Dual‐wavelength‐assisted thermal hemostasis for treatment of benign prostate hyperplasia

Laser treatment on a large size of prostate gland often encounters significant bleeding that can prolong the entire procedure and cause urinary complications. The current study investigates the feasibility of dual‐wavelength (532 and 980 nm) application to achieve rapid hemostasis for 532‐nm laser prostatectomy. Porcine kidney and bleeding phantom models were tested to quantify the degree of the irreversible tissue coagulation and to estimate the time for the complete hemostasis, respectively. The ex vivo kidney testing verifies that the dual‐wavelength created up to 40% deeper and 25% wider coagulation regions than a single wavelength does. The bleeding phantom testing demonstrates that due to the enhanced thermal effects, the simultaneous irradiation yields the complete photocoagulation (~11 seconds) whereas 532 or 980 nm hardly stops bleeders. Numerical simulations validate that the combined optical‐thermal characteristics of both the wavelengths account for the augmented thermal coagulation. The dual‐wavelength‐assisted coagulation can be a feasible treatment to entail the rapid hemostasis and to facilitate the laser prostatectomy in an effective manner.      

Microlesion healing dynamics in in vivo porcine skin after treatment with 1064 nm picosecond-domain Nd:YAG laser

The fractionated picosecond laser produces microscopic lesions in the epidermis and dermis due to laser-induced optical breakdown (LIOB). There have been multiple histological reports, but the present literature lacks detailed in vivo studies after treatment with high-power laser systems. Our study aimed to characterize the healing patterns of microlesions induced with 150 ps duration 1064 nm MLA-type picosecond laser. The induced picosecond laser-tissue reactions with pulse energy of 50–250 mJ and different treatment modes were observed in in vivo porcine skin model over 10 days after the laser procedure. A macroscopic evaluation was combined with microscopic histological analysis to observe the healing dynamics of laser-induced microlesions. Superficial, intraepidermal cavitation bubbles were induced using microbeam fluence of 4–20 J/cm². Skin irritation scores positively correlated with pulse energy and dose. Our findings demonstrate that dose and pulse energy had a direct impact on epidermal thickness and lesions healing dynamics.     

Q开关Nd:YAG 1064nm和532nm激光对犬心肌切割作用的研究

目的 :研究 10 64nm和 53 2nm波长激光在激光能量为 14 0mJ/pulse(脉冲 )时对犬心肌切割效率。方法 :用Q开关Nd :YAG 10 64和 53 2nm波长脉冲激光分别照射犬离体和在体心肌组织 ,光学显微镜和偏振光学显微镜行组织学分析 ,观察不同条件下激光切割组织的深度和光热对组织的损伤。结果 :离体和在体实验 ,10 64nm波长激光的切割效率高于 53 2nm(p <0 .0 1)。在体和离体实验显示 10 64nm激光能量和重复率相同时 ,所致的切割效率无明显差异 (p >0 .0 5) ,血液对 10 64nm激光的切割效率影响较小。相反 ,在 53 2nm时血液对其影响较大 ,相同的激光能量和重复率 ,离体实验切割效率高于在体 (p <0 .0 1)。 10 64nm激光所致的光热和机械损伤均轻于 53 2nm激光。结论 :在切割效率方面 ,10 64nm激光比 53 2nm更适用于TMLR。 10 64nmQ开关Nd :YAG激光可通过光导纤维传输 ,是TMLR的一个有潜力的激光源     

Cancer cell‐specific protein delivery by optoporation with laser‐irradiated gold nanorods

The delivery of macromolecules into living cells is challenging since in most cases molecules are endocytosed and remain in the endo‐lysosomal pathway where they are degraded before reaching their target. Here, a method is presented to selectively improve cell membrane permeability by nanosecond laser irradiation of gold nanorods (GNRs) with visible or near‐infrared irradiation in order to deliver proteins across the plasma membrane, avoiding the endo lysosomal pathway. GNRs were labeled with the anti‐EGFR (epidermal growth factor receptor) antibody Erbitux to target human ovarian carcinoma cells OVCAR‐3. Irradiation with nanosecond laser pulses at wavelengths of 532 nm or 730 nm is used for transient permeabilization of the cell membranes. As a result of the irradiation, the uptake of an anti‐Ki‐67 antibody was observed in about 50 % of the cells. The results of fluorescence lifetime imaging show that the GNR detached from the membrane after irradiation.     

