The 2023 Nobel Prize in Chemistry was awarded to the scientists who discovered and developed quantum dots (QDs), tiny particles made up of a few thousand atoms, whose size bears the same relationship to a soccer ball as a soccer ball bears to the size of the Earth. These particles with unique properties –determined by quantum effects– are already being used in various commercial products, such as TV screens and LED lamps, as well as in different scientific disciplines, ranging from physics and chemistry to medicine: they catalyze chemical reactions, can be used as markers in tumor tissue, etc. What is more, new applications are expected to be developed in the future. In this respect, several CIC biomaGUNE laboratories are working with particles of this type, both at the level of synthesis, as well as in the development of properties and in the search for applications, in a whole host of aspects.
The Carbon Bionanotechnology group headed by Ikerbasque research professor and AXA chair Maurizio Prato is leading the e-DOTs (ERC Advanced Grant) project in which they are working on the design and synthesis of carbon nanodots. “They are carbon-based nanoparticles, similar in size to QDs (less than 10 nm) and with similar luminescent properties, but do not contain metals, which makes them much less toxic than QDs,” he explained. “We are mainly seeking to achieve specific properties so that they can be put to use in many areas of application. We are working to tune them in terms of light absorption, fluorescence emission, redox and chiroptical properties. One of our main aims is to prepare contrast agents for magnetic resonance imaging in which we incorporate transition metals such as gadolinium into the nanodots.” The group is working to design new structures to tackle important social challenges, such as photocatalysis, optoelectronics and biomedicine.
The Biomolecular Nanotechnology group led by Ikerbasque research professor and the center’s scientific director Aitziber L. Cortajarena has synthesized QDs using designer proteins, “to promote the controlled synthesis and stabilization of highly photoluminescent CdS QDs, and also to modulate their optical properties through the proteins. These QDs have very long lifetimes, are highly stable under physiological conditions and are non-toxic which, unlike most QDs, means that they are biocompatible and have+++ particular potential in the biomedical field,” explained the professor.
The group has also synthesized fluorescent CdS QDs stabilized on antibodies, which have been used to create new detection methods based on their photocatalytic properties. This technology improves the sensitivity of current immunoassays using enzyme-conjugated antibodies.
The European GREENER project that the group is participating in is aiming to develop new methods for synthesizing QDs based on environmentally friendly metals capable of absorbing and emitting light in the near infrared. These characteristics will allow them to be subsequently implemented in a detection device capable of determining the presence of contaminants in water for the purpose of monitoring its quality and safety.
QDs have also been generated enzymatically through a wide range of enzymes and DNAzymes traditionally used as recognition and labeling elements in bioanalysis. “We have developed optical and photoelectrochemical methods for the specific and sensitive detection of DNA and small molecules, or cancer biomarkers, among others,” added Cortajarena.
Lastly, the Bionanoplasmonics group led by Ikerbasque research professor Luis Liz-Marzán is participating in the POSEIDON project in which they are studying the combination of QDs with plasmonic gold nanoparticles. “The goal is to use QDs as light emitters in 'photonic chips,' where information is managed through light, rather than through electrons (as in conventional microelectronics),” explained Liz-Marzán. This project is seeking to amplify the emission of QDs and, above all, to improve control over their directionality and thus improve the efficiency of these photonic chips. In this project “we have succeeded in demonstrating that a specific configuration of gold nanoparticles and QDs leads to amplified light emission as well as electric field-induced emission”.