title: Microphase mechanism of "superquenching" of luminescent probes in aqueous solutions of DNA and some other polyelectrolytes.
abstract: A new approach in terms of microphase model of aqueous solutions of polyelectrolytes is proposed for explanation of a very strong quenching of luminescent probes ("superquenching") in these solutions. This phenomenon is used in literature for creation of extremely sensitive chemical and biosensors and was attributed predominantly to efficient energy or electron transfer. Microphase approach considers this phenomenon in terms of local concentrations of both the luminescent compound and of the quencher in microphase, formed by DNA and other polyelectrolytes, which can be several (4-10) orders of magnitude greater than their apparent concentrations in solution. Large local concentrations of the light absorbing centers in the microphase also provide conditions for aggregation of these centers and efficient energy transfer, which provides a significant increase in quenching constants (∼10(2)-10(5)). Microphase approach provides good quantitative description of all the features of the superquenching, new possibilities for analysis and control of kinetics of DNA reactions, and for improvement of the sensitivity of luminescent sensors. It reveals nonspecific localization of the luminescent centers and of Aun nanoparticles in different positions of DNA molecules that hinders from the simultaneous use of optical methods and electron or tunneling microscopy for the combined study of the structure of DNA.
authors.affiliation: Department of Chemistry, Moscow M. V. Lomonosov University , Leninskie Gory, Moscow 119991, Russia.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Kuzmin
authors.forename: Irina V
authors.initials: IV
authors.lastname: Soboleva
authors.forename: Nikita A
authors.initials: NA
authors.lastname: Durandin
authors.forename: Ekaterina S
authors.initials: ES
authors.lastname: Lisitsyna
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Kuzmin
mesh_terms: D004247:DNA / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007700:Kinetics; D049408:Luminescent Agents / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry
chemical_list: D004573:Electrolytes; D049408:Luminescent Agents; D011108:Polymers; D012996:Solutions; D014867:Water; D006046:Gold; D004247:DNA