Inductively Coupled Plasma Mass Spectrometry-Based Techniques for Single Cell Analysis

Abstract

Previous studies generally focused on the cell colony and the obtained information was commonly the average of many cell individuals. However, each cell has a different behavior, which is known as cell heterogeneity. Single cell analysis can accurately obtain valuable information of each cell in the microenvironment and thus there is an urgent need for single cell analysis. Many methods have been successfully employed to single cell analysis, such as flow cytometry, fluorescence microscopy, capillary electrophoresis and microfluidic chips. In these methods, single cells are usually stained by a fluorescent label (e.g. fluorescein, quantum dots, green fluorescent protein, etc.) and then detected via the fluorescent signal. However, simultaneous analysis of multiple parameters in a single cell is always challenging because of the overlap in fluorescent spectrum. In addition, the linear range of the fluorescence method is relatively narrow, making difficulty for accurate quantification, especially when comparing signals with considerable difference. To meet these challenges, a new method based on inductively coupled plasma mass spectrometry (ICP-MS) has emerged for single cell analysis. Intracellular elements can be determined directly by ICP-MS at a single cell level. In combination with labeling techniques(e.g. element labeling of an antibody), biomolecules in single cells can also be determined via elements analysis by ICP-MS. This paper summaries both the ICP-MS-based methodology and selected applications in immunoassay, disease detection, drug screen, and nanoanalysis at a single cell level. A prospective of this method and its applications is also discussed.