Abstract:

Biological systems can be regarded as complex and open thermodynamic systems. All processes involved in biological growth and metabolism are accompanied by material and energy exchange. During metabolism, energy in the organisms is released in the form of heat, i.e., metabolic heat, which is the basis for development in the field of biothermochemistry. The calorimetric method considers the thermal effects produced by the various forms of action as the research object, to reveal the law of energy change and quantitative energy conversion. Studying the thermodynamic processes of complex biological systems and related reactions through microcalorimetry and thermodynamic methods reflects the intrinsic laws of life-related processes macroscopically and intrinsically. With the tremendous development and progress in microcalorimetry in terms of the temperature measurement accuracy, stability of temperature control, automation, and multi-functionalization, calorimetry has been widely used in life sciences. It can be used to describe macroscopic processes such as ecosystems and biological evolution, observe organismal and cell growth, examine mitochondrial metabolism, and study problems at the molecular level, including enzymatic reactions and interactions between small molecules and biomacromolecules. Herein, the application of biomass calorimetry in the life sciences is reviewed. The status and progress of biomass calorimetry at different biological and structural levels, such as the ecosystem, biological, organ, cellular, subcellular, and molecular levels are introduced. For example, soil microbial metabolic activity is a universal index for evaluating soil quality. The growth and metabolism of organisms as well as the physical and chemical processes of substances in soil are often accompanied by heat release, which is usually a non-selective signal. The use of isothermal microcalorimetry to nonspecifically monitor and record soil microbial metabolic characteristics has promoted the study of microbial metabolism in complex soil systems. The application of calorimetry to the study of tissues and organs mainly involves the calorimetric study of isolated animal and plant tissues and organs. Calorimetry of animal and microbial cells is considered the most common application of calorimetry in life sciences research. It mainly involves the classification and identification of bacteria, their growth and metabolism, inhibition mechanisms of drugs on microbial growth, principles of kinetics, and the thermodynamic characteristics of microbial growth and metabolism. However, owing to the lack of specificity of biomass calorimetry and the lack of direct access to information at the molecular level, more applications of calorimetry combined with other analytical techniques (especially in biology, medicine, and pharmacy) are needed in the future.

Key words: Flash DSC, Polymer, Crystallization kinetics