Blue-Violet Light

Blue-Violet Light Emitting Diode (LED) Irradiation

Blue-violet light emitting diode (LED) irradiation immediately controls socket bleeding following tooth extraction: clinical and electron microscopic observations

Isao Ishikawa, Tomohiro Okamoto, Seigo Morita, Fumika Shiramizu, Yoshihiro Fuma, Shizuko Ichinose, Teruo Okano, Tomohiro Ando Institute of Advanced Biomedical Engineering and Science, Tokyo, Japan.
Photomedicine and laser surgery. 05/2011; 29(5):333-8. DOI: 10.1089/pho.2010.2856

Abstract
Bleeding control is a major concern during dental surgery. A novel photocoagulation method using an irradiating blue-violet light emitting diode (LED) was investigated. Some dental light-curving units can emit blue-violet wavelengths around 380-515 nm with two peaks (410 nm and 470 nm). These wavelengths can cover the maximum absorption spectra of hemoglobin (430 nm).

Blue-violet LED 380-515 nm, 750 mW/cm(2), 10 sec (7.5 J/cm(2)) was used. Irradiation was performed for 10 sec or an additional 10 sec for 10 cases of tooth extraction at a distance of 1 cm from the socket. Bleeding was stopped by conventional roll pressure in another five cases as a control. Bleeding time for both procedures was measured. A Mann-Whitney U test was used for statistical analysis. In vitro transmission electron microscope (TEM) studies were performed to clarify the mechanism of hemostasis by blue-violet LED irradiation.

Irradiation with the blue-violet LED yielded immediate hemostasis of the socket. Five cases showed coagulation within the first 10 sec, and another five cases required an additional 10 sec to fully control the bleeding. In contrast, the conventional method required 2-5 min (median 180 sec) to obtain hemostasis. The difference between the time required to stop the bleeding in the two methods was found to be statistically significant (p =0.0014). A week later, the LED-irradiated sockets were healed uneventfully with epithelial covering. TEM showed the formation of a thin amorphous layer and an adjacent agglutination of platelets and other cellular elements under the layer at the interface of the irradiated blood.

Blue-violet LED irradiation of bleeding sockets caused immediate clot formation and hemostasis. This procedure was safe and reliable and showed no adverse effects.

Blue-light irradiation regulates proliferation and differentiation in human skin cells.

Liebmann J, Born M, Kolb-Bachofen V.
J Invest Dermatol.
2010 Jan;130(1):259-69.

Sunlight influences the physiology of the human skin in beneficial as well as harmful ways, as has been shown for UV light. However, little is known about the effects of other wavelengths of solar irradiation. In this study we irradiated human keratinocytes and skin-derived endothelial cells with light-emitting-diode devices of distinct wavelengths to study the effects on cell physiology. We found that light at wavelengths of 632-940 nm has no effect, but irradiation with blue light at 412-426 nm exerts toxic effects at high fluences. Light at 453 nm is nontoxic up to a fluence of 500 J/cm(2). At nontoxic fluences, blue light reduces proliferation dose dependently by up to 50%, which is attributable to differentiation induction as shown by an increase of differentiation markers. Experiments with BSA demonstrate that blue-light irradiation up to 453 nm photolytically generates nitric oxide (NO) from nitrosated proteins, which is known to initiate differentiation in skin cells. Our data provide evidence for a molecular mechanism by which blue light may be effective in treating hyperproliferative skin conditions by reducing proliferation due to the induction of differentiation. We observed a photolytic release of NO from nitrosated proteins, indicating that they are light acceptors and signal transducers up to a wavelength of 453 nm.

Clinical and histological effects of blue light on normal skin.

Kleinpenning MM, Smits T, Frunt MH, van Erp PE, van de Kerkhof PC, Gerritsen RM.
Photodermatol Photoimmunol Photomed. 2010 Feb;26(1):16-21.

INTRODUCTION: Phototherapy with visible light is gaining interest in dermatological practice. Theoretically, blue light could induce biological effects comparable to ultraviolet A (UVA) radiation.

OBJECTIVES: To study the effects of blue light on normal skin in terms of photodamage, skin ageing and melanogenesis.

