Bioanalysis in single cells: current advances and challenges

Cells, basic units of living structures and functions, build up a complicated small world, and their order and complexity resemble a small universe. The detailed understanding and elucidation of the matter transport and energy conversion mechanisms within a single cell will expand our knowledge about the origin and evolution of life, the disease mechanisms and much more. In past decades, single-cell analysis has been rapidly and significantly improved and various methodologies have been developed to reveal the complexity of mass, energy, and information within single cells. In this review, we focused on the methods developed in recent years for single-cell analysis, including electrochemical method, optical method, and mass spectrometry method. We reviewed the recent advances and representative studies in this research field, and also discussed the strengths and limitations of each method. Finally, we presented the existing technical challenges and further directions for single-cell analysis.