This PDF file contains the front matter associated with SPIE Proceedings Volume 9309, including the Title Page, Copyright information, Table of Contents, Invited Panel Discussion, and Conference Committee listing.

Low level laser (light) therapy (LLLT) also known as photobiomodulation (PBM) therapy has been practiced for almost fifty years, and hundreds of positive clinical trials and thousands of laboratory studies have been published. Despite these impressive accomplishments LLLT has still not reached the stage of acceptance by mainstream medicine. The reasons for this were discussed at a recent Optical Society of America (OSA) Incubator meeting in Washington DC in 2014. Uncertainty about mechanisms was highlighted, and this paper will describe the current thinking. To drive LLLT towards mainstream medicine, we need better guidelines with standardized protocols and consistent parameters. Studies should be published in higher impact scientific and medical journals. Companies should avoid false promises and deceptive marketing, and physicians should receive a clearly defined return on investment with insurance reimbursement.

Light delivery for potential bacterial disinfection (UV/blue) and photobiomodulation (near-IR) requires specific, concentrated and controllable local irradiance and dose. Dental targets for light irradiation involve dentine, which scatters, absorbs and reflects light, reducing local irradiance. This study compared the effectiveness of LEDs (400-900nm) and lasers (660nm and 810nm) to penetrate dentine. Caries-free wisdom teeth were sectioned through the Pulpchamber by either cutting perpendicular to the crown, the buccal aspect or obliquely. Specimens were wet-polished to 1, 2 or 3mm thicknesses to expose the dentine on opposing surfaces. The beam profile of the LEDs/lasers were measured through dentine specimens (n=5) to obtain beam width following optical calibration, and spatial irradiance distribution following photodiode power calibration. There were no significant differences in the percentage power and irradiance transmitted through different dentine specimens between LEDs and lasers (P>0.05). However, light penetration through tissue was wavelength dependent and highest for red and near-IR wavelengths (P<0.05) for specimens cut perpendicular to the crown compared with buccal and oblique specimens. The beam diameters increased and irradiance decreased significantly (P<0.05) with increasing specimen thickness/distance for both LEDs and lasers. There was a noticeable shift in beam position for all light sources in buccal and oblique specimens. Data indicated that dentine tubule orientation may alter the direction of light through the tissue. Optimal light penetration and distribution through dentine at specific distance is best achieved with a flat-top beam distribution vertically through the crown of the tooth.

Human dental pulp cells (DPCs) were isolated and cultured in phenol-red-free α-MEM/10%-FCS at 37ºC in 5% CO₂. DPCs at passages 2-4 were seeded (150μL; 25,000 cell/ml) in black 96-microwell plates with transparent bases. 24h post-seeding, cultures were irradiated using a bespoke LED array consisting of 60 LEDs (3.5mW/cm²) of wavelengths from 400-900nm (10 wavelengths, n=6) for time intervals of up to 120s. Metabolic and mitochondrial activity was assessed via a modified MTT assay. Statistical differences were identified using multi-factorial analysis of variance and post-hoc Tukey tests (P=0.05). The biological responses were significantly dependent upon post-irradiation incubation period, wavelength and exposure time (P<0.05). At shorter wavelength irradiances (400nm), a reduction in mitochondrial activity was detected although not significant, whereas longer wavelength irradiances (at 633, 656, 781 and 799nm) significantly increased mitochondrial activity (P<0.05) in DPCs. At these wavelengths, mitochondrial activity was generally increased for exposures less than 90s with 30s exposures being most effective with 24h incubation. Increasing the post-irradiation incubation period increased the measured response and identified further significance (P<0.05). The biological responses of human DPCs were wavelength, exposure-time and incubation period dependent. The optimisation of irradiation parameters will be key to the successful application of LLLT in dentistry.

