preliminary evidence supports the potential of non-retinal PBM as a novel treatment for MDD. Future studies should clarify the ideal stimulation parameters as well as the overall efficacy, effectiveness and safety profile of this treatment.

The low-usage of solar energy and the sluggish separation efficiency of the photogenerated electrons/holes pairs are the obstacles in the practical application of photocatalysts. The integration of upconversion and Z-scheme heterojunction is expected to break the barriers to achieve the efficient charge separation and broaden near-infrared light absorption. Herein, an effective indirect Z scheme AgInS2/In2S3 heterostructure with carbon quantum dots (CQDs, as the electron conduction medium) and Lu3NbO7:Yb, Ho (as upconversion function) has been successfully synthesized. Consequently, the Lu3NbO7: Yb, Ho/CQDs/AgInS2/In2S3 heterostructure exhibited superior photocatalytic activities for Cr(VI) reduction and H2O2 production, reducing 99.9% of Cr(VI)(20 ppm, 15 min) and 78.5% of Cr(VI) (40 ppm, 30 min) with visible light irradiation as well as 94.0% of Cr(VI) (20 ppm, 39 min) under NIR light irradiation. Simultaneously, the heterostructure could generate 902.9 μM H2O2 for 5 h under visible light irradiation. The intensive photocatalytic properties could primarily be attributed to the boosted light absorption capacity, the improved solar-to-energy conversion by the remarkable upconversion capacity of Lu3NbO7: Yb, Ho/CQDs and the faster charge transfer through a Z-schematic pathway. This work is anticipated to open a novel “window” for designing the efficient photocatalysts by coupling of Lu3NbO7: Yb, Ho and CQDs.

The BiOBr:Yb3+,Er3+/g-C3N4 (BYE/CN) p-n junction photocatalysts were successfully fabricated by a stepwise method. Experimental results show that Er3+/Yb3+ were successfully doped into BiOBr lattice. As-obtained BYE/CN exhibited strong NIR light absorption and upconversion emission from NIR to UV–visible due to the upconversion transition of Er3+. The p-n junction was constructed due to the appropriate alignment band structure of BYE and g-C3N4, which distinctly suppresses the recombination rate of electron-hole pairs. Compared with pure BYE and CN, as-synthesized BYE/CN samples exhibit distinctly improved photoactivities under the irradiation of visible or NIR light, which can be attributed to the upconversion effect of Er3+ and the construction of p-n junction. This result may provides a promising system for efficient harvest of the NIR light, which will contribute to the utilization of solar energy in the future.

Photoplethysmography has been routinely used for health monitoring in the past decades. Even though in daily medical practice, photoplethysmograms (PPGs) are recorded at red and near infra-red light (rPPGs), during the last decade, PPGs obtained at green light (gPPGs) have been widely used in wearable devices, such as wristbands and smartwatches, thus providing highly usable and accessible daily health monitoring. It is well recognized that PPG signals obtained at NIR light contain sufficient information about a person's health; furthermore, they are well-studied and highly complex. By contrast, green light PPGs have not been sufficiently studied; thus, it is not clear whether the provided information is as valuable as that obtained by rPPGs, as green light photoplethysmography is formed at papillary dermis and higher skin levels. However, the gPPG signal is recognized to be more robust to motion artifacts compared with rPPGs. As rPPG dynamics has been recognized as chaotic, this study is aimed at investigating the properties of gPPGs and compare them with those of rPPGs to determine whether gPPG dynamics is chaotic as well. The motivation for this question was not only to investigate whether gPPGs can be used for the same range of applications as rPPGs but also to obtain insight into whether the complexity of rPPGs is solely due to processes in deeper layers of the tissue or it is influenced by the higher-skin layers processes that create gPPGs. The obtained results demonstrated that gPPGs, as well as rPPGs, are chaotic, which implies that processes in the upper layers create chaos in PPG data, whereas the contribution of arterial blood volume changes is not completely clear.

Rare-earth doped upconversion nanophosphors (UCNPs), which convert low energy near-infrared (NIR) photons into high energy photons such as ultraviolet, visible light and NIR light, have found various applications in optical bioimaging. In this review article, we summarize recent advances in the synthesis and applications of UCNPs achieved by us and other groups in the past few years. The approaches for the synthesis of UCNPs are presented, with an emphasis on the role of green chemistry in the advancement of this field, followed by a focused overview on their latest applications in optical bioimaging from subcellular structures through cells to living animals. Challenges and opportunities for the use of UCNPs in biomedical diagnosis and therapy are discussed.

