Laser Dose Research Articles

Evaluation of biological agent association anti-TNF induced arthritis and laser therapy: an experimental study

Rheumatoid arthritis is a chronic, systemic inflammatory illness that predominantly affects the joints. Recent works tested inductor agents of arthritis models and their effects when associated to low intensity laser therapy. In this work the effects of the biological agent Infliximab and low intensity laser therapy were investigated in an animal experimental model of Zymosan induced arthritis. This model is widely used in pharmacological studies because it enhances the hypernociception of inflammation, detected throughout the observation of joint articular incapacitation, increase of vascular permeability, release of inflammatory mediators in the joint space and histological changes.A laser instrument (GaAlAs) DMC brand, model Photon Laser III was used, and the radiation was applied at wavelength 808 nm, power density of 200 mW/cm2, energy density of 2000 mJ/cm2, dose of energy or fluence 2 J/cm2, spot area of 0.02 mm, length of 5 dots per second. Rats with 250g were separated in 5 groups; the control (GI) received intra-articular 50µl of 0.9% saline solution in the right knee. The experimental group GII received intra articular injections of Zymosan (AZy) in the right knee at day zero (1mg, in 50µl of saline solution 0.9%); group GIII received daily doses of the same solution in the medial face of the right knee and 10 applications of laser (904 nm); Group GIV received 3 doses of 1,6ml of endovenous Infliximab in the vein of tail; Group GV received 3 doses of infliximab and daily doses of laser (904 nm). In the 14th day of the experiment the group GII was not treated. The organisms were sacrificed 24 hours after each protocol was completed and submitted to histopathological analysis using standard histological procedures.Results showed that, with 14 days of AZy, the groups presented a moderate to intense inflammation, presence of giant cell granulomas and synovial hyperplasia. When treatment was associated with laser therapy the inflammation was substantially reduced. The results suggest the efficiency of laser therapy associated or not with the biological agent application, to the treatment of induced chronical synovitis.

Laser exposure of gold nanorods can induce intracellular calcium transients

Uncoated and poly(styrene sulphonate) (PSS)-coated gold nanorods were taken up by NG108-15 neuronal cells. Exposure to 780 nm laser light at the plasmon resonance wavelength of the gold nanorods was found to induce intracellular Ca(2+) transients. The higher Ca(2+) peaks were observed at lower laser doses, with the highest levels obtained at a radiant exposure of 0.33 J/cm(2) . In contrast, the cells without nanoparticles showed a consistently small response, independent of the laser dose. These initial results open up new opportunities for peripheral nerve regeneration treatments and for more efficient optical stimulation techniques.

Nano Slit And Dot Array Pattern Of Au On SiO2 substrates Using Laser Beam Lithography

Highly monochromatic coherent light intensity of lasers provides the possibility of fabricating periodic nano-patterns which are needed in many applications. Here, we report 2D grating structure and periodic nano hole and dot arrays fabricated using two laser beam interference lithography. Using this method periodic grating as well as dot patterns have been fabricated with structure size of 50 -100 nm and pitch of 200-300 nm on SiO2 substrate. The nano-patterns are formed by inverting an array of photoresist posts by a lift-off process and subsequent reactive-ion etching using chromium as an etch mask. The depth of patterns can be tuned simple by laser dose to obtain high aspect ratio gratings. Transmission spectra measured in Au slits shows strong resonance features at 520 and 640 nm. Finite difference time domain simulations are used to estimate the near-field enhancement at the center of the slit pattern. Copyright © 2013 VBRI press.

Histomorphometrical and radiological comparison of low-level laser therapy effects on distraction osteogenesis: experimental study

Distraction osteogenesis (DO) is the application of traction to the callus formed between bone segments and stimulation of bone formation by creating stress on the callus with this traction. Shorten the duration of DO and increasing the capacity of bone formation is important to prevent the possible complications of DO. For this reason, it was considered that low-level laser therapy (LLLT) may affect positively DO and it can decrease the complication range by shortening the period. Unilateral mandibular distractors were applied on 16 female white New Zealand rabbit to prove this hypothesis with micro CT, plain radiograph and histomorphometric analyses. Eight rabbits were applied LLLT with GaAlAs laser on the distraction area during the distraction period. On the post-distraction 28th day, four rabbits from study group and four rabbits from control groups were sacrificed. The rest of the rabbits were sacrificed on post-distraction 56th day. As a result of this study, significant positive effects of LLLT on post-distraction 28th day were revealed with all analyses. In histomorphometrical analyses, new bone formation was significantly higher in short-term laser applied group comparing to that of short-term control group (p = 0.029). In both microCT and plain radiograph, the highest radioopacity values were observed in short-term laser group when compared with that of the controls (p = 0.043 and p = 0.025, respectively). Even though LLLT increased the healing capacity on short-term, it was not sufficient on long-term (post-distraction 56th day) healing. LLLT application on distraction period, activate healing on bone so it may decrease DO period. The result of this study should be supported with clinical studies and the most effective laser source, dose and application time should be revealed with experimental and clinical studies.

