Hybridization and Immobilization of Long ds-DNAs on Polystyrene Microspheres

Here, we develop a system where long double-stranded DNAs (ds-DNAs) are immobilized on the surface of a polystyrene (PS) microsphere. A simple synthetic strategy is adopted in order to achieve this goal in which a single DNA chain is anchored by one of its extremities to a latex (PS) microsphere. We chose hybridization as a unique method to attach long ds-DNA chains in solution with oligonucleotides grafted on modified aminated polystyrene microspheres. The DNAs chosen were of various sizes and sources: T7A1 DNA (4.48 kilobase pair (kbp)), a plasmid DNA; and ΔDIIIT7 DNA (39.34 kbp), a mutant of bacteriophage T7 DNA. The temperature dependence of the kinetics of hybridization of T7A1 DNA (4.48 kbp) in solution with an appropriate oligonucleotide (20-mer sequence) grafted on modified aminated polystyrene microspheres yielded a value of activation energy of ∼5.3 kcal/mol, consistent with a non-diffusion-controlled mechanism.