CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China.
ACS Nano. 2020 Mar 24;14(3):3696-3702. doi: 10.1021/acsnano.0c00847. Epub 2020 Mar 11.
Light emission induced by chemical reactions, known as chemiluminescence (CL), has been widely used for bioassays, biosensors, imaging, and illumination applications. Most known CL systems exhibit flash-type single-color light emissions, which limit their applications. Long-lasting multicolor CL in aqueous solutions is highly desirable, especially for biological applications, but remains a challenge. Herein, we report a simple strategy of achieving highly efficient cascade Förster resonance energy transfer (FRET) in the dynamic nanoassembly of β-cyclodextrin (β-CD), CL reagents, and fluorophores in aqueous solution, which emits intensive multicolor CL with adjustable wavelength within 410-610 nm. β-CD can bind CL reagents and fluorophores to form a dynamic nanoassembly. These nanoassemblies can bring the included luminescent intermediate and fluorophores into close proximity and proper alignment, which should greatly enhance the FRET efficiency between luminescent intermediate and fluorophores. Indeed, the cascade FRET efficiency in this supramolecular nanoassembly reaches up to 92%, which is comparable with the cascade FRET systems based on covalently linked donors and acceptors. By using hydroxypropyl methylcellulose as the thickener to slow the diffusion (to elongate the CL emission), and using Ca(OH) solid (a low solubility strong base) as buffer to maintain the pH in the optimal range for the CL reaction, this nanoassembly system has been further developed to achieve slow-diffusion-controlled catalytic CL reactions, which enables long-lasting multicolor CL in aqueous solution that is visible to naked eyes and lasts for more than 20 h. The multicolor CL systems can be used to prepare transformable two-dimensional multicolor codes for encryption application.
化学反应引起的发光，称为化学发光（CL），已被广泛应用于生物测定、生物传感器、成像和照明应用。大多数已知的 CL 系统表现出闪烁型单色彩光发射，这限制了它们的应用。在水溶液中具有长余辉的多色 CL 是非常需要的，特别是对于生物应用，但仍然是一个挑战。在此，我们报告了一种在水溶液中通过β-环糊精（β-CD）、CL 试剂和荧光团的动态纳米组装中实现高效级联Förster 共振能量转移（FRET）的简单策略，该策略在 410-610nm 范围内发射可调波长的强多色 CL。β-CD 可以将 CL 试剂和荧光团结合形成动态纳米组装体。这些纳米组装体可以使包含的发光中间体和荧光团靠近并适当排列，这应该大大提高发光中间体和荧光团之间的 FRET 效率。事实上，这种超分子纳米组装体中的级联 FRET 效率高达 92%，与基于共价连接供体和受体的级联 FRET 系统相当。通过使用羟丙基甲基纤维素作为增稠剂来减缓扩散（延长 CL 发射），并使用 Ca(OH) 固体（低溶解度强碱）作为缓冲液来维持 CL 反应的最佳 pH 值，该纳米组装体系统进一步发展为实现缓慢扩散控制的催化 CL 反应，从而在水溶液中实现长余辉多色 CL，肉眼可见，持续时间超过 20 小时。多色 CL 系统可用于制备用于加密应用的可转换二维多色码。
