College of Food and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, P. R. China.
College of Biological and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
ACS Appl Mater Interfaces. 2021 Dec 8;13(48):57058-57066. doi: 10.1021/acsami.1c19746. Epub 2021 Nov 16.
Lipopolysaccharide (LPS), as the major component of the outer membrane of Gram-negative bacteria, can trigger a variety of biological effects such as sepsis, septic shock, and even multiorgan failure. Herein, we developed a near-infrared-fluorescent probe for fluorescent turn-on analysis of LPS based on plasmon-enhanced fluorescence (PEF). Gold nanorods (Au NRs) modified polyethylene glycol (PEG) was used as PEF materials. Au NRs were prepared with different longitudinal surface plasmon resonance (LSPR), and their fluorescence enhancement was investigated. Three kinds of molecular weights (1000, 5000, and 10000) of polyethylene glycol (PEG) were employed to control the distance between the Au NRs and the fluorescence substances of cyanine 7 (Cy7). Experimental analysis showed that the enhancement was related to the spectral overlap between the plasmon resonance of Au NRs and the extinction/emission of fluorophore. The three-dimensional finite-difference time-domain (3D-FDTD) simulation further revealed that the enhancement was caused by local electric field enhancement. Furthermore, the probe was used for the ultrasensitive analysis of LPS with a detection limit of 3.85 ng/mL and could quickly distinguish the Gram-negative bacterium- () (with LPS in the membrane) from Gram-positive bacterium- () (without LPS), as well as quantitative determination of with a detection limit of 1.0 × 10 cfu/mL. These results suggested that the prepared probe has great potential for biomedical diagnosis and selective detection of LPS from different bacterial strains.
脂多糖（LPS）作为革兰氏阴性菌外膜的主要成分，可以引发多种生物学效应，如败血症、感染性休克，甚至多器官衰竭。在此，我们基于等离子体增强荧光（PEF）开发了一种用于 LPS 的荧光开启分析的近红外荧光探针。金纳米棒（Au NRs）修饰的聚乙二醇（PEG）被用作 PEF 材料。Au NRs 具有不同的纵向表面等离子体共振（LSPR），并研究了它们的荧光增强。使用了三种分子量（1000、5000 和 10000）的聚乙二醇（PEG）来控制 Au NRs 与菁染料 7（Cy7）的荧光物质之间的距离。实验分析表明，增强与 Au NRs 的等离子体共振与荧光团的消光/发射之间的光谱重叠有关。三维有限差分时间域（3D-FDTD）模拟进一步表明，增强是由局部电场增强引起的。此外，该探针可用于 LPS 的超灵敏分析，检测限低至 3.85ng/mL，可快速区分革兰氏阴性菌（）（膜内有 LPS）和革兰氏阳性菌（）（无 LPS），并对 进行定量测定，检测限低至 1.0×10 cfu/mL。这些结果表明，所制备的探针在生物医学诊断和不同细菌菌株 LPS 的选择性检测方面具有巨大的潜力。