Low level laser irradiation (LLLI) is the application of red or near infrared lasers irradiating between 600-1100 nm with an output power of 1-500 mW. Several researches indicate that LLLI modulates cellular mechanisms and leads to enhance proliferation. Although the biological mechanisms are not fully understood, it is known that the effects depend on several parameters such as wavelength, irradiation duration, energy level, beam type and energy density. The aim of this study is to investigate the effect of low level laser irradiation at varying energy densities with two different wavelengths (635 nm and 809 nm) on the proliferation of human osteoblasts in vitro. The cells are seeded on 96 well plates (10⁵cells/well) and after 24 h incubation cells are irradiated at energy densities 0.5 J/cm², 1 J/cm² and 2 J/cm². Cell viability test is applied after 24 h, 48 h and 72 h in order to examine effects of laser irradiation on osteoblast proliferation. 635 nm light irradiation did not appear to have significant effect on the proliferation of osteoblasts as compared to the control. On the other hand, 809 nm laser irradiation caused significant (p ≤ 0.01) biostimulation effect on the osteoblast cell cultures at 48 h and 72 h. In conclusion, irradiation of both wavelengths did not cause any cytotoxic effects. 809 nm light irradiation can promote proliferation of human osteoblasts in vitro. On the other hand, 635 nm light irradiation has no positive effect on osteoblast proliferation. As a result, LLLI applied using different wavelengths on the same cell type may lead to different biological effects.

Low level laser/light therapy (LLLT) or photobiomodulation is a biophysical approach that can be used to reduce pain, inflammation and modulate tissue healing and repair. However, its application has yet to be fully realized for dental disease treatment. The aim of this study was to assess the modulation of dental pulp cell (DPC) responses using two LLLT lasers with wavelengths of 660nm and 810nm. Human DPCs were isolated and cultured in phenol-red-free α- MEM/10%-FCS at 37°C in 5% CO₂. Central wells of transparent-based black walled 96-microplates were seeded with DPCs (passages 2-4; 150μL; 25,000 cell/ml). At 24h post-seeding, cultures were irradiated using a Thor Photomedicine LLLT device (THOR Photomedicine, UK) at 660nm (3, 6 or 13s to give 2, 5 and 10J/cm²) or 810nm (for 1, 2 or 5s to deliver 5, 10 and 20J/cm²). Metabolic activity was assessed via a modified MTT assay 24h post-irradiation. Statistical differences were identified using analysis of variance and post-hoc Tukey tests (P=0.05) and compared with nonirradiated controls. Significantly higher MTT activity was obtained for both lasers (P<0.05) using the high and intermediate radiant exposure (5-20J/cm²). The MTT response significantly decreased (P<0.05) at lower radiant exposures with no statistical significance from control (P>0.05). Consequently, enhanced irradiation parameters was apparent for both lasers. These parameters should be further optimised to identify the most effective for therapeutic application.

Blue light is known for its anti-microbial, anti-proliferative and anti-inflammatory effects. Furthermore, it is already used for the treatment of neonatal jaundice and acne. However, little is known about the exact mechanisms of action on gene expression level. The aim of this study was to assess the impact of blue LED irradiation on the proliferation and gene expression in immortalized human keratinocytes (HaCaT) in vitro. Furthermore its safety was assessed. XTT-tests revealed a decrease in cell proliferation in blue light irradiated cells depending on the duration of light irradiation. Moreover, gene expression analysis demonstrated deregulated genes already 3 hours after blue light irradiation. 24 hours after blue light irradiation the effects seemed to be even more pronounced. The oxidative stress response was significantly increased, pointing to increased ROS production due to blue light, as well as steroid hormone biosynthesis. Downregulated pathways or biological processes were connected to anti-inflammatory response. Interestingly, also the melanoma pathway contained significantly downregulated genes 24 hours after blue light irradiation, which stands in accordance to literature that blue light can also inhibit proliferation in cancer cells. First tests with melanoma cells revealed a decrease in cell proliferation after blue light irradiation. In conclusion, blue light irradiation might open avenues to new therapeutic regimens; at least blue light seems to have no effect that induces cancer growth or formation.

Vascular damage occurs frequently at the injured brain causing hypoxia and is associated with poor outcomes in the clinics. We found high levels of glycolysis, reduced ATP generation, and increased formation of reactive oxygen species (ROS) and apoptosis in neurons under hypoxia. Strikingly, these adverse events were reversed significantly by noninvasive exposure of injured brain to low-level light (LLL). LLL illumination sustained the mitochondrial membrane potential, constrained cytochrome C leakage in hypoxic cells, and protected them from apoptosis, underscoring a unique property of LLL. The effect of LLL was further bolstered by combination with metabolic substrates such as pyruvate or lactate both in vivo and in vitro. The combinational treatment retained memory and learning activities of injured mice to a normal level, whereas those treated with LLL or pyruvate alone, or sham light displayed partial or severe deficiency in these cognitive functions. In accordance with well-protected learning and memory function, the hippocampal region primarily responsible for learning and memory was completely protected by a combination of LLL and pyruvate, in marked contrast to the severe loss of hippocampal tissue due to secondary damage in control mice. These data clearly suggest that energy metabolic modulators can additively or synergistically enhance the therapeutic effect of LLL in energy-producing insufficient tissues like injured brain. Keywords:

