532-nm Light Research Articles

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.

Development of a hydrated electron dosimeter for radiotherapy applications: A proof of concept.

Hydrated electrons, which are short-lived products of radiolysis in water, increase the optical absorption of water, providing a pathway toward near-tissue-equivalent clinical radiation dosimeters. This has been demonstrated in high-dose-per-pulse radiochemistry research, but, owing to the weak absorption signal, its application in existing low-dose-per-pulse radiotherapy provided by clinical linear accelerators (linacs) has yet to beinvestigated. The aims of this study were to measure the optical absorption associated with hydrated electrons produced by clinical linacs and to assess the suitability of the technique for radiotherapy (⩽ 1 cGy per pulse)applications. 40 mW of 660-nm laser light was sent five passes through deionized water contained in a 10 2 cm3 glass-walled cavity by using four broadband dielectric mirrors, two on each side of the cavity. The light was collected with a biased silicon photodetector. The water cavity was then irradiated by a Varian TrueBeam linac with both photon (10 MV FFF, 6 MV FFF, 6 MV) and electron beams (6 MeV) while monitoring the transmitted laser power for absorption transients. Radiochromic EBT3 film measurements were also performed forcomparison. Examination of the absorbance profiles showed clear absorption changes in the water when radiation pulses were delivered. Both the amplitude and the decay time of the signal appeared consistent with the absorbed dose and the characteristics of the hydrated electrons. By using literature value for the hydrated electron radiation chemical yield (3.0±0.3), we inferred doses of 2.1±0.2 mGy (10 MV FFF), 1.3±0.1 mGy (6 MV FFF), 0.45±0.06 mGy (6 MV) for photons, and 0.47±0.05 mGy (6 MeV) for electrons, which differed from EBT3 film measurements by 0.6%, 0.8%, 10%, and 15.7%, respectively. The half-life of the hydrated electrons in the solution was ∼ 24 s. By measuring 660-nm laser light transmitted through a cm-scale, multi-pass water cavity, we observed absorption transients consistent with hydrated electrons generated by clinical linac radiation. The agreement between our inferred dose and EBT3 film measurements suggests this proof-of-concept system represents a viable pathway toward tissue-equivalent dosimeters for clinical radiotherapyapplications.

Laboratory evaluation of the broad-spectrum antibacterial efficacy of a low-irradiance visible 405-nm light system for surface-simulated decontamination

PurposeLighting systems which use visible light blended with antimicrobial 405-nm violet-blue light have recently been developed for safe continuous decontamination of occupied healthcare environments. This paper characterises the optical output and antibacterial efficacy of a low irradiance 405-nm light system designed for environmental decontamination applications, under controlled laboratory conditions.MethodsIn the current study, the irradiance output of a ceiling-mounted 405-nm light source was profiled within a 3×3×2 m (18 m3) test area; with values ranging from 0.001-2.016 mWcm-2. To evaluate antibacterial efficacy of the light source for environmental surface decontamination, irradiance levels within this range (0.021-1 mWcm-2) at various angular (Delta ϴ=0-51.3) and linear (∆s=1.6-2.56 m) displacements from the source were used to generate inactivation kinetics, using the model organism, Staphylococcus aureus. Additionally, twelve bacterial species were surface-seeded and light-exposed at a fixed displacement below the source (1.5 m; 0.5 mWcm-2) to demonstrate broad-spectrum efficacy at heights typical of high touch surfaces within occupied settings.ResultsResults demonstrate that significant (P≤0.05) inactivation was successfully achieved at all irradiance values investigated, with spatial positioning from the source affecting inactivation, with greater times required for inactivation as irradiance decreased. Complete/near-complete (≥93.28%) inactivation of all bacteria was achieved following exposure to 0.5 mWcm-2 within exposure times realistic of those utilised practically for whole-room decontamination (2-16 h).ConclusionThis study provides fundamental evidence of the efficacy, and energy efficiency, of low irradiance 405-nm light for bacterial inactivation within a controlled laboratory setting, further justifying its benefits for practical infection control applications.

Upgrading the Toolbox: Two-Photon Absorption Induced Cleavage of Coumarin Dimers for Light-Based 4D Printing.

