Photosensitizer-Functionalized Nanocomposites for Light-Activated Cancer Theranostics

Photosensitizers (PSs) have received significant attention recently in cancer treatment due to its theranostic capability for imaging and phototherapy. These PSs are highly responsive to light source of a suitable wavelength for image-guided cancer therapy from generated singlet oxygen and/or thermal heat. Various organic dye PSs show tremendous attenuation of tumor cells during cancer treatment. Among them, porphyrin and chlorophyll-based ultraviolet-visible (UV-Vis) dyes are employed for photodynamic therapy (PDT) by reactive oxygen species (ROS) and free radicals generated with 400–700 nm laser lights, which have poor tissue penetration depth. To enhance the efficacy of PDT, other light sources such as red light laser and X-ray have been suggested; nonetheless, it is still a challenging task to improve the light penetration depth for deep tumor treatment. To overcome this deficiency, near infrared (NIR) (700–900 nm) PSs, indocyanine green (ICG), and its derivatives like IR780, IR806 and IR820, have been introduced for imaging and phototherapy. These NIR PSs have been used in various cancer treatment modality by combining photothermal therapy (PTT) and/or PDT with chemotherapy or immunotherapy. In this review, we will focus on the use of different PSs showing photothermal/photodynamic response to UV-Vis or NIR-Vis light. The emphasis is a comprehensive review of recent smart design of PS-loaded nanocomposites for targeted delivery of PSs in light-activated combination cancer therapy.

ENHANCEMENT OF GREEN ALGAE HYDROGEN PRODUCTION BY LASER IRRADIATION

Biohydrogen is an alternative to support the increasing hydrogen demand in the future. Biohydrogen is hydrogen gas produced by green algae and bacteria in certain quantity. The aim of this research is to enhance hydrogen gas production by green algae (Closterium sp.) using laser light. The laser used in this experiment was a diode laser operating in continuous mode with wavelength of 655 nm. Green algae are placed in a sulphur deprived medium so it will produce hydrogen gas. This algae is irradiated with diode laser for 30 minutes then stop before continue for the next 30 minutes. This process is repeated until the total irradiation is 120 minutes. Both strains of green algae are set up into measuring system under exposure of sunlight in a constant room temperature. The volume and rate of hydrogen gas produced is examined by measuring the dye position in capillary tube of 0.5 mm radius. The results showed that there is a 9.0% increase of hydrogen gas production in radiated strain of green algae compared to the wild strain. The rate of hydrogen gas production of radiated algae is faster than the wild strain. This showed that, red light laser has absorbed cell green algae and mutated its behaviour for producing more hydrogen gas. This result is in good agreement with other researcher.

Effect of Sunflower (Helianthus annuus L.) Seeds Treatment by Diode Laser Radiation in Seedlings and Calli Growth

The effect of the exposure of sunflower (Helianthus annuus L.) seeds to red light laser radiationwith 650 nm 50 mw/cm2by diode laser in germination and growth of seedlings and calli had beenstudied. Seeds were irradiated with red light for different periods of time 5, 10, 15 and 20minutes. The percentage of seeds germination and the average of roots length were differentaccording to exposure time used. Increasing the time of exposure led to the best results in seedgermination percentage (100%), rooting and shooting behavior and flowering accelerationcompared with control. Initiation of calli from explants (roots, stems and leaves) of sunflowerseedlings on Murashige and Skoog media containing 1.0 mg/l of Benzyl adenine and 0.5 mg/l ofNaphthalene acetic acid were succeeded very well from the irradiated seeds. The best irradiationtime was 20 minutes for growth and durability of leaf calli. The fresh weight, protein, DNA, RNAcontents and the specific activity of dihydrofolate reductase of calli of different explants wereincreased with increasing the duration of seeds exposure to red light at 30 and 60 days of growthon media. Results also illustrate increases in protein and oil contents in the irradiated seeds overcontrol seeds, specially at 20 minutes. Using red laser rays for 5 and 20 minutes, resulted in rootsand shoots production from calli of stem and leaf respectively

Sensitivity Improvement of Ammonia Gas Sensor Based on Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) by Employing Doping of Bromocresol Green

The aim of this research is to improve the sensitivity of ammonia gas sensor (hereafter referred to as sensor) based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by employing the doping dye of bromocresol green (BCG). The doping process was carried out by mixing the BCG and the PEDOT:PSS in a solution with an optimum ratio of 1 : 1 in volume. The sensor was fabricated by using spin-coating technique followed by annealing process. For comparison, the BCG thin film and the PEDOT:PSS thin film were also deposited with the same method on glass substrates. For optical characterization, a red-light laser diode with a 650 nm wavelength was used as light source. Under illumination with the laser diode, the bare glass substrate and BCG film showed no absorption. The sensor exhibited linear response to ammonia gas for the range of 200 ppm to 800 ppm. It increased the sensitivity of sensor based on PEDOT:PSS with BCG doping being about twofold higher compared to that of without BCG doping. Furthermore, the response time and the recovery time of the sensor were found very fast. It suggests that the optical sensor based on BCG-doped PEDOT:PSS is promising for application as ammonia gas sensor.