Increasing concern is evident over the epidemic of traumatic brain injury in both civilian and military medicine, and the lack of approved treatments. Transcranial low level laser therapy tLLLT) is a new approach in which near infrared laser is delivered to the head, penetrates the scalp and skull to reach the brain. We asked whether tLLLT at 810-nm could improve memory and learning in mice with controlled cortical impact traumatic brain injury. We investigated the mechanism of action by immunofluorescence studies in sections from brains of mice sacrificed at different times. Mice with TBI treated with 1 or 3 daily laser applications performed better on Morris Water Maze test at 28 days. Laser treated mice had increased BrdU incorporation into NeuN positive cells in the dentate gyrus and subventricular zone indicating formation of neuroprogenitor cells at 7 days and less at 28 days. Markers of neuron migration (DCX and Tuj1) were also increased, as was the neurotrophin, brain derived neurotrophic factor (BDNF) at 7 days. Markers of synaptogenesis (formation of new connections between existing neurons) were increased in the perilesional cortex at 28 days. tLLLT is proposed to be able to induce the brain to repair itself after injury. However its ability to induce neurogenesis and synaptogenesis suggests that tLLLT may have much wider applications to neurodegenerative and psychiatric disorders.

Red and near-infrared light have been widely employed in optical therapies. Skin is the most common optical barrier in non-invasive techniques and in many cases it is the target tissue itself. Consequently, to optimize the outcomes brought by lightbased therapies, the optical properties of skin tissue must be very well elucidated. In the present study, we evaluated the dorsal skin optical properties of albino (BALB/c) and pigmented (C57BL/6) mice using the Kubelka-Munk photon transport model. We evaluated samples from male and female young mice of both strains. Analysis was performed for wavelengths at 630, 660, 780, 810 and 905 nm due to their prevalent use in optical therapies, such as low-level light (or laser) and photodynamic therapies. Spectrophotometric measurements of diffuse transmittance and reflectance were performed using a single integrating sphere coupled to a proper spectrophotometer. Statistic analysis was made by two-way ANOVA, with Tukey as post-test and Levenne and Shapiro-Wilks as pre-tests. Statistical significance was considered when p<0.05. Our results show only a slight transmittance increment (<10 %) as wavelengths are increased from 630 to 905 nm, and no statistical significance was observed. Albino male mice present reduced transmittance levels for all wavelengths. The organization and abundance of skin composing tissues significantly influence its scattering optical properties although absorption remains constant. We conclude that factors such as subcutaneous adiposity and connective tissue structure can have statistically significant influence on mice skin optical properties and these factors have relevant variations among different gender and strains.

Although the mechanism of low level laser therapy (LLLT) is unclear, many studies demonstrated the positive clinical performance of LLLT for skin rejuvenation. An increase in dermal collagen plays an important role in skin rejuvenation and wound healing. This study aimed to investigate collagen generation after interstitial low level laser stimulation (ILLS). Rabbits were divided into two groups: surfacing irradiation and minimally invasive irradiation. 660nm diode laser of 20mW with 10J, 13J and 15J was applied to the backside of rabbits. Collagen formation was evaluated with ultrasound skin scanner every 12 hours. Results shows that ILLS groups have denser collagen density than surfacing groups.

