Signal enhancement in spark-assisted laser-induced breakdown spectroscopy for discrimination of glioblastoma and oligodendroglioma lesions.

Here, the discrimination of two types of lethal brain cancers, i.e., glioblastoma multiforme (GBM) and oligodendroglioma (OG) are investigated under the laser-induced breakdown spectroscopy (LIBS) and the electrical spark-assisted laser-induced breakdown spectroscopy (SA-LIBS) in order to discriminate the human brain glioma lesions against the infiltrated tissues. It is shown there are notable differences between the plasma emissions over the brain gliomas against those of infiltrated tissues. In fact, a notable enhancement appears in the characteristic emissions in favor of SA-LIBS against those of conventional LIB spectra. Moreover, the plasma properties such as temperature, electron density, and degree of ionization are probed through the data processing of the plasma emissions. The corresponding parameters, taken from SA-LIBS data, attest to be lucidly larger than those of LIBS up to one order of magnitude. In addition, the ionic species such as Mg II characteristic line at 279 nm and caII emission at 393 nm are notably enhanced in favor of SA-LIBS. In general, the experimental evidence verifies that SA-LIBS is beneficial in the discrimination and grading of GBM/OG neoplasia against healthy (infiltrate) tissues in the early stages.

Evaluation of photobiomodulation effect on cesarean-sectioned wound healing: a clinical study.

The effects of low-level laser on the wound healing and burn injuries have been previously examined to demonstrate some satisfactory results. Despite there are a few articles available to study photobiomodulation (PBM) effects on the pain relief of cesarean sectioned wound, however no systematic examination has been carried out so far regarding its healing. Here, the aim of this clinical study was to evaluate PBM effect on the cesarean-sectioned wound healing. PBM effects of semiconductor lasers are investigated at 658 and 660 nm with 100, 150 and 350 mW output powers on 40 patients. Due to the global increasing number of cesarean sections, we have decided to investigate the effect of laser as a reliable technique to recover the wounds fast. We considered women as the target group who had their first delivery giving the birth of their children by cesarean section. We selected patients are who treated by laser therapy using indium gallium aluminum phosphide (InGaAlP) semiconductor linear scanning type with beam cross section of 12 cm2 and the output power of 100 mW at 658 nm exposing a therapeutic dose of 2 J/cm2. The purpose is to accelerate the healing process of the wounds after delivery as an intervention group against the people who chose the conventional methods (using ointments, pills, etc.) to heal their cesarean sectioned wounds as the control group. Regarding the wounds of these two groups, the questionnaires were filled by patients to assess the severity of pain from visual analogue scale (VAS) based on the healing of wounds from redness, edema, ecchymosis, discharge, and distance between the two edges of the wound (REEDA) scale in the early hours after surgery and the post-treatment follow-up on the third, seventh, and the tenth days. The data collected by these questionnaires were analyzed using statistical package for social science)SPSS( as a statistical software to give out the comparative histograms. This study reports a clinical examination of PBM under intervention group of 40 patients ranging 18-40 years old with body mass index (BMI) of 29-36, during post-cesarean surgery to elucidate successful healing of the wounds and scars against conventional methods which considered as control group. Comparison of mean REEDA scores on the third day (p = 0.035), seventh day (p = 0.03), and tenth day (p = 0.02) after delivery exhibits that the two groups benefit a statistically significant difference with each other. For instance, the mean wound healing score in the intervention group was almost half of the mean wound healing score on the tenth day in the control group (1.09 ± 0.586 vs. 2.25 ± 0.422). The post-cesarean follow-up indicates that the patients treated by the laser therapy (intervention group) encounter better recovery than the control group.

Laser-induced fluorescence spectroscopy of plant-based drugs: Opium and hashish provoking at 405 nm.