The use of light for shaping and changing matter is of high relevance in polymer and material science. Herein, a photopolymer method is presented, which comprises the combination of 3D photo-printing at 405nm light and subsequent modification under two-photon absorption (TPA) conditions at 532nm light, adding the fourth dimension. The TPA-triggered cycloreversion reaction of an intramolecular coumarin dimer (ICD) structure occurs within the absorbing material. The 3D-printable matrix does not show any degradation under the TPA conditions. With the presented photochemical tool of TPA processes inside absorbing 3D photo-printable matrices, new possibilities for post-printing modification, e. g. for smart materials, are added.

Continuous wave 670nm LED light therapy improves short‐ and long‐term object recognition, locomotion, and reduces phosphorylated tau burden in 3xTgAD mice

AbstractBackgroundPhotobiomodulation (PBM) therapy uses 620‐1100nm red to near‐infrared light to modulate biological processes including neuroinflammation, amyloid and tau oligomerization, and apoptosis. We have shown that 670nm light therapy reduces synaptic vulnerability to amyloid‐β oligomers in wild‐type (WT) mice and reduces tau oligomerization in mouse models of tauopathy. Here we sought to determine if 670nm light therapy could rescue cognitive and motor dysfunction and reduce tau hyperphosphorylation in 14‐to‐18‐month‐old 3xTgAD mice.Method14‐to‐18‐month‐old 3xTgAD mice were treated with continuous‐wave 670nm LED light applied directly to the head for 90s per day, 5 days per week for 4 weeks. 3xTgAD sham and WT controls were held under the LED device with the light turned off for the same amount of time. During the fourth week of treatment, spontaneous locomotor behavior was measured by placing animals in an empty chamber for 10 minutes using ANY‐maze software to track mobility data. Animals were then tested for working memory in the Y maze spontaneous alternation task and short‐and long‐term memory in the novel object recognition task. At the completion of behavioral testing on treatment day 20, brains were collected for western blot analysis of total tau and phospho‐tau (pTau).ResultLight‐treated 3xTgAD mice showed increased distance traveled compared to sham (17.43 ± 3.46 vs. 9.97 ± 3.03, one‐way ANOVA p = 0.03), and decreased immobile episodes (4.50 ± 1.92 vs 10.00 ± 1.83, one‐way ANOVA p = 0.02) in the spontaneous locomotor activity test. Light‐treated animals also showed significant object recognition at 2 hours (DI 32.75 ± 7.71, one sample t‐test p<0.001) and 24 hours (DI 44.14 ± 15.73, one sample t‐test p = 0.001) post‐training. Light treatment also reduced the ratio of hippocampal pTau/Tau in 3xTg AD mice as compared to sham (0.11 ± 0.05 vs. 0.32 ± 0.13, one‐way ANOVA p = 0.04).ConclusionHere we show rescue of locomotor behavior and cognitive dysfunction, and reduction of Tau phosphorylation in the hippocampus of 3xTgAD mice using a non‐invasive transcranial treatment with 670nm LED light. Our data suggest that treatment with 670nm red light could significantly improve cognitive function in AD patients and reduce hyperphosphorylation of tau thus possibly preventing further neurodegeneration.

Assessing CaMPARI as new approach methodology for evaluating neurotoxicity

Developmental exposure to environmental toxicants has been linked to the onset of neurological disorders and diseases. Despite substantial advances in the field of neurotoxicology, there remain significant knowledge gaps in our understanding of cellular targets and molecular mechanisms that mediate the neurotoxicological endpoints associated with exposure to both legacy contaminants and emerging contaminants of concern. Zebrafish are a powerful neurotoxicological model given their high degree sequence conservation with humans and the similarities they share with mammals in micro- and macro-level brain structures. Many zebrafish studies have effectively utilized behavioral assays to predict the neurotoxic potential of different compounds, but behavioral phenotypes are rarely able to predict the brain structures, cell types, or mechanisms affected by chemical exposures. Calcium-modulated photoactivatable ratiometric integrator (CaMPARI), a recently developed genetically-encoded calcium indicator, undergoes a permanent green to red switch in the presence of elevated intracellular Ca2+ concentrations and 405-nm light, which allows for a “snapshot” of brain activity in freely-swimming larvae. To determine whether behavioral results are predictive of patterns of neuronal activity, we assessed the effects of three common neurotoxicants, ethanol, 2,2′,3,5′,6-pentachlorobiphenyl (PCB 95), and monoethylhexyl phthalate (MEHP), on both brain activity and behavior by combining the behavioral light/dark assay with CaMPARI imaging. We demonstrate that brain activity profiles and behavioral phenotypes are not always concordant and, therefore, behavior alone is not sufficient to understand how toxicant exposure affects neural development and network dynamics. We conclude that pairing behavioral assays with functional neuroimaging tools such as CaMPARI provides a more comprehensive understanding of the neurotoxic endpoints of compounds while still offering a relatively high throughput approach to toxicity testing.

