A novel 785-nm laser diode-based system for standardization of cell culture irradiation.

OBJECTIVE: The purpose of this study was to develop a novel device that concatenates alignment of infrared lasers and parallel procedure of irradiation. The purpose of this is to seek standardization of in vitro cell irradiation, which allows analysis and credible comparisons between outcomes of different experiments. BACKGROUND DATA: Experimental data obtained from infrared laser therapies have been strongly dependent upon the irradiation setup. Although further optical alignment is difficult to achieve, in contact irradiation it usually occurs. Moreover, these methods eventually use laser in a serial procedure, extending the time to irradiate experimental samples. METHODS: A LASERTable (LT) device was designed to provide similar infrared laser irradiation in 12 wells of a 24 well test plate. It irradiated each well by expanding the laser beam until it covers the well bottom, as occurs with unexpanded irradiation. To evaluate the effectiveness of this device, the spatial distribution of radiation was measured, and the heating of plain culture medium was monitored during the LT operation. The irradiation of LT (up to 25 J/cm(2) - 20 mW/cm(2); 1.250 sec) was assessed on odontoblast-like cells adhered to the bottom of wells containing 1 mL of plain culture medium. Cell morphology and metabolism were also evaluated. RESULTS: Irradiation with LT presented a Gaussian-like profile when the culture medium was not heated >1°C. It was also observed that the LT made it 10 times faster to perform the experiment than did serial laser irradiation. In addition, the data of this study revealed that the odontoblast-like cells exposed to low-level laser therapy (LLLT) using the LT presented higher metabolism and normal morphology. CONCLUSIONS: The experimental LASERTable assessed in this study provided parameters for standardization of infrared cell irradiation, minimizing the time spent to irradiate all samples. Therefore, this device is a helpful tool that can be effectively used to evaluate experimental LLLT protocols.

Thermography applied during exercises with or without infrared light-emitting diode irradiation: individual and comparative analysis.

OBJECTIVE: The aim of our study was to evaluate the cutaneous temperature during an exercise on a treadmill with or without infrared light-emitting diode (LED) irradiation in postmenopausal women. BACKGROUND DATA: Thermography is an imaging technique in which radiation emitted by a body in the middle and far infrared spectrum is detected and associated with the temperature of the body's surface. MATERIALS AND METHODS: Eighteen postmenopausal women were randomly divided into two groups: (1) the LED group, which performed the exercises on a treadmill associated with phototherapy (n=9) and; (2) the exercise group, which performed the exercises on a treadmill without additional phototherapy (n=9). The irradiation parameters for each women's thigh were: array of 2000 infrared LEDs (850 nm) with an area of 1,110 cm(2), 100 mW, 39 mW/cm(2), and 108 J/cm(2) for 45 min. The submaximal constant-speed exercise on the treadmill at intensities between 85% and 90% maximal heart rate (HRmax) with or without phototherapy were performed during 45 min, to perform the thermographic analysis. Thermography images were captured before the exercise (t=0), after 10, 35, and 45 min of exercising (t=10, t=35, and t=45) and at 5 min post-exercising (t=50). RESULTS: The LED group showed an increased cutaneous thigh temperature during the exercise (from 33.5±0.8°C to 34.6±0.9°C, p=0.03), whereas the exercise group showed a reduced cutaneous temperature (from 33.5±0.6 to 32.7±0.7°C, p=0.02). The difference between the groups was significant (p<0.05) at t=35, t=45, and t=50. CONCLUSIONS: These data indicate an improved microcirculation, and can explain one possible mechanism of action of phototherapy associated with physical exercises.

Chemiluminescence as a PDT light source for microbial control.

The photodynamic therapy (PDT) is a combination of using a photosensitizer agent, light and oxygen that can cause oxidative cellular damage. This technique is applied in several cases, including for microbial control. The most extensively studied light sources for this purpose are lasers and LED-based systems. Few studies treat alternative light sources based PDT. Sources which present flexibility, portability and economic advantages are of great interest. In this study, we evaluated the in vitro feasibility for the use of chemiluminescence as a PDT light source to induce Staphylococcus aureus reduction. The Photogem® concentration varied from 0 to 75 µg/ml and the illumination time varied from 60 min to 240 min.The long exposure time was necessary due to the low irradiance achieved with chemiluminescence reaction at µW/cm² level. The results demonstrated an effective microbial reduction of around 98% for the highest photosensitizer concentration and light dose. These data suggest the potential use of chemiluminescence as a light source for PDT microbial control, with advantages in terms of flexibility, when compared with conventional sources.