Here, the fluorescence properties of some plant-based drug samples are characterized using a coherent excitation source at 405 nm. The laser-induced fluorescence (LIF) spectroscopy is examined to analyze opium and hashish. In order to improve traditional fluorescence methods for better analysis of optically dense materials, we have proposed five characteristic parameters based on solvent densitometry assay as the fingerprints of drugs of interest. The signal emissions are recorded in terms of various drug concentrations, such that the best fitting over experimental data determines the fluorescence extinction (α) and self-quenching (k) coefficients according to the modified Beer-Lambert formalism. The typical α value is determined to be 0.30 and 0.15 mL/(cm∙mg) for opium and hashish, respectively. Similarly, typical k is obtained 0.390 and 1.25 mL/(cm∙mg), respectively. Furthermore, the concentration at max fluorescence intensity (Cp) is determined for opium and hashish to be 1.8 and 1.3 mg/mL, respectively. Results reveal that opium and hashish benefit their own characteristic fluorescence parameters to discriminate those illicit substances promptly using the present method.

Hybrid laser activated phycocyanin/capecitabine treatment of cancerous MCF7 cells.

Laser-induced fluorescence is recently used as an efficient technique in cancer diagnosis and non-invasive treatment. Here, the synergic therapeutical efficacies of the Capecitabine (CAP) chemodrug, photosensitive Phycocyanin (PC) and graphene oxide (GO) under laser irradiation were investigated. The therapeutical efficacies of diverse concentrations of CAP (0.001-10 mg/ml) and PC (0.5-10 mg/ml) alone and with laser irradiation on human breast adenocarcinoma (MCF-7) cells were examined. The interactional effects of 100 mW SHG Nd:YAG laser at 532nm and GaAs laser at 808 nm ranging power of 150 mW- 2.2W were considered. The contribution of graphene oxide (GO) in biocompatible concentrations of 2.5-20 ng/ml and thermal characteristics of laser exposure at 808 nm on GO + fluorophores have been studied. The effects of the bare and laser-excited CAP + PC on cell mortality have been obtained. Despite the laser irradiation could not hold up the cell proliferation in the absence of drug interaction considerably; however, the viability of the treated cells (by a combination of fluorophores) under laser exposure at 808 nm was significantly reduced. The laser at 532 nm excited the fluorescent PC in (CAP + PC) to trigger the photodynamic processes via oxygen generation. Through the in-vitro experiments of laser-induced fluorescence (LIF) spectroscopy of PC + CAP, the PC/CAP concentrations of the maximum fluorescence signal and spectral shifts have been characterized. The synergic effects of the laser exposures and (CAP + PC) treatment at different concentrations were confirmed. It has been shown here that the laser activation of (CAP + PC) can induce the mortality of the malignant cells by reducing the chemotherapeutic dose of CAP to avoid its non-desirable side effects and by approaching the minimally invasive treatment. Elevation of the laser intensity/exposure time could contribute to the therapeutic efficacy. Survival of the treated cells with a combination of GO and fluorophores could be reduced under laser exposure at 808 nm compared to the same combination therapy in the absence of GO. This survey could benefit the forthcoming clinical protocols based on laser spectroscopy for in-situ imaging/diagnosis/treatment of adenocarcinoma utilizing PC + CAP + GO.

Optical characterization of the liver tissue affected by fibrolamellar hepatocellular carcinoma based on internal filters of laser-induced fluorescence.

Laser-induced fluorescence (LIF) spectroscopy has recently gained regards for diagnosis of the cancer in various tissues of the human body. This method in its conventional form, when used for assay of highly scattering media, encounters a lot of noise due to multiple scattering and inner filter effects which overshadows the sensitivity and specificity of the method. Here, angular dependence of the LIF spectral shift due to the reabsorption events have been investigated for characterization of the bio-tissues. The aim was to determine the tissue morphological changeovers due to the cancer progression. The assessment of a rare type of the liver cancer i. e. fibrolamellar hepatocellular carcinoma revealed the significant difference in optical anisotropy of the parenchyma and liver tumor. As a result, utilizing LIF spectroscopy as a fast, highly sensitive and easy-to-use method one can evaluate the optical anisotropy for diagnosing tissues during the cancer progression.

In Vitro Evaluation of DSPE-PEG (5000) Amine SWCNT Toxicity and Efficacy as a Novel Nanovector Candidate in Photothermal Therapy by Response Surface Methodology (RSM).