NIR-II Light Accelerated Prodrug Reduction of Pt(IV)-Incorporating Pseudo Semiconducting Polymers for Robust Degradation and Maximized Photothermal/Chemo-Immunotherapy.

Selective activation of Pt(IV) prodrugs within tumors is particularly attractive because of their low damage to normal tissues. However, current common activation via chemical/photoreduction of Pt(IV) prodrugs into Pt(II) counterparts is limited by undesirable spatial-temporal control over this reduction process and the ineffective tissue penetration depth of undesirable light. Here, a pseudo-conjugated-polymer is designed via Stille polymerization, resulting in PSP-Pt with a Pt(IV) prodrug of oxaliplatin (Oxa(IV)) in the polymer main chain that can be activated by NIR-II light. PSP-Pt can co-assemble with a commercially available lipid polymer, namely mPEG2k -DSPE, into NPPSP-Pt . Under 1064nm light irradiation, NPPSP-Pt can be photoactivated to accelerate the Pt(IV) reduction to release oxaliplatin, thereby killing the cancer cells by photothermal effect and chemo-immunotherapy inside a mouse model with CT26 colon cancer. This work reports the application of NIR-II light for accelerating Pt(IV) reduction for cancer tumor therapy.

Photothermal treatment of glioblastoma cells based on plasmonic nanoparticles.

Photothermal therapy based on plasmonic gold nanoparticles is considered a promising approach for cancer treatment. Here, we investigate the in vitro photothermal effect of 30-nm gold nanoparticles, optically excited with a 532-nm continuous laser, on the U87MG malignant glioblastoma cells, and demonstrate the role of nanoparticle concentration and exposure power density in achieving its optimum performance. Laser-induced collective oscillation of electrons in plasmonic gold nanoparticles is employed to generate localized heat to denature tumor cells. Optical spectroscopy is used to measure the plasmonic band of nanoparticles and select the excitation laser light. The MTT assay for the IC50 viability assessment is performed to evaluate the live and metabolically active cells after treatment with plasmonic nanoparticles. The quantitative data is statistically analyzed using analysis of variance followed by Tukey's post hoc test. The viability test demonstrates that the metabolic activity of treated U87MG was decreased compared with untreated cells, leading to the determination of the IC50 as 92 [Formula: see text]. A 532-nm laser light was selected for the excitation of gold nanoparticles since the maximum plasmonic band is at 524 nm. The viability tests show that although cells have natural photothermal agents, their absorption efficiency is very low; therefore, the laser-induced plasmonic effect is necessary to observe photothermal effects. The optimal condition was achieved when the nanoparticle concentration was 92 [Formula: see text], and the exposure power density was 96 [Formula: see text]. Thus, it is demonstrated that plasmonic nanoparticle concentration and laser exposure power density are among the key parameters in the photothermal treatment of cancer cells, and higher concentrations of Au-NPs and laser power density lead to less cell viability in the selected range due to the excitation of gold nanoparticles' localized surface plasmon resonance.

Optically activated MEK1/2 inhibitors (Opti-MEKi) as potential antimelanoma agents.

