Facile synthesis of a nanocomposite based on graphene and ZnAl layered double hydroxides as a portable shelf of a luminescent sensor for DNA detection

Abstract

Recently, nanocomposites based on graphene and layered double hydroxides (LDH) have been developed and used in many fields. However, to the best of our knowledge, there is no report on the luminescence sensor applications of graphene/LDH composites. Herein, a hybrid graphene–ZnAl-LDH nanocomposite has been developed using a facile one-step process and the presence of LDH in the composite can effectively prevent the restacking of graphene and improve both its luminescence properties and thermal stability. Furthermore, the composite can be used as a portable shelf of the Ru(phen)₃Cl₂ (tris(1,10-phenanthroline)ruthenium(II) dichloride) sensor to selectively discriminate DNA. It was found that the graphene–ZnAl-LDH composite can effectively quench the emission of the Ru(phen)₃Cl₂ sensor. After the addition of a certain amount of DNA into the system, Ru(phen)₃Cl₂ was released from the graphene–ZnAl-LDH composite and it interacted with DNA immediately, leading to the luminescence recovery of the sensor. The results indicate that the RGO–ZnAl-LDH composite displayed an excellent luminescence response and good linear correlation to DNA. Therefore, the composite can be employed as a portable shelf of Ru(phen)₃Cl₂ to discriminate DNA. Moreover, both the shelf and the sensor can be easily collected and made ready for the next sample if there is no DNA in the solution. The proposed method was further applied to detect the immunodeficiency virus gene (HIV), thus providing a new field of application for hybrid graphene/LDH composites.