Driven by the growing demand for healthcare and point-of-care test applications, next-generation diagnostic tools of diseases require sensing platforms that enable rapid, quantitative readout of analytes with excellent specificity and sensitivity. Although label-free detection permits simplicity, flexibility and high specificity, it has usually poor throughput, limited sensitivity and requires professional instrumentation. Label-based detection using optical labels overcomes many of these drawbacks and has been demonstrated to be an effective alternative for improved sensing performances. The current research focus has been directed towards innovating high-performance optical labels for ultrasensitive biosensing and disease diagnostics in place of conventional optical labels. Surface-enhanced Raman scattering (SERS) labels have proven to be excellent labels for biosensing because of their merits in many aspects, such as flexibility, less interference from biological matrices, high photostability, easy multiplex encoding, etc. These fantastic features make SERS labels particularly suitable for ultrasensitive detection of disease biomarkers in body fluids and targeted imaging of diseased cells and tissues, respectively. In this Review, we introduce the design and deployment of SERS labels for ultrasensitive detection, and summarize recent research progress in the development of SERS label-based sensing platforms and their applications in disease biomarker detection, targeted cellular imaging and spectroscopic detection of tumor lesions. First, we will discuss the design principles and comprehensive considerations of SERS labels, and the on-demand integration of functionalities. Next, we introduce the design of SERS sensing platforms on basis of SERS labels for ultrasensitive and selective detection of diverse pathology-related biomarkers, including proteins, nucleic acids, small molecules and inorganic ions. In addition, through the rational incorporation of targeting ligands on SERS labels, novel SERS probes are created for targeting near-infrared (NIR) imaging and spectroscopic detection of tumor, taking advantages of large NIR light penetration depth, high brightness, stability, etc. Our and other research efforts have demonstrated the promising potential of SERS label-based sensing platforms for detection of diverse circulating biomarkers for non-invasive disease diagnostics and deep-tissue spectroscopic detection of tumor. It is believed that this review will motivate further exploration of clinical applications of SERS labels in near future.

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New UV–Vis–NIR light responsive Er/Tm/Yb/Y 2 O 3 -SiC composites are designed by coupling different structured Er/Tm/Yb/Y 2 O 3 upconversion luminescence materials (UCLMs) with 3C-SiC ultrafine nanocrystals (NCs) and explored as an efficient photocatalytic material. The Er/Tm/Yb/Y 2 O 3 UCLMs can convert near-infrared (NIR) light into visible light which can be absorbed by 3C-SiC NCs, thus extend the optical responsive range of the photocatalysts to NIR light region. The structure effect of UCLMs on their upconversion luminescence performance is explored, indicating that the chain-like Er/Tm/Yb/Y 2 O 3 UCLMs display much more preferable luminescence activity than flake-like structure. Compared with pure 3C-SiC NCs, both the two hybrid structures offer excellent performance in catalyzing decomposition of methylene blue (MB) under illumination of NIR light as well as UV–Vis–NIR light. Moreover, the photocatalytic activity of chain-like Er/Tm/Yb/Y 2 O 3 -SiC composites is better than that of the flake-like composites, profiting from the high light absorption efficiency induced by the multiple reflection-absorption effect. It is anticipated that this work provides new insights into the fabrication of photocatalysts with excellent light responses to a broader spectral range.

The "partial matching" between upconversion nanoparticle (UCNP) emission and absorption by photosensitizers (PSs) often leads to a theoretically reduced therapeutic efficiency in UC-based photodynamic therapy (PDT) strategies in which the chosen PSs have limited capabilities and are unable to utilize all the near-infrared-upconverted light. In this study, needle-like SnWO4 nanocrystals (SWs) with a broad UV-vis absorption region were synthesized to solve the problem. After covalent conjugation with UCNPs, all the UCNP-emitted light was effectively absorbed by SWs, triggering the type-I PDT process to activate ROS maxima. The unique nanostructure of the as-formed UCNP-SnWO4 nanohybrids (USWs) also enhanced the receiving light intensities of SW, which further boosted the antitumor efficacy. Meanwhile, the strong X-ray attenuation capacity of both tungsten and tin elements qualified the USWs as excellent radio-sensitizers for radiotherapy (RT) enhancement, which played a complementary role with PDT treatment because PDT-mediated induction arrested the cells in the G0-G1 cell cycle phase, and RT was more damaging toward cells in the G2/M phase. The remarkably enhanced UC-PDT/RT efficiency of USWs was next validated in vitro and in vivo, and the combined NIR light and ionizing irradiation treatment completely suppressed tumor growth, revealing its great potential as an efficient anticancer therapeutic agent against solid tumors.

Transport ions into cells through nanocarrier to achieve ion-interference therapy provides new inspiration for cancer treatment. In this work, a pH-targeted and NIR-responsive NaCl-nanocarrier is prepared using surfactant Vitamin E-O(EG2-Glu) and modified with polydopamine (PDA) and pH-sensitive zwitterionic chitosan (ZWC). The NaCl-nanocarrier is decorated with NH4HCO3 and IR-780 to introduce near-infrared (NIR)-responsive performance and imaging. Once the NaCl-nanocarrier is exposed to NIR laser, the temperature rises rapidly because of the excellent photothermal conversion ability of PDA, then NH4HCO3 is decomposed into NH3 and CO2, which burst the nanocarrier, resulting in Cl− and Na+ “bomb-like” release. This pH-targeted nanocarrier accumulates more at tumor site and when irradiating the site with NIR light, the temperature rises and excessive Cl− and Na+ are released to destroy the ion homeostasis and inhibit tumor growth effectively. Through this strategy, the unique combination of ion interference therapy and photothermal therapy is achieved.

