The last decade observed immense growth in applications of graphene, a carbon allotrope with applications in diverse areas of science, including fluorescent nanoparticles like quantum dots. However, the applications of graphene-based nanodevices in biological contexts have still been a bit slow. This is primarily due to the metal-free nature of graphene nanoparticles, leading to poor fluorescence abilities, and their lack of sensing abilities for various analytes.
Lin et al., in the current work, intelligently overcome these two problems by doping graphene quantum dots with nitrogen-containing species like amines, which not only make the dots much brighter, but also sensitive to various analytes. They show the detection of trinitrophenol, one of the most explosive materials in aqueous solutions, with good sensitivity and a detection limit of 300 nM. The stability of these doped dots to various acidic and alkaline conditions make them suitable for sensing applications in different samples and solutions, especially with biological samples, since the conditions are extremely diverse in these samples. The sensitive detection of trinitrophenol in solutions using simple fluorescence based assays can actually be explored for commercial low cost detectors.
Although much remains to be done to make these dots universally applicable, like doping with different molecules to sense specific analytes, the initial platform technology makes these nanoparticles suitable for applications in biosensing to detect materials like toxins, poisons or even explosives.
A facile synthesis of highly luminescent nitrogen-doped graphene quantum dots for the detection of 2,4,6-trinitrophenol in aqueous solution
Liping Lin, Mingcong Rong, Sisi Lu, Xinhong Song, Yunxin Zhong, Jiawei Yan, Yiru Wang and Xi Chen
Nanoscale, 2015, 7, 1872-1878. DOI: 10.1039/C4NR06365A
Dr Dhiraj Bhatia is a guest web writer for the Nanoscale blog. He is a chemist by training and received his PhD in Chemical Biology of Nucleic Acids from the National Center for Biological Sciences, TIFR India with an outstanding thesis award in 2013. He joined the Chemical Biology department at the Curie Institute, Paris, as an HFSP long term Postdoctoral Fellow and is currently investigating the mechanisms of endocytois using various chemical biology tools.