title: Light Effect on Water Viscosity: Implication for ATP Biosynthesis.
abstract: Previous work assumed that ATP synthase, the smallest known rotary motor in nature, operates at 100% efficiency. Calculations which arrive to this result assume that the water viscosity inside mitochondria is constant and corresponds to that of bulk water. In our opinion this assumption is not satisfactory for two reasons: (1) There is evidence that the water in mitochondria prevails to 100% as interfacial water. (2) Laboratory experiments which explore the properties of interfacial water suggest viscosities which exceed those of bulk water, specifically at hydrophilic interfaces. Here, we wish to suggest a physicochemical mechanism which assumes intramitochondrial water viscosity gradients and consistently explains two cellular responses: The decrease and increase in ATP synthesis in response to reactive oxygen species and non-destructive levels of near-infrared (NIR) laser light, respectively. The mechanism is derived from the results of a new experimental method, which combines the technique of nanoindentation with the modulation of interfacial water layers by laser irradiation. Results, including the elucidation of the principle of light-induced ATP production, are expected to have broad implications in all fields of medicine.
authors.affiliation: Institute of Micro and Nanomaterials, University of Ulm, 89081 Ulm, Germany.
authors.forename: Andrei P
authors.initials: AP
authors.lastname: Sommer
authors.affiliation: Institute of Micro and Nanomaterials, University of Ulm, 89081 Ulm, Germany.
authors.forename: Mike Kh
authors.initials: MKh
authors.lastname: Haddad
authors.affiliation: Institute of Micro and Nanomaterials, University of Ulm, 89081 Ulm, Germany.
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Fecht
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D053898:Biosynthetic Pathways / Q000528:radiation effects; D007834:Lasers; D008027:Light; D014783:Viscosity / Q000528:radiation effects*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D000255:Adenosine Triphosphate