Nowadays, finding a novel, effective, biocompatible, and minimally invasive cancer treatment is of great importance. One of the most promising research fields is the development of biocompatible photothermal nanocarriers. PTT (photothermal therapy) with an NIR (near-infrared) wavelength range (700-2000 nm) would cause cell death by increasing intercellular and intracellular temperature. PTT could also be helpful to overcome drug resistance during cancer treatments. In this study, an amine derivative of phospholipid poly ethylene glycol (DSPE-PEG (5000) amine) was conjugated with SWCNTs (single-walled carbon nanotubes) to reduce their intrinsic toxicity. Toxicity studies were performed on lung, liver, and ovarian cancer cell lines that were reported to show some degree of drug resistance to cisplatin. Toxicity results suggested that DSPE-PEG (5000) amine SWCNTs might be biocompatible photothermal nanocarriers in PTT. Therefore, our next step was to investigate the effect of DSPE-PEG (5000) amine SWCNT concentration, cell treatment time, and laser fluence on the apoptosis/necrosis of SKOV3 cells post-NIR exposure by RSM and experimental design software. It was concluded that photothermal efficacy and total apoptosis would be dose-dependent in terms of DSPE-PEG (5000) amine SWCNT concentration and fluence. Optimal solutions which showed the highest apoptosis and lowest necrosis were then achieved.

Gold fineness measurement using single-shot spark assisted laser-induced breakdown spectroscopy.

Here, a homemade gold fineness analyzer is fabricated based on calibration-free spark assisted laser-induced breakdown spectroscopy (CF SA-LIBS). The experimental arrangement consists of a Q-switched Nd:YAG laser combined with a spark generator and a single-channel CCD spectrometer. The well-arranged optical system, coupled with an electrical setup, allows us to successfully run SA-LIBS even at low energy single shots. The electric discharge contributes LIBS to reheat and promote more energetic plasma. Subsequently, plasma temperature elevates up to ∼20%, and its lifetime is elongated as much as 6 times. As a consequence, the relative signal intensity is enhanced up to 1 order of magnitude against that of LIBS at the same pulsed energy. Furthermore, the electron density is also measured based on the broadened spectral width of the intensified Hα line. The latter is used to obtain the ionic species concentrations more accurately according to the Saha-Eggert equation. As a result, we have assessed the gold karat with an analytical error less than 0.5% using CF SA-LIBS. In addition, the surface patterns recorded by the stylus profilometer reveal that the single-shot SA-LIBS benefits a smaller ablative mass against standard LIBS.

Spectroscopic Characteristics of Xeloda Chemodrug.

Introduction: Spectroscopic properties of Xeloda chemodrug have been studied over varying concentrations ranging between 0.001 and 10 mg/mL, using laser-induced fluorescence (LIF) spectroscopy. The alternative photoluminescence (PL) and near infrared (NIR) measurements are carried out to authenticate the obtained results by the LIF method. Methods: The XeCl laser as the excitation coherent source with 160 mJ/pulse at 308 nm is employed for LIF measurements of the fluorophore of interest in the modular spectroscopic set-up. Results: Xeloda as a significant chemodrug acts as a notable fluorophore. LIF, PL and NIR spectroscopy techniques are employed to investigate the spectral properties of the chemodrug in terms of concentration. The maximum LIF peak intensity of Xeloda is achieved at λmax=410.5 nm and the characteristic concentration of CP1=0.05 mg/mL. PL signals are in good agreement with the data given by the LIF measurements. The characteristic NIR spectra of Xeloda as solid evidence of chemical bonding formation attest to fluorescence quenching at the fluorophore concentration of ~ 0.2 mg/ mL. Besides, the spectral shift of fluorescence signals which is obtained in terms of fluorophore concentration- demonstrating as a diagnostic marker for the purpose of optimized chemotherapy. Conclusion: Xeloda exhibits outstanding fluorescence properties over the allowable concentration in human serum (Cmax). These characteristics could benefit potential advantage of simultaneous laser-based imaging of cell-chemodrug interaction over in-vivo studies.

