In recent years there has been significant development in microscale methods for the assessment, separation and concentration of intact cells, that is, without carrying out lysis. Miniaturization offers excellent advantages for the handling and analysis of cells, such as short response time, portability, high resolution and sensitivity, and low requirement of sample and reagents. Different science and industry fields, such as food industry, clinical and biomedical analysis, environmental monitoring, etc., have benefited from the use of micro-laboratories or micro analytical systems. Due to these advantages, significant research efforts worldwide are being devoted towards the development of techniques than can be applied on the microscale for cell assessment.

The present article is a tutorial review that depicts the fundamentals and recent applications of the most important microscale techniques for the analysis of intact cells. A brief description and examples of applications of six strategically selected techniques have been included, with the objective of providing the reader with a comprehensive overview on the advances in this field. The techniques presented here cover the main mechanisms employed in miniaturized methods for handling intact cells. These mechanisms are electric fields (electrophoresis, dielectrophoresis, electrorotation and electric impedance), flow effects (inertial focusing) and optical effects (flow cytometry).