Key Laboratory of Functional Polymer Materials of Ministry of Education, State Key Laboratory of Medicinal Chemical Biology, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
Shenzhen Institute of Aggregate Science and Technology, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China.
J Am Chem Soc. 2021 Sep 8;143(35):14147-14157. doi: 10.1021/jacs.1c04597. Epub 2021 Jul 21.
Sensing temperature at the subcellular level is of great importance for the understanding of miscellaneous biological processes. However, the development of sensitive and reliable organic fluorescent nanothermometers remains challenging. In this study, we report the fabrication of a novel organic fluorescent nanothermometer and study its application in temperature sensing. First of all, we synthesize a dual-responsive organic luminogen that can respond to the molecular state of aggregation and environmental polarity. Next, natural saturated fatty acids with sharp melting points as well as reversible and rapid phase transition are employed as the encapsulation matrix to correlate external heat information with the fluorescence properties of the luminogen. To apply the composite materials for biological application, we formulate them into colloidally dispersed nanoparticles by a technique that combines surface polymerization and nanoprecipitation. As anticipated, the resultant zwitterionic nanothermometer exhibits sensitive, reversible, reliable, and multiparametric responses to temperature variation within a narrow range around the physiological temperature (i.e., 37 °C). Taking spectral position, fluorescence intensity, and fluorescence lifetime as the correlation parameters, the maximum relative thermal sensitivities are determined to be 2.15% °C, 17.06% °C, and 17.72% °C, respectively, which are much higher than most fluorescent nanothermometers. Furthermore, we achieve the multimodal temperature sensing of bacterial biofilms using these three complementary fluorescence parameters. Besides, we also fabricate a cationic form of the nanothermometer to facilitate efficient cellular uptake, holding great promise for studying thermal behaviors in biological systems.
在亚细胞水平上感知温度对于理解各种生物过程非常重要。然而，开发灵敏和可靠的有机荧光纳米温度计仍然具有挑战性。在本研究中，我们报告了一种新型有机荧光纳米温度计的制备，并研究了其在温度传感中的应用。首先，我们合成了一种双重响应的有机发光体，它可以响应聚集态和环境极性的分子状态。接下来，我们采用具有尖锐熔点以及可逆和快速相转变的天然饱和脂肪酸作为封装基质，将外部热信息与发光体的荧光性质相关联。为了将复合材料应用于生物学，我们通过一种结合表面聚合和纳米沉淀的技术将它们配制成胶体分散的纳米颗粒。正如预期的那样，所得的两性离子纳米温度计对生理温度（即 37°C）附近的窄温度范围内的温度变化表现出灵敏、可逆、可靠和多参数响应。以光谱位置、荧光强度和荧光寿命作为相关参数，确定最大相对热灵敏度分别为 2.15%°C、17.06%°C 和 17.72%°C，均高于大多数荧光纳米温度计。此外，我们还使用这三种互补的荧光参数实现了细菌生物膜的多模态温度传感。此外，我们还制备了纳米温度计的阳离子形式，以促进有效的细胞摄取，这对于研究生物系统中的热行为具有很大的应用前景。