Engineered anaerobic bacteria known as live biotherapeutic products (LBPs) have shown great advances in cancer therapy. One advantage of anaerobic bacteria as drug carrier is that it spontaneously target to tumor and persistently release anti-tumor factors. To realize effective anti-cancer therapeutics, one essential premise is to improve the controllability of treatment. Here, we designed near-infrared (NIR)-light responsive bacteria as anti-tumor agent, which is based on a blue-light responsive module and upconversion nanoparticles. The upconversion nanoparticles converted external NIR light to local blue light to noninvasively activate blue-light responsive module (EL222) in engineered LBPs. The activated LBPs then produce tumor necrosis factor α (TNFα) for precise tumor ablation. In vitro and in vivo results have proven that this engineered NIR-light-responsive bacteria could efficiently inhibit tumor growth. We anticipate that this controllable and safe bacteria-based therapy can facilitate the application of LBPs to accurately and effectively regulate diseases.

Photoactivatable protecting groups (PPGs) or caged compounds are beneficial tools for spatiotemporal controlled release of bioagents, fluorescent probes, polymerization initiators and gasotransmitters such as carbonmonoxide, nitric oxide, and hydrogen sulfide. Most of the reported PPGs absorbs in the UV light, suffers from poor tissue penetrations and undesirable photochemical transformation whereas visible/NIR light has better tissue penetration and less bio autofluorescence and has attracted researchers to develop PPGs activated by visible/NIR light. Thus, visible/NIR light absorbing BODIPY PPGs with easily tunable spectral properties and low phototoxicity are used for non-invasive photorelease of protecting groups. The review will mainly focus on the advance research on the molecular designing, spectroscopic properties, structure activity relationship, discussions of photorelease mechanisms and applications (wherever applicable) of visible/red light absorbing photoactivatable BODIPY fluorophore as PPGs. We strongly believe that this review will present a broad perspective for BODIPY dyes as PPGs and provide guidance to the beginners and young researchers for the rational designing of BODIPY based fluorescent dyes of biological importance.

The increasing emergence of pathogenic bacterial infection have been regarded as urgent threats. Notwithstanding, developing simplified and effective means for accurate bacterial target diagnosis and therapy remains a considerable challenge. Here we report a reasonable method for accurate and rapid theranostic of bacteria by in situ self-assembly strategy. By introducing aqueous gold and zinc ions into E.coli cells, the gold and zinc nanoclusters (NCs) could be spontaneously constructed by utilizing the in situ self-assemble biosynthetic strategy that takes advantage of the unique microenvironment of pathogenic bacteria and efficiently enhanced the uptake of DNA into the bacteria cells in the presence of Herring sperm DNA. The self-assembling biosynthetic approach improved image sensitivity and specificity toward the bacterial and exhibited highly efficient disinfection activities coupled with NIR light irradiation. This may raise the possibility of establishing a unique theranostic nanoplatform that possess great potential for accurate bacteria bioimaging and disinfection.

Lead-free double-perovskite Cs2SnX6 (X = Cl, Br, I) containing Sn4+ is a more stable lead-free photovoltaic material than its homologue CsSnX3. However, its stability in air still affects its application. In this Letter, lead-free inorganic Cs2SnX6 (X = Cl, Br, I) nanocrystals (NCs) were synthesized by a hot injection method and in-situ loaded into mesoporous SiO2. With the change of halogen content, the PL emission peak of pristine Cs2SnX6 NCs were tuned from 430 nm to 780 nm covering the visible and near infrared spectrum region. Taking Cs2SnI6/SiO2 NCs as an example, the optical property stability in solution is obviously improved, and it can be stored in air for over 2 h. Especially, the more stable NIR emission, non-toxicity and easy hydrolysis characteristics of Cs2SnX6/SiO2 composite nanoparticles will have potential medical applications like photothermal and photodynamic therapies for cancers.

β-NaYF4:Yb3+, Tm3+ @ TiO2 core-shell upconversion nanoparticles (UCNPs) were synthesized and incorporated into the TiO2 mesoporous layer of perovskite solar cells (PSCs). Changes of the upconversion spectra of the UCNPs suggest the existence of the electron injection from NaYF4:Yb3+, Tm3+ to the conduction band (CB) of TiO2 through the NaYF4:Yb3+, Tm3+/TiO2 nano-heterojunctions. The core-shell UCNPs that incorporated into the TiO2 mesoporous layer not only act as the upconversion centers to use the NIR light but also serve as the light scatter centers to enhance the light harvesting. When using mesoporous layer containing the core-shell UCNPs in PSCs, the efficiency of the best devices is 16.27%, which is about 16.38% higher than that of the devices without core-shell UCNPs (13.98%). The significant enhancement in the performance of the PSCs is attributed to light scattering, NIR light upconversion and electron injection from the UCNPs to the CB of TiO2.

