1. Could you explain the significance of your article to the non-specialist? 

The main aim of our work was to use fluorescent semiconductor (CdTe) nanocrystals (also know as quantum dots, QDs) as assays for biological imaging. QDs possess characteristic spectral emission properties which are tunable to a desired energy by selection of the particle size and composition of the nanoparticle. In addition, QDs display dimensional similarities to many biomolecules permitting their bioconjugation and use as biosensors. The CdTe QD fluorescence, which can be greatly enhanced by their photoetching, allows us to monitor their behaviour and localisation by fluorescent confocal microscopy in vitro. In our studies we have found that CdTe QDs can effectively and quickly (within 10 minutes) penetrate the outer membrane of phagocytic white blood cells (involved in the immune system) illuminating the intracellular components. This research demonstrates the great potential of CdTe QDs to serve as probes for specific in vitro biolabelling. In addition CdTe QD based nanocomposites could also be potentially utilised for monitoring of targeted drug delivery and for controlled modification of structural and functional properties of intracellular components. In the long term this research might also enable us to understand the mechanistic pathways of penetration by very small toxic particles (for example cancerogenous dust nanoparticles) and viruses into immune systems cells and help in diagnostic recognition and treatment of cancer, HIV and many other diseases.

 

2. What has motivated you to conduct this work? 

Traditional methods for detecting biological compounds in vivo and in vitro rely mostly on the use of radioactive markers or fluorescent dyes as tags. However, these have a number of chemical and physical limitations which include the cost and complexity of methods utilizing multiple fluorescent dyes and the deterioration of their fluorescence intensity upon prolonged exposure to excitation light (photobleaching). 

In addition, the differences in the chemical properties of standard organic fluorescent dyes make multiple, parallel assays quite impractical since different chemical reactions may be involved for each dye used in the variety of applications of fluorescent labels. Currently there are a lot of efforts towards new methods of detecting biological objects. The main motivation of our work was the need to develop fluorescent CdTe QDs, which could serve as new assays for biological cellular imaging.

 

3. Where do you see this work developing in the future? 

The next steps will be to develop CdTe quantum dots possessing specific functionalities for targeted intracellular localisation and investigation of the mechanistic pathways. Then potential applications of quantum dots for monitoring of drug delivery and examination of various intracellular processes should be explored.

 

4. Are there any particular challenges facing future research in this area?

We believe that anticipated challenges and technical problems will be related to the synthesis of QD nanocomposites having various functional groups, their physiological stability, toxicity and biocompatibility.