Abstract
Novel nanocomposites of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) derivatized zinc phthalocyanine (TEMPO-ZnPc) with graphene quantum dots (GQDs) or S/N co-doped graphene quantum dots (SNGQDs) were synthesized. The fluorescence of both GQDs and SNGQDs was quenched ("turned OFF") upon non-covalent coordination with TEMPO-ZnPc. However, the emission of GQDs (or SNGQDs) was restored ("turned ON") in the presence of ascorbic acid (AA) due to the selective and specific interaction of TEMPO-ZnPc with AA. Among the tested biomolecules and ions, only AA induced the restoration of the quenched GQDs fluorescence emission resulting in the "Off-On" mode of the GQDs. The "turn ON" fluorescence signal was modulated by different concentrations of AA and the limits of detection were in the nanomolar range of 0.2 nM and 0.8 nM for SNGQDs-TEMPO-ZnPc and GQDs-TEMPO-ZnPc, respectively. The quenching mechanism was elucidated based on Forster resonance energy transfer (FRET) in which the GQDs acted as the energy donor.
| Original language | English |
|---|---|
| Pages (from-to) | 8727-8736 |
| Number of pages | 10 |
| Journal | New Journal of Chemistry |
| Volume | 40 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - 31 Aug 2016 |
| Externally published | Yes |
Bibliographical note
Funding Information:This work was supported by the Department of Science and Technology (DST) and National Research Foundation (NRF), South Africa through DST/NRF South African Research Chairs Initiative for Professor of Medicinal Chemistry and Nanotechnology (UID 62620) as well as Rhodes University/DST Centre for Nanotechnology Innovation, Rhodes University, South Africa.
Publisher Copyright:
© 2016 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.