Introduction: Pressure sores (decubitus ulcer) are a serious problem in health care management, especially for middleaged to older people who are bed-ridden. Although preventative measures are used, the condition remains common and development of novel, improved treatment methods are desirable. This article reviews the application of laser-based methods, previously shown to be effective in accelerating wound-healing in animal models and in the treatment of decubitus ulcers in humans. Methods: About 23 scientific articles on the effect of low level laser therapy (LLLT) on wound healing in animals and humans from 2000-2014 were reviewed. Additionally, results of several randomized controlled trials (RCTs) were reviewed, and compared with other treatment methods available. Results: Whilst carefully controlled, laboratory-based animal studies indicated that LLLT can reduce healing time for several types of injuries, however similar studies in humans failed to demonstrate consistent beneficial effects in the clinical setting. An acceleration of decubitus ulcer healing has been occasionally found, although limited to certain wavelengths and sometimes only in combination with other types of therapies. Indeed, some of the clinical articles indicated that certain laser wavelengths can have detrimental effects on time of healing. Conclusions: To date, there remains no convincing evidence that LLLT has consistent medical benefit in treating decubitus ulcers. Caution should be applied when considering LLLT since only certain wavelengths utilized have shown beneficial effects. It is concluded that, more RCTs are needed since, there is no clinical justification for LLLT, alone or in combination with other methods, in treating decubitus ulcers.

A laser therapy device using three combined wavelengths 532nm, 808nm, and 1064nm has been demonstrated in clinical studies. Primarily, therapeutic lasers have used wavelengths in the ranges of 632nm through 1064nm, where the optical density (OD) < 5, to achieve pain relief and tissue regeneration. Conventional wisdom would argue against using wavelengths in the region of 532nm, due to poor penetration (OD ~ 8); however, the author’s observations are to the contrary. The 532nm light is efficiently absorbed by chromophores such as oxyhemoglobin, deoxyhemoglobin, and cytochrome c oxidase thereby providing energy to accelerate the healing process. The 808nm light is known to result in Nitric Oxide production thereby reducing inflammation and oxidative stress. All three laser wavelengths likely contribute to pain relief by inhibiting nerve conduction; however, the 1064nm has the deepest penetration. Through the use of this device on over 1000 patients with a variety of acute and chronic neuro-musculoskeletal disorders, the author observed that a majority of these individuals experienced rapid relief from their presenting conditions and most patients reported a tingling sensation upon irradiation. Patient testimonials and thermal images have been collected to document the results of the laser therapy. These studies demonstrate the ability of laser therapy to rapidly alleviate pain from both acute and chronic conditions.

Temporomandibular disorders (TMD) are commonly found in the population and usually involve inflammatory processes. Previous studies have shown positive effects of LED (Light emitting diodes) phototherapies on TMD but its action and mechanism in the inflammatory infiltrate of the temporomandibular joint are still poorly understood. The aim of this study was to assess through histological analysis the effectiveness LED (10 J/cm², λ850 nm, 100 mW, CW) on the inflammation of the temporomandibular joint of rats induced by carrageenan. Thirty animals were divided in two groups with five animals per subgroup according to the experimental times of two, three and seven days: Inflammation and Inflammation + LED phototherapy. The first irradiation was performed 24 h after induction with an interval of 48 h between sessions. After animal death, specimens were processed and stained with HE and Picrosirius. Then the samples were examined histologically. Data were statistically analyzed. The inflammation group showed mild to moderate chronic inflammatory infiltrate among the bone trabecules of the condyle. Over the time-course of the study in the LED group the condyle showed aspects of normality and absent inflammation in some specimens. In all the time-points, no statistically significant differences were found for collagen deposition in the in the condyle and disc when LED was compared to Inflammation group. LED treated groups also demonstrated a smaller number of the layers of the synovial membrane when compared to the non-irradiated groups. It was concluded that, in general, LED phototherapy resulted in a reduction of inflammatory infiltrate in the temporomandibular joint of rat.

A quick bone formation after maxillary expansion would reduce treatment timeand the biomodulating effects of LED light could contribute for it. The aim of this study was to analyze the effect of LED phototherapy on the acceleration of bone formation at the midpalatal suture after maxilla expansion. Thirty rats divided into 6 groups were used on the study at 2 time points - 7 days: Control; Expansion; and Expansion + LED; and 14 days: Expansion; Expansion + LED in the first week; Expansion and LED in the first and second weeks. LED irradiation occurred at every 48 h during 2 weeks. Expansion was accomplished using a spatula and maintained with a triple helicoid of 0.020” stainless steel orthodontic wire. A LED light (λ850 ± 10nm, 150mW ± 10mW, spot of 0.5cm², t=120 sec, SAEF of 18J/cm²) was applied in one point in the midpalatal suture immediately behind the upper incisors. Near infrared Raman spectroscopic analysis of the suture region was carried and data submitted to statistical analyzes (p≤0.05). Raman spectrum analysis demonstrated that irradiation increased hydroxyapatite in the midpalatal suture after expansion. The results of this indicate that LED irradiation; have a positive biomodulation contributing to the acceleration of bone formation in the midpalatal suture after expansion procedure.

