A Combined Conjugation and Hybridization Technology for Different Types of DNA and Nanoparticles

Abstract

This study develops a new technology for conjugation between surface-modified Fe₃O₄ nanoferrofluid and DNA that can be applied for biological sensors. After fabrication by chemical disposition and thorough washing, centrifuging and sieving, pure Fe₃O₄ nanoferrofluid with mean particle size of 15 nm was obtained. PVP-k30 (Polyvinyl pyrrolidone) acts as dispersant to maintain a stable suspension of the Fe₃O₄ nanoferrofluid, which is then added to and fully mixed with deionized water (ddwater) (pH >7). Experimental evidence shows that the surfaces of the Fe₃O₄ particles carry positive charge and can effectively create a conjugating reaction with DNA. In addition, this TiO₂ nanofluid with mean particle size of 20 nm and high suspension stability is used to conjugate with another type of DNA. Finally, two sets of fluids, Fe₃O₄ and TiO₂, that have undergone conjugating reactions with different types of DNA are mixed in a culturecell, so they are linked together through the hybridization between different types of DNA. By spectrophotometer analysis, it is shown that DNA still exists in the fluid after hybridization, verifying that the hybridization technology between different types of DNA developed in this study is very successful.