External Laser Light Research Articles

Synergistic effect of polymer functionalized graphene oxide system for breast cancer treatment

The multifaceted drug carrier system is an emerging trend in delivering chemotherapeutic drugs and photosensitizers for the synergistic effect. In this work, we have designed a functionalized graphene oxide (GO) based carrier system for combined chemo-photodynamic therapeutic effects. Doxorubicin (DOX) and rose bengal (RB) were entrapped on the surface of GO via hydrophobic and π-π stacking interactions. The functional group determination, crystalline properties, surface morphology, and hydrodynamic size were evaluated using FT-IR, XRD, SEM, TEM, AFM, and DLS analysis. At 24 h, the entrapment efficiency was 65 % DOX and 40.92 % RB, and the loading capacities were 16.9 % DOX and 5.68 % RB observed at 30 min. The drug release percentage was higher in pH-2.6 rather than in pH-5.5, 6.8, and 7.4 pH environments. The in-vitro toxicity analysis using the LDH assay reveals that the DOX and RB co-loaded carriers had a significant cytotoxic effect on MCF-7 cells, indicating that the carrier could improve the therapeutic efficacy of DOX. Morphological changes were studied using inverted light microscopy; the cells were irradiated with a laser 525 nm 10 J/cm2 for 2 min 51 sec, and it was observed that the DOX and RB co-loaded carrier with laser-irradiated cells exposed the high-level morphological changes with the occurrence of apoptotic cell death. Compared to free DOX, the DOX/RB co-loaded carrier + laser had an efficient anticancer activity, as confirmed by DAPI staining cell uptake, flow cytometry, and intracellular ROS generation analysis. The DOX and RB co-loaded carrier clearly exhibits the RB-mediated photodynamic action on MCF-7 cells in response to external laser light irradiation. It permits an on-demand dual-payload release to trigger an instantaneous photodynamic and chemo treatment for cancer cell eradication. Finally, the ensuing dual-agent release is probable to successfully fight cancer via a synergistic effect.

Chemo-photodynamic therapy by pulmonary delivery of gefitinib nanoparticles and 5-aminolevulinic acid for treatment of primary lung cancer of rats.

Lung cancer is a severe disease with high mortality. Chemotherapy is one major treatment for lung cancer. However, systemic chemotherapeutics usually distribute throughout the body without specific lung distribution so that serious side effects are unavoidable. Photodynamic therapy (PDT) is occasionally used for lung cancer treatment but photosensitizers are also systemically administered and the bronchoscopic intervention under anesthesia may hurt lung tissues. Here, we combined inhaled chemotherapeutics and photosensitizers for chemo-photodynamic therapy (CPDT) of primary lung cancer of rats with external laser light irradiation. Gefitinib PLGA nanoparticles (GNPs) were prepared. The anti-cancer effects of GNPs and/or a common photosensitizer 5-aminolevulinic acid (5-ALA) were explored on A549 cells (adenocarcinomic human alveolar basal epithelial cells) and primary lung cancer rats after intratracheal administration. External light irradiation was applied due to its higher safety compared to internal light irradiation that may result in injuries after a laser optic fiber was intubated into the lung. The remarkable synergistic effect of CPDT was confirmed although the single therapies were also effective, where the high anti-lung cancer effects were shown and some typical lung cancer markers, including CD31, VEGF, NF-κB p65 and Bcl-2, significantly decreased. Moreover, the treatments attenuated inflammation with the downregulation of TNF-α. The combination of pulmonary drug delivery and chemo-photodynamic therapy is a promising strategy for treatment of lung cancer.

Electrical Excitation of Long-Range Surface Plasmons in PC/OLED Structure with Two Metal Nanolayers

HighlightsLong-range surface plasmons were first excited in a hybrid photonic-crystal/organic-light-emitting-diode microstructure containing two metal nanolayers.These surface plasmons were excited without any external laser light, but by injecting current through the two metal nanolayers, which serve as thin metal electrodes for organic light-emitting microfilm between the layers.