METHODS: Eight healthy volunteers were included and irradiation with visible blue light was given on five consecutive days. Skin biopsies were analysed with respect to photodamage (p53, vacuolization, sunburn cells), skin ageing (elastosis, MMP-1) and melanogenesis (Melan-A).

RESULTS: No inflammatory cells and sunburn cells were visible before or after irradiation. A significant increase in the perinuclear vacuolization of keratinocytes was demonstrated during treatment (P=0.02) with a tendency towards significance after cessation of treatment (P=0.09). No significant change in p53 expression was seen. Signs of elastosis and changes in MMP-1 expression were absent. Minimal clinical hyperpigmentation of the irradiated skin was confirmed histologically with a significant increase in Melan-A-positive cells (P=0.03).

CONCLUSIONS: Visible blue light, as given in the present study, does not cause deoxyribonucleic acid damage or early photo-ageing. The biological effects of blue light on normal skin are transient melanogenesis and inexplicable vacuolization without resulting apoptosis. In conclusion, the (short-term) use of visible blue light in dermatological practice is safe.

Comparative study of the bactericidal effects of 5-aminolevulinic acid with blue and red light on Propionibacterium acnes.


Choi MS, Yun SJ, Beom HJ, Park HR, Lee JB.
J Dermatol. 2010 Nov 3. doi: 10.1111/j.1346-8138.2010.01094.x. [Epub ahead of print]

Propionibacterium acnes naturally produces endogenous porphyrins that are composed of coproporphyrin III (CPIII) and protoporphyrin IX (PpIX). Red light alone and photodynamic therapy (PDT) improve acne vulgaris clinically, but there remains a paucity of quantitative data that directly examine the bactericidal effects that result from PDT on P. acnes itself in vitro. The purpose of this study was to measure the difference of bactericidal effects of 5-aminolevulinic acid (ALA)-PDT with red and blue light on P. acnes. P. acnes were cultured under anaerobic conditions and divided into two groups (ALA-treated group and control group), and were then illuminated with blue (415 nm) and red (635 nm) lights using a light-emitting diode (LED). The cultured P. acnes were killed with both blue and red LED light illumination. The efficacy increased with larger doses of light and a greater number of consecutive illuminations. We demonstrated that red light phototherapy was less effective for the eradication of P. acnes than blue light phototherapy without the addition of ALA. However, pretreatment with ALA could enhance markedly the efficacy of red light phototherapy.

Effects of blue light irradiation on human dermal fibroblasts

Christian Oplandera, Sarah Hiddingb, Frauke B. Wernersb, Matthias Bornc, Norbert Palluab and Christoph V. Suschekb

Previous studies have reported that separately from UV-radiation also blue light influences cellular physiology in different cell types. However, little is known about the blue light action spectrum. The purpose of this study was to investigate effects of blue light at distinct wavelengths (410, 420, 453, 480 nm) emitted by well defined light-emitting-diodes on viability, proliferation and antioxidative capacity of human dermal fibroblasts. We found that irradiation with blue light (410, 420 nm) led to intracellular oxidative stress and toxic effects in a dose and wavelength dependent manner. No toxicity was observed using light at 453 nm and 480 nm. Furthermore, blue light (410, 420, 453 nm) at low doses reduced the antioxidative capacity of fibroblasts. At non-toxic doses, irradiations at 410, 420 and 453 nm reduced proliferation indicating a higher susceptibility of proliferating fibroblasts to blue light. Our results show that blue light at different wavelengths may induce varying degrees of intracellular oxidative stress with different physiological outcome, which could contribute to premature skin photoaging. On the other hand, the use of blue light due to its antiproliferative and toxic properties may represent a new approach in treatment and prevention of keloids, hypertrophic scars and fibrotic skin diseases.

Killing of methicillin-resistant Staphylococcus aureus by low-power laser light.

Wilson M, Yianni C.
Med Microbiol. 1995 Jan;42(1):62-6

The purpose of this study was to determine whether a methicillin-resistant strain of Staphylococcus aureus (MRSA) could be sensitised by toluidine blue O (TBO) to killing by light from a low-power helium/neon (HeNe) laser. Suspensions containing c. 10(10) cfu of MRSA were irradiated with light from a 35 mW HeNe laser (energy dose: 0.5-2.1 J) in the presence of TBO (1.6-12.5 micrograms/ml) and the survivors were enumerated. The kills attained depended on both the light energy dose and concentration of TBO employed. A 4.47 log10 reduction in the viable count was achieved with a TBO concentration of 12.5 micrograms/ml and a light dose of 2.1 J (energy density 43 J/cm2). MRSA were susceptible to killing by the laser light within 30 s of exposure to the TBO. The results of this study have demonstrated that MRSA can be rapidly sensitised by TBO to killing by HeNe laser light and that killing depends on the light energy dose and sensitiser concentration.