NIR responsive inorganic hybrid (Ti@GO) was synthesized. It could absorb NIR light and convert it into local hyperthermia and ROS synchronously. Ti@GO was firstly developed as a photosensitizer and a photothermal agent to realize tumor PTT and PDT. For anti-tumor application, HA was grafted on Ti@GO simultaneously as water solubility improver and tumor targeting moiety. ICG was chosen as a model drug. Results demonstrated that HA-Ti@GO could remarkably improve ICG stability and drug accumulation in 4T1 cells, enhance tumor phototherapy efficiency and reduce light-associated side effects. HA-Ti@GO/ICG under NIR laser irradiation showed a significant decreased cell viability of 20.7±2.6% and a high DNA damage degree of 82.4±8.3%. Moreover, in vivo results showed that HA-Ti@GO/ICG plus NIR laser achieved almost complete tumor regression on 4T1 tumor-bearing mice, with a tumor volume of 67.0 mm3. Taken together, our study provided a promising strategy to realize synergistic PTT/PDT tumor therapy with a single NIR light.

Summary Recombinant bacterial colonization plays an indispensable role in disease prevention, alleviation, and treatment. Successful application mainly depends on whether bacteria can efficiently spatiotemporally colonize the host gut. However, a primary limitation of existing methods is the lack of precise spatiotemporal regulation, resulting in uncontrolled methods that are less effective. Herein, we design upconversion microgels (UCMs) to convert near-infrared light (NIR) into blue light to activate recombinant light-responsive bacteria (Lresb) in vivo, where autocrine “functional cellular glues” made of adhesive proteins assist Lresb inefficiently colonizing the gut. The programmable engineering platform is further developed for the controlled and effective colonization of Escherichia coli Nissle 1917 (EcN) in the gut. The colonizing bacteria effectively alleviate DSS-induced colitis in mice. We anticipate that this approach could facilitate the clinical application of engineered microbial therapeutics to accurately and effectively regulate host health.

Near infrared (NIR) light sources play vital roles in bioimaging, medical treatments, food analysis and machine vision. Herein, we report unusual broadband NIR emission in BaMgAl10O17:Cr3+ (BAM:Cr3+) via site engineering. Both the emission maximum and spectral bandwidth of BAM:Cr3+ can be tailored by controlling the site occupancy of Cr3+ on two different Al sites. The optimal BAM:0.2Cr3+ phosphor exhibits both a sharp line spectrum (λem = 696 nm) and a broadband emission centered at 762 nm, having an internal quantum efficiency (IQE) of ~ 94%. A prototype NIR light source was demonstrated by combining a blue laser diode with BAM:Cr3+ phosphor-in-glass (PiG) and revealed an NIR light output power of 3.4 mW when driven by a 100 mW blue laser diode.

In this work, we report a novel strategy to construct cell pattern on titanium substrates by using upconversion nanoparticles (UCNPs). When irradiating with a NIR laser (980 nm) through a photomask, the UCNPs could transfer NIR light into UV light in situ, which results in photocleavage and detachment of unsheltered cells for the formation of cell pattern. This work provides a new perspective for the application of UCNPS in biomedical field.

Recently, finding a novel near-infrared (NIR) photocatalyst has been the focus in photocatalysis. Here, VS4 sub-microspheres with a chain-like structure were prepared via a facile solvothermal method. As a new photocatalyst, it presents excellent NIR photocatalytic and photoelectrochemical (PEC) activity. Theoretical calculations and experimental results demonstrate that the improved NIR photocatalytic property originated from the narrow band gap of VS4, which significantly improves the NIR light absorption.

The drug instability, toxicity and the barrier to the target area necessitate a suitable drug delivery system with an external or internal control of the release. Spatio-temporal control using a surface functionalized nano-carrier seems to be the best alternative for guided drug delivery and release. This manuscript provides a broad spectrum about the drug carrier interface modification to cover the need for temporal drug delivery control under neglect side effects. On the other hand, recent advances related to the drug vehicle are highlighted, besides physical (Electric field, magnetic field, light) or mechanical (Ultrasound, mechanical strain), chemical (pH, redox gradient, enzyme) stimuli mediated DDS. Precisely, the paper focus on the NIR light as an effective external stimulus for remotely-triggered DDS. NIR responsive drug delivery systems are considered as novel drug modality that ensures an eco-friendly spatiotemporal control and an administrated meditation. This study also investigated the NIIR spectroscopy (NIRS) combined with partial least square (PLS) for quantitative analysis of a polyvinyl alcohol based prodrug (PVA-DOX) in order to reveal the high potential of NIRS for drug release monitoring and the extraction of concise calibration models.

