532-nm Light Research Articles

Booklice Liposcelis bostrychophila are efficiently attracted by the combination of 2,3,5,6-tetramethylpyrazine and ultraviolet light.

Booklice Liposcelis bostrychophila are frequently found almost everywhere, including private houses and cleanrooms of factories and institutes. They often cause serious hygienic as well as agricultural problems, but a useful trap has not been developed so far. Therefore, an effective way to monitor and capture booklice is required. We here identified a new attractant, 2,3,5,6-tetramethylpyrazine (TMP), which efficiently captured booklice in combination with UV light. When booklice placed at both right and left edges of an assay tray were exposed to light stimulus from the center, test insects gathered at the center. The attraction was stronger with shorter wavelengths than longer ones: 365-nm ultraviolet (UV)light showed the strongest attraction of four tested light wavelengths. We found that cocoa powder attracted booklice weakly but significantly under total darkness. Furthermore, the cocoa smell was confirmed to enhance the attraction to light at all tested wavelengths irrespective of the difference between two brands of cocoa powders. Gas chromatography-mass spectrometry indicated that both cocoa products contain TMP as a major odor compound. Exposure of booklice to TMP significantly enhanced the attraction to UV light: the combined use with TMP almost doubled the attraction compared to the light only. By contrast, TMP homologs, pyrazine and dimethylpyrazines, showed strong repellent activities under UV light exposure. TMP enhanced the UV light attraction for booklice while pyrazine and dimethylpyrazines diminished it. Use of these attractant and repellent pyrazine derivatives together with UV light would enable us to develop a practical new way to monitor and capture booklice. © 2023 Society of Chemical Industry.

A mitochondria-targeted multifunctional nanoplatform combining carbon monoxide delivery with O2-independent free radical burst under 1064nm light irradiation for efficient hypoxic tumor therapy.

In situ mitochondrial oxidative stress amplification is an effective strategy to improve efficacy of cancer treatment. In this work, a tumor and mitochondria dual-targeted multifunctional nanoplatform CMS@AIPH@PDA@COTPP@FA (CAPCTF) was prepared, in which a thermally decomposable radical initiator AIPH was loaded inside the mesoporores of CuxMoySz (CMS) nanoparticles with polydopamine (PDA) covered films that were further covalently functionalized by a mitochondria-targeted CO donor (COTPP) and a directing group of folic acid (FA). The prepared CAPCTF nanoplatform selectively accumulated in cancer cells and further targeted the mitochondrial organelle where carbon monoxide (CO) and O2-independent free radicals (•OH/•R) were in situ generated upon 1064nm laser irradiation. Furthermore, the CMS nanocarrier was capable of depleting the GSH overexpressed in the tumor microenvironment (TME), thus preventing free radical scavenging. As a result, the CAPCTF nanoplatform exhibited outstanding in vitro and in vivo antitumor efficacy under hypoxic conditions. This provides an innovative strategy that combines O2-independent free radicals (•OH/•R) generation, CO delivery and GSH consumption to amplify intracellular oxidative stresses and induce mitochondrial dysfunction, thus leading to cancer cells eradication, which may have significant implications for personalized hypoxic tumor treatment.

Photobiomodulation enhances M2 macrophage polarization properties of tonsil-derived mesenchymal stem cells.

