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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers

Das, Prolay 12 November 2007 (has links)
Long-distance radical cation transport was studied in DNA condensates where linearized pUC19 plasmid was ligated to an oligomer and transformed into DNA condensates with spermidine. DNA condensates were detected by Dynamic Light Scattering and observed by Transmission Electron Microscopy. Introduction of charge into the condensates causes long-distance charge migration, which is detected by reaction at the remote guanines. The efficiency of charge migration in the condensate is significantly less than it is for the corresponding oligomer in solution. This result is attributed to a lower mobility for the migrating radical cation in the condensate, caused by inhibited formation of charge-transfer-effective states. Radical cation transport was also studied in DNA condensates made from an oligomer sandwiched between two linearized plasmids by double ligation. Unlike the single ligated plasmid condensates, the efficiency of charge migration in the double ligated plasmid-condensates is high, indicative of local structural and conformational transformation of the DNA duplexes. Organic monomer units having extended ð-conjugation as part of a long conducting polymer was synthesized and characterized. The monomer units were covalently attached to particular positions in DNA oligonucleotides by either the convertible nucleotide approach or by phosphoramidite chemistry. Successful attachment of the monomer units to DNA were confirmed by mass spectral analysis. The DNA-conjoined monomer units can self assemble in the presence of complementary sequences which act as templates that can control polymer formation and structure. By this method the para-direction of the polymer formation can be enforced and may be used to generate materials having nonrecurring, irregular structures.

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