Photothermal effect was for the first time utilized to capture the energy from infrared light and to promote the photocatalytic oxidation activity of NO by a simply mechanical mixing of traditional photocatalysts and core-shell structured Fe3O4@SiO2. Fe3O4@SiO2 absorbed the infrared light, transferred it into thermal energy based on photothermal effect, which then accelerated the NO photocatalytic activity of traditional photocatalysts. This promotion effect led by the addition of Fe3O4@SiO2 was confirmed by several classical photocatalysts such as TiO2, g-C3N4, BiOI and CeO2. To quantitatively characterize the photothermal effect, thermo images were taken with a thermo imager to obtain the average temperature rise of samples under the illumination of simulated solar light. Specially, P25/Fe3O4@SiO2 was studied in depth for illustration of the promotion mechanism. Experimental results showed that with the contribution of SiO2 shell, the photocorrosion of Fe3O4 didn’t occur during photocatalytic oxidation process and the photothermal effect of Fe3O4 was maintained. The quantity of Fe3O4@SiO2 was a vital factor for promotion of photocatalytic activity and the optimum mass ratio of P25 and Fe3O4@SiO2 was 3–1. After 120 min of illumination, the temperature of optimum P25/Fe3O4@SiO2 rose to 57.4 °C from 25 °C and its NO conversion capability showed an enhancement of 38.9% with the comparison to pure P25. The experimental results confirmed that the rise of temperature was attributed to the photothermal effect and its contribution was the same as the directly heating of photocatalysts. Furthermore, the enhancement of NO conversion capability around 30–40% was observed for the Fe3O4@SiO2 mixed anatase TiO2, g-C3N4, ZnO, BiOI and CeO2. In sum, we developed a new strategy for utilization of NIR light of solar energy to facilitate the photocatalytic reactions.

The near-infrared (NIR) light in the wavelength range of 780−1700 nm is regarded as transparency therapeutic window for light-activated delivery system in vivo due to the deep tissue penetration and minimum cellular damage of it. Numerous reports about NIR light-sensitive nanocarriers have emerged in the past few years. Here, strategies for the design and fabrication of nanocarriers for NIR light-controlled release are reviewed, which are based on three triggering mechanisms: (1) photoreactions of chromophores, including NIR light-induced photoreactions and upconversion nanoparticles (UCNPs)-mediated photochemical reactions; (2) photothermal effect, triggered by inorganic or organic photothermal conversion agents (PCAs) with the excitation of NIR light; (3) photo-oxidation, induced by reactive oxygen species (ROS) generated by photosensitizers under NIR light radiation. Finally, the challenges and perspectives of NIR light-sensitive nanocarriers for future development are given.

Optogenetics is a cutting-edge tool in neuroscience that employs light-sensitive proteins and controlled illumination for neuromodulation. Its main advantage is the ability to demonstrate causal relationships by manipulating the activity of specific neuronal populations and observing behavioral phenotypes. However, the tethering system used to deliver light to optogenetic tools can constrain both natural animal behaviors and experimental design. Here, we present an optically powered and controlled wireless optogenetic system using near-infrared (NIR) light for high transmittance through live tissues. In vivo optogenetic stimulations using this system induced whisker movement in channelrhodopsin-expressing mice, confirming the photovoltaics-generated electrical power was sufficient, and the remote controlling system operated successfully. The proposed optogenetic system provides improved optogenetic applications in freely moving animals.

Phototherapies are almost entirely ineffective against deep-sited tumors, due to the poor tissue-penetration ability of light, including ultraviolet light, visible light and infrared light. Although tissue optical clearing (TOC) technique, based on refractive index matching between scatterers and media, has been used to improve in vivo optical imaging quality, it is the first time that TOC technique was employed to realize efficient phototherapeutic effect on deep-sited tumor in the present work. A hybrid TOC agent consisting of glycerol, polyethylene glycol 400 and butylbenisothiazolene (TGP), were optimized for achieving the synergistic antitumor efficacy of photothermal therapy (PTT) and chemotherapy on a simulated deep-sited tumor model (with the coverage of pigskin). Temperature-sensitive gold nanocages (PGNCs) was used to load doxorubicin (DOX@PGNCs) as a nano-platform model of PTT and chemotherapy, for a proof of concept to prove the TOC effect of TGP on the phototherapeutic efficacy against deep-sited tumor. As the pigskin was treated by TGP for 30 min, the ΔT of DOX@PGNCs increased to 12.1 °C under NIR irradiation, while it only increased to ca. 2.0 °C with the coverage of untreated-pigskin. Moreover, PTT-triggered release of DOX increased from 6.3% with the coverage of untreated pigskin up to 22.8% with the coverage of TGP-treated pigskin under three times of NIR irradiation, indicating enhanced photothermal conversion efficiency. Meanwhile, the TOC effect of TGP enhanced cellular uptakes of DOX@PGNCs and boosted delivery efficiency of DOX@PGNCs into the tumor by photothermal-induced hydrophilicity–hydrophobicity transition. Owing to the improvement on the tissue-penetration depth of NIR light, DOX@PGNCs accomplished a robustly synergistic antitumor efficacy of PTT-chemotherapy on a deep-sited H22 tumor model. It is promising to be developed as a versatile strategy for improving PTT efficacy on deep-sited tumors and showed great potential in the improvement of clinical application of various phototherapies.