In this study, the effect of photobiomodulation (PBM) treatment using 630nm light emitting diode (LED) array (continuous wave type, 10mW power) on tonsil-derived mesenchymal stem cells (TMSCs) and its interaction with RAW 264.7 macrophage cells via co-culture in vitro were investigated. PBM treatment was used as a priming method for TMSCs to improve therapeutic efficacy. TMSCs were subjected to multi-dose PBM treatments before co-culture with M1 activated (1μg/mL lipopolysaccharide, LPS) macrophage cells with total energy doses of 0, 15, 30, and 60J. Irradiation set at 15J (1500s treatment time) was performed once, twice for 30J, and four times for 60J in an incubator kept at 37°C and 5% CO2. No significant anti-inflammatory response was observed for TMSCs co-cultured with macrophage cells without PBM. But PBM treatment of TMSCs with 630nm LED array at 30J reduced expression of inducible nitric oxide synthase, iNOS (M1) and increased expression of Arginase-1, Arg-1 (M2) phenotype macrophage markers. Anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA) gene expression also increased significantly. Based on the results, PBM priming of TMSCs supports M2 macrophage polarization. PBM can be used to improve the therapeutic efficacy of TMSCs for potential applications in oral mucositis and wound healing.

Effect of the Combined Use of Morning Blue-Enriched Lighting and Night Blue-Suppressed Lighting (MENS) on Sleep Quality

Objectives: Previous studies have shown that exposure to blue-enriched light in the morning or blue-suppressed light in the evening may positively affect sleep. In this study, we aimed to investigate the effect of combination of morning blue-enriched and night blue-suppressed lighting (MENS) on sleep quality. Methods: Thirty workers were recruited. After one-week baseline evaluation, the participants were randomly assigned to either an experimental or a control group. Both were exposed to light in the morning and evening for two weeks. The experimental group used a lighting device emitting 480-nm wavelength maximized light in the morning and minimized light in the evening, while the control group used 450-nm wavelength light in the same way. The final evaluation was conducted using questionnaires and sleep diaries. Results: Both groups showed statistically significant improvements in seven out of nine sleep quality measures (<i>p</i><0.05). The experimental group showed improvement in sleep latency and sleep fragmentation compared to that in the control group (<i>p</i>=0.017). The control group showed improvement in wake after sleep onset. The ratio of participants who showed improvement and transitioned from abnormal to normal values was significantly higher in the experimental group for sleep latency (<i>p</i>=0.046) and in the control group for fatigue (<i>p</i>=0.012). Conclusions: The findings suggest that the use of MENS significantly improves sleep quality. Although the difference in the improvement effect between different wavelengths of blue light was not substantial, the use of 480-nm blue light appears to be effective in reducing sleep latency.

Introducing Ferroelasticity into 1D Hybrid Lead Halide Semiconductor by Halogen Substitution Strategy.

Organic-inorganic hybrid lead halide perovskites (OLHPs), represented by (CH3 NH3 )PbI3 , are one of the research focus due to their exceptional performance in optoelectronic applications, and ferroelastic domain walls are benign to their charge carrier transport that is confirmed recently. Among them, the 1DOLHPs feature better stability against desorption and moisture, but related 1D ones possessing ferroelasticity are rarely investigated and reported so far. In this work, the 1D ferroelastic semiconductor (N-iodomethyl-N-methyl-morpholinium)PbI3 ((IDMML)PbI3 ) is prepared successfully by introducing successively halogenate atoms from Cl, Br to I into the organic cation of the prototype (N,N-dimethylmorpholinium)PbI3 ((DMML)PbI3 ). Notably, (IDMML)PbI3 shows the narrow bandgap energy (≈2.34eV) according to the ultraviolet-visible absorption spectrum and the theoretical calculation, and possesses the evident photoconductive characteristic with the on/off ratio of current of ≈50 under the 405nm light irradiation. This work provides a new case for the ferroelastic OLHPs and will inspire intriguing research in the field of optoelectronic.

Carbon-Encapsulated Magnetite Nanodoughnut as a NIR-II Responsive Nanozyme for Synergistic Chemodynamic-Photothermal Therapy.

