This 3D-printed wearable mosquito repellent could finally end re-applying sprays

We use body sprays to get rid of mosquitos most of the time. We can even use herbs such as sage and rosemary to keep them out of our homes.

Martin Luther University Halle-Wittenberg scientists have created a novel method of delivering insect repellent (MLU). The results were published in the International Journal of Pharmaceutics on August 25.

The active component is initially "encapsulated" and created into the desired shape using a 3D printer, such as a ring, which may then be worn and emit a long-lasting mosquito repellent.

The researchers used "IR3535," an insect repellent created by MERCK, to create their prototypes.

"Sprays that repel mosquitoes and contain IR3535 have been used for many years all over the world. We have been utilizing the agent in our tests because of this ", said MLU Professor René Androsch in the release. It typically comes in the form of a spray or lotion and protects for several hours.

The agent may, however, be released over a much longer period by being contained in a wearable ring or bracelet, as Androsch and his team are searching for ways to do.

3D printing technology has been used

Insect repellent was carefully inserted into a biodegradable polymer using specialized 3D printing technology, and the mixture of materials was successfully shaped in various ways.

As Fanfan Du — the study's primary author and a doctorate candidate at MLU — suggested that the core notion is that the insect repellent continuously evaporates and forms a barrier for insects.

The rate at which the insect repellent evaporates is affected by a variety of parameters, including temperature, concentration, and the polymer structure employed. Following several trials and calculations, the team expects that the insect repellent will take well over a week to evaporate fully at 37°C (98,6 °F, or body temperature).

Although the researchers say that this is possible, the study is still in the early phase. According to Androsch, more research is needed to evaluate how well the rings perform in real-world settings. The encapsulating material could also be improved.

Abstract:

The polymer/solvent system poly (l-lactic acid)/ethyl butyl-acetylamino propionate (PLLA/IR3535) is regarded as an insect-repellent-delivery system, serving, e.g., for fighting mosquito-borne tropical diseases. In such systems the solid polymer hosts the liquid repellent, with the latter slowly released to the environment, expelling mosquitoes. As a new approach, exceeding prior work about application of different technologies to obtain such devices, in this work, samples of the polymer/repellent system PLLA/IR3535 were prepared by 3D-printing. The experiments showed that it is possible to print 3D-parts containing up to 25 m% repellent, with an only minor loss of repellent during the printing process. For samples containing low amount of repellent, crystallization of PLLA was suppressed due to the rather fast cooling step and the low bed temperature of around 25 °C, being lower than the glass transition temperature of the homogeneous polymer/repellent strands. At higher repellent concentration, due to the lowering of the glass transition temperature to near or even below ambient temperature, the crystallinity slowly increased during storage after printing. For all samples, regardless of the initial repellent concentration, the repellent-release rate increases with temperature, and at ambient temperature the release-time constant is in the order of 10 days. The study successfully proved the applicability of the technology of extrusion-based 3D-printing for the preparation of polymer parts with a specific shape/design containing mosquito-repellent at a concentration which raises the expectation to be used as a repellent delivery-device.