低强度532nm与633nm激光血管内照射生物效应比较

目的：研究同等照射条件的低强度532nm与633nm激光血管内照射对家兔白细胞计数与淋巴细胞凋亡的影响,比较两种激光生物效应的特点。方法：用532nm和633nm激光对健康日本大耳白家兔血管内照射,平均照射功率均设在5mW左右,照射总能量约12J。两组家兔均于照前及照后1d、4d、7d、11d进行外周血白细胞计数,于照前及照后1d、5d进行淋巴细胞凋亡分析。结果：532nm激光照射后,家兔外周血白细胞计数表现为先显著升高后趋向恢复,633nm激光照射后白细胞计数变化类似,但与照前相比升高不明显;与照前相比,两组家免外周血淋巴细胞凋亡比例于照后1d均明显降低,照后5d均显著升高;两组家兔相比,照射后白细胞计数差别明显,但淋巴细胞凋亡比例差异不显著。结论：同等照射条件下,低强度532nm与633nm激光照射血液的生物效应相似,都可以促进白细胞的代谢更新,只是532nm激光的效应略强一些。     

Antimicrobial blue light for decontamination of platelets during storage

Platelet (PLT) storage is currently limited to 5 days in clinics in the United States, in part, due to an increasing risk for microbial contamination over time. In light of well‐documented antimicrobial activity of blue light (405‐470 nm), we investigated potentials to decontaminate microbes during PLT storage by antimicrobial blue light (aBL). We found that PLTs produced no detectable levels of porphyrins or their derivatives, the chromophores that specifically absorb blue light, in marked contrast to microbes that generated porphyrins abundantly. The difference formed a basis with which aBL selectively inactivated contaminated microbes prior to and during the storage, without incurring any harm to PLTs. In accordance with this, when contamination with representative microbes was simulated in PLT concentrates supplemented with 65% of PLT additive solution in a standard storage bag, all “contaminated” microbes tested were completely inactivated after exposure of the bag to 405 nm aBL at 75 J/cm² only once. While killing microbes efficiently, this dose of aBL irradiation exerted no adverse effects on the viability, activation or aggregation of PLTs ex vivo and could be used repeatedly during PLT storage. PLT survival in vivo was also unaltered by aBL irradiation after infusion of aBL‐irradiated mouse PLTs into mice. The study provides proof‐of‐concept evidence for a potential of aBL to decontaminate PLTs during storage.      

Self-phase-modulated femtosecond laser source at 1603 nm and its application to deep-brain 3-photon microscopy in vivo

3-photon microscopy (3PM) excited at the 1700 nm window enables deep-tissue imaging in vivo, especially in brain. PC rod soliton source has previously been exclusively used as the excitation source, which is rather costly and difficult to align. Here we demonstrate a novel nonlinear optical technique to build femtosecond laser source at the 1700 nm window, based on self-phase modulation (SPM) in a short span of large-mode-area fiber. The spectral broadening experienced by the pump pulse leads to the generation of a red-shifted sidelobe at 1603 nm. After spectral filtering, this sidelobe corresponds to 170-fs, 167-nJ pulses at 1603 nm. Using this SPM source, we further demonstrate deep-brain 3 PM to a depth of 1500 μm below the mouse brain surface in vivo. Our SPM femtosecond laser source thus provides a cost effective and easy-to-align alternative excitation source to the PC rod soliton source.     

