Surface fabrication of magnetic core-shell silica nanoparticles with perylene diimide as a fluorescent dye for nucleic acid visualization

Abstract

• Design and synthesis of non-toxic and economic magnetic nanoparticle colorant dye for nucleic acid visualization. • Development dual-functional nanoparticle have strong magnetic properties and intense fluorescent light. • Evaluation of particle adsorption loading efficiency and their release of nucleic acid. • The magnetic dye can be easy recovered and controlled their movement by applying external magnetic. Up to date most traditional fluorescent dyes that serve to detect nucleic acids in a selective manner face growing environmental and economic challenges due to their high toxicity, expensiveness, the long staining times required and the low sensitivities. Further attention went to replace the current widely used ethidium bromide (EB) by more safe and stable dyes but still some of the above drawbacks persist. In this work an innovative fluorescent dye has been designed and synthesized via impregnating perylene diimide into the functionalized surface of magnetic core–shell silica nanoparticles. One of the free hydroxyl groups on the perylene diimide enables the colored magnetic nanoparticles to easily disperse in water and their movement can be controlled with magnetism which allow the separation after their used. These particles are of low toxicity, environmentally friendly and have high sensitivity. Fluorescent properties and molecular interaction were studied. The designed particles show high DNA binding capacity which makes the developed particle promising for DNA extraction, delivery and fluorescent labeling. Theoretical studies confirm that the dye is placed between two DNA base pair similar with pervious observation with EB and the distance was less than 6 Å which is much less than the distance of EB dye interaction (15 Å) as reported before [1] .