Polymorphonuclear neutrophils (PMN) participate in an active way in the innate immunity developed after the fungal infection paracoccidioidomycosis (PCM). Nevertheless, the sole participation of neutrophils is not sufficient to eradicate PCM`s pathogenic fungus: Paracoccidioides brasiliensis (Pb). In that way, we aimed to develop a treatment capable of stimulating PMN to the site of injury through low-level laser therapy (LLLT). (LLLT) is safe to use and has not been linked to microorganism resistance so far; in addition, based on previous studies we understand that LLLT may be useful to treat several medical conditions through the stimulation and activation of certain types of cells. This brief review is based on the novel attempt of activating PMN against a fungal infection.

Nowadays photodynamic inactivation has been proposed as an alternative treatment for localized bacterial infections as a response to the problem of antibiotic resistance. Much is already known about the photodynamic inactivation of microorganisms: both antibiotic-sensitive and -resistant strains can be successfully photoinactivated and there is the additional advantage that repeated photosensitization of bacterial cells does not induce a selection of resistant strains. Staphylococcus spp. are opportunistic microorganisms known for their capacity to develop resistance against antimicrobial agents. The emergence of resistant strains of bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) poses a major challenge to healthcare. MRSA is a major cause of hospital-acquired infection throughout the world and is now also prevalent in the community as well as nursing and residential homes. The aim of this study was to evaluate the phagocytic function of macrophages J774 against S. aureus in the presence and absence of AmPDT with phenothiazine compound (12.5 μg/mL) and low level laser (λ=660nm, 12 J/cm²). Experimental groups: Control group (L-P-), Phenothiazine group (L-P+) Laser group (L+P-), AmPDT group (L+P+).The tests presented in this study were performed in triplicate. This study showed that AmPDT induced bacterial death in about 80% as well as increasing phagocytic capacity of macrophages by approximately 20% and enhanced the antimicrobial activity by approximately 50% compared to the control group and enabling more intense oxidative burst.

Far red/near infrared light (NIR) is beneficial against cardiac ischemia and reperfusion injury (I/R), although the exact underlying mechanism is unknown. Previously we established that NIR enhanced the cardioprotective effect of nitrite in the rabbit heart. Furthermore, we observed that the nitrosyl myoglobin (MbNO) level in ischemic tissue decreased upon irradiation of the heart. Our hypothesis was that protection against I/R is dependent on nitric oxide (NO)-release from heme-proteins, and remains present during diabetes. When mice were subjected to I/R NIR (660 nm) applied during the beginning of reperfusion reduced infarct size dose dependently compared to untreated animals. Similarly, the isolated (Langendorff) heart model resulted in sustained left ventricular diastolic pressure after I/R in NIR-treated hearts. NIRinduced protection was preserved in a diabetic mouse model (db/db) and during acute hyperglycemia. NIR liberated NO from nitrosyl hemoglobin (HbNO) and MbNO as well as from HbNO isolated from the blood of diabetic animals. In the Langendorff model, after application of the nitrosylated form of a hemoglobin-based oxygen carrier as an NO donor NIR induced an increase in NADH level, suggesting a mild inhibition of mitochondrial respiration by NO during reperfusion. Taken together, NIR applied during reperfusion protects the myocardium against I/R in a NO-dependent and mitochondrion-targeted manner. This unique mechanism is conserved under diabetic conditions where other protective strategies fail.