The current near-infrared (NIR) light-induced photodynamic therapy (PDT) can enhance the tissue penetration depth to trigger photosensitizers (PSs) far from the surface. NIR-mediated PDT is still challenged by overheating effect on normal tissues, limited tumor selectivity and low reactive oxygen species (ROS) yields. Here we construct a dual-agent photosensitizing nanoplatform by combining UV-blue upconversion emitting NaYF4:Yb/Tm@NaYF4:Yb@NaNdF4:Yb@NaYF4 (labeled as UCNPs) multi-shell nanocrystals with titanium dioxide (TiO2, UV-light-excited PS) and hypocrellin A (HA, blue-light-excited PS), which can induce cancer cell apoptosis by 808 nm light-triggered and hyaluronic acid (Hyal)-targeted PDT. In this construction strategy, the crystallized TiO2 shells on the surface of UCNPs can play dual roles as UV-light excited PS and conjugation site for Hyal, and then Hyal is served as targeting-ligand as well as the carrier of HA simultaneously. The step-by-step reactive mode of loading PSs and modifying targeting-ligands is a controllable and ordered design based on the use of one intermediate product as the reaction site for the next component. The Nd(3+)-sensitized UCNPs with quenching reduction layer can efficiently convert 808 nm NIR light to UV-blue emission for simultaneous activation of two PSs with enhanced intracellular ROS generation. Through the in vitro and in vivo experiment results, the dual-photosensitizers nanoplatform presents enhanced anti-tumor efficacy by effective targeting cellular uptake and taking full advantage of upconversion emission, which may make a major step toward next generation of NIR-mediated PDT.

Optical imaging emerges as a vital component of the various techniques needed to meet the stringent requirements of modern bioanalysis and bioimaging. Lanthanide luminescent bioprobes (LLBs) have greatly contributed to this field during the past 35 years because they have definite advantages such as little or no photobleaching and, thanks to time-gated detection, high sensitivity. The review summarizes the numerous tools offered by LLBs under their various forms, coordination compounds, nanoparticles, upconverting nanoparticles and their bioconjugates. It then focuses on biosensing, including point-of-care analysis, and then on both in vitro and in vivo bioimaging with visible and NIR light. The last section compares the performances of LLBs versus those of other commonly used bioprobes (organic dyes, quantum dots, and transition metal complexes). It is concluded that although LLBs will not replace all of existing bioprobes, they add invaluable new specific technologies to the biologist and medical doctor toolboxes. A good deal of improvements are achieved through nanotechnologies, which demonstrates that progresses in biosciences depend on the intersection of different disciplines, photophysics, chemistry, biochemistry, nanotechnology, and materials science. (C) 2015 Elsevier B.V. All rights reserved.

In the last decade, it has been proposed that the sun's IR-A wavelengths might be deleterious to human skin and that sunscreens, in addition to their desired effect to protect against UV-B and UV-A, should also protect against IR-A (and perhaps even visible light). Several studies showed that NIR may damage skin collagen content via an increase inMMP-1 activity in the same manner as is known for UVR. Unfortunately, the artificial NIR light sources used in such studies were not representative of the solar irradiance. Yet, little has been said about the other side of the coin. This article will focus on key information suggesting that IR-A may be more beneficial than deleterious when the skin is exposed to the appropriate irradiance/dose of IR-A radiation similar to daily sun exposure received by people in real life.IR-A might even precondition the skin--a process called photo prevention--from an evolutionary standpoint since exposure to early morning IR-A wavelengths in sunlight may ready the skin for the coming mid-day deleterious UVR. Consequently IR-A appears to be the solution, not the problem. It does more good than bad for the skin. It is essentially a question of intensity and how we can learn from the sun. © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

One of important factors for improving the power conversion efficiency (PCE) of quantum dot-sensitized solar cells is to enhance the utilization of sunlight. Herein, we modified the wavelength range of incident sunlight from the counter electrode (CE) side to investigate the photoelectric performance of solar cells. The effect of illuminating CuS and Cu2S CE with different light ranges (including non-illumination, UV–visible light, NIR light and full-spectrum light) on cell performance was investigated. It has been shown that illuminating from both sides of cell induce substantial increase in PCE, and a 42.8% enhancement in PCE compared with that irradiating from the photoanode side has been achieved with a champion PCE of 5.6% (Voc = 0.6 V, Jsc = 21.7 mA cm−2) based on CuS CE. This strategy focuses on the neglected problem of light utilization of the CE, and provides a direction for realizing full-spectrum absorption of liquid-junction solar cells.