532 nm和808 nm激光及其线偏振激光辐照人正常膀胱与膀胱癌组织光学特性

采用双积分球系统和光辐射测量技术的基本原理 ,以及运用生物组织的光学模型 ,研究了 5 32nm和80 8nm激光及其线偏振激光辐照人正常膀胱和膀胱癌组织的光学特性 .结果表明 :膀胱癌组织对同一波长的激光或其线偏振激光的衰减明显较正常膀胱组织的要大 ,膀胱癌组织对 5 32nm和 80 8nm激光的衰减均较其线偏振激光的要略大一些 .膀胱癌组织对 5 32nm和 80 8nm激光及其线偏振激光的衰减明显较正常膀胱组织的要大 .正常膀胱或膀胱癌组织对同一波长的激光及其线偏振激光的折射率均没有明显的差异 ,膀胱癌组织对 5 32nm和80 8nm激光的折射率比正常膀胱的明显要大 .Kubelka Munk二流模型下 ,两种组织对同一波长的激光或其线偏振激光的光学特性均有显著性差异 (P <0 0 1) .同一组织对不同波长的激光及其线偏振激光的光学特性也有显著性差异 (P <0 0 1) ,正常膀胱组织对同一波长的激光及其线偏振激光的光学性有明显差异 ,而膀胱癌组织对同一波长的激光及其线偏振激光的光学特性则没有明显差异 .膀胱癌组织对 5 32nm和 80 8nm激光及其线偏振激光的前向散射通量i (x)、后向散射通量 j (x)、总散射通量I (x)的衰减均较正常膀胱组织的明显要大得多 ,且其i (x)均明显较j (x)要强     

Concentric photothermal coagulation with basket‐integrated optical device for treatment of tracheal stenosis

A basket‐integrated optical device is developed to consistently treat tubular tissue by centering an optical diffuser in the lumen. Four nitinol arms in conjunction with the optical diffusing applicator are deployed to induce homogeneous circumferential light emission and concentric photothermal coagulation on tracheal tissue. A 1470‐nm laser light is employed for the tissue testing at various irradiation conditions and evaluated in terms of thermal gradient and temperature evolution. Preliminary experiments on liver tissue demonstrate the concentric development of the radial thermal coagulation in the tissue (eccentric ratio = ~5.5%). The interstitial tissue temperature increases with the total amount of energy delivery (around 65°C). Ex vivo trachea testing yields up to 16.5% tissue shrinkage due to dehydration as well as uniform ablation of the cilia and goblet cells in a mucosa layer under 7‐W irradiation for 10 s. The proposed optical device may be a feasible therapeutic method to entail the circumferential coagulation in the tubular tissues in a reliable manner.      

Accelerated inactivation of M13 bacteriophage using millijoule femtosecond lasers

Irradiation of femtosecond (fs) pulse lasers in the visible and near‐infrared ranges have been proposed as a promising approach for inactivating viruses. However, in order to achieve significant virus inactivation, past works have required relatively long irradiation times (1 hour or longer), even for small volumes. Given its advantages compared with other techniques, there is an urgent need to shorten the time required to inactivate viruses using fs laser technology. In this study, we investigate the inactivation of purified M13 bacteriophage in phosphate‐buffered saline with large active volume (1 cm³), and short exposure time (several minutes), using lasers with 20 mJ/pulse energy at various wavelengths (800, 400 nm or both 800 and 400 nm combined). For an exposure time of 15 and 2 minute, the use of a 400 nm wavelength laser results in a high load reduction of 5.8 ± 0.3 and 2.9 ± 0.15, respectively, on the log₁₀ scale of viability. We show that virus inactivation using the 400 nm laser is much more efficient compared with that using an 800 nm laser, or the simultaneous irradiation of 400 and 800 nm lasers. Higher pathogen inactivation is observed for lasers with shorter pulse duration, whereas at longer pulse durations, the inactivation is reduced. For millijoule‐energy fs laser irradiation, the M13 bacteriophage inactivation, via the reduction of the functionality of M13 bacteriophages, is accompanied with relatively small amounts of genetic damage.     

不同光源对K562细胞ALA-PDT作用的实验研究

目的:利用532 nm脉冲激光、532 nm连续激光和氙灯对K562细胞进行基于5-氨基乙酰丙酸的光动力疗法(ALA-PDT),研究在不同光照条件下细胞抑制率的变化情况,为实现体外ALA-PDT的高效率选择合适的光源。方法:在其他条件相同的情况下,采用不同的光源、不同的光剂量对ALA-PDT组细胞进行辐照,利用O-LYMPUS倒置荧光显微镜和显微镜数码相机系统观察细胞的形态学变化并拍照,利用光学显微镜进行台盼兰拒染法检测细胞的抑制率变化情况。结果:532 nm连续激光和脉冲激光对K562细胞的ALA-PDT抑制率均较低,增加光剂量也不能有效提高ALA-PDT的抑制率;氙灯在功率密度为350 mW/cm2、光照5 min时就能达到最佳的光剂量,此时单纯光照对K562细胞的光损伤作用很小且ALA-PDT效率很高。结论:宽光谱、高功率的氙灯对K562细胞的ALA-PDT效果远优于532 nm激光,对体外ALA-PDT实验比较适用。     