Low power laser irradiation (LPLI) is becoming an increasingly popular and fast growing therapeutic modality in dermatology to treat various ailments without any reported side effects. In the present study an attempt was made to investigate the proliferative potential of red laser light during tissue repair in Swiss albino mice. To this end, full thickness excisional wounds of diameter 15 mm created on mice were exposed to single dose of Helium-Neon laser (632.8 nm; 7 mW; 4.02 mWcm^-2; Linear polarization) at 2 Jcm^-2 and 10 Jcm^-2 along with un-illuminated controls. The granulation tissues from all the respective experimental groups were harvested on day 10 post-wounding following euthanization. Subsequently, tissue regeneration potential of these laser doses under study were evaluated by monitoring proliferating cell nuclear antigen and Ki-67 following the laser treatment and comparing it with the un-illuminated controls. The percentages of Ki-67 or PCNA positive cells were determined by counting positive nuclei (Ki-67/PCNA) and total nuclei in five random fields per tissue sections. Animal wounds treated with single exposure of the 2 Jcm-2 indicated significant elevation in PCNA (P<0.01) and Ki-67 (P<0.05 compared to un-illuminated control and P<0.01 compared to 10 Jcm^-2) expression as compared to other tested experimental groups as evidenced by the microscopy results in the study. In summary, the findings of the present study have clearly demonstrated the regulation of cell proliferation by LPLI via PCNA and Ki-67 expression during tissue regeneration.

The use of low-level laser therapy (LLLT) for therapeutic purposes in medicine has become widespread recently. There are many studies in literature supporting the idea of therapeutic effects of laser irradiation on biological tissues. The aim of this study is to investigate the biostimulative effect of 809nm infrared laser irradiation on the healing process of cutaneous incisional skin wounds. 3-4 months old male Wistar Albino rats weighing 300 to 350 gr were used throughout this study. Lowlevel laser therapy was applied through local irradiation of 809nm infrared laser on open skin incisional wounds of 1 cm length. Each animal had six identical incisions on their right and left dorsal region symmetrical to each other. The wounds were separated into three groups of control, 1 J/cm² and 3 J/cm² of laser irradiation. Two of these six wounds were kept as control group and did not receive any laser application. Rest of the incisions was irradiated with continuous diode laser of 809nm in wavelength and 20mW power output. Two of them were subjected to laser irradiation of 1 J/cm² and the other two were subjected to laser light with energy density of 3 J/cm². Biostimulation effects of irradiation were studied by means of tensile strength tests and histological examinations. Wounded skin samples were morphologically examined and removed for mechanical and histological examinations at days 3, 5 and 7 following the laser applications. Three of the six fragments of skin incisions including a portion of peripheral healthy tissue from each animal were subjected to mechanical tests by means of a universal tensile test machine, whereas the other three samples were embedded in paraffin and stained with hematoxylin and eosin for histological examinations. The findings of the study show that tissue repair following laser irradiation of 809nm has been accelerated in terms of tissue morphology, strength and cellular content. These results seem to be consistent with the results of many researches previously published in literature and support the idea that LLLT has therapeutic effect on wound healing process.

Low-level light irradiation (LLLI) reported to stimulate the proliferation or differentiation of a variety of cell types. However, very little is known about the effect of light therapy on stem cells. The aim of the present study was to evaluate the effect of LLLI on the molecular physiological change of human bone marrow derived stem cells (hBMSC) by wavelength (470, 630, 660, 740 and 850, 50mW). The laser diode was performed with different time interval (0, 7.5, 15, 30J/cm², 50mW) on hBMSC. To determine the molecular physiological changes of cellular level of hBMSC, the clonogenic assay, ATP assay, reactive oxygen species (ROS) detection, mitochondria membrane potential (MMPΦ) staining and calcium efflux assay were assessed after irradiation. There was a difference between with and without irradiation on hBMSCs. An energy density up to 30 J/cm² improved the cell proliferation in comparison to the control group. Among these irradiated group, 630 and 660nm were significantly increased the cell proliferation. The cellular level of ATP and calcium influx was increased with energy dose-dependent in all LLLI groups. Meanwhile, ROS and MMPΦ were also increased after irradiation except 470nm. It can be concluded that LLLI using infrared light and an energy density up to 30 J/cm² has a positive stimulatory effect on the proliferation or differentiation of hBMSCs. Our results suggest that LLLI may influence to the mitochondrial membrane potential activity through ATP synthesis and increased cell metabolism which leads to cell proliferation and differentiation.