Utilization of infrared (IR)/near-infrared (NIR) light paves an opportunity to improve the efficiency of N2 photofixation under full-spectrum irradiation, but remains as a grand challenge. Herein, a highly active photocatalyst toward NIR light-driven N2 photofixation was successfully developed by construction of plasmonic Ti3C2Tx MXene and TiO2 hybrid structures (Ti3C2Tx/TiO2-400). Impressively, Ti3C2Tx/TiO2-400 exhibited remarkable activity in N2 photofixation under full-spectrum irradiation of Xenon lamp, attaining an NH3 production rate of 422 μmol gcat.–1 h–1 without any sacrificial agents. More importantly, superior activity under NIR light was even achieved for Ti3C2Tx/TiO2-400 with the NH3 production rate up to 82 μmol gcat.–1 h–1 by applying 740-nm monochromatic light. Further mechanistic studies revealed that plasmonic Ti3C2Tx Mxene phase in Ti3C2Tx/TiO2-400 enabled the harvesting of NIR light. Moreover, oxygen vacancies in TiO2 phase of Ti3C2Tx/TiO2-400 served as the active centers to efficiently adsorb and activate N2.

Cancer could seriously threaten people's health, even life. Rare earth upconversion nanoparticles (UCNPs) that emit higher energy UV/visible light when excited by low energy NIR light have aroused considerable attention in biomedical fields, which stems from their unique optical and chemical properties including the low spontaneous fluorescence, high signal-to-noise ratio, tunable emission, low toxicity and high penetration depth properties. NIR light can effectively stimulate the photoinduced reaction through UV/visible emissions from RE3+ UCNPs. This review article mainly summarizes the recent progress of RE3+ based stimuli-responsive nanocompounds for drug delivery in biomedical research, along with the various functional modification methods. Under special stimuli-responsive conditions, such as pH, temperature, light and redox gradients, the drugs can be transferred and released controllably. The traceable targeted drug delivery manner can boost drug efficacy in tumor therapy, while minimizing the side effects of cytotoxic drugs. Finally, the future developments and challenges for upconversion materials are discussed.

A new strategy to prepare NIR light-responsive Poly-lactide-co-glycolide (PLGA) drug delivery systems via carbon quantum dots-stabilized Pickering emulsion polymerization was developed. We successfully fabricated oil-in-water single emulsion and water-in-oil-in-water double emulsion for loading hydrophobic and hydrophilic drugs, respectively.

It is challenging and urgent in neurosurgery to improve therapeutic effect of the most common and lethal malignant glioma in central nervous system. The superadditive therapeutic effect of photothermal therapy and photodynamic therapy holds great promise. Herein, a highly efficient photothermal-photodynamic therapy nanoplatform was developed on the basis of Fe3O4-IR806 superparticles. The introduction of the near-infrared (NIR) dye IR806 and the fabrication of the self-assembled structure of the superparticles warrant 3.5 times increase in the photothermal conversion efficiency compared with the Fe3O4 nanoparticles. The Fe3O4-IR806 superparticles generated reactive oxygen species (ROS) with the NIR light irradiation by virtue of the dye IR806. Both in vitro and in vivo experiments demonstrated that the Fe3O4-IR806 superparticles exhibited negligible toxicity. The Fe3O4-IR806 superparticles efficiently inhibited the cultured glioma cells via photothermal ablation and ROS cytotoxicity in vitro, as well as suppressed the bearing glioma growth in vivo with the NIR light induction. Our results highlight the promise of the Fe3O4-IR806 superparticles for improved photothermal-photodynamic therapy of cancer.

Microbial contamination in water has evoked worldwide attention owing to their greatest threats to the public safety. In this work, the sea urchin-like Bi2S3 hollow microspheres have been synthesized by a hard template-assisted polyol method using ZnS composite microspheres as sacrificed template on the large scale, which shows good biocompatibility and photothermal conversion properties. Thermal-sensitive biocompatible 1-tetradecanol (TD) combined antibacterial agents (Linalool) were loaded into the hollow cavity of the sea urchin-like Bi2S3 hollow microspheres to form TD/Linalool@Bi2S3 composites. The Bi2S3 in the TD/Linalool@Bi2S3 composites can convert the absorbed NIR energy into heat energy under the irradiation of near infrared (NIR) light, which would make the temperature to reach the melting point of the TD and Linalool can be released at same time. Thus, the antibacterial agent Linalool can be precisely controlled releasing from the formed TD/Linalool@Bi2S3 composites, which provided rapid and effective killing outcome in vitro for Gram-negative Escherichia coli (E. coli) and Gram-positive Stahylococcus aureus (S. aureus). Additionally, the as-prepared TD/Linalool@Bi2S3 composites exhibited superior antibacterial ability as compared to antibacterial agent treatment or photothermal therapy (PTT) alone, which can be attributed to the synergistic effects of the NIR light driven photothermal killing and antibacterial agent releasing. It endowed that the designed TD/Linalool@Bi2S3 composites is a promising antibacterial platform for cleaning the microbial contaminated water environment, which is of great strategic significance and remains a formidable challenge for practical applications.

This paper presents a novel structural design of a biometric recognition sensor based on wrist vein, comprised by an array of NIR light source, a charge-coupled device (CCD) and a circle frame for a moving camera, to obtain the 3D vein image for security identification in mobile environment. An algorithm based on this structure was also proposed and explored preliminarily. It is believed what has been proposed can improve the accuracy by 3D vein image, reduce the influence of hand positon and pose in vein recognition and be more applicable to wearable devices.

