New optical nanoparticle sensor can detect very low glucose concentrations

The Optical Research Group of the Universitat Jaume I (GROC-UJI) has developed an optical nanoparticle sensor capable of detecting very low glucose concentrations, such as those present in a person's tear, by means of fluorescent carbon quantum dots, applying synthesis of nanomaterials based on irradiation with ultra-short lasers, which is an alternative, sustainable and non-polluting method.

The main objective of this project is to create a tool for the diagnosis of non-invasive diabetes through the detection of ocular glucose in vitro, which can be integrated into a smartphone for both clinical and private use. Therefore, diabetics would not have to prick themselves several times a day to control their glucose levels, thus avoiding the discomfort it entails. In addition, the use of mobile phones will enable the systematic collection and management of electronic glucose level records to reduce errors and improve diabetes control.

This invention is part of the development of the GlucoTear research project, funded by the European Union through the Marie Skłodowska-Curie Actions-IF programme, in the framework of the Horizon 2020 research and innovation programme, with the participation of GROC-UJI, the Ophthalmology Service of the University General Hospital of Castellón and the company BQ. There is currently a glucose sensor validated for development and adaptation to specific applications through specific agreements.

Laser-based synthesis enables the development of a green and sustainable nanotechnology, because it does not require an excess of polluting chemical products, nor does it necessarily produce waste. Furthermore, the functionalization of nanoparticles is simple and efficient, since it is obtained in situ during the synthesis process with a pulsed laser. Finally, thanks to the manufacturing process, nanosensors are not blocked by any other chemical component or residue that may cause unwanted chemical effects.

This invention has allowed for the synthesis of a single carbon quantum dot (which had never been obtained before by other procedures) that has proven to be capable of detecting very low glucose levels, thanks to its high quantum efficiency in fluorescence, around 63% and with a high photo-stability, demonstrated for more than 15 hours. This new type of carbon quantum dot opens the door to numerous applications in companies specialising in the synthesis of nanoparticles; sensor manufacturers (optical, analyte detection or biomarkers); in the health and food sectors and in R&D and innovation centres.

The GROC-UJI research group, coordinated by lecturers Gladys Mínguez and Enrique Tajahuerce, has been aided by international researcher Wycliffe K. Kipnusu, who joined the team in April 2018 to participate in this project, after obtaining the first Marie Sklodowska-Curie grant in the modality of individual grants of the Horizon 2020 European programme of the Universitat Jaume I.