The aim of this study was to evaluate in vitro the bactericidal effect of Antimicrobial Photodynamic Therapy - AmPDT using a phenothiazinium compound (toluidine blue O and methylene blue, 12.5 μg/mL) on Staphylococcus aureus (ATCC 23529) irradiated or not with the red laser (λ 660 nm, 12J/cm²). All tests were performed in triplicate and samples distributed into the following groups: Negative control, Laser, Photosensitizer, and AmPDT. Bactericidal effect of the Antimicrobial Photodynamic Therapy was assessed by counting of colony-forming units and analyzed statistically (ANOVA, Tukey test, p<0.05). The results showed, comparing the Laser group with Negative control, a statistically significant increase of counting on the Laser group (p = 0.003). The use of the photosensitizer alone reduced the mean number of CFU (64.8%) and its association with the Laser light resulted in 84.2% of inhibition. The results are indicative that the use of Antimicrobial Photodynamic Therapy presented in vitro bactericidal effect on Staphylococcus aureus.

Prospective studies are based on the analysis of patent documents and aims to assess the both technological history and development providing innovation opportunities. This study was a technological prospection mapping aiming to identify breakthrough in PDT and the new possibilities of the technology. Therefore, research in the bank patent 'Spacenet Patent Search' was performed using determinants descriptors associated with the theme: 'A61K41', 'A61N5 / 06'. Were analyzed in this study 326 documents. In evaluating these patents, it was possible to observe an increase in the number of deposits over time, with peak between 1990 and 2000. The highest number of inventors of this area are part of the private sector and the US appear as main producer of technology. It was also observed that blue light, porphyrins and their derivatives are the main topics. It may be concluded that PDT still offers a large opportunity for growth as several wavelengths, and photosensitizers that may be used in the technique.

Antimicrobial Photodynamic therapy is a technique in which microorganisms are exposed to a photosensitizing drug and then irradiated with low-intensity visible light of the appropriate wavelength. The resulting photochemical reaction generates cytotoxic reactive oxygen species, such as singlet oxygen and free radicals, which are able to exert bactericidal effect. Much is already known about the photodynamic inactivation of microorganisms: both antibiotic-sensitive and - resistant strains can be successfully photo inactivated, and there is the additional advantage that repeated photosensitization of bacterial cells does not induce a selection of resistant strains. Recently, a series of studies have shown that it is possible to kill bacteria with a light source after the microorganisms have been sensitized with low concentration of dye, such as phenothiazines. The aim of this study was to evaluate the phagocytic function of macrophages J774 against S. aureus in the presence and absence of AmPDT with phenothiazine compound (12.5 μg/mL) and red-orange LED. Experimental groups: Control Group (L-F-), Phenothiazine group (L-F+) LED group (L+F-), Photodynamic therapy group (L+F+). The tests presented in this study were carried out in triplicate. This study demonstrated that AmPDT is able to increase about twice the phagocytic ability of macrophages; however, the bactericidal capacity of these cells did not show a substantial improvement, probably because the oxidative burst was less intense.

Phototherapies have shown positive effects on the bone repair process, increasing the blood supply to the injured area. The aim of this study was to assess through Raman spectroscopy, the efficacy of laser phototherapy (λ = 780 nm, P = 70 mW, CW, 20.4 J/cm² per session, 163.2 J/cm² per treatment) on the bone repair process of osteoporotic rats. The osteoporosis induction was achieved by ovariectomy surgery. Thirty Wistar rats were divided into 4 groups (Basal; OVX, OVX + Clot and OVX + Clot + Laser), then subdivided into 2 subgroups according to the experimental time (15 and 30 days). After the osteoporosis induction time (60 days), a bone defect with 2 mm was created with a trephine drill in the right femur in the animals of groups OVX, Clot and Clot + Laser. After surgery, the irradiation protocol was applied in the same groups on repeated sessions every 48 hours during 15 days. The samples were analyzed by Raman Spectroscopy to assess the inorganic content of phosphate and carbonated hydroxyapatite (~960 and 1070 cm^-1, respectively) and organic lipids and proteins (~1454 cm^-1). Statistical analysis (ANOVA, Student-T test) showed significant difference between groups Basal, OVX + Clot, and OVX + Clot + Laser for the inorganic content peaks at ~960 (p≤0.001), and ~1070 cm^-1 (p≤0.001) in both periods of 15 and 30 days, however on peak at ~1450 cm⁻¹ no differences were detected. It was concluded that the Laser phototherapy increased deposition of HA on bone repair process of osteoporotic rats.