Effects of combined 405-nm and 880-nm light on Staphylococcus aureus and Pseudomonas aeruginosa in vitro.

Wilson M, Yianni C.
Med Microbiol. 1995 Jan;42(1):62-6

The purpose of this study was to determine whether a methicillin-resistant strain of Staphylococcus aureus (MRSA) could be sensitised by toluidine blue O (TBO) to killing by light from a low-power helium/neon (HeNe) laser. Suspensions containing c. 10(10) cfu of MRSA were irradiated with light from a 35 mW HeNe laser (energy dose: 0.5-2.1 J) in the presence of TBO (1.6-12.5 micrograms/ml) and the survivors were enumerated. The kills attained depended on both the light energy dose and concentration of TBO employed. A 4.47 log10 reduction in the viable count was achieved with a TBO concentration of 12.5 micrograms/ml and a light dose of 2.1 J (energy density 43 J/cm2). MRSA were susceptible to killing by the laser light within 30 s of exposure to the TBO. The results of this study have demonstrated that MRSA can be rapidly sensitised by TBO to killing by HeNe laser light and that killing depends on the light energy dose and sensitiser concentration.

Effects of combined 405-nm and 880-nm light on Staphylococcus aureus and Pseudomonas aeruginosa in vitro.

Guffey JS, Wilborn J.
Photomed Laser Surg. 2006 Dec;24(6):680-3.

OBJECTIVE: The aim of this study was to determine the effect of a combination of 405- nm blue light and 880-nm infrared light on Staphylococcus aureus and Pseudomonas aeruginosa in vitro.

BACKGROUND DATA: Reports indicate that certain wavelengths and treatment parameters of light promote the growth of bacteria, but our earlier study indicates that light at specific wavelengths and intensities are bactericidal for specific organisms (1).

METHODS: Two common aerobes, Staphylococcus aureus and Pseudomonas aeruginosa were tested because of their frequent isolation from skin infections and wounds. Each organism was treated simultaneously with a combination of 405-nm and 880-nm light emitted by a cluster of Super Luminous Diodes (SLDs). Doses of 1, 3, 5, 10, and 20 Jcm2 were used. Colony counts were performed and compared to untreated controls using Student t tests and one-way ANOVA with Tukey and Scheffe post hoc analyses.

RESULTS: The results revealed significant dose-dependent bactericidal effects of the combined blue and infrared light on Staphylococcus aureus (F 4,94 = 5.38, p = 0.001) and Pseudomonas aeruginosa (F 4,95 = 21.35, p < 0.001). With P. aeruginosa, the treatment reduced the number of bacteria colonies at all doses, achieving statistical significance at 1, 3, and 20 J cm2 doses and reducing bacterial colony by as much as 93.8%; the most effective dose being 20 J cm2. Irradiation of S. aureus resulted in statistically significant decreases in bacterial colonies at all dose levels; the most decrease, 72%, was also achieved with 20 Jcm2.

CONCLUSION: Appropriate doses of combined 405-nm and 880-nm phototherapy can kill Staphylococcus aureus and Pseudomonas aeruginosa in vitro, suggesting that a similar effect may be produced in clinical cases of bacterial infection.

In vitro bactericidal effects of 405-nm and 470-nm blue light.

Guffey JS, Wilborn J.
Photomed Laser Surg. 2006 Dec;24(6):684-8

OBJECTIVE: The aim of this study was to determine the bactericidal effect of 405- and 470-nm light on two bacteria, Staphylococcus aureus and Pseudomonas aeruginosa, in vitro.

BACKGROUND DATA: It is well-known that UV light kills bacteria, but the bactericidal effects of UV may not be unique since recent studies indicate that blue light produces a somewhat similar effect. The effects of blue light seem varied depending on wavelength, dose and the nature of the bacteria, hence this study.