Magnetite-based nanozymes have attracted great interest for catalytic cancer therapy enabled by catalyzing hydrogen peroxide (H2 O2 ) to produce highly toxic hydroxyl radicals (•OH) to kill tumor cells. However, their therapeutic efficacies remain low due to insufficient •OH. Here, a light-responsive carbon-encapsulated magnetite nanodoughnuts (CEMNDs) with dual-catalytic activities for photothermal-enhanced chemodynamic therapy (CDT) is reported. The CEMNDs can accumulate in tumor and get into tumor cells and effectively act as peroxidase to convert H2 O2 to •OH that causes tumor cell death. The CEMNDs also possess intrinsic glutathione oxidase-like activity that which catalyzes the oxidation of reduced glutathione and produce lipid peroxidase for enhanced catalytic therapy. Furthermore, the CEMNDs can absorb 1064nm light to elevate local temperature and increase release of Fe ions for photothermal therapy and enhanced CDT respectively. The in vivo experiments in an aggressive and drug-resistant metastatic mouse model of triple negative breast cancer model demonstrate excellent synergistic anti-tumor function and no measurable systemic toxicity of CEMNDs.

Hospital, Catheter, Peritoneal Dialysis Acquired Infections: Visible Light as a New Solution to Reduce Risk and Incidence.

Healthcare-associated infections, often identified as hospital-acquired infections (HAIs), are typically not present during patient contact or admission. Healthcare-associated infections cause longer lengths of stay, increasing costs and mortality. HAI occurring in trauma patients increases the risk for length of stay and higher inpatient costs. Many HAIs are preventable. Antibiotic resistance has increased to a high level making proper treatment increasingly difficult due to organisms resistant to common antibiotics. Therefore, there is a need for alternate forms of attack against these pathogens. Currently, the application of light for the treatment of topical infections has been used. Ultraviolet (UV) light has well-documented antimicrobial properties. UV is damaging to DNA and causes the degradation of plastics, etc., so its use for medical purposes is limited. Using visible light may be more promising. 405-nm light sterilization has been shown to be highly efficacious in reducing bacteria. Light Line Medical, Inc.'s (LLM) patented visible-light platform technology for infection prevention may create a global shift in the prevention of healthcare-associated infections. LLM has developed a proprietary method of delivering light to prevent catheter-associated infections. This technology uses non-UV visible light and can kill both bacteria and prevent biofilm inside and outside a luminal catheter. This is significant as prevention is key. Independent analysis of the prototype system showed the application of the device met the acceptance criterion of 4 x 109-10 reduction in Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, and other bacteria and fungal species. Further design evolution for this technology continues, and the FDA submission process is underway.

Attenuation Aβ1-42-induced neurotoxicity in neuronal cell by 660nm and 810nm LED light irradiation.

Oligomeric amyloid-β 1-42 (Aβ1-42) has a close correlation with neurodegenerative disorder especially Alzheimer's disease (AD). It induces oxidative stress and mitochondrial damage in neurons. Therefore, it is used to generate AD-like in vitro model for studying neurotoxicity and neuroprotection against amyloid-β. A low-level light therapy (LLLT) is a non-invasive method that has been used to treat several neurodegenerative disorders. In this study, the red wavelength (660nm) and near infrared wavelength (810nm) at energy densities of 1, 3, and 5 J/cm2 were used to modulate biochemical processes in the neural cells. The exposure of Aβ1-42 resulted in cell death, increased intracellular reactive oxygen species (ROS), and retracted neurite outgrowth. We showed that both of LLLT wavelengths could protect neurons form Aβ1-42-induced neurotoxicity in a biphasic manner. The treatment of LLLT at 3 J/cm2 potentially alleviated cell death and recovered neurite outgrowth. In addition, the treatment of LLLT following Aβ1-42 exposure could attenuate the intracellular ROS generation and Ca2+ influx. Interestingly, both wavelengths could induce minimal level of ROS generation. However, they did not affect cell viability. In addition, LLLT also stimulated Ca2+ influx, but not altered mitochondrial membrane potential. This finding indicated LLLT may protect neurons through the stimulation of secondary signaling messengers such as ROS and Ca2+. The increase of these secondary messengers was in a functional level and did not harmful to the cells. These results suggested the use of LLLT as a tool to modulate the neuronal toxicity following Aβ1-42 accumulation in AD's brain.

