Scientists at the Department of Applied Physics II of the University of Malaga have participated in the design of a new technology that controls fluids and particles in three dimensions through virtual thermal barriers generated using light.

Known as reconfigurable optofluidic barriers, they enable the manipulation of the environment in a precise, quick and contactless manner, managing to deflect, trap or split particles without the need for fixed physical structures. This finding has been published in the scientific journal ‘Nature Photonics’.

This is an international research within the field of microfluidics –which studies and manipulates the behavior of small quantities of fluids with microscopic dimensions–, which, together with the Multiphysics Modeling School (MMS) of the UMA, has been conducted by the Nanophotonic Systems Laboratory (ETH Zurich) and the Nanoparticle Trapping Laboratory (NanoTLab) of the University of Granada.
These barriers were developed by optically induced temperature gradients. More specifically, they were created by illuminating surfaces coated in elongated gold nanoparticles (AuNRs), inducing these localized temperature gradients via photothermal conversion and the fluid flow, using phenomena such as thermo-osmosis, thermophoresis and natural convection.
“Thanks to the fact that they can be configured in real time, this technology can be dynamically adjusted to tasks such as steering or splitting particles, as well as simulating real biological environments,” explains UMA researcher Emilio Ruiz Reina, one of the authors of this paper, who adds that, as it enables multiple functions, it facilitates the design of fast, precise and portable tools for, among other things, clinical analysis, pharmacological studies or basic research.

In this regard, the expert assures its direct impact on personalized medicine and biotechnology and highlights that this innovative solution opens the door to lab-on-chip systems –miniaturized devices that integrate multiple functions of a conventional laboratory into a single chip of a few millimeters in size–, which are reconfigurable, compact and highly efficient.
“This research has been based on a hybrid methodology that combines advanced experimentation with high-fidelity numerical simulations. Computational models allowed us to predict thermal and fluidic behavior in complex geometries, optimizing the design of the experiments. In turn, the experimental results enabled the validation and refining of the models, in a process of continuous feedback that was key to achieve the level of control demonstrated,” concludes Professor Ruiz Reina, who is also coordinator at the UMA MMS.