David Fernández Rivas

Cuban engineer award winner

He studied the degree in Nuclear and Energy Installations Engineering from 2000 to 2004 at InSTEC (Higher Institute of Science and Advanced Technologies), formerly ISCTN (Higher Institute of Nuclear Science and Technologies). During his master's degree, completed at InSTEC, he made a visit to ICTP (International Center for Theoretical Physics) in Trieste, Italy; this would be the key that would open the doors of the University of Twente for him.

During a conference in Algeria in 2006, a professor whom he had met the previous year in Trieste, offered him the possibility of choosing between two projects; he then opted for biomedical work, within which the development of needle-free injections is what generates the most interest. When asked about this research, he responds:

"The idea itself is quite old, at least since the 19th century in France there is a reference. Starting in 1950 there have been examples with varying success rates, in vaccination campaigns, etc. But some risks were detected due to contamination between injections to different people.

"In the last two decades there has been an increase in the number of articles and a few products on the market. The novelty of my vision is that it focuses on injecting very small amounts of liquid (pL and nL) into the most superficial layers of skin. Previously, the goal was to inject approximately 1mL and in an intramuscular manner."

The project is made up of several postgraduate students and a business developer, which allows for greater interdisciplinarity. This is vital for scientific efficiency, as well as for social recognition and the consequent obtaining of budget.

"We are still in an early phase, but we have accumulated very interesting and important results. About six publications in high-caliber journals and one published patent. We have received funding from the European Union, and recently from the Dutch government," he adds. During this time they have been working with ex vivo porcine skin tissue, and plan to start working with human skin soon.

There are several methods of needle-free injections, he explains. "Ours is based on heating the liquid to be injected with continuous-wave lasers as an energy source. The heating results in the formation of a vapor bubble that grows rapidly. Due to the confinement provided to contain the liquid within a channel of microscopic dimensions and the explosive nature of the phenomenon, the liquid in front of the bubble is expelled at speeds on the order of 360 km/h. The high velocity and small dimensions of the liquid droplets (or jet) approximately 50 µm, allow it to penetrate the skin causing imperceptible damage.

"Many times people wonder if the medicine is not damaged due to the heating and, so far, studies that we and other working groups have conducted indicate that there is no detectable change, but we have to continue conducting research to corroborate it. Other researchers have solved the problem by building a membrane that separates the liquid you are heating from the liquid you are going to inject, so there is no risk of damaging what will be inoculated by the heat."

"We are using less powerful continuous-wave lasers, and we are still investigating the exact timing, but everything happens in less than a millisecond," he states.

During this first phase, needle-free injections have been used for medical tattoos. Fernández Rivas explains the reasons: "Indeed, I chose to start with medical tattoos because the ink used is not affected by the laser heat, as can happen with medications; this is opportune to test the technology and learn. The learning can lead to using the same technology in recreational tattoos, something very popular lately.

At a time when COVID-19 is frightening the world and vaccine prototypes are already a reality, a massive vaccination campaign at the global level is on the way. According to the engineer, his project could help a lot: by eliminating the needle, the preparation time for the injection is shortened, material and sterilization costs are saved. "No less important, many people are afraid of needles; approximately one in five people," he states.

According to estimates from the World Health Organization (WHO), 44 million needles are used every day. If we can in some way alleviate the suffering of people who need to be injected, and at the same time reduce environmental contamination, we kill two birds with one stone.