The optical control of phase locking of polariton condensates

The phase and the frequency of an exciton polariton condensate excited by a nonresonant pump can be efficiently manipulated by an external coherent light. Being tuned close to the resonance with the condensate eigenfrequency, the external laser light imposes its frequency to the condensate and locks its phase, thereby manifesting a synchronization effect. The conditions of formation of the phase synchronized regime are determined. The synchronization of a couple of closely spaced polariton condensates by a spatially uniform coherent light is examined. At the moderate strength of the coherent driving the synchronization is accompanied by the appearance of symmetry-breaking states of the polariton dyad, while these states are superseded by the symmetric state at the high-intensity driving. By employing a zero-dimensional model of coupled dissipative oscillators with both dissipative and conservative coupling, we study the bifurcation scenario of the symmetry-breaking state formation.

A 512-Pixel 3kHz-Frame-Rate Dual-Shank Lensless Filterless Single-Photon-Avalanche-Diode CMOS Neural Imaging Probe.

Optical functional neural imaging has revolutionized neuroscience with optical reporters that enable single-cell-resolved monitoring of neuronal activity in vivo. State-of-the-art microscopy methods, however, are fundamentally limited in imaging depth by absorption and scattering in tissue even with the use of the most sophisticated two-photon microscopy techniques [1]. To overcome this imaging depth problem, we develop a lens-less, optical-filter-less, shank-based image sensor array that can be inserted into the brain, allowing cellular-resolution recording at arbitrary depths with excitation provided by an external laser light source (Fig. 11.5.1). Lens-less imaging is achieved generally by giving each pixel a spatial sensitivity function, which can be introduced by near-field or far-field, phase or amplitude masking. Since probe thickness must be less than $70 \mu \mathrm {m}$ to limit tissue damage and far-field masks are characterized by distances on the order of $200 \mu \mathrm {m}$ between the mask and the detector [2], we employ a near-field amplitude mask formed by Talbot gratings in the back-end metal of the CMOS process, which gives each pixel a diffraction-grating-induced angle-sensitivity [3]. Filter-less fluorescence imaging is achieved with time-gated operation in which the excitation light source is pulsed and pixel-level time-gated circuitry collects photons only after the excitation source has been removed.

Gas-generating nanoparticles for contrast-enhanced ultrasound imaging.

We present gas-generating solid nanoparticles as a new concept of an ultrasound contrast agent. The developed nanoparticles are sufficiently small (less than 100 nm in diameter) to escape vasculature and yet, upon external pulsed laser light activation, release nitrogen gas for enhanced contrast in ultrasound imaging. The gas-generating nanoconstructs combine the photocatalytic function of gold nanoparticles and photolysis of azide compounds. Using ultrasound imaging, we demonstrate the controlled, on-demand generation of nitrogen gas from nanoparticles due to the decomposition of azide groups triggered by pulsed laser irradiation. The resulting gas forms bubbles that cause backscattered ultrasound signals and, therefore, modulate the contrast in ultrasound imaging.

Laser light and external magnetic field control of polaron in asymmetric quantum dot

The possibility of controlling a polaron in an asymmetric quantum dot with external magnetic field and laser light is examined in this paper. Analytical studies are done using a modified Lee-Low-Pines method. We calculate the fundamental and first state energies which form a single qubit and further determine the probability density and the Shannon's entropy. These quantities as well as the mobility are influenced by the laser parameters, the size of the system and the magnetic field. The results performed show that the energy increases with the cyclotron frequency and the confinement strength of the potential. The analytical results highlight the fact that the application of the magnetic fields and laser enhances the possibility of finding discrete electronic states in quantum dots. The decoherence process is found to be greatly affected by the high-frequency laser field considered. Furthermore, it is reduced when particles are more confined in the nanostructure. It is established that a strong magnetic field and a low laser frequency enable the trapping and cooling of the polaron.