Spectroscopic properties of various blood antigens/antibodies.

Since the traditional method generates biological waste, there is a significant demand for an easy, quick technique of blood type identification without contamination. In fact, individuals can be divided into four main blood groups whose antigens are available in red blood cell (RBC) membranes and the antibodies in the plasma. Here, UV-vis and photoluminescence (PL) spectroscopic methods are systematically used to find the spectra of blood typing antigens (A, B and AB) and antibodies i.e. A-Anti, B-Anti, AB-Anti and D reagent. The PL spectra of RBCs in different blood groups as well as the corresponding antibodies are successfully resolved for the purpose of blood typing. The unique photophysical characteristics of these biomolecules including signal intensity and peak emission wavelength in PL spectra are lucidly anticipated to accurately discriminate ABO groups. PL spectra of RBC in positive blood typing indicate larger signal and shorter emission peak wavelength corresponding to negative ones. Furthermore, the monoclonal antibody PL emissions emphasize that Anti-A benefits higher intensity and shorter peak wavelength (blue shift) than B-Anti. In the following, lucid blue shifts are obtained in terms of antibody concentrations accompanying the elevation of fluorescence signal, most likely due to the aggregation induced emission (AIE) phenomenon, quite the opposite of the aggregation-caused quenching (ACQ) that is widely observed from conventional chromophore. Those are envisaged as unique properties of each antibody to utilize in the spectral blood typing.

Angular distribution of laser-induced fluorescence emission of active dyes in scattering media.

Angular dependence of the intensity and the emissive wavelength of the laser-induced fluorescence emission in hybrid media (fluorophores+nanoparticles) are investigated using various TiO2 densities as guest nanoscatterers in the ethanolic solutions of the host Rd6G and coumarin 4 (C4) molecules. It is shown that the intensity of the scattered photons varies in terms of the detection angle. When the nanoscatterer density increases at a certain excitation energy, the angular anisotropy enhances. While the emissive wavelength exhibits the spectral shift in terms of the angular variation for Rd6G fluorophores, it remains invariant for C4-based suspension. In the former case, the emissive wavelength undergoes a spectral shift in terms of angular variation. Several factors such as the optical path length in the scattering media, the excitation volume, and the re-absorption events of the fluorescence emissions by the non-excited molecules strongly affect the spectral features. In fact, the density of the scatterers, the dye concentration, and the interplay between Stokes shift rate and the overlapping between absorption/emission spectra of the given fluorophores are taken into account as the major parameters to form the angular distribution.

Fluorescence properties of doxorubicin coupled carbon nanocarriers.

The effect of graphene oxide (GO) and nanodiamond (ND) is investigated on the spectral properties of doxorubicin (DOX) fluorescence emissions in the form of (DOX+GO) and (DOX+ND) biomaterials. It is shown that carbon nanostructure additives lead to sensible blueshifts, due to their optical properties and surface functionality. The quenching coefficient KND is obtained to be KND=0.043 (µg/ml)-1 and KGO=0.342 (µg/ml)-1 in DOX solutions. In general, Stern-Volmer attests that excited (DOX+GO) strongly quenches with respect to that of (DOX+ND) regarding its privileged bonding affinity.

Effect of hydrocarbon molecular decomposition on palladium-assisted laser-induced plasma ablation.

The Q-switched Nd:YAG laser is focused on a palladium target in the control chamber filled with various hydrocarbon atmospheres (C1-C4) to investigate their effect on the palladium ablated mass, gas reaction products, and corresponding plasma parameters (such as electron density Ne and plasma temperature Te) during molecular decomposition. The plasma parameters arise mainly from the Pd nanocatalytic activity during the laser-induced plasma process. We compare synthetic air atmosphere to hydrocarbon media to understand how the latter generates excess heat via oxygen-free exothermic (recombination) reactions. Subsequently, this gives rise to more energetic plasma and higher temperature, regarding the large amount of nanoparticles released into the plasma. The dynamics of the decomposition/recombination events accompany the nanocatalyst activity, leading to soot deposition all over the chamber.