Effect of low-level laser therapy on odontoblast-like cells exposed to bleaching agent

The aim of the present study was to evaluate the effect of low-level laser therapy (LLLT) on odontoblast-like MDPC-23 cells exposed to carbamide peroxide (CP 0.01%-2.21 μg/mL of H2O2). The cells were seeded in sterile 24-well plates for 72 h. Eight groups were established according to the exposure or not to the bleaching agents and the laser energy doses tested (0, 4, 10, and 15 J/cm(2)). After exposing the cells to 0.01% CP for 1 h, this bleaching solution was replaced by fresh culture medium. The cells were then irradiated (three sections) with a near-infrared diode laser (InGaAsP-780 ± 3 nm, 40 mW), with intervals of 24 h. The 0.01% CP solution caused statistically significant reductions in cell metabolism and alkaline phosphate (ALP) activity when compared with those of the groups not exposed to the bleaching agent. The LLLT did not modulate cell metabolism; however, the dose of 4 J/cm(2) increased the ALP activity. It was concluded that 0.01% CP reduces the MDPC-23 cell metabolism and ALP activity. The LLLT in the parameters tested did not influence the cell metabolism of the cultured cells; nevertheless, the laser dose of 4 J/cm(2) increases the ALP activity in groups both with and without exposure to the bleaching agent.

Multimodal assessment of the magnitude of necrosis in the tracheobronchial tree after laser therapy

The use of lasers for treating cancerous lesions of the tracheobronchial tree has gained world-wide interest. As the prevalence of superficial cancer increases, lasers have been increasingly used to ablate superficial lesions. The extent of the effects of laser ablation on bronchial tissue is still unknown, and there may be a risk of bronchial wall perforation. In order to explore the magnitude of necrosis after laser treatment in the tracheobronchial tree, we investigated the microscopic appearance, histologic changes, and images of damaged mucosal lesions taken by optical coherence tomography (OCT). Endoscopic OCT is complementary to endobronchial ultrasonography (EBUS), which has a spatial resolution of about 100μm and a penetration depth of about a few centimeters. Multimodal investigation using both OCT and EBUS is a powerful in vivo tool for evaluating the efficacy of laser therapy in the tracheobronchial tree. In this study, we performed an ex vivo feasibility test that provided an adequate laser dose without cartilage injury. Injury extent was evaluated using OCT, EBUS, and histologic images.

Can He-Ne Laser Induce Changes in Oxidative Stress and Antioxidant Activities of Wheat Cultivars from Kazakhstan and Egypt?

Recently the biostimulatory role of physical methods have been observed in major agricultural crop plants, He-Ne laser is one of the most significant biophysical method for enhancing not only seed germination but also plant growth and development. Seeds of wheat cultivars from Kazakhstan (cultivars; aksay, kazakhstanskaya-10 and eretrospermum-350) and from Egypt (cultivar; sakha-168) were exposed to He-Ne laser irradiations with 5 mW. mm −2 power intensity for 1 to 1800 seconds exposition time. Various germination and growth parameters and indices were recorded and calculated. Changes on the rate of superoxide dismutase activity, lipid peroxidation level and hydrogen peroxide accumulation were monitored. Wheat seed pre-treatment caused significant increase in various germination parameters including germination percentage, germination rate (seed.h −1 ), relative germination rate coefficient ( Wk) and enhancing various growth parameters. Several doses of He-Ne laser promoted the germination to a maximum of 100 germination, increasing also the germination rate. Moreover, seed pretreatment with different doses of He-Ne laser caused significant changes in levels of hydrogen peroxide, lipid peroxidation an d Cu-Zn superoxide dismutase activity. Hydrogen peroxide accumulation and lipid peroxidation levels increased dramatically with the incre asing doses of helium neon laser compared to control. However Cu-Zn superoxide dismutase activities dropped following seed pretreatment with He-Ne laser compared to control.