Highlighting nuances of blue light phototherapy: Mechanisms and safety considerations

The efficacy of blue light therapy in dermatology relies on numerous clinical studies. The safety remains a topic of controversy, where potentially deleterious effects were derived from in vitro rather than in vivo experiments. The objectives of this work were (1) to highlight the nuances behind “colors” of blue light, light propagation in tissue and the plurality of modes of action; and (2) to rigorously analyze studies on humans reporting both clinical and histological data from skin biopsies with focus on DNA damage, proliferation, apoptosis, oxidative stress, impact on collagen, elastin, immune cells, and pigmentation. We conclude that blue light therapy is safe for human skin. It induces intriguing skin pigmentation, in part mediated by photoreceptor Opsin-3, which might have a photoprotective effect against ultraviolet irradiation. Future research needs to unravel photochemical reactions and the most effective and safe parameters of blue light in dermatology.     

In Situ Optical Extinction Measurement for Locally Control of Surface Plasmon Resonance During Nanosecond Laser Irradiation of Silver Ion Exchanged Silicate Glass

Online UV/visible extinction measurement have been achieved during nanosecond Nd:YAG laser irradiation at 532 nm of a silver-exchanged silicate glass after each shot. We have explained the evolution of the integrated spectral evolution with the help of a few observed spots after the laser/glass interaction and completed them by optical and surface measurements. This optical method allows to in situ follow silver ions precipitation in nanoparticles (NPs) and the consequently surface plasmon resonance evolution (SPR). In this study, we focus on the interest of this method for one silver-exchanged soda-lime glass by direct observation of the sample surface. Scanning electron microscopy measurement and optical microscopy were used to identify the various ablation mechanisms. Profilometry was used to evaluate the material distribution and the surface roughness evolution (Rms parameter). Thus, we explain the silver NPs effect on glass matrix at various micrometric scales according to the deposited fluence and silver concentration.     

Specificity of the lethal and mutagenic actions of pico-second laser pulses of 532-nm wavelength

A study was made of the lethal effect of pulse laser (second harmonic Nd+3:YAG laser of 532 nm, pulse length 3.3.10(-11) s, peak intensity from 4.10(12) to 1.10(14) W/m2) on HeLa cells at the phases of active and stationary growth, and lethal and mutagenic effects of this radiation on E. coli cells. As was shown, HeLa cells at both growth phases and E. coli cells exhibited low sensitivity to laser radiation at lambda = 532 nm.     

Structural damage of Bacillus subtilis biofilms using pulsed laser interaction with gold thin films

There is a huge interest in developing strategies to effectively eliminate biofilms due to their negative impact in both industrial and clinical settings. In this study, structural damage was induced on two day‐old B. subtilis biofilms using the interaction of 532 nm pulsed laser with gold thin films. Radiant exposure of 225 mJ/cm² induced distinct changes on the surface structure and overall morphology of the matured biofilms after laser irradiation. Moreover, at the radiant exposure used, changes in the colour and viscosity of the biofilm were observed which may indicate a compromised extracellular matrix. Irradiated biofilms in the presence of gold film also showed strong propidium iodide signal which implies an increase in the number of dead bacterial cells after laser treatment. Thus, this laser‐based technique is a promising approach in targeting and eradicating matured biofilms attached on surfaces such as medical implants.

     

Theoretical study of the Raman optical activity spectra of with M = Co,Rh

Vibrational Raman optical activity (ROA) spectra were calculated under off-resonance, near-resonance, and at-resonance conditions for ( A ) and under off-resonance conditions for ( B ) using a new driver software for calculating the ROA intensities from complex (damped) time-dependent linear response Kohn-Sham theory. The off-resonance spectra of A and B show many similarities. At an incident laser wavelength of 532 nm, used in commercial ROA spectrometers, the spectrum of A is enhanced by near-resonance with the ligand-field transitions of the complex. The near-resonance spectrum exhibits many qualitative differences compared with the off-resonance case, but it remains bi-signate. Even under full resonance with the ligand-field electronic transitions, the ROA spectrum of A remains bi-signate when the electronic transitions are broadened such as to yield absorption line widths that are comparable with those in the experimental UV-vis absorption and electronic circular dichroism spectra.     