Exposure to long wavelength light that improves aged mitochondrial function shifts acute cytokine expression in serum and the retina.

Aged mitochondrial function can be improved with long wavelength light exposure. This reduces cellular markers of inflammation and can improve system function from fly through to human. We have previously shown that with age there are increases in cytokine expression in mouse serum. Here, we ask what impact 670nm light has on this expression using a 40 cytokine array in blood serum and retina in C57Bl6 mice. 670nm exposure was delivered daily for a week in 12 month old mice. This shifted patterns of cytokine expression in both serum and retina inducing a selective increase. In serum examples of significant increases were found in IL (interleukins) 1α, IL-7, 10, 16, 17 along with TNF-α and CXCL (chemokines) 9 and 10. In retina the increases were again mainly in some IL's and CXCL's. A few cytokines were reduced by light exposure. Changes in serum cytokines implies that long wavelengths impact systemically even to unexposed tissues deep in the body. In the context of wider literature, increased cytokine expression may be protective. However, their upregulation by light merits further analysis as cytokines upregulation can also be negative and there are probably complex patterns of interaction in the dynamics of their expression.

Investigating the characteristics of fluorescence features on sweet peppers using UV light excitation.

Sweet peppers are popular worldwide due to their nutrition and taste. Conventional vegetable tracing methods have been trialed, but the application of such labels or tags can be laborious and expensive, making their commercial application impractical. What is needed is a label-free method that can identify features unique to each individual fruit. Our research team has noted that sweet peppers have unique textural fluorescence features when observed under UV light that could potentially be used as a label-free signature for identification of individual fruit as it travels through the postharvest supply chain. The objective of this research was to assess the feature of these sweet pepper features for identification purposes. The macroscopic and microscopic images were taken to characterize the fluorescence. The results indicate that all sweet peppers possess dot-like fluorescence features on their surface. Furthermore, it was observed that 93.60% of these features exhibited changes in fluorescence intensity within the cuticle layer during the growth of a pepper. These features on the macro-image are visible under 365nm UV light, but challenging to be seen under white LEDs and to be classified from the fluorescence spectrum under 365nm light. This research reported the fluorescence feature on the sweet pepper, which is invisible under white light. The results show that the uniqueness of fluorescent features on the surface of sweet peppers has the potential to become a traceability technology due to the presence of its unique physical modality.

Synthesis, characterization and exploration of the NIR luminescent properties in HfO2: Er, HfO2:Tm and HfO2:Er/Tm films photochemically prepared

The photolysis of the Hf(dbm)4, Er(dbm)3 and Tm(dbm)3 complexes on silicon substrates results in the production of pure HfO2, HfO2/Er, HfO2/Tm, and HfO2/Er/Tm films. The photochemistry of these complex precursors was monitored using UV–Visible and FT-IR spectroscopy. Under 254-nm light photolysis, the ligands were detached from the complexes, leading to the release of metal ions. These ions gradually oxidized and formed the respective oxide. Subsequently, the resulting films were calcined at 600 °C for 2 h to achieve complete oxidation and crystallinity. To characterize selected samples, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM-EDX) were employed.NIR luminescent studies revealed that when excited at 980 nm, the HfO2/Er samples exhibited emissions corresponding to the 4I13/2 → 4I15/2 transitions of the Er3+ ions. Conversely, the HfO2/Tm samples displayed emissions attributed to the 3H4 → 3F4 and 3F4 → 3H6 transitions of the Tm ions. In the case of HfO2 co-doped with Er/Tm, some of these emissions overlapped, resulting in a broadband centered at 590 nm. To explain the observed emissions, a mechanism based on energy transfer processes between both activators (Tm ↔ Er) has been proposed.

