Quantum dot nanoparticles are highly sensitive to charge and energy transfer processes, which can be used to develop sensing platforms. The researchers from the University of Granada in Spain and the University of Cambridge in the UK, take advantage of the high pH sensitivity of anthraquinones to examine the photoluminescence pH dependency of the new nanocomposites.

The new family

The attachment of six different anthraquinone dyes on the surface of QDs results in an electron transfer-based quenching of the photoluminescence (PL) intensity. The efficiency of this quenching was found to vary at different pH values; consistent with the pH-sensitive anthraquinone redox chemistry. The PL of the resultant conjugates exhibits pH sensitivity in a broad response range, making them very interesting for the determination of pH in samples of different natures.

Physiological applications

The usefulness of the proposed nanosensors is successfully demonstrated with the determination of pH in samples mimicking the intracellular environment. Currently, the researchers are working on the incorporation of these and other QD-based nanosensors into the cellular cytoplasm to measure in cellulo and in real time the changes of pH related to different metabolic processes.

More information can be found in the journal Nanotechnology 25 195501.

Further reading

Sensing team examines DNA thymine-dependent formation of fluorescent copper nanoparticles (Aug 2013)
Upgraded silver nanoclusters benefit bioimaging (Feb 2013)