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Microcapsules moving through the human body as tiny transport vessels

Capsules can contain liquids and transport them inside the human body… for biomedical or pharmaceutical purposes but also in order to monitor environmental conditions.

October 2014

IMA Lab Microscopic capsules

In the 1987 film Innerspace, a special vessel commanded by Lieutenant Pendleton was miniaturized and injected inside the body of a rabbit. We haven’t reached this level yet, but researchers from the Italian Institute of Technology (IIT) in Genoa have developed a kind of “vessel” capable of transporting tiny quantities of liquid and transporting them either inside the human body or in other special contexts.

The microcapsules may potentially be employed for many different functions, to serve as micro-sensors for environmental analysis, micro-operators for diagnostic operations or systems for releasing pharmaceutical products inside the body.

The group of researchers in Genoa developed a new kind of encapsulation technique departing from studies into structures and “techniques” already present in nature, and then proceeding to imitate their mechanisms. Similar capsules exist in certain plants, mushrooms and seaweeds, where fibrous membranes, also known as cellular walls, trap tiny quantities of liquid and encapsulate them with a degree of mechanical resistance and shape. These fibrous natural microcapsules also possess the ability to exchange molecular nutrients in a controlled fashion between the structure’s interior and the exterior.

The microcapsules created at the IIT consist of an impermeable fibrous shell that is both soft and robust (being ten times stronger than similar capsules produced by other research groups), and is capable of containing small quantities of liquid or other substance forms.

 “The chemical composition of the outer cloak allows it to contain reactive molecules… thus creating micro-sensors which can, for example, register the presence of pollutants in the environment… or to act as a vessel to carry medicine and release it in a selected and limited part of the body”, explains Athanassia Athanassiou, head of IIT’s intelligent materials group.

The method used for generating these new microcapsules is reminiscent of the way drops become covered with flour when we pour water onto a pyramid of flour: the drops roll down the slope and become coated with white. In the same way, in this case tiny drops of water are made to fall from a height of 2-3 centimeters onto a sloping plane of synthetic micro-fiber, and when the drops enter into contact with the fiber they roll on it, dragging elements of fiber with them that cover their surface and form a coating.

 

“In order to create the biomimetic shell, we selected two synthetic polymers to create the hydrophobic nanofibrillar cloak: a fluoroacrylic copolymer (known in commerce as Capstone) and cellulose acetate. The former provides the ability to repel water, while the cellulose acetate guarantees that the cloak is biocompatible and biodegradable”, explains Elisa Mele, first author of the study and research specialist at the Italian Institute of Technology.

 

The IIT microcapsules also display a high degree of stability in contact with various liquid or solid materials, such as paper, glass, aluminum and other metals, and plastic. They also retain their stability if immersed in water or oil, and show no signs of damage or liquid loss even when submitted to fast stirring and many other forms of mechanical stress.

The research study was published in Langmuir, the international scientific journal published by the American Chemical Society, with the title “Biomimetic approach for liquid encapsulation with nanofibrillar cloaks”.
 

 

 

References:

The research study published in Langmuir in February 2014

http://pubs.acs.org.pros.lib.unimi.it/doi/abs/10.1021%2Fla4048177

 

Article of 23 June 2014 on the IIT website (Istituto Italiano di Tecnologia)

http://www.iit.it/it/notizie-a-eventi/notizie/2014-news/2479-novel-microcapsules-for-biotechnological-and-pharmaceutical-applications.html