Devices utilizing near-infrared (NIR) spectroscopy have been used to assess regional intracerebral oxygen saturation (rSO2) during anaesthesia for a decade. The presence of wide differences among individuals reduces their applicability to steady-state measurements. Current devices may not adequately account for variations in skin pigmentation.From our ongoing departmental registry, 3282 consecutive patients underwent cardiac surgery between 2010 and 2012 and their pre-induction measurements of rSO2 were available. Of these, 2096 identified themselves as Caucasian (Cauc) and 1186 as African-American (AA). Pre-induction rSO2, clinical and operative features were compared.Clinical and operative details of these patients differed widely between the two populations. High-risk features were more common in AA patients, but no difference in mortality was observed (4.8% in AAs vs 4.7% in Caucs, P=0.87). Preprocedure rSO2 was systematically higher in Cauc (65.5% vs 53.3%, P0.001). After multivariate linear regression adjustment, AA ethnicity proved to be associated independently with low rSO2 [odds ratio (OR) -8.28, 95% confidence interval (CI) -9.12 to -7.44, P0.001]. Multivariate logistic regression analysis showed that preprocedural rSO2 was independently associated with operative mortality both in the Cauc group (OR 0.97, 95% CI 0.96-0.99, P=0.001) and in the AA group (OR 0.97, 95% CI 0.95-0.99, P=0.01).AAs have a lower rSO2 than Caucs as measured by the INVOS 5100C cerebral oximeter. Reasonably, this could be attributed to attenuation of the NIR light by skin pigment. Despite this limitation, in both ethnic groups, lower preoperative rSO2 was predictive of greater operative mortality.

ZnO:Er, Li light conversion film has been successfully fabricated by sol–gel method. XRD measurement demonstrated the successful incorporation of Er3+ and Li+ into ZnO films. The as-grown film co-doped with 2% Er3+ and 3% Li+ is featured with a transmittance of about 86.8% in the range of 400–900 nm. Moreover, the film exhibits a visible light emission either being excited by 355 nm or 980 nm. Due to its relatively high transmittance characteristics and promising properties of converting both UV and NIR light to visible light, the developed film is considered to have a potential application in novel light conversion devices including solar cells.

Near-infrared (NIR, 700–1600 nm) emitting lanthanide complexes offer great advantages over the conventional visible light emitting materials for bioimaging and sensing due to the deep penetration of NIR light in the biological fluids and low bleaching effect to the substrates. However, the application has been hampered by their poor NIR emission efficiency and the requirement of short excitation wavelengths. The porphyrin and BODIPY dyes are excellent chromophores with great potential to address these issues due to their unique photophysical properties and structural functionalities. In this review, our recent investigation on synthesis, structural analysis and photophysical properties of their lanthanide complexes is summarized and some important findings are highlighted. We focused on the synthesis and structural characterization of Yb 3+ , Nd 3+ and Er 3+ complexes of porphyrin and BODIPY dyes and the impact of structural changes on the NIR emission efficiency. Sensitization mechanism in these complexes is also discussed.

Poor penetration into tumor stem cells of nanomedicine leads to the low therapeutic efficacy, metastasis and recurrence of tumors. Herein, doxorubicin (DOX) modified gold nanorods (GNRs) and chlorin e6 (Ce6) were loaded simultaneously on the surface of polydopamine (PDA) nanospheres (PDA@GNRs-DOX/Ce6), which was called structure-tunable “remote-controlled cluster bomb”. The “cluster bomb” were accumulated primarily to the tumor tissues via enhanced permeability and retention effect. Subsequently, the nanosystem was disintegrated to release DOX and singlet oxygen and kill the superficial tumor cells under NIR laser irradiation. Meanwhile, the small-size GNRs (48 nm × 15 nm) fall off from the primary nanocarriers and penetrated into the interior tumor tissue to damage the tumor stem cells. The novel variable structure nanosystem avoided the possibility of tumor metastasis and recurrence. The results also verified its excellent tumor therapeutic efficiency, the relative tumor volume was 0.47 ± 0.31 in the PDA@GNRs-DOX/Ce6 group, which was lower significantly than that of control group (26.50 ± 0.98). We believe the design of structure-tunable “remote-controlled cluster bomb” can provide an inspiration for the future tumor therapy.

Infectious diseases caused by bacteria is always a serious problem. In this work, Ag2S nanoparticles decorated nanocubes (Ag2S/NCs) were synthesized, in which NCs were obtained by pyrolyzing the metal-organic frameworks (MOFs) at 800 °C while Ag2S were prepared by a simple ultrasonic process and solvent reaction. The former carbon nanocubes exhibited an excellent photothermal conversion efficiency of 29%, and the latter composite structure exhibited good photodynamic ability. As a consequence, under the 808 nm NIR light irradiation, Ag2S/NCs can produce heat and reactive oxygen species (ROS) within a short time, which endowed the composites enhanced antibacterial properties of 97.3% against Staphylococcus aureus in 20 min. The cell test in vitro also displayed that these composites had good biocompatibility.