Histological and modeling study of skin thermal injury to 2.0 μm laser irradiation

Chen, Bin; Thomsen, Sharon; Thomas, Robert J.; Oliver, Jeffrey W.; Welch, Ashley J.

doi:10.1002/lsm.20630

Cited by 75 publications

(54 citation statements)

References 22 publications

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“…S8 and S9). These injuries are seen in NIR laser burns (36,37) and set an upper bound on acceptable dosing levels. Such high powers are not required to trigger our devices; however, safer therapies could be achieved by (i) using devices with higher on-state kinetics, which would require shorter irradiation times, (ii) designing devices with a lower on-state irradiation threshold, or (iii) using a pulsed laser source, which also heats nanoparticles but causes less tissue damage (38).…”

Section: Resultsmentioning

confidence: 99%

Near-infrared–actuated devices for remotely controlled drug delivery

Timko

Arruebo

Shankarappa

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

183

175

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A reservoir that could be remotely triggered to release a drug would enable the patient or physician to achieve on-demand, reproducible, repeated, and tunable dosing. Such a device would allow precise adjustment of dosage to desired effect, with a consequent minimization of toxicity, and could obviate repeated drug administrations or device implantations, enhancing patient compliance. It should exhibit low off-state leakage to minimize basal effects, and tunable on-state release profiles that could be adjusted from pulsatile to sustained in real time. Despite the clear clinical need for a device that meets these criteria, none has been reported to date to our knowledge. To address this deficiency, we developed an implantable reservoir capped by a nanocomposite membrane whose permeability was modulated by irradiation with a near-infrared laser. Irradiated devices could exhibit sustained onstate drug release for at least 3 h, and could reproducibly deliver short pulses over at least 10 cycles, with an on/off ratio of 30. Devices containing aspart, a fast-acting insulin analog, could achieve glycemic control after s.c. implantation in diabetic rats, with reproducible dosing controlled by the intensity and timing of irradiation over a 2-wk period. These devices can be loaded with a wide range of drug types, and therefore represent a platform technology that might be used to address a wide variety of clinical indications.gold | nanoshell | poly(n-isopropylacrylamide) | ethylcellulose | diabetes

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Section: Resultsmentioning

confidence: 99%

Near-infrared–actuated devices for remotely controlled drug delivery

Timko

Arruebo

Shankarappa

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

183

175

View full text Add to dashboard Cite

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“…In previous skin studies, [4][5][6][7] the results of experiments and tests on Yucatan miniature pigs were presented for a 2000-nm thulium fiber laser for various exposure durations and incident beam diameters. Some damage threshold studies have been completed at 1315 nm for pulses in the microsecond regime, as reported by Cain et al 8 A preliminary skin damage threshold study at 1214 and 1319 nm has also been documented.…”

Section: Introductionmentioning

confidence: 99%

“…Increased accuracy has been demonstrated when temperature-dependent surface cooling associated with the evaporation of water is included. 26 In the comprehensive analysis of Chen et al, 6 thermal damage was shown to most accurately mimic histology for an Arrhenius model when based upon the parameters presented by Gaylor. 27 Chen et al reported that the extent of damage reached a depth of 200 to 300 microns at the observed minimal visible lesion threshold.…”

Section: Introductionmentioning

confidence: 99%

Infrared skin damage thresholds from 1319-nm continuous-wave laser exposures

Oliver

Vincelette²,

Noojin³

et al. 2013

J. Biomed. Opt

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Abstract. A series of experiments were conducted in vivo using Yucatan miniature pigs (Sus scrofa domestica) to determine thermal damage thresholds to the skin from 1319-nm continuous-wave Nd:YAG laser irradiation. Experiments employed exposure durations of 0.25, 1.0, 2.5, and 10 s and beam diameters of ∼0.6 and 1 cm. Thermal imagery data provided a time-dependent surface temperature response from the laser. A damage endpoint of fifty percent probability of a minimally visible effect was used to determine threshold for damage at 1 and 24 h postexposure. Predicted thermal response and damage thresholds are compared with a numerical model of opticalthermal interaction. Resultant trends with respect to exposure duration and beam diameter are compared with current standardized exposure limits for laser safety. Mathematical modeling agreed well with experimental data, predicting that though laser safety standards are sufficient for exposures <10 s, they may become less safe for very long exposures. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…Thermal exposures to 43-45 o C for at least 15 minutes induces adipocyte cell death in vivo. 8 According to the literature, the threshold temperature for skin damage is approximately 50 o C. 9 However, previous studies have shown that the heat-pain threshold for normal subjects is about 43 o C. 10,11 In addition, researchers have also reported that 43 o C is a safe temperature for prolonged exposure to a hot object. The RF device used in this study emits 27.12 MHz radiofrequency energy with a maximum power of 200 W. It comprises multipolar applicator panels that can generate an electromagnetic field without contacting the subject.…”

Section: Discussionmentioning

confidence: 99%

Impact of Contactless Apoptosis-Inducing RF on Temperature of Human Skin Surface and Subcutaneous Layer as well as Porcine Histology: A Pilot Study

Goo¹,

Kim²

2016

Medical Lasers

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Background and ObjectivesRadiofrequency (RF) technology has been developed as a noninvasive method to reduce subcutaneous abdominal fat. The aim of this study was to measure the changes of human skin surface temperature and human subcutaneous fat layer temperature, as well as to evaluate the histologic change in porcine adipocytes during and after treatment with contactless apoptosis-inducing RF device. Materials and MethodsA single pig was treated with RF device for 30 minutes at maximum power of 200 Watts. The skin was biopsied and evaluated immediately after the therapy. A female human volunteer was also treated with RF device for 45 minutes. The temperatures of the skin surface and subcutaneous fat layer were measured during the therapy. ResultsSkin biopsy specimens from the pig revealed changes in the adipocyte shape and size. Many of the adipocytes had shrunken, with a few showing consensed chromatin and fragmented nuclei, reflecting signs of adipocyte apoptosis. In the human volunteer, subcutaneous fat layer maintained a temperature of [43][44][45] o C, while the skin surface temperature did not reach 43 o C during the treatment. ConclusionThe contactless selective RF device achieved the ideal temperature for fat reduction in subcutaneous fat layer during the treatment, while maintaining skin surface temperate below the threshold of heat-induced pain for humans. Apoptosis of subcutaneous adipocytes was confirmed in porcine skin. Further clinical trials are necessary to evaluate the efficacy and safety. Key words

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Histological and modeling study of skin thermal injury to 2.0 μm laser irradiation

Cited by 75 publications

References 22 publications

Near-infrared–actuated devices for remotely controlled drug delivery

Near-infrared–actuated devices for remotely controlled drug delivery

Infrared skin damage thresholds from 1319-nm continuous-wave laser exposures

Impact of Contactless Apoptosis-Inducing RF on Temperature of Human Skin Surface and Subcutaneous Layer as well as Porcine Histology: A Pilot Study

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