Mitogen-activated protein kinase kinases 1/2 (MEK1/2) play critical roles in the canonical RAS/RAF/MEK/ERK pathway. Highly selective and potent non-ATP-competitive allosteric MEK1/2 inhibitors have been developed, and three of them were clinically approved for the treatment of BRAFV600 -mutant melanoma. However, the accompanying side effects of the systemically administered MEK1/2 drugs largely constrain their tolerable doses and efficacy. In this study, a series of mirdametinib-based optically activatable MEK1/2 inhibitors (opti-MEKi) were designed and synthesized. A structural-based design led to the discovery of photocaged compounds with dramatically diminished efficacy in vitro, whose activities can be spatiotemporally induced by short durations of irradiation of ultraviolet (365nm) light. We demonstrated the robust photoactivation of MEK1/2 inhibition and antimelanoma activity in cultured human cells, as well as in a xenograft zebrafish model. Taken together, the modular approach presented herein provides a method for the optical control of MEK1/2 inhibitor activity, and these data support the further development of optically activatable agents for light-mediated antimelanoma phototherapy.

Photocatalytic H2-production and benzyl-alcohol-oxidation mechanism over CdS using Co2+ as hole cocatalyst

The sluggish oxygen evolution reaction (OER) is often the bottleneck of photocatalytic overall water splitting, greatly suppressing the hydrogen-production activity. Herein, the slow OER was replaced by selective benzyl alcohol (BA) oxidation to benzaldehyde (BD) to promote H2 production. The photocatalytic reaction was conducted over CdS quantum dots, which were modified with Co2+ hole cocatalysts to further accelerate the rate-limiting BA oxidation. The photocatalytic system exhibits an ultra-high H2-production rate of 257.8 mmol g−1 h−1 with a remarkable apparent quantum yield of 69.3% under 365-nm light irradiation. The high performance is attributed to the Co2+ hole cocatalysts on CdS surfaces, which not only enhance light absorption but also facilitate photogenerated carrier transfer. More importantly, both photogenerated electrons and holes are fully utilized in meaningful reactions. This work exemplifies a bifunctional photocatalytic system for simultaneous production of self-separated hydrogen and benzaldehyde, both of which are important industrial products.

Photothermal-Responsive Intelligent Hybrid of Hierarchical Carbon Nanocages Encapsulated by Metal-Organic Hydrogels for Sensitized Photothermal Therapy.

Hierarchical carbon nanocages as emerging nanomaterials have a great potential for photothermal therapy due to their unique porous structure, high specific surface area, and excellent photothermal property. Herein, a hierarchical nitrogen-doped carbon nanocage (hNCNC) is introduced as a second near-infrared photothermal agent, and then functionalizes it with metal-organic hydrogel (MOG) to form a thermal-responsive switch for sensitized photothermal therapy. Upon 1064nm light irradiation, the hNCNCs exhibit a remarkable photothermal conversion efficiency of 65.9% owing to a high near-infrared extinction coefficient. Meanwhile, due to the hierarchical structure, hNCNCs show 60.2% (wt./wt.) loading efficiency of quercetin, a heat shock protein (Hsp70) inhibitor. Through thermal-driven dry-gel transformation, the coating MOGs intelligently release the encapsulated quercetin for sensitizing cancer cells to heat. Based on the synergistic effect of hyperthermia elevation and thermal-driven drug release, the dual thermal utilization platform achieves effective photothermal tumor ablation in vivo under low concentration of hNCNCs and mild irradiation, which provides a new diagram of intelligent responsive photothermal agents for enhanced photothermal therapy.

Disinfection of methicillin-resistant Staphylococcus Aureus on flat surface by 460 nm light and hydrogen peroxide combination