Antimicrobial Photodynamic Therapy of Resistant Bacterial Strains by Indocyanine Green and 809-nm Diode Laser

This research aimed to investigate the bactericidal effect of indocyanine green (ICG) with 809-diode laser on wild type and resistant strains of Staphylococcus aureus and Pseudomonas aeruginosa in vitro. ICG and 809 nm combination can be a powerful tool for the treatment of wound-infecting, antibiotic-resistant bacteria. The effect of ICG and 809 nm laser light on wild type and resistant strains of S. aureus and P. aeruginosa was examined in vitro. ICG concentrations and laser doses were initially optimized for wild type S. aureus and P. aeruginosa. After determining the most effective ICG concentrations with specified light dose, they were applied on resistant strains. Viable bacterial cells were counted by serial dilution method. Photodynamic therapy (PDT) with ICG was totally efficient to kill all of these bacterial strains, and light/ICG alone did not cause any lethal effect on any of the strains. Optimum ICG laser doses varied with respect to the bacteria type: 84 J/cm(2) of light dose with 6 μg/mL of ICG concentration caused more than 95% killing of wild type S. aureus strains. The same bactericidal effect was achieved with a lower amount of ICG (4 μg/mL) on resistant strain S. aureus. Optimum parameters for 99% killing of wild type P. aeruginosa were 125 μg/mL ICG and 252 J/cm(2) of light dose. Similarly, their bactericidal effect was stronger on resistant strain; 100 μg/mL ICG with 252 J/cm(2) was enough to cause a 99% decrease in viable cells. The combination of ICG and 809 nm laser light was found as an effective antibacterial method to destroy antibiotic-resistant strains of gram-positive and gram-negative bacteria.

Hydrogen storage property of laser induced Pd-nanoparticle decorated multi-walled carbon nanotubes

Hybrid nanomaterials consisting of multi-walled carbon nanotubes (MWCNT) decorated with palladium nanoparticles are fabricated by the nanosecond laser irradiation of solid foil Pd target submerged in the suspension of MWCNTs in deionized water. The aim is to characterize the hydrogen storage property of laser-induced Pd-decorated MWCNTs for various laser doses. The corresponding structural surface properties as well as the yield of induced Pd nanoparticles on the MWCNTs are investigated by means of several characterization methods. The hydrogen storage measurement was carried out based on the cyclic voltammetric method and discharging curves. In general, the hydrogen storage capacity is enhanced with Pd decoration with respect to the pristine MWCNTs.

Single component photoacid/photobase generators: potential applications in double patterning photolithography

193 nm light as an excitation source for resist patterning is limited due to the inability to achieve pitch division much below limits of λ/2. Current techniques are examining the use of a variety of photochemical manipulations as a means to extend lithographic patterning to small, more defined images. Double patterning, or dual tone lithography, has recently garnered considerable interest due to the potential of patterning two features within one excitation exposure. In this contribution, single component carbamate photoacid/photobase (PAG/PBG) generators are studied as potential substrates for implementing dual tone lithography. At lower exposure powers, only the acid is generated and complete film dissolution was observed, while at higher 193 nm laser powers, photobase activation resulted in little to no film dissolution. Ideally, at intermediate laser doses, both the photoacid and photobase are activated giving rise to the desired double patterning. The energy required to initiate dual tone characteristics was found to be easily adjusted using the additional of amine quenchers or via manipulation of the PAG/PBG concentration. Film thickness measurements were used to determine the energies required for both photoacid and photobase activation, while laser flash photolysis and NMR spectroscopy studies were used in an attempt to understand the PAG/PBG activation mechanism.

Large-Area Diode Laser Defect Annealing of Polycrystalline Silicon Solar Cells

A new process was presented to anneal crystallographic defects in solid-phase crystallized silicon that produces higher Suns-V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">oc</sub> voltages than the conventional belt-furnace annealing (BFA) process. A few-millisecond continuous-wave diode laser treatment anneals defects present in the polycrystalline silicon and activates dopants. It is shown that the silicon/glass-interface system reaches an effective steady state at every point during the laser treatment, and the relative temperature profile is determined by the laser beam profile rather than its power or scanning speed. The peak temperature that is reached during a few-millisecond laser exposure is shown to increase and then level off with laser dose, indicating partial recrystallization of the film. A reduction in boron-doped p-type sheet resistance and phosphorus-doped emitter resistance is reported for a wide range of laser dose and scanning speed. The highest substrate temperature required during the process sequence is reduced from 960°C to 620°C. A peak 1-sun voltage of 492 mV is achieved using a 4-ms exposure at 500-J·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> laser dose, which is an improvement of 32 mV over the voltage after optimized BFA.

