Experimental Retinal Ablation Using a Fourth-Harmonic 266 nm Laser Coupled with an Optical Fiber Probe

Yu, Paula K.; Miller, Joseph; Cringle, Stephen J.; Yu, Dao‐Yi

doi:10.1167/iovs.05-1187

Cited by 8 publications

(8 citation statements)

References 19 publications

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“…The heating of biological tissue can be achieved by several physical mechanisms including microwave irradiation [14, 15], Ohmic heating [16], optical laser irradiation [17] or water bath heating [18, 19]. With these heating methods, it remains a challenge to control the spatial extent of heating in tissue.…”

Section: Introductionmentioning

confidence: 99%

Magnetic hyperthermia enhance the treatment efficacy of peri-implant osteomyelitis

et al. 2017

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BackgroundWhen bacteria colony persist within a biofilm, suitable drugs are not yet available for the eradication of biofilm-producing bacteria. The aim of this study is to study the effect of magnetic nano-particles-induced hyperthermia on destroying biofilm and promoting bactericidal effects of antibiotics in the treatment of osteomyelitis.MethodsSixty 12-weeks-old male Wistar rats were used. A metallic 18G needle was implanted into the bone marrow cavity of distal femur after the injection of Methicillin-sensitive Staphylococcus aureus (MSSA). All animals were divided into 5 different treatment modalities. The microbiological evaluation, scanning electron microscope examination, radiographic examination and then micro-CT evaluation of peri-implant bone resorption were analyzed.ResultsThe pathomorphological characteristics of biofilm formation were completed after 40-days induction of osteomyelitis. The inserted implants can be heated upto 75 °C by magnetic heating without any significant thermal damage on the surrounding tissue. We also demonstrated that systemic administration of vancomycin [VC (i.m.)] could not eradicate the bacteria; but, local administration of vancomycin into the femoral canal and the presence of magnetic nanoparticles hyperthermia did enhance the eradication of bacteria in a biofilm-based colony. In these two groups, the percent bone volume (BV/TV: %) was significantly higher than that of the positive control.ConclusionsFor the treatment of chronic osteomyelitis, we developed a new modality to improve antibiotic efficacy; the protection effect of biofilms on bacteria could be destroyed by magnetic nanoparticles-induced hyperthermia and therapeutic effect of systemic antibiotics could be enhanced.

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Section: Introductionmentioning

confidence: 99%

Magnetic hyperthermia enhance the treatment efficacy of peri-implant osteomyelitis

et al. 2017

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“…This thermal shock often results in cracking of the adjacent material in an uncontrolled manner. These effects can be observed in Figure 1(a) and (b), where the ablations of porcine retina using a conventional Er: YAG (λ = 2.94 μm) and ND: YAG laser (λ = 1.064 μm) are shown [11,12]. Meanwhile, fs-pulses (800 nm) having sufficient intensity for multi-photon ionization throughout its beam waist ablate the retinal vessel walls in an extremely controlled manner (Figure 1(c)).…”

Section: Laser Interactions With Biomaterialsmentioning

confidence: 96%

Ablation of Materials Using Femtosecond Lasers and Electron Beams

Sidhu¹,

Dhingra²

2022

Terahertz, Ultrafast Lasers and Their Medical and Industrial Applications

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The advancements in producing interactions of concentrated energy fluxes, such as femtosecond lasers and high-energy electron beams with the absorbing substances, have facilitated new discoveries and excitement in various scientific and technological areas. Since their invention, significant improvements in temporal, spatial, energetic, and spectroscopic characteristics have been realized. Due to the ultrashort pulse width and higher intensity (1012 W/cm2), it is possible to ablate the materials with negligible damage outside the focal volume, thereby allowing the treatment of biological samples, such as live cells, membranes, and removal of thin films, as well as bulk materials for many applications in diverse fields, including micro-optics, electronics, and even biology under extremely high precision. Since most biological systems are transparent toward the NIR spectral range, it follows the nonlinear multi-photon absorption interaction mechanism. In contrast, the electron beam follows linear absorption mechanism for material modifications even at lower energies. For realizing the fs-laser nano-processing in material applications, such as silicon microchips, or in biology like retinal cells, it is crucial to find a way to deliver these pulses precisely at the site of action and enhance the selectivity. The utilization of electron beams in material modification has also been exercised widely to attain nanoscale precision. In the next section, biological materials, such as cornea, retina, and silk, are discussed.

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“…20,21 We have previously succeeded in delivering 266-nm laser light through optic fibers and have used this wavelength to ablate retinal tissue and vascular sheath tissue at the arteriovenous crossing point. 18,19 The present study extends the work using 266-nm radiation and examines the properties of 213-nm radiation, which can also be generated from a solid state laser and delivered through a flexible fiber-optic probe suitable for intraocular work. We compared the performance of 266-nm and 213-nm wavelengths in ablating porcine retinal tissue.…”

mentioning

confidence: 87%

“…Laser and associated optics enabled pulsed ultraviolet laser radiation to be delivered to the tissue surface through an optical fiber; the system is a development of one previously reported. 18 The fourth (266-nm) or fifth (213-nm) harmonic of a pulsed Nd:YAG laser (Surelite II10; Continuum, Santa Clara, CA) was launched into an optical fiber using a custom-made hollow glass taper as a beam concentrator. 19 The 266-nm and 213-nm pulse durations last 4 to 6 nanoseconds, and each harmonic was only used in isolation; the beam not in use was terminated by a beam stop.…”

Section: Laser Parametersmentioning

confidence: 99%

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Ablation of Intraocular Tissue with Fiber-optic Probe–Delivered 266-nm and 213-nm Laser Energy

Miller

Yu³

et al. 2009

Invest. Ophthalmol. Vis. Sci.

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Experimental Retinal Ablation Using a Fourth-Harmonic 266 nm Laser Coupled with an Optical Fiber Probe

Abstract: Pulsed laser (266 nm) irradiation at low pulse counts and high fluence levels is a possible alternative for localized retinal ablation with minimal collateral damage in a fluid environment.

Cited by 8 publications

References 19 publications

Magnetic hyperthermia enhance the treatment efficacy of peri-implant osteomyelitis

Magnetic hyperthermia enhance the treatment efficacy of peri-implant osteomyelitis

Ablation of Materials Using Femtosecond Lasers and Electron Beams

Ablation of Intraocular Tissue with Fiber-optic Probe–Delivered 266-nm and 213-nm Laser Energy

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