Staphyloxanthin (STX) is a carotenoid pigment produced by Staphylococcus aureus to protect the bacteria from oxidation stress. Eliminating Staphyloxanthin from S. aureus cell membrane by inducing the pigment photolysis using 460nm light, then killing weakened bacteria with an H2O2 solution could be a new approach to develop anti - Staphylococcus aureus procedure. A model to prove the feasibility of this combination to kill Methicillin-Resistant Staphylococcus Aureus (MRSA) bacteria on a flat surface was tested. Material and method: Staphyloxanthin pigment extracted from MRSA bacteria was treated with 460nm light at different light intensities to evaluate the photolysis potential of 460nm light. The change in MRSA shape after 460nm light treatment was also investigated by Scanning electron microscopy. Using glass cover-slips as an emulated model for contact surface in public, the combination of different 460nm light intensities and H2O2 0.75% was tested on the surface loaded with MRSA living cells, and the number of MRSA cells survived after treatment was enumerated. Result: Higher intensity and longer light treatment yielded a higher photolysis effect, as 100 and 200 mW/cm2 light intensity could degrade 77.50% to 83.45% of STX pigment after 20 minutes of irradiation. Also, MRSA cells had significant changes as more wrinkles and bumps appeared under high-intensity 460nm light. When tested on the flat surface of the coverslip, the strongest MRSA eradication effect can be observed in the combination of 200 mW/cm2 light treatment with 0.75% H2O2 solution, as 100% MRSA cells were completely killed after 20 minutes of treatment.

Abstract 3568: Developing pediatric glioblastoma microtumors with a three-dimensional bioprinter

Abstract Background:Glioblastoma multiforme is one of the most devastating forms of brain cancer seen in children. Children diagnosed with high-grade gliomas have poor prognosis, and there remains a need for improvement in the standard of care. In order to improve the standard of care for this condition, it is necessary to develop in vitro models which better recapitulate the nature of the tumors. Three-dimensional bioprinting has proven to be an effective technique in creating microtumors using adult glioblastoma cell lines but remains unexplored in pediatric glioblastoma. As such, we sought to develop a protocol which would allow for the creation of three-dimensionally bioprinted microtumors using patient-derived pediatric glioblastoma cells. Methods:A Bio X three-dimensional bioprinter (Cellink) was utilized to create the microtumor constructs. The composition of the bioink was modified through varying concentrations of sodium alginate and gelatin, or gelatin-methacrylate (Gel-MA). The microtumor size and volume was optimized through the variation of extrusion time, nozzle pressure, and both nozzle and print bed temperature. The crosslinking technique was also optimized through the utilization of 2% calcium chloride for varying exposure times, and also a 405-nm light (for Gel-MA bioink) at varied light intensity, length of time of application to, and distance from, the printed structure. Bioprinted pediatric XD456 brain tumor initiating cell constructs were treated with both chemotherapeutics and radiation to determine the model’s capacity to respond to treatment. PamStation 12 (PamGene Inc.) Kinomic data and RNA-seq (Illumina) data were generated for the constructs. Imaging was performed using Cytation 5 imager (Agilent). Results:Fluorescent microscopy with Calcein AM and Sytox™ Orange (ThermoFisher), along with viability assessments via CellTiter-Glo®, demonstrated expected cytotoxic effects after exposure to 10 μM Cisplatin. Additionally, PamStation 12 Kinomic and RNA-seq data indicated a difference in kinomic signaling between the bioprinted constructs as compared to the XD456 cells cultured as neurospheres. Conclusions:The utilization of a three-dimensional bioprinter allows for the creation of microtumors using patient-derived pediatric glioblastoma cells. Future studies will investigate the microtumors’ capacity as a drug screening model. The model will also be developed to further recapitulate the native tumor microenvironment of pediatric glioblastoma. Citation Format: Andee M. Beierle, Taylor L. Schanel, Hasan Alrefai, Joshua C. Anderson, Patricia H. Hicks, Lauren C. Nassour, Christopher D. Willey. Developing pediatric glioblastoma microtumors with a three-dimensional bioprinter. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3568.

Abstract 2423: Image-guided interstitial photodynamic therapy with palliative radiotherapy for ablating extrabronchial malignant central airway obstruction