WS10-7 - Taraporfin PDT as a New Salvage Treatment of Local Failure after Chemoradiotherapy for Esophageal Cancer

ABSTRACT Background Since salvage surgery after failure of cheomradiotherapy (CRT) for esophageal cancer (EC) is associated with high morbidity and mortality, the development of curative and safety salvage treatment options has been needed to improve the patients' survival. Aim We conducted a phase I/II study to establish the recommended dose (RD) of laser irradiation and to evaluate safety and efficacy of Taraporfin sodium-based photodynamic therapy (PDT) as a salvage treatment after CRT (UMI03970). Patients and methods We recruited patients with residual or recurrent EC at primary site and who were treated with more than 50 Gy of (chemo)radiotherapy. To determine the dose-limiting toxicity (DLT) according to the energy of the diode laser, dose escalation was set at three energy levels (50, 75 and 100 J/cm2). The primary end point of phase I and II study were RD of laser irradiation and the complete response (CR) rate, respectively. Results In the phase I study, 9 patients were recruited and were treated using up to the third energy level in groups of three individuals. Since none of the patients experienced DLT at all energy levels, the recommended laser dose was 100 J/m2. In the phase II study, 10 patients were recruited and a complete response of the patients treated by RD was achieved in 6 of 13 patients (46%), which included the patients in level 3 of phase I. There was no patient with PDT-related adverse events. Conclusion Taraporfin sodium-based PDT could be a safe and effective treatment option for the local failure after CRT for EC.

Protection Properties of He-Ne Laser (632.8 nm) Against UV-light (253.7 nm) On the Lymphocytes Blood Cellsand Its DNA.

Background: He-Ne laser (632.8 nm) pre-irradiation may lead to modulate the damaging effects of ionizing radiation and decreasing in radiation damage on cells, by the induction of antioxidant defence mechanisms and accelerated the repair.Objective: To study the protection properties of He-Ne laser (632.8 nm) pre-irradiation against UV light (253.7 nm) damage on human lymphocyte blood cells and its DNA.Subject &amp; Methods: 27 samples were processed only for lymphocyte blood cells separation, while a 45 samples for the extracted DNA from lymphocyte. The total of 72 sampleswere employed to evaluate the influence of He-Ne laser pre- irradiation against UV-light.Results: The results showed that He-Ne laser (632.8 nm) pre-irradiation on human lymphocyte blood cells and its DNA leads to a decrease in the damage which caused by UV light (253.7 nm) irradiation.Conclusion:The magnitude of protection depends on the He-Ne laser pre-exposure doses. A higher survival percentage of lymphocyte blood cells and its DNA occurred with low He-Ne laser dose.

Investigating the killing effect of photodynamic therapy induced by different photosensitizers on human leukemia cell in vitro

Objective To investigate and compare the killing effect of photodynamic therapy (PDT)induced by hematoporphyrin derivative (HpD),hematoporphyrin monomethyl ether (HMME) and photocarcinorin (PsD007) on human leukemia cells K562 in vitro.Methods Human leukemia cells were cultured with serial concentrations of photosensitizers followed by irradiation of different dosage of laser light,then MTT colorimetric assay was applied to measure the relative survival rate of PDT for the cells.Results Significant difference in the inhibitory between the PDT group and control group was observed (P＜0.05).The survival rate of PDT for the cells elevated along with the increase in the concentration of sensitizer and dose of laser light.When the photosensitizer concentration was bigger (25 μg/ml) or the energy density was bigger (7.2 J/cm2),the effect of PsD007 was better than HMME,and they were significantly better than HpD (P＜0.05).Conclusion PDT has significant killing effect on human leukemia cells K562,and its relative inhibitory rate appears to be correlated with the dose of sensitizer and laser light irritation.The effect of PDT is related to the photosensitizers.The effect of HpD-PDT is not as effective as PsD007 and HMME.On the conditions of higher energy density and larger photosensitizer concentration,the effect of PsD007-PDT is better than HMME-PDT. Key words: Photodynamic therapy; Leukemia; Hematoporphyrin derivative; Photocarcinorin; Hematoporphyrin monomethyl ether

Laser irradiation affects enzymatic antioxidant system of streptozotocin-induced diabetic rats

