Monte Carlo方法模拟光在生物组织中传播的新进展

Monte Carlo方法已被广泛用于模拟复杂的随机介质如生物组织中光的辐射传输.在生物光子应用中,早期的Monte Carlo模拟模型忽略了光在组织中传输的波动性,而用中性粒子光子包来模拟其传播过程.然而,许多光学诊断技术是基于光在组织中的偏振效应和多重散射的相干性来揭示组织的生理和病理信息,这就要涉及光辐射的波动性.本文阐述了用Monte Carlo方法模拟光在生物组织中传播的最新进展.     

未来十年纳米光子学若干重点发展领域

纳米光子学已经对人们的日常生活产生了重要影响,并且纳米光子学器件产品有强大的市场需求,因此其研究结果可以很快转化为商品。文章介绍了在未来5到10年内对光子工业有重大影响并且有望进入商品市场的11个纳米光子学领域,其中包括:纳米尺度量子光子学、全光路由、用于增强磁存储的表面等离子体光子学、用于诊断治疗和药物输送纳米光子学、纳米成像、分子尺度上的化学与生物传感器、纳米标签、纳米尺度上操控光场的分布(光伏器件和LED/OLED)、原型试制的新技术、量身定制光学特性的纳米光子材料以及太赫兹技术等,希望文章能对中国的纳米光子学研究及其工业化应用有一定帮助。     

Photodegradable Polymers for Biotechnological Applications

Photodegradable polymers constitute an emerging class of materials that finds numerous applications in biotechnology, biomedicine, and nanoscience. This article highlights some of the emerging applications of photodegradable polymers in the form of homopolymers, particles and self‐assembled constructs in solution, hydrogels for tissue engineering, and photolabile polymers for biopatterning applications. Novel photochemistries have been combined with controlled polymerization methods, which result in well‐defined photodegradable materials that exhibit light mediated and often controlled fragmentation processes.     

Mathematical models in nanooptics and biophotonics based on the discrete sources method

The state of the art of the discrete sources method is reviewed. The method can be used to construct effective numerical models for problems in nanooptics and biophotonics.     

Coherent fiber supercontinuum for biophotonics

Biophotonics and nonlinear fiber optics have traditionally been two independent fields. Since the discovery of fiber‐based supercontinuum generation in 1999, biophotonics applications employing incoherent light have experienced a large impact from nonlinear fiber optics, primarily because of the access to a wide range of wavelengths and a uniform spatial profile afforded by fiber supercontinuum. However, biophotonics applications employing coherent light have not benefited from the most well‐known techniques of supercontinuum generation for reasons such as poor coherence (or high noise), insufficient controllability, and inadequate portability. Fortunately, a few key techniques involving nonlinear fiber optics and femtosecond laser development have emerged to overcome these critical limitations. Despite their relative independence, these techniques are the focus of this review, because they can be integrated into a low‐cost portable biophotonics source platform. This platform can be shared across many different areas of research in biophotonics, enabling new applications such as point‐of‐care coherent optical biomedical imaging.     

Gas in scattering media absorption spectroscopy – from basic studies to biomedical applications

The recently introduced Gas in Scattering Media Absorption Spectroscopy (GASMAS) technique provides novel possibilities for analysis in biophotonics. Free gas in pores or cavities is monitored with narrow‐band laser radiation, which can discern the gas absorptive imprints which are typically several orders of magnitude more narrow than the features of the surrounding tissue through which the diffusely scattered light emerges to the detector. Important gases monitored are oxygen and water vapour. Applications include diagnosis of human sinus cavities and surveillance of neonatal children, but also characterization of food‐stuffs, food packages and pharmaceutical preparations. Non‐biological applications include the study of construction materials such as wood, polystyrene foams and ceramics. For nano‐porous materials, information on the pore sizes can be obtained from observed line broadening. Apart from concentration measurements, the GASMAS technique also allows the study of gas transport and diffusion, and pressure and temperature information can also be obtained.     

Multifold Fluorescence Enhancement in Nanoscopic Fluorophore–Clay Hybrids in Transparent Aqueous Media

Valuable emissive properties of organic fluorophores have become indispensable analytical tools in biophotonics, but frequently suffer from low solubilities and radiationless deactivation in aqueous media, that is, in biological ambience as well. In this report, nanoscaled dye–clay hybrids based on laponite, Na_0.7{(Li_0.3Mg_5.5)[Si₈O₂₀(OH)₄]}, are taken advantage of to solubilize neutral dyes, which are natively not encountered in water. Previously reported efficiency and solubility bottlenecks of such hybrids can to a large extent be overcome by comparably simple chemical measures, as demonstrated here for two prominent examples, the fluorescent dyes Nile Red and Coumarin 153. On controlled co‐adsorption of small bifunctional quaternary ammonium ions (Me₃N⁺C₂H₅OH and Me₃N⁺C₂H₅NH₂) we observed an outright efficiency boost by an order of magnitude, and a 30‐fold brightness gain. Even at higher concentrations, transparency and stability of the hybrid dispersions are retained, rendering them useful for employment as optically functional nanoparticles in bioassays and beyond.     

淀粉自由基弛豫发光

为了研究淀粉自由基的变化规律,以生物光子辐射理论为基础.根据化学发光的动力学模型,建立了淀粉自由基的发光动力学方程,并根据自由基发光强度与自由基浓度的关系,通过分析得到了淀粉自由基的湮没方程,得到了光强随时间的变化函数.通过拟合发现,函数在不同温度下随时间的变化曲线与实验曲线的相关系数都在0.98以上,能很精确地刻画自由基的弛豫发光规律.     

第二讲光电子技术在保健医疗和生物学应用中的进展

文章论述了激光与光电子技术在人类保健、医疗以及生命科学应用中的作用和意义.综述了光活检技术、光美容医疗和生物光子技术等光电子技术在保健、医疗和生物学领域中的具体应用.重点介绍了：（1）用于组织病理诊断的光活检技术,其中包括光活检的发展历史、技术优点、研究现状,以及荧光光谱和成像技术等实用光活检技术的临床应用;（2）非消融性光疗的基本作用机制和研究进展;（3）扫描共焦显微术、多光子荧光显微术、近场光学扫描显微术和光镊等显微生物成像技术的工作原理和应用.最后,展望了激光与光电子技术在生命科学中的应用前景.     

飞秒激光与细胞的相互作用

近年来,高速发展的激光技术已经广泛应用于医疗领域,比如眼科手术和光学相干层析成像。尤为特殊的是,飞秒激光更可专用于对活体细胞的基础研究。飞秒激光具有别种激光无法获得的特殊性质。它对于细胞的伤害很小,因为它的线性吸收和热效应远远低于连续光。此外,由于飞秒光的超高峰值功率,它可以对细胞形成多光子电离而在细胞膜上开孔,因此可以转基因和融合细胞,同时不会太过于伤害细胞。在这个报告里,将阐述我们的以下研究：飞秒光致转基因、细胞融合以及细胞在凋亡中的动态过程。在单细胞水平上提出了一些凋亡过程的可能机制,如活性氧化合物、核管和细胞内自由钙离子的产生。