METHODS: Two common aerobes, Staphylococcus aureus and Pseudomonas aeruginosa, and anaerobic Propionibacterium acnes were tested. Each organism was treated with Super Luminous Diode probes with peak emission at 405 and 470 nm. Treatment was timed to yield 1, 3, 5, 10, and 15 Jcm2 doses. Colony counts were performed and compared to untreated controls.

RESULTS: The 405-nm light produced a dose dependent bactericidal effect on Pseudomonas aeruginosa and Staphylococcus aureus (p

CONCLUSION: The results indicate that, in vitro, 405- and 470-nm blue light produce dose dependent bactericidal effects on Pseudomonas aeruginosa and Staphylococcus aureus but not Propionibacterium acnes.

Blue 470-nm light kills methicillin-resistant Staphylococcus aureus (MRSA) in vitro.

Enwemeka CS, Williams D, Enwemeka SK, Hollosi S, Yens D.
Photomed Laser Surg. 2009 Apr;27(2):221-6.

BACKGROUND DATA: In a previous study, we showed that 405-nm light photodestroys methicillin-resistant Staphylococcus aureus (MRSA). The 390-420 nm spectral width of the 405-nm superluminous diode (SLD) source may raise safety concerns in clinical practice, because of the trace of ultraviolet (UV) light within the spectrum.

OBJECTIVE: Here we report the effect of a different wavelength of blue light, one that has no trace of UV, on two strains of MRSA—the US-300 strain of CA-MRSA and the IS-853 strain of HA-MRSA—in vitro. MATERIALS AND METHODS: We cultured and plated each strain, and then irradiated each plate with 0, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 25, 30, 35, 40, 45, 50, 55, or 60 J/cm2 of energy a single time, using a 470-nm SLD phototherapy device. The irradiated specimens were then incubated at 35 degrees C for 24 h. Subsequently, digital images were made and quantified to obtain colony counts and the aggregate area occupied by bacteria.

RESULTS: Photo-irradiation produced a statistically significant dose-dependent reduction in both the number and the aggregate area of colonies formed by each strain (p < 0.001). The higher the dose the more bacteria were killed, but the effect was not linear, and was more impressive at lower doses than at higher doses. Nearly 30% of both strains was killed with as little as 3 J/cm2 of energy. As much as 90.4% of the US-300 and the IS-853 colonies, respectively, were killed with an energy density of 55 J/cm2. This same dose eradicated 91.7% and 94.8% of the aggregate area of the US-300 and the IS-853 strains, respectively.

CONCLUSION: At practical dose ranges, 470-nm blue light kills HA-MRSA and CA-MRSA in vitro, suggesting that a similar bactericidal effect may be attained in human cases of cutaneous and subcutaneous MRSA infections.

Phototherapy with blue (415 nm) and red (660 nm) light in the treatment of acne vulgaris

British Journal of Dermatology Volume 142 Issue 5 Page 973-978, May 2000

ABSTRACT: In this study we have evaluated the use of blue light (peak at 415 nm) and a mixed blue and red light (peaks at 415 and 660 nm) in the treatment of acne vulgaris. One hundred and seven patients with mild to moderate acne vulgaris were randomized into four treatment groups: blue light, mixed blue and red light, cool white light and 5% benzoyl peroxide cream. Subjects in the phototherapy groups used portable light sources and irradiation was carried out daily for 15 min. Comparative assessment between the three light sources was made in an observer-blinded fashion, but this could not be achieved for the use of benzoyl peroxide. Assessments were performed every 4 weeks. After 12 weeks of active treatment a mean improvement of 76% (95% confidence interval 66-87) in inflammatory lesions was achieved by the combined blue-red light phototherapy; this was significantly superior to that achieved by blue light (at weeks 4 and 8 but not week 12), benzoyl peroxide (at weeks 8 and 12) or white light (at each assessment). The final mean improvement in comedones by using blue-red light was 58% (95% confidence interval 45-71), again better than that achieved by the other active treatments used, although the differences did not reach significant levels. We have found that phototherapy with mixed blue-red light, probably by combining antibacterial and anti-inflammatory action, is an effective means of treating acne vulgaris of mild to moderate severity, with no significant short-term adverse effects.