Bose-Einstein condensate as a diagnostic tool for an optical lattice formed by 1064-nm laser light

Bose-Einstein condensate as a diagnostic tool for an optical lattice formed by 1064-nm laser light

High-energy parametric oscillator and amplifier pulsed light source at 2-µm.

A laser system generating high-energy pulses at 2-µm wavelength with pulse widths tunable from 10-24 ns is described. It comprises an optical parametric oscillator that generates mJ-level signal seed radiation and an optical parametric amplifier that boosts the output to 800 mJ of combined signal and idler when pumped with 2 J pulses of 1064-nm laser light. The system operated with KTP crystals and running at 10 Hz repetition rate is characterized in the spatial, temporal, and spectral domains. The effect of saturation leads to an output pulse approaching flat-top spatial and box-shaped temporal profiles, as desired in various applications. The amplified pulses can be imaged down to sub-100 µm diameters, making this laser system a suitable driver for plasma sources of extreme ultraviolet light.

Regulation of IL-24/IL-20R2 complex formation using photocaged tyrosines and UV light.

Human interleukin 24 (IL-24) is a multifunctional cytokine that represents an important target for autoimmune diseases and cancer. Since the biological functions of IL-24 depend on interactions with membrane receptors, on-demand regulation of the affinity between IL-24 and its cognate partners offers exciting possibilities in basic research and may have applications in therapy. As a proof-of-concept, we developed a strategy based on recombinant soluble protein variants and genetic code expansion technology to photocontrol the binding between IL-24 and one of its receptors, IL-20R2. Screening of non-canonical ortho-nitrobenzyl-tyrosine (NBY) residues introduced at several positions in both partners was done by a combination of biophysical and cell signaling assays. We identified one position for installing NBY, tyrosine70 of IL-20R2, which results in clear impairment of heterocomplex assembly in the dark. Irradiation with 365-nm light leads to decaging and reconstitutes the native tyrosine of the receptor that can then associate with IL-24. Photocaged IL-20R2 may be useful for the spatiotemporal control of the JAK/STAT phosphorylation cascade.

Light tolerance of extended spectrum β-lactamase producing Escherichia coli strains after repetitive exposure to far-UVC and blue LED light.

The aim of this study was to investigate dual far-UVC (Ultraviolet-C) (222nm) and blue LED (Light Emitting Diode) (405nm) light on the inactivation of extended spectrum β-lactamase-producing Escherichia coli (ESBL-Ec) and to determine if repetitive exposure to long pulses of light resulted in changes to light tolerance, and antibiotic susceptibility. Antimicrobial efficiency of dual and individual light wavelengths and development of light tolerance in E. coli was evaluated through a spread plate method after exposure to light at 25cm. Dual light exposure for 30min resulted in a 5-6 log10 CFU mL-1 reduction in two ESBL-Ec and two antibiotic-sensitive control E. coli strains. The overall inhibition achieved by dual light treatment was always greater than the combined reductions (log10 CFU) observed from exposure to individual light wavelengths (combined 222-405nm), indicating a synergistic relationship between blue LED and far-UVC light when used together. Repetitive long pulses of dual and individual far-UVC light exposure resulted in light tolerance in two ESBL-Ec strains but not the antibiotic-sensitive E. coli strains. Subsequent passages of repetitive light-treated ESBL-Ec strains continued to exhibit light tolerance. Antibiotic susceptibility was determined through a standard disk diffusion method. No changes were observed in the antibiotic susceptibility profiles for any of the four strains after exposure to either dual or individual wavelengths. Dual light exposure was effective in the disinfection of ESBL-Ec in solution; however, antibiotic-resistant E. coli were able to develop light tolerance after repetitive exposure to light.

LED irradiation at 630nm alleviates collagen-induced arthritis in mice by inhibition of NF-κB-mediated MMPs production.

