Fluorescence enhancement of organic dyes by femtosecond laser-induced cavitation bubbles for crystal imaging.
Fluorescence enhancement of organic dyes by femtosecond laser-induced cavitation bubbles for crystal imaging.
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通过飞秒激光诱导空化气泡增强有机染料的荧光以进行晶体成像。
作者：
Jiachen Yu;Jianfeng Yan;Lan Jiang;Jiaqun Li;Heng Guo;Ming Qiao;L. Qu
有机染料的荧光在成像、生物传感和诊断等领域有着广泛的应用。荧光成像的一个缺点是发射强度的限制。荧光信号的放大可以通过增强局部电磁场来实现。金属纳米粒子被广泛应用于产生等离子体共振，但它们会对脆弱的生物材料造成热损伤。在这项研究中，我们提出了一种方法，无纳米颗粒的荧光增强超快激光诱导空化气泡在有机染料溶液中。不使用纳米颗粒的荧光增强防止了包括热效应和生物毒性在内的潜在危害。为了实现在纯染料溶液中的荧光增强，通过聚焦800 nm的超快激光束来诱导空化气泡。另一个400 nm的激光束用于泵浦增益介质。在各种染料溶液中观察到荧光增强。荧光发射的强度和光谱可以通过改变激发激光的功率和焦点来控制。根据时间分辨显微镜和模拟结果，由激光诱导的气泡形成的空腔导致局部电磁场的增强，并诱导荧光信号的放大。气泡增强的荧光发射用于蛋白质晶体的成像，而不会对样品造成热损伤。该研究为生物相容性荧光增强提供了一种有效的方法，在生物成像等领域具有应用前景。
Fluorescence from organic dyes can be applied in many research fields such as imaging, bio-sensing and diagnosis. One shortcoming of fluorescence imaging is the limitation in emission intensity. Amplification of fluorescence signals can be achieved by the enhancement of localized electromagnetic fields. Metallic nanoparticles are widely applied to produce plasmon resonance, but they cause thermal damage to fragile bio-materials. In this study, we propose a method for nanoparticle-free fluorescence enhancement by ultrafast laser-induced cavitation bubbles in organic dye solutions. Fluorescence enhancement without the use of nanoparticles prevents potential hazards including thermal effects and biotoxicity. In order to achieve fluorescence enhancement in neat dye solution, cavitation bubbles were induced by focusing an 800 nm ultrafast laser beam. Another 400 nm laser beam was used to pump the gain medium. Fluorescence enhancement was observed in various dye solutions. The intensity and spectra of the fluorescence emission can be controlled by changing the power and focus of the excitation laser. According to time-resolved microscopy and simulation results, the cavity formed by the laser-induced bubbles results in the enhancement of the localized electromagnetic field and induces the amplification of the fluorescence signal. The bubble-enhanced fluorescence emission was used for imaging of protein crystals without causing thermal damage to the samples. This study provides an effective method for bio-compatible fluorescence enhancement and has application prospects in fields such as bio-imaging.