Laser-induced linear and non-linear optical features in novel benzoxazole-based on donor-acceptor chromophores

The photophysical properties of donor-acceptor based benzoxazoles were investigated by means of steady-state and time-resolved fluorescence techniques. Additionally, laser stimulated second-order optical effects (preliminary second harmonic generation (SHG) were studied. The studies show that the nitro-benzoxazole derivatives decorated with different alkylo/arylo amino groups dissolved in medium polar aprotic solvents: tetrahydrofuran and butyl chloride, exhibit dual fluorescence from the locally excited state (1LE) and a highly polar charge transfer (CT) state. Ambient-temperature time-resolved fluorescence investigations prove the bimodal kinetics of the excited-state electron transfer reaction 1LE→1CT. The lack of any CT emissions in cyclohexane and highly polar acetonitrile is presumably due to an efficient inter-system crossing process or fast deactivation of a low-lying CT state. In addition, strong CT properties inspired us to check a possibility to vary the absorption of the first UV–Vis maxima under influence of the external bicolour coherent laser light and the related optical second harmonic generation (SHG). The two coherent beams of the infrared Er:glass laser at 1540 nm/770 nm formed gratings in the photopolymer solidified chromophore. The performed experiments are compared with the theoretically calculated electronic parameters within the B3LYP DFT approach. The presented data open novel type of materials, allowing to operate its transparency using external IR laser light in the near IR spectral range.

Photoconductivity and laser operated piezoelectricity the Ag-Ga-Ge-(S,Se) crystals and solid solutions

A new type of chalcogenide semiconductors possessing different laser operated optoelectronic features is studied for the AgGaGeS4–AgGaGe3Se8 crystalline system give a rare opportunity to form continuous solid solution series based on the substrate compounds. This one allow to perform efficient operation by their optical and electronic features using an external laser light due to presence of huge number of intrinsic defects and high electron-phonon anharmonicities [1].With accordance to previously reported method were prepared specimens of high quality and homogenous in centimeter range (confirmed by SEM and EPMA) AgGaGeS4 and AgGaGe3Se8 single crystals and the series of intermediate solid solution, in particular AgGaGe1.8S2.4Se3.2, AgGaGe2S2Se4 and AgGaGe2.2S1.6Se4.8. The investigated Ag-Ga-Ge-(S,Se) crystals and solid solutions posses high non-linear optical efficiencies as well as high birefringence that make them efficient for coherent laser frequency conversion in the near-infrared spectral range. So they may be promising for the coherent laser frequency convertors. To expand the possibilities of applications as pressure sensors, optical triggers, modulators or radiation detectors and for better understanding of relation between composition-structure-properties for these materials we perform the complex investigation of temperature dependences of the transparency, photoconductivity, rise and decreasing photocurrent relaxation for determination parameters of localized states and temperature dependent, photoinduced piezoelectric properties.

Instrumentation for the non-destructive optical measurement of trapped electrons in feldspar

A facility for the measurement of infrared photoluminescence (IRPL) has been developed for the Risø TL/OSL reader. The new IRPL measurement system uses an external laser light source at 1.49 eV (830 nm) and two photomultiplier tubes (PMT) for detecting emissions at ∼1.41 eV (880 nm) and ∼1.3 eV (955 nm) and an EMCCD. Pulsed IRPL measurement ensures a low background count rate by allowing the rejection of breakthrough from excitation light. We present the results of integrated IRPL measurements on both multiple- and single-grain aliquots, and finally demonstrate the potential of imaging natural K-feldspar samples and a granite rock slice.

Influence of Cr3+ doping on the enhanced dielectric and nonlinear optical features of pyroelectric Pb5Ge3O11 single crystals

It was shown a possibility to enhance the output laser stimulated second harmonic susceptibility for Pb5Ge3O11 single crystals in their ferroelectric phase using an external laser light and appropriate doping by Cr3+ ions. The improvement of the Nonlinear Optical effect is achieved due to local enhancement of the local charge density non-centrosymmetry (acentricity), changes of the effective excitation of the occupied states and additional photo-polarization of the 3d-localized Cr3+ states. The addition of Cr3+ ions leads to additional enhancement of hyperpolarizability. To clarify the origin of the observed effect, and to understand the origin of its interesting properties, the calculations of the band structure of Pb5Ge3O11 were performed using, for the first time, the first-principles DFT calculations. These reveal that Pb5Ge3O11 has an indirect energy band gap Eg equal to about 2.6 eV and that the highest occupied valence band is very flat and is separated from the remaining valence bands by a small energy gap equal to about 0.3–0.4 eV. This discovery could explain many unexplained puzzling experimental results and especially the different photo-activated effects found previously in Pb5Ge3O11. The possible origin of the DFT calculated band structure is discussed. The enhancement of the second order optical susceptibility was explained within a framework of additional charges of the particular dopants during the coherent laser illumination.

