Metal/Matrix Enhanced Time-of-Flight Secondary Ion Mass Spectrometry for Single Cell Lipids Analysis / 分析化学

The chemical components analysis of single cell is important for understanding of physiological processes such as cell growth, signal transduction and apoptosis.Time-of-flight secondary ion mass spectrometry ( ToF-SIMS) is a sensitive surface analysis technique with high spatial resolution and can be used for single cell and micro-area analysis.However, relatively low ioniZation yield of biomolecules limited its wide application in single cell analysis.Herein, we used metal substrate and matrix material to enhance the ioniZation yield of lipids.The signal intensity of the phosphatidylcholine PC (40:0) casted on the matrix/gold coated silicon substrate was 65 times higher than that on the silicon wafer.Signal enhancement of phosphatidylcholine PC (34:1) on the single cell surface cultured on matrix/gold coated silicon substrate was observed as well.Due to the influence of irregular topography and complex chemical environment of cell, the increase of lipids signal was smaller.Delayed extraction mode of ToF-SIMS overcame the effects of cell topography, leading to further enhancement of the signal intensity of lipids.Meanwhile, simultaneous high spatial resolution of chemical imaging and high mass resolution of the mass spectra of single cells were obtained.Our strategies provided new insights into the study of cell metabolism and cell-environment interactions.

Development of Biological Nanopore Technique in Non-gene Sequencing Application / 分析化学

Nanopore technique is a low-cost, ultrafast method for single-molecule level analysis without labels. Nanopore technique was first proposed more than 20 years ago and exhibited an excellent potential in DNA sequencing. So far, the commercial development of nanopore strand-sequencing as a portable device has been realized. Meanwhile, a remarkable number of studies have demonstrated that nanopore represents versatile single-molecule sensors for a wide range of molecule. Therefore, in this article we mainly review the use of nanopore technique based on the interface interactions between biological pore and the analytes such as protein/peptide to obtain kinetic and thermodynamic information at single-molecule level. And a large number of biological molecules and metal ions are quantitatively detected by nanopore analysis, allowing its development for the future biotechnologies and medicine applications. Besides, electrochemical detection system is crucial to nanopore technique. Therefore, we focus on advancements in relative software and ultralow current instrumentations with high-bandwidth.