We report the fabrication of enthalpy arrays and their use to detect molecular interactions, including protein-ligand binding, enzymatic turnover, and mitochondrial respiration. Enthalpy arrays provide a universal assay methodology with no need for specific assay development, such as fluorescent labeling for a competitive assay or immobilization of reagents, which can adversely affect the interaction. Micro-scale fabrication technology enables the fabrication of 96-detector enthalpy arrays on large substrates. The reduction in scale results in large reductions in both the sample quantity and the measurement time compared with conventional microcalorimetery. We demonstrate the utility of the enthalpy arrays by showing measurements for two protein-ligand binding interactions (RNase A + cytidine 2'-monophosphate and streptavidin + biotin), phosphorylation of glucose by hexokinase, and respiration of mitochondria in the presence of 2,4-dinitrophenol uncoupler.
Torres, F. ; Kuhn, P.; De Bruyker, D. ; Bell, A. G. ; Wolkin, M. V. ; Peeters, E. ; Williamson, J. R.; Anderson, G. B. ; Schmitz, G. P. ; Recht, M. I. ; Schweitzer, S. ; Scott, L. G.; Ho, J. H. ; Elrod, S. A. ; Schultz, P. G.; Lerner, R. A.; Bruce, R. H. Enthalpy arrays. Proceedings of the National Academy of Sciences. 2004 June 29; 101 (26): 9517-9522.