Treatment of tumor in lymph nodes using near-infrared laser light-activated thermosensitive liposome-encapsulated doxorubicin and gold nanorods.

Tumor metastasis to lymph nodes is an important contributory factor for cancer-related deaths despite recent developments in cancer therapy. In this study, we demonstrate that tumor in the proper axillary lymph node (PALN) of the mouse can be treated by the application of external laser light to trigger the unloading of doxorubicin (DOX) encapsulated in thermosensitive liposomes (TSLs) administered together with gold nanorods (GNRs). GNRs + DOX-TSLs were injected into a mouse lymph node containing cancer cells (malignant fibrous histiocytoma-like cells) and intranodal DOX release was activated using near-infrared (NIR) laser irradiation. The temperature changes arising from the laser-irradiated GNRs triggered the release of DOX from the TSLs. A greater degree of inhibition of tumor growth was found in the co-therapy group compared to the other groups. The treatment effect was achieved by a combination of chemotherapy and NIR-activated hyperthermia. In vivo bioluminescence imaging and histological analysis confirmed tumor necrosis in response to combined treatment. This work presents a theranostic approach with excellent treatment results that has the potential to be developed into an alternative to surgery for the treatment of breast cancer metastasis.

Photoinduced Operation by Absorption of the Chalcogenide Nanocrystallite Containing Solar Cells

Abstract It is shown that for the solar cells containing chalcogenide nanocrystallites using external laser light, one can achieve some enhancement of the photovoltaic efficiency. Photoinduced treatment was carried out using two beams of splitted Er: glass laser operating at 1.54 μm. The light of the laser was incident at different angles and the angles between the beams also were varied. Also, the studies of nanocomposite effective structures have shown enhancement of effective nanocrystalline sizes during the laser treatment. Nanocrystallites of CuInS2 and CuZnSnS4 (CZTS) were used as chalcogenide materials. The optimization of the laser beam intensities and nanoparticle sizes were explored.

Multistimuli-Responsive Bilirubin Nanoparticles for Anticancer Therapy.

Although stimuli-responsive materials hold potential for use as drug-delivery carriers for treating cancers, their clinical translation has been limited. Ideally, materials used for the purpose should be biocompatible and nontoxic, provide "on-demand" drug release in response to internal or external stimuli, allow large-scale manufacturing, and exhibit intrinsic anticancer efficacy. We present multistimuli-responsive nanoparticles formed from bilirubin, a potent endogenous antioxidant that possesses intrinsic anticancer and anti-inflammatory activity. Exposure of the bilirubin nanoparticles (BRNPs) to either reactive oxygen species (ROS) or external laser light causes rapid disruption of the BRNP nanostructure as a result of a switch in bilirubin solubility, thereby releasing encapsulated drugs. In a xenograft tumor model, BRNPs loaded with the anticancer drug doxorubicin (DOX@BRNPs), when combined with laser irradiation of 650 nm, significantly inhibited tumor growth. This study suggests that BRNPs may be used as a drug-delivery carrier as well as a companion medicine for effectively treating cancers.

Multistimuli‐Responsive Bilirubin Nanoparticles for Anticancer Therapy

AbstractAlthough stimuli‐responsive materials hold potential for use as drug‐delivery carriers for treating cancers, their clinical translation has been limited. Ideally, materials used for the purpose should be biocompatible and nontoxic, provide “on‐demand” drug release in response to internal or external stimuli, allow large‐scale manufacturing, and exhibit intrinsic anticancer efficacy. We present multistimuli‐responsive nanoparticles formed from bilirubin, a potent endogenous antioxidant that possesses intrinsic anticancer and anti‐inflammatory activity. Exposure of the bilirubin nanoparticles (BRNPs) to either reactive oxygen species (ROS) or external laser light causes rapid disruption of the BRNP nanostructure as a result of a switch in bilirubin solubility, thereby releasing encapsulated drugs. In a xenograft tumor model, BRNPs loaded with the anticancer drug doxorubicin (DOX@BRNPs), when combined with laser irradiation of 650 nm, significantly inhibited tumor growth. This study suggests that BRNPs may be used as a drug‐delivery carrier as well as a companion medicine for effectively treating cancers.