Matrix metallopreteinase (MMP), a family of matrix degrading enzyme, plays a significant role in persistent and irreversible joint damage in rheumatoid arthritis (RA). Photobiomodulatory therapy (PBMT) has become an emerging adjunct therapy for RA. However, the molecular mechanism of PBMT on RA remains unclear. The purpose of this study is to explore the effect of 630nm light emitting diode (LED) irradiation on RA and its underly molecular mechanism. Arthritis clinic scores, histology analysis and micro-CT results show that 630nm LED irradiation ameliorates collagen-induced arthritis (CIA) in mice with the reduction of the extents of paw swelling, inflammation and bone damage. 630nm LED irradiation significantly reduces MMP-3 and MMP-9 levels and inhibits p65 phosphorylation level in the paws of CIA mice. Moreover, 630nm LED irradiation significantly inhibits the mRNA and protein levels of MMP-3 and MMP-9 in TNF-α-treated MH7A cells, a human synovial cell line. Importantly, 630nm LED irradiation reduces TNF-α-induced the phosphorylated level of p65 but not alters STAT1, STAT3, Erk1/2, JNK and p38 phosphorylation levels. Immunofluorescence result showed that 630nm LED irradiation blocks p65 nuclear translocation in MH7A cells. In addition, other MMPs mRNA regulated by NF-κB were also significantly inhibited by LED irradiation in vivo and in vitro. These results indicates that 630nm LED irradiation reduces the MMPs levels to ameliorate the development of RA by inhibiting the phosphorylation of p65 selectively, suggesting that 630nm LED irradiation may be a beneficial adjunct therapy for RA.Graphical abstract.

Polarization-Sensitive Photodetector Based on High Crystallinity Quasi-1D BiSeI Nanowires Synthesized via Chemical Vapor Deposition.

Bismuth chalcohalides (BiSeI and BiSI), a class of superior light absorbers, have recently garnered great attention owing to their promise in constructing next-generation optoelectronic devices. However, to date, the photodetection application of bismuth chalcohalides is still limited due to the challenge in controllable preparation. Herein, the synthesis of large-scale quasi-1D BiSeI nanowires via chemical vapor deposition growth is reported. By precisely tuning the growth temperature and the Se supply, it can effectively control the growth thermodynamics and kinetics of BiSeI crystal, and thus achieve high purity quasi-1D BiSeI nanowires with high crystal quality, uniform diameter, and tunable domain length. Theory and optical characterizations of the quasi-1D BiSeI nanowires reveal an indirect bandgap of 1.57eV with prominent optical linear dichroism. As a result, the quasi-1D BiSeI nanowire-based photodetector demonstrates a broadband photoresponse (400-800nm) with high responsivity of 5880mAW-1 , fast response speed of 0.11ms and superior air stability. More importantly, the photodetector displays strong polarization sensitivity (anisotropic ratio = 1.77) under the 532nm light irradiation. This work will provide important guides to the synthesis of other quais-1D metal chalcohalides and shed light on their potential in constructing novel multifunctional optoelectronic devices.