The aim of the present study was to analyze the effect of low-power laser irradiation in the antioxidant enzymatic system of submandibular (SMG) and parotid (PG) salivary glands of streptozotocin-induced diabetic rats. The animals were randomly divided into six groups: three diabetic groups (D0, D5, and D20) and three non-diabetic groups (C0, C5, and C20), according to laser dose received (0, 5, and 20 J/cm(2), respectively). Areas of approximately 1 cm(2) were demarcated in the salivary glands (each parotid and both submandibular glands) and after irradiated according to Simões et.al. (Lasers Med Sci 24:202-208, 2009). A diode laser (660 nm/100 mW) was used, with laser beam spot of 0.0177 cm(2). The group treated with 5 J/cm(2) laser dose was subjected to irradiation for 1 min and 4 s (total irradiation time) and the group treated with 20 J/cm(2) laser dose was subjected to irradiation for 4 min and 16 s. Twenty-four hours after irradiation the animals were euthanized and the salivary glands were removed for biochemical analysis. The total antioxidant values (TA), the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase enzymes were determined. SOD and CAT activities, as well as TA were higher in SMG of irradiated diabetic rats. However, in SMG of non-diabetic rats, laser irradiation decreased TA values and led to an increase in the CAT activity. In addition, there was a decrease in the activity of CAT in PG of diabetic and non-diabetic animals after laser irradiation. According to the results of the present study, low-power laser irradiation can affect the enzymatic antioxidant system of salivary glands of streptozotocin-induced diabetic rats.

Design and application of a weed damage model for laser-based weed control

Horticultural weed control strategies based on chemical and thermal methods are environmentally and energetically questionable. A promising alternative appears to be the use of laser technology. This study evaluates the influence of CO 2 laser radiation (10,600 nm) taking into account three laser spot diameters , three laser spot positions and six laser intensities on three growth stages of two weed species (monocotyledonous: Echinochloa crus-galli , dicotyledonous: Amaranthus retroflexus ). The lethal impact of irradiation was characterised by a decrease of the weed fresh mass of 90% compared to untreated plants two weeks after irradiation. Weed-specific laser damage models were developed and validated, mapping the probabilities of success ( p success ) of the laser application. Selective lethal laser doses with p success = 0.95 were determined. The results showed that lethality was greatest if treatment was performed at early growth stages with high intensity. Monocotyledonous 2-leaf-plants were damaged at high energy levels, whilst 4-leaf-plants were difficult to kill. Dicotyledonous 2-leaf-plants were already damaged at moderate intensities. Thus, the damage of monocots required higher minimum laser doses than the damage of dicots . The influence of the spot position was important, as the unfocused treatment resulted in a decrease in lethality. In combination with robotics and image processing , the damage models developed here can be used to develop laser-based weed control. A model simulation of two driving concepts for the laser system showed that accurate aiming at the meristem as well as specific parameter adjustment is required for an efficient weed control. ► Weed damage caused by selective laser radiation was modelled. ► Influence of laser and plant parameters on the treatments success was examined. ► The prediction rate of lethal damage increased with increasing laser power. ► At least 54 J has to be applied to each weed plant for effective weed control. ► Two driving concept simulations show the advantages of a stop and go application.

Phase I study of photodynamic therapy using talaporfin sodium and diode laser for local failure after chemoradiotherapy for esophageal cancer

BackgroundPhotodynamic therapy (PDT) is a less invasive and effective salvage treatment for local failure after chemoradiotherapy (CRT) for esophageal cancer, however it causes a high rate of skin phototoxicity and requires a long sun shade period. Talaporfin sodium is a rapidly cleared photosensitizer that is expected to have less phototoxicity. This study was undertaken to clarify the optimum laser fluence rate of PDT using talaporfin sodium and a diode laser for patients with local failure after CRT or radiotherapy (RT) for esophageal cancer.MethodsThis phase I, laser dose escalation study used a fixed dose (40 mg/m2) of intravenous talaporfin sodium administered 4 to 6 hours before irradiation in patients with local failure limited to T2 after CRT or RT (≥ 50 Gy). The primary endpoint was to assess the dose limiting toxicity (DLT) of PDT, and the secondary endpoints were to evaluate the adverse events and toxicity related to PDT. The starting fluence of the 664 nm diode laser was 50 J/cm2, with an escalation plan to 75 J/cm2 and 100 J/cm2.Results9 patients with local failure after CRT or RT for ESCC were enrolled and treated in groups of 3 individuals to the third fluence level. No DLT was observed at any fluence level. Phototoxicity was not observed, but one subject had grade 1 fever, three had grade 1 esophageal pain, and 1 had grade 1 dysphagia. Five of 9 patients (55.6%) achieved a complete response after PDT.ConclusionsPDT using talaporfin sodium and a diode laser was safe for local failure after RT in patients with esophageal cancer. The recommended fluence for the following phase II study is 100 J/cm2.