LIF spectroscopy of stained malignant breast tissues.

We employ laser induced fluorescence (LIF) spectroscopy to discriminate between normal and cancerous human breast (in-vitro) tissues. LIF signals are usually enhanced by the exogenous agents such as Rhodamine 6G (Rd6G) and Coumarin 7 (C7). Although we observe fluorescence emissions in both fluorophores, Rd6G-stained tissues give notable spectral red shift in practice. The latter is a function of dye concentration embedded in tissues. We find that such red shifts have a strong dependence on the dye concentration in bare, in stained healthy, and in malignant breast tissues, signifying variations in tubular abundances. In fact, the heterogeneity of cancerous tissues is more prominent mainly due to their notable tubular densities- which can provide numerous micro-cavities to house more dye molecules. We show that this can be used to discriminate between the healthy and unhealthy specimens in different biological scaffolds of ordered (healthy) and disordered (cancerous) tissues. It is demonstrated that the quenching process of fluorophore' molecules slows down in the neoplastic tumors according to the micro-partitioning, too.

Laser induced breakdown spectroscopy and acoustic response techniques to discriminate healthy and cancerous breast tissues.

Laser induced breakdown spectroscopy and subsequent acoustic response during microplasma formation are employed to identify cancerous human breast tissues. The characteristic optical emissions identify Ca, Na, and Mg rich species in cancerous tissues compared to those of healthy ones. Furthermore, we show that the characteristic parameters of the microplasma, generated on the unhealthy tissues, are elevated. We report higher decibel audio signals emanating from laser induced microplasma and a subsequent audio blueshift for malignant tissues. The higher abundance of trace elements in cancerous tissues as well as higher plasma temperature and electron density in laser induced microplasma (leading to a stronger shockwave) intensify the acoustic signals.

Fluorescence properties of several chemotherapy drugs: doxorubicin, paclitaxel and bleomycin.

Several chemo-drugs act as the biocompatible fluorophores. Here, the laser induced fluorescence (LIF) properties of doxorubicin, paclitaxel and bleomycin are investigated. The absorption lines mostly lie over UV range according to the UV-VIS spectra. Therefore, a single XeCl laser provokes the desired transitions of the chemo-drugs of interest at 308 nm. It is shown that LIF spectra are strongly dependent on the fluorophore concentration giving rise to the sensible red shift. This happens when large overlapping area appears between absorption and emission spectra accordingly. The red shift is taken into account as a characteristic parameter of a certain chemo-drug. The fluorescence extinction (α) and self-quenching (k) coefficients are determined based on the best fitting of the adopted Lambert-Beer equation over experimental data. The quantum yield of each chemo-drug is also measured using the linearity of the absorption and emission rates.

Changeover in the molecular and atomic fluorine laser transitions.

Measurements of molecular and atomic fluorine laser emissions were done from 2?psi (absolute) to 5?atm to determine pressure-dependent spectral lines. While at low pressures, the atomic transitions are dominant; however, both atomic and molecular transitions are detected simultaneously at atmospheric pressures above approximately 2?atm, where a changeover occurs. The excitation mechanisms are strongly dependent on the excited and ionized He species within the gain medium. Initially it affects the atomic transitions of the submanifolds and the corresponding molecular transition takes place via collisional events. The gain competitions among the doublet and quartet atomic transitions have also been investigated.

Acoustic effects of metal vapor lasers.

Some fluctuations in the output power of a copper vapor laser with a 16 mm bore were recorded by varying the excitation frequency from 13 to 33 kHz. The effect arises from the laser tube, which performs both as an optical and an acoustic resonator at the acoustic resonant frequencies. It is shown that a similar effect occurs in other metal vapor and copper halide lasers as well.

Pressure dependence of the small-signal gain and saturation intensity of a copper vapor laser.

The small-signal gain coefficient and the saturation intensity of a copper vapor laser have been measured for both 510.6- and 578.2-nm transitions through the implementation of a discharge driven oscillator-amplifier configuration. Pressure dependence of the gain and saturation property of the laser has been investigated.