Abstract Background: Patients with extrabronchial tumors that induce malignant central airway obstruction (MCAO) face dire prognoses with significant morbidity and 1-7 months overall survival. These tumors are inoperable. High-dose curative radiotherapy is associated with significant toxicity. Chemotherapy has limited localized benefits and immunotherapy cannot address the immediate need to halt tumor progression. Our preliminary data suggest that image-guided interstitial photodynamic therapy (I-PDT) with porfimer sodium is safe and potentially effective in patients with extrabronchial tumors that induce MCAO and there is a need to further improve the rate of response. Here we present results showing an improved tumor response rate by augmenting I-PDT with palliative radiotherapy (p-XRT). Methods: We investigated the addition of p-XRT prior to I-PDT to sensitize the target tumor to subsequent photoreaction in mouse models. Eight- to twelve-week-old C3H and C57B/6 mice with locally advanced (400-600 mm3) SCC-VII or LLC tumors, respectively, were treated with I-PDT alone or with p-XRT followed by I-PDT. The p-XRT regimen was 10 Gy x2 over two days. At 24-26 h after the second 10 Gy fraction, the I-PDT was administered with 5 mg/kg porfimer sodium activated with 630-nm laser light at 5.0 mW/cm2 and 45 J/cm2 at tumor margins. Photoacoustic imaging and light dosimetry measurements were used to investigate the impact of p-XRT on the tumor microenvironment as it pertains to the response to I-PDT. Tumor progression was monitored over 60 days. Image-based treatment planning was used to translate the preclinical findings into a treatment in clinical settings (8 Gy x1 followed by I-PDT) for patients with extrabronchial MCAO. Results: Preceding I-PDT with p-XRT increases tumor oxygenation for 1-2 days after the last radiation fraction and improves light penetration within mouse tumors. Administering p-XRT 24-48 h before I-PDT significantly (p<0.05, log-rank test) increases the rate of complete tumor response and control from 0% in p-XRT alone or 0-6% in I-PDT alone, to 31-64% for p-XRT followed by I-PDT. In patients, administration of I-PDT with porfimer sodium 48 h after 8Gy x1 p-XRT is feasible and can provide control of extrabronchial MCAO accompanied by symptomatic relief. Conclusions: Augmenting I-PDT with p-XRT improves the rate of tumor response. Murine studies show that p-XRT increases tumor blood oxygenation and light penetration which could contribute to better response to I-PDT. I-PDT with porfimer sodium preceded by p-XRT is feasible with possible benefits in patients with extrabronchial MCAO. Citation Format: Emily Oakley, Sarah Chamberlain, Nathaniel Ivanick, Alan Hutson, Theresa Busch, Gal Shafirstein. Image-guided interstitial photodynamic therapy with palliative radiotherapy for ablating extrabronchial malignant central airway obstruction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2423.

1.1: Invited Paper: A novel scheme of projection film screen for ultra‐large color gamut with photonic band gap reflection mechanism

A novel scheme of projection film screen to get ultra large color gamut using photonic band gap reflection mechanism is proposed. The projection screen made by a kind of film that can only reflect three narrowband R/G/B light emitted from projector (E.g., 460nm, 560nm and 650nm), as well as absorb other visible light wavelengths. The film has a well‐designed nano level multilayer structure which can form three photonic band gaps to reflect 460nm, 560nm and 650nm light respectively. An ultra large color gamut of 73.44% Rec2020 (138.68% sRGB) was obtained even under a bright room ambient light, that makes projection image quality comparable to a traditional TV. It could be an effective way to help solve the problem of dull color performance shown on traditional projection screens.

Light-Triggered Nitric Oxide Nanogenerator with High l-Arginine Loading for Synergistic Photodynamic/Gas/Photothermal Therapy.

The development of nanomedicines that combine photothermal therapy (PTT) with photodynamic therapy (PDT) is considered promising for cancer treatment, but still faces the challenge of enhancing tumoricidal efficiency. Fortunately, apart from the well-acknowledged effect on direct tumor cell-killing, nitric oxide (NO) is also considered to be effective for the enhancement of both PTT and PDT. However, both the low loading efficiency of NO precursor and the short half-life time and diffusion distance of NO hamper the synergistic therapeutic efficacy of NO. Taking the aforementioned factors into account, a mitochondria-targeted nitric oxide nanogenerator, EArgFe@Ce6, is constructed to achieve high loading of the NO donor l-Arginine (l-Arg) for synergistic photodynamic/gas/photothermal therapy upon single 660nm light irradiation. The coordination of epigallocatechin gallate (EGCG) and ferric ions (Fe3+ ) provides EArgFe@Ce6 supreme photothermal capability to perform low-temperature PTT (mPTT). EGCG endows EArgFe@Ce6 with mitochondria-targeting capability and meanwhile favors hypoxia alleviation for enhanced PDT. The PDT-produced massive reactive oxygen species (ROS) further catalyzes l-Arg to generate a considerable amount of NO to perform gas therapy and sensitize both mPTT and PDT. In vitro and in vivo studies demonstrate that the synergistic photodynamic/gas/photothermal therapy triggered by single 660nm light irradiation is highly effective for tumor treatments.