Tissue Damage in the Canine Normal Esophagus by Photoactivation with Talaporfin Sodium (Laserphyrin): A Preclinical Study

BackgroundTreatment failure at the primary site after chemoradiotherapy is a major problem in achieving a complete response. Photodynamic therapy (PDT) with porfimer sodium (Photofrin®) has some problems such as the requirement for shielding from light for several weeks and a high incidence of skin phototoxicity. PDT with talaporfin sodium (Laserphyrin) is less toxic and is expected to have a better effect compared with Photofrin PDT. However, Laserphyrin PDT is not approved for use in the esophagus. In this preclinical study, we investigated tissue damage of the canine normal esophagus caused by photoactivation with Laserphyrin.Methodology/Principal FindingsDiode laser irradiation was performed at 60 min after administration. An area 5 cm oral to the esophagogastric junction was irradiated at 25 J/cm2, 50 J/cm2, and 100 J/cm2 using a three-step escalation. The irradiated areas were evaluated endoscopically on postirradiation days 1 and 7, and were subjected to histological examination after autopsy. The areas injured by photoactivation were 52 mm2, 498 mm2, and 831 mm2 after irradiation at 25 J/cm2, 50 J/cm2, and 100 J/cm2, respectively. Tissue injury was observed in the muscle layer or even deeper at any irradiation level and became more severe as the irradiation dose increased. At 100 J/cm2 both inflammatory changes and necrosis were seen histologically in extra-adventitial tissue.Conclusions/SignificanceTo minimize injury of the normal esophagus by photoactivation with Laserphyrin, diode laser irradiation at 25 J/cm2 appears to be safe. For human application, it would be desirable to investigate the optimal laser dose starting from this level.

The influence of red laser irradiation timeline on burn healing in rats

Low-level laser therapy (LLLT) promotes biomodulation of wound healing and literature reports that light delivery during the inflammation could play a different role compared with latter phases of the healing process. The objective of this study was to investigate whether single dose of a red laser (λ = 660 nm) is different from fractionated delivery protocol in full thickness burns. Two lesions were inflicted on the back of 36 rats. In the fractionated dose group (FG), the lesions were irradiated with 1 J/cm² on days 1, 3, 8, and 10 post-wounding. In the single dose group (SG), the lesions were irradiated with 4 J/cm² on day 1, immediately after injury. Control lesions (CG) received no light and were left to heal spontaneously. Blood flow was measured on days 1, 3, 8, 10, 15, and 21 using laser Doppler flowmetry. Animals were killed on days 3, 8, 10, 15, and 21. Skin specimens were obtained and routinely processed for hematoxylin and eosin. The specimens were evaluated according to differential leukocyte counting and angiogenesis. Statistical analysis was performed, and significance was accepted at p < 0.05. Irradiated groups showed a peak of new vessels on day 15 while, for CG, the peak was on day 21. On day 21, FG exhibited a significantly greater number of cumulative neutrophils while SG showed a higher number of mononuclear cells. Our results confirm that both protocols used accelerate angiogenesis and stimulate leukocyte chemotaxis on burn treatment. In addition, this work suggests that a single-dose LLLT accelerates the inflammatory phase of skin repair.

Ultraclean Derivatized Monodisperse Gold Nanoparticles through Laser Drop Ablation Customization of Polymorph Gold Nanostructures

We report a novel nanosecond laser ablation synthesis for spherical gold nanoparticles as small as 4 nm in only 5 s (532 nm, 0.66 J/cm(2)), where the desired protecting agent can be selected in a protocol that avoids repeated sample irradiation and undesired exposure of the capping agent during ablation. This method takes advantage of the recently developed synthesis of clean unprotected polymorph and polydisperse gold nanostructures using H(2)O(2) as a reducing agent. The laser drop technique provides a unique tool for delivering controlled laser doses to small drops that undergo assisted fall into a solution or suspension of the desired capping agent, yielding monodisperse custom-derivatized composite materials using a simple technique.