Noninvasive multimodal imaging by integrating optical coherence tomography with autofluorescence imaging for dental applications

We report the development of an integrated multifunctional imaging system capable of providing anatomical (optical coherence tomography, OCT), functional (OCT angiography, OCTA) and molecular imaging (light‐induced autofluorescence, LIAF) for in vivo dental applications. Blue excitation light (405 nm) was used for LIAF imaging, while the OCT was powered by a 1310 nm swept laser source. A red‐green‐blue digital camera, with a 450 nm cut‐on broadband optical filter, was used for LIAF detection. The exciting light source and camera were integrated directly with the OCT scanning probe. The integrated system used two noninvasive imaging modalities to improve the speed of in vivo OCT data collection and to better target the regions of interest. The newly designed system maintained the ability to detect differences between healthy and hypomineralized teeth, identify dental biofilm and visualize the microvasculature of gingival tissue. The development of the integrated OCT‐LIAF system provides an opportunity to conduct clinical studies more efficiently, examining changes in oral conditions over time.     

In vivo detection of tumor boundary using ultrahigh‐resolution optical coherence angiography and fluorescence imaging

Accurate detection of early tumor margin is of great preclinical and clinical implications for predicting the survival rate of subjects and assessing the response of tumor microenvironment to chemotherapy or radiation therapy. Here, we report a multimodality optical imaging study on in vivo detection of tumor boundary by analyzing neoangiogenesis of tumor microenvironment (microangiography), microcirculatory blood flow (optical Doppler tomography) and tumor proliferation (green fluorescent protein [GFP] fluorescence). Microangiography demonstrates superior sensitivity (77.7 ± 6.4%) and specificity (98.2 ± 1.7%) over other imaging technologies (eg, optical coherence tomography) for tumor margin detection. Additionally, we report longitudinal in vivo imaging of tumor progression and show that the abrupt tumor cell proliferation did not occur until local capillary density and cerebral blood flow reached their peak approximately 2 weeks after tumor implantation. The unique capability of longitudinal multimodality imaging of tumor angiogenesis may provide new insights in tumor biology and in vivo assessment of the treatment effects on anti‐angiogenesis therapy for brain cancer.     

Comparative study on the inactivation of MS2 and M13 bacteriophages using energetic femtosecond lasers

Femtosecond (fs) laser irradiation techniques are emerging tools for inactivating viruses that do not involve ionizing radiation. In this work, the inactivation of two bacteriophages representing protective capsids with different geometric constraints, that is, the near‐spherical MS2 (with a diameter of 27 nm) and the filamentous M13 (with a length of 880 nm) is compared using energetic visible and near‐infrared fs laser pulses with various energies, pulse durations, and exposure times. Intriguingly, the results show that inactivation using 400 nm lasers is substantially more efficient for MS2 compared to M13. In contrast, using 800 nm lasers, M13 was slightly more efficiently inactivated. For both viruses, the genome was exposed to a harmful environment upon fs‐laser irradiation. However, in addition to the protection of the genome, the metastable capsids differ in many properties required for stepwise cell entry that may explain their dissimilar behavior after (partial) disassembly. For MS2, the dominant mechanism of fs‐laser inactivation was the aggregation of the viral capsid proteins, whereas aggregation did not affect M13 inactivation, suggesting that the dominant mechanism of M13 inactivation was related to breaking of secondary protein links.     

In vivo study of metabolic dynamics and heterogeneity in brown and beige fat by label‐free multiphoton redox and fluorescence lifetime microscopy

In this work, the metabolic characteristics of adipose tissues in live mouse model were investigated using a multiphoton redox ratio and fluorescence lifetime imaging technology. By analyzing the intrinsic fluorescence of metabolic coenzymes, we measured the optical redox ratios of adipocytes in vivo and studied their responses to thermogenesis. The fluorescence lifetime imaging further revealed changes in protein bindings of metabolic coenzymes in the adipocytes during thermogenesis. Our study uncovered significant heterogeneity in the cellular structures and metabolic characteristics of thermogenic adipocytes in brown and beige fat. Subgroups of brown and beige adipocytes were identified based on the distinct lipid size distributions, redox ratios, fluorescence lifetimes and thermogenic capacities. The results of our study show that this label‐free imaging technique can shed new light on in vivo study of metabolic dynamics and heterogeneity of adipose tissues in live organisms.