Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612 00, Brno, Czech Republic.
Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
Mikrochim Acta. 2021 Apr 2;188(5):147. doi: 10.1007/s00604-021-04816-y.
Immunohistochemistry (IHC) and immunocytochemistry (ICC) are widely used to identify cancerous cells within tissues and cell cultures. Even though the optical microscopy evaluation is considered the gold standard, the limited range of useful labels and narrow multiplexing capabilities create an imminent need for alternative readout techniques. Laser-induced breakdown spectroscopy (LIBS) enables large-scale multi-elemental analysis of the surface of biological samples, e.g., thin section or cell pellet. It is, therefore, a potential alternative for IHC and ICC readout of various labels or tags (Tag-LIBS approach). Here, we introduce Tag-LIBS as a method for the specific determination of HER2 biomarker. The cell pellets were labeled with streptavidin-conjugated upconversion nanoparticles (UCNP) through a primary anti-HER2 antibody and a biotinylated secondary antibody. The LIBS scanning enabled detecting the characteristic elemental signature of yttrium as a principal constituent of UCNP, thus indirectly providing a reliable way to differentiate between HER2-positive BT-474 cells and HER2-negative MDA-MB-231 cells. The comparison of results with upconversion optical microscopy and luminescence intensity scanning confirmed that LIBS is a promising alternative for the IHC and ICC readout.
免疫组织化学（IHC）和免疫细胞化学（ICC）广泛用于鉴定组织和细胞培养物中的癌细胞。尽管光学显微镜评估被认为是金标准，但有限的有用标签范围和狭窄的多重分析能力迫切需要替代读出技术。激光诱导击穿光谱（LIBS）能够对生物样本表面进行大规模多元素分析，例如薄切片或细胞沉淀。因此，它是 IHC 和 ICC 读出各种标签或标记物的潜在替代方法（Tag-LIBS 方法）。在这里，我们介绍了 Tag-LIBS 作为一种用于特定测定 HER2 生物标志物的方法。细胞沉淀通过与上转换纳米粒子（UCNP）结合的链霉亲和素通过针对 HER2 的一抗和生物素化的二抗进行标记。LIBS 扫描能够检测到作为 UCNP主要成分的钇的特征元素特征，从而间接提供了一种可靠的方法来区分 HER2 阳性 BT-474 细胞和 HER2 阴性 MDA-MB-231 细胞。与上转换光学显微镜和发光强度扫描的结果比较证实，LIBS 是 IHC 和 ICC 读出的一种很有前途的替代方法。