Viricidal Efficacy of a 405-nm Environmental Decontamination System for Inactivation of Bacteriophage Phi6: Surrogate for SARS-CoV-2.

The highly transmittable nature of SARS-CoV-2 has increased the necessity for novel strategies to safely decontaminate public areas. This study investigates the efficacy of a low irradiance 405-nm light environmental decontamination system for the inactivation of bacteriophage phi6 as a surrogate for SARS-CoV-2. Bacteriophage phi6 was exposed to increasing doses of low irradiance (~0.5 mW cm-2 ) 405-nm light while suspended in SM buffer and artificial human saliva at low (~103-4 PFU mL-1 ) and high (~107-8 PFU mL-1 ) seeding densities, to determine system efficacy for SARS-CoV-2 inactivation and establish the influence of biologically relevant suspension media on viral susceptibility. Complete/near-complete (≥99.4%) inactivation was demonstrated in all cases, with significantly enhanced reductions observed in biologically relevant media (P < 0.05). Doses of 43.2 and 172.8 J cm-2 were required to achieve ~3 log10 reductions at low density, and 97.2 and 259.2 J cm-2 achieved ~6 log10 reductions at high density, in saliva and SM buffer, respectively: 2.6-4 times less dose was required when suspended in saliva compared to SM buffer. Comparative exposure to higher irradiance (~50 mW cm-2 ) 405-nm light indicated that, on a per unit dose basis, 0.5 mW cm-2 treatments were capable of achieving up to 5.8 greater log10 reductions with up to 28-fold greater germicidal efficiency than that of 50 mW cm-2 treatments. These findings establish the efficacy of low irradiance 405-nm light systems for inactivation of a SARS-CoV-2 surrogate and demonstrate the significant enhancement in susceptibility when suspended in saliva, which is a major vector in COVID-19 transmission.

Optically levitated, single-particle reactor for the study of surface and heterogeneous chemistry-reactions of particulate-bound mercury with ozone in air

We created a micron-sized, single-particle reactor (SPR) freely levitated in air using optical trapping of a single particulate-bound mercury particle formed by mixing HgCl2, HgBr2, or HgBrCl (HgX2, X = Cl, Br) with single-walled carbon nanotubes. Position- and time-resolved, single-particle Raman spectra show clear evidence of reactions of solid-state HgX2 in the presence of excessive O3 under the illumination of 532-nm light. We propose a reaction mechanism: Hg(II)X2 (solid) + O → Hg(I)X + XO, XO + O → O2 + X on the surface of the SPR. This exploratory study demonstrates that the SPR is a new tool for the study the surface and heterogeneous chemistry of mercury at atmospherically relevant surfaces, e.g., aerosols.

Photo-Induced Fluorochromism of a Star-Shaped Photochromic Dye with 2,4-Dimethylthiazole Attaching to Triangle Terthiophene.

A photochrmic triangle terthiophene dye with 2,4-dimethylthiazole attached was synthesized and shows regular photochromic properties when irradiated with UV/Vis light alternately. It was found that the attaching of 2,4-dimethylthiazole has a significant effect on both the photochromism and fluorescence of triangle terthiophene. During the photocyclizatioin prcess, not only the color but also the fluorescence of the dye in THF can be toggled between ring-open and ring-closed forms of the dye. Additionally, the absolute quantum yields (AQY) of ring-open and ring-closed forms of the dye (0.32/0.58) were greatly larger than the literature report. Along with the 254nm light irradiation, the fluorescence color changed from deep blue (428nm) to sky blue (486nm) in THF. A fluorochromism cycle could be established based on the UV/visible light irradiation cycle, which provides a strategy for the design of new type fluorescent diarylethene derivatives for biological application.