Publication Date

Summer 2015

Degree Type


Degree Name

Master of Science (MS)




Daryl K. Eggers


desolvation energy model, excluded volume effects, macromolecular crowding, polymer crowding agents

Subject Areas

Chemistry; Biochemistry


Macromolecular crowding refers to the excluded volume in the cell by macromolecules (proteins, DNA, etc.). Crowding in the cell is relevant to the free motion of each macromolecule and may influence biological equilibria in general. The surface hydration of the crowding agents is expected to alter the average properties of water in the solution, which in turn may also affect molecular interactions. Because the living cell contains a concentration of 300-400 g/L of macromolecules, it is crucial to study the properties of crowded solutions to understand the environment of a cell. The focus was to study the thermodynamic properties of water in solutions containing model crowding agents such as Ficoll, Dextran, PEG (polyethylene glycol), and PVP (polyvinylpyrrolidone). Crowding effects on water were measured by comparing the thermodynamic properties of reactions in dilute solution versus crowded solutions and/or by direct calorimetric methods. The results obtained from the calorimetric method were not consistent with the thermodynamic properties observed in the non-crowded solutions, but the enthalpy and solubility results indicated that crowding has a negligible effect on small molecule interactions. Future studies that adjust the sample preparation and experimental parameters for calorimetry should provide a better indication of the thermodynamic properties of water in the crowded solutions.