CNR-IFN, Institute for Photonics and Nanotechnologies, C/o University of Bari, Physics Department, Bari, Italy.
CSGI (Center for Colloid and Surface Science), Bari, Italy.
Appl Spectrosc. 2023 Nov;77(11):1253-1263. doi: 10.1177/00037028231200511. Epub 2023 Sep 13.
Nanoparticle-enhanced laser-induced breakdown spectroscopy (NELIBS) is an optical emission technique based on the laser-induced plasma (LIP) on a sample after the deposition of plasmonic nanoparticles (NPs) on its surface. The employment of the NPs allows an enhancement of the signal with respect to the one obtained with the conventional laser-induced breakdown spectroscopy (LIBS) enabling an extremely high sensitivity and very low limits of detection compared with the LIBS performance. Recently, NELIBS was used for monitoring the NP protein corona formation. As a matter of fact, the NPs in the presence of proteins adsorbed on the surface change their surface properties, therefore the sensing of protein corona formation was possible because of the strong dependence of NELIBS effects on the NP organization on the substrate, which in turn is deeply affected by the surface properties of the NPs. A correlation was found between NELIBS enhancement and the structure of the NP-protein conjugate in terms of protein content absorbed on the NP surface. An interesting question that was not yet exploited regards the role of LIP during the NELIBS when the NPs are covered with proteins. Since the presence of organic matter can strongly quench the LIP emission, the study of the LIP properties during protein corona sensing by NELIBS is of interest for two main reasons: (i) to understand whether the plasma parameters can vary in the presence of proteins adsorbed on the NP surface and (ii) to investigate how and if the plasma parameters themselves can influence the NELIBS processes. With this aim, the study of plasma parameters, i.e., electron densities and temperatures, during the sensing of NP protein corona by NELIBS is presented and discussed. The NPs used during these experiments were ultrapure gold NPs (AuNPs) produced by pulsed laser ablation in liquid, which are stable without any stabilizer. The human serum albumin protein is used to form AuNP-protein conjugates further deposited on a titanium target in NELIBS measurements. Dynamic light scattering, surface plasmon resonance spectroscopy, and laser Doppler electrophoresis for ζ-potential determination were employed to monitor the protein coverage of NP surface in the conjugate solutions before the NELIBS measurements.
纳米颗粒增强激光诱导击穿光谱（NELIBS）是一种基于样品表面沉积等离子体纳米颗粒（NPs）后激光诱导等离子体（LIP）的光学发射技术。使用 NPs 可以增强相对于传统激光诱导击穿光谱（LIBS）获得的信号，从而实现极高的灵敏度和极低的检测限，与 LIBS 性能相比。最近，NELIBS 被用于监测 NP 蛋白冠的形成。事实上，在存在吸附在表面上的蛋白质的情况下，NPs 会改变其表面特性，因此可以通过强烈依赖于 NP 在基底上的组织来感应蛋白冠的形成，而 NP 在基底上的组织又受到 NPs 表面特性的深刻影响。在 NP-蛋白缀合物的结构方面，发现了 NELIBS 增强与 NP 表面上吸收的蛋白含量之间的相关性。一个尚未得到充分利用的有趣问题是，当 NPs 被蛋白质覆盖时，在 NELIBS 中 LIP 会发生什么。由于有机物的存在会强烈猝灭 LIP 发射，因此，在 NELIBS 中研究蛋白冠感应过程中的 LIP 特性具有两个主要原因：（i）了解在吸附在 NP 表面的蛋白质存在的情况下，等离子体参数是否会发生变化；（ii）研究等离子体参数本身如何以及是否可以影响 NELIBS 过程。为此，介绍并讨论了通过 NELIBS 感应 NP 蛋白冠期间等离子体参数（即电子密度和温度）的研究。在这些实验中使用的 NPs 是通过液体中脉冲激光烧蚀产生的超纯金 NPs（AuNPs），它们在没有任何稳定剂的情况下是稳定的。人血清白蛋白蛋白用于形成 AuNP-蛋白缀合物，然后在 NELIBS 测量中进一步沉积在钛靶上。动态光散射、表面等离子体共振光谱和激光多普勒电泳用于 ζ-电位测定，以监测缀合物溶液中 NP 表面的蛋白质覆盖度，然后进行 NELIBS 测量。