1772-P: Alpha-Cell Heterogeneity Contributes to Phasic Glucagon Release

Glucagon, produced by α-cells of pancreatic islets, is one of the body’s primary tools for elevating blood glucose during hypoglycemia. The exact mechanism linking hypoglycemia to glucagon release by islet α-cells is, however, unclear; we therefore aimed to investigate it using optogenetics. We generated mice harboring the light-activated ion channel channelrhodopsin-2 (ChR2) specifically in α-cells and imaged the effect of optically induced depolarization of plasma membrane (10-ms 470-nm light pulses at 20Hz) at the level of membrane potential, cytosolic Ca2+ ([Ca2+]i) and ATP/ADP ratio. At 1 mmol/L glucose, optostimulation depolarized the electrically active α-cells from -76mV to -8mV, induced a transient surge in [Ca2+]i and elevated glucagon secretion by 200%. In contrast, the glucagonostatic effect of high glucose (>6 mmol/L) was mitigated by optostimulation of α-cells. At 1 mmol/L glucose, the stimulatory effects were abolished by the KATP channel activator diazoxide (100μmol/L) and L-type Ca2+ channel blocker isradipine (10μmol/L). Notably, KATP channel inhibitor tolbutamide (100μmol/L) induced electrical activity in the fraction of α-cells insensitive to low glucose (35%). As stimulation of electrical activity persisted significantly beyond optoactivation, we probed the interplay between electrical activity and energy metabolism. The depolarizing stimulus induced by a cocktail of amino acids ((AA) 2 mmol/L of alanine + arginine +glutamine) or a moderate increase of extracellular K+ (from 4 to 15 mmol/L) reduced ATP/ADP in α-cells exhibiting spontaneous Ca2+ oscillations at low glucose. Surprisingly, in the population of inactive α-cells, the stimulation increased ATP/ADP ratio. These data indicate that α-cells are functionally heterogeneous due to metabolic differences. The observed secretory responses reflect the combination of stimulatory and inhibitory effects in electrically active and silent cells, which may contribute to the phasic nature of AA-induced glucagon secretion. Disclosure C.A.Miranda: None. H.Dou: None. J.Tolö: None. A.I.Tarasov: None. P.Rorsman: None. Funding Svenska Sällskapet för Medicinsk Forskning (PD20-0056); Swedish Vetenskap Rådet

Highly Tunable Cascaded Metasurfaces for Continuous Two-Dimensional Beam Steering.

Cascaded metasurfaces can exhibit powerful dynamic light manipulation by mechanically tuning the far-field interactions in the layers. However, in most current designs, the metasurfaces are separated by gaps smaller than a wavelength to form a total phase profile, representing the direct accumulation of the phase profiles of each layer. Such small gap sizes may not only conflict with the far-field conditions but also pose great difficulties for practical implementations. To overcome this limitation, a design paradigm taking advantage of a ray-tracing scheme that allows the cascaded metasurfaces to operate optimally at easily achievable gap sizes is proposed. Enabled by the relative lateral translation of two cascaded metasurfaces, a continuous two-dimensional (2D) beam-steering device for 1064nm light is designed as a proof of concept. Simulation results demonstrate tuning ranges of ±45° for biaxial deflection angles within ±3.5mm biaxial translations, while keeping the divergence of deflected light less than 0.007°. The experimental results agree well with theoretical predictions, and a uniform optical efficiency is observed. The generializeddesign paradigm can pave a way towards myriad tunable cascaded metasurface devices for various applications, including but not limited to light detection and ranging (LiDAR) and free space optical communication.

Enhanced photocatalytic activity of Bi2WO6/ZnO nanocomposite in degradation of methylene blue under sunlight irradiation and for antimicrobial activity

Photocatalytic degradation of organic pollutants is crucial although this process effectively disintegrates the toxicants that pollute drinking water, which, in turn, result in environmental pollution. Orthorhombic bismuth tungstate (Bi2WO6) in combination with hexagonal zinc oxide (ZnO) effectively degrades toxic methylene blue (MB) from water, by the photocatalytic technique. Composite of Bi2WO6 nanoplates with ZnO was synthesized by the simple hydrothermal method. Raman analysis shows the presence of vibrational and functional modes present in the prepared catalysts. The obtained Bi2WO6/ZnO composite absorbed 650 nm of light and promoted an efficient photocatalytic process. The photocatalytic process was carried out for the degradation of MB under various light irradiation sources such as visible light, UV light, and sunlight (direct). The photocatalyst (50 mg of Bi2WO6/ZnO and 3.2 mg/L MB solution) provided a maximum percentage for the degradation of MB (74%) under sunlight irradiation compared to that under other light irradiation sources. Furthermore, the Bi2WO6/ZnO composite was used to analyze its antimicrobial activity, and it shows the best antimicrobial activities against both gram-positive bacteria and gram-negative bacteria such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Vibrio cholera.