WE-FG-BRA-12: Research Work of the Radio-Dynamic Treatment Mechanism

Purpose: The finite penetration depth of Laser light has limited clinical applications for PDT. This present work investigates the activation of photosensitizers using Cerenkov light emission from 45MV photon beams produced in an LA45 cancer therapy accelerator. We have named this new treatment technique Radio-Dynamic Therapy (RDT). Methods: Monte Carlo simulations were made on various Cerenkov emission energies and their spectroscopy in excited target areas in order to estimate their photosensitizer inner activation efficiency. The Cerenkov light excitation efficiency used in RDT has been theoretically compared with the exotic excitation efficiency of external Laser light used in PDT. In addition, laboratory tests showed the differences of the excitation efficiencies between a patented catalyst coenzyme added as a substrate, and then without the coenzyme. A specific probe of DMA (Singlet Oxygen fluorescent probe-9, 10-dimethylanthracene) was also used to detect singlet oxygen. Finally, we also compared our results with similar previous experimental work reported in the scientific literature. Results: Our Monte Carlo results showed that the Cerenkov light intensity induced with 45MV beams from an LA45 is 8 – 10 times the Cerenkov light intensity induced with 6MV beams from conventional accelerators. Furthermore, the patented catalyst coenzyme enhanced the excitation efficiency of photosensitizers by 3–6 times under different conditions. In clinical situations, the new RDT technique also showed favorable outcomes for early and late stages of specific cancers and it is also good at metastatic cancer treatment. Conclusion: Our results indicated that the process of using the Cerenkov light emission to excite photosensitizers from 45MV photons has a similar process and efficiency as the conventional laser in PDT. Comparing the advantages of RDT with a conventional PDT, the RDT may be developed into a potential treatment modality for a wider range of cancers stages as well as for other diseases.

Tl4SnS3, Tl4SnSe3 and Tl4SnTe3 crystals as novel IR induced optoelectronic materials

A new type of chalcogenide crystals Tl4SnS3, Tl4SnSe3, Tl4SnTe3 easily processing by external IR laser light is fabricated. For the titled crystals linear electrooptical effect was induced by external IR polarized light formed by two coherent beams of Er:glass nanosecond laser at fundamental wavelength 1540 nm. The detection of the electrooptical coefficient was performed by continuous-wave 1 W CO2 laser at probing wavelength 10.6 μm. The origin of the effect is caused by an occurrence of the thin (up to 50 nm) photoexcited nanosheets which forms near the surface space charge density non-centrosymmetry. The relaxation of the electrooptics after switching off of the photoinduced Er:glass laser beam is explored for different types of samples at different power densities. The crystals may be used for IR optical triggering.

Fluorophore, Protoporphyrin IX (PpIX), Excited From Cerenkov Emission Produced by 45MV Radiation for Cancer Therapy

Fluorophore, Protoporphyrin IX (PpIX), Excited From Cerenkov Emission Produced by 45MV Radiation for Cancer Therapy

Isotropic-planar illumination for PIV experiments

A new method for laser illumination in particle image velocimetry (PIV) has been introduced: internal “isotropic-planar” illumination that provides laser light to regions of the flow field that were previously cast into shadow using the conventional external (laser light sheet) illumination method. To demonstrate the effectiveness of the isotropic-planar illumination method, a comparison of the measured velocity field around five side-by-side circular cylinders that are immersed in uniform flow is made against the conventional external illumination method. The new method is effective at eliminating the shadow region, allowing the velocity field of the upstream, gap and downstream regions around the five side-by-side circular cylinders to be measured simultaneously. These PIV measurements provide new insight into the behavior of the gap flow that passes between the cylinders.

δ-BIBO:Nd crystals as promising laser operated piezoelectric materials

A possibility to operate piezoelectric efficiency of δ-BIBO:Nd crystals using external nanosecond laser light at 1064nm and 532nm was shown. Depending on the kind of the photoexciting light the behavior of the output piezoelectricity was quite different. The measurements of temperature and temporary features for the photoinduced piezoelectricity confirmed the main role of the incorporation of Nd ions in the δ-BiB3O6 structure with respect to piezoelectricity. The DFT simulations of the local charge density re-distribution were done using the norm-conserving pseudopotential method to confirm principal role of the space charge density redistribution.