Nanotechnology enables companies to manipulate the properties of the outer shell of a capsule in order to control the release of the substance to be delivered. ‘Controlled release’ strategies are highly prized in medicine since they can allow drugs to be absorbed more slowly, at a specific location in the body or at the say-so of an external trigger. With potential applications across the food chain (in pesticides, vaccines, veterinary medicine and nutritionally-enhanced food), these nano- and micro-formulations are being developed and patented by agribusiness and food corporations such as Monsanto, Syngenta and Kraft.
Different Types of Encapsulation at the Nanoscale
Examples of nano and microcapsule designs:
• Slow release - the capsule releases its payload slowly over a longer period of time (e.g., for slow delivery of a substance in the body);
• Quick-release - the capsule shell breaks upon contact with a surface (e.g. when pesticide hits a leaf );
• Specific release - the shell is designed to break open when a molecular receptor binds to a specific chemical (e.g., upon encountering a tumour or protein in the body);
• Moisture release - the shell breaks down and releases contents in the presence of water (e.g. in soil);
• Heat-release - the shell releases ingredients only when the environment warms above a certain temperature;
• pH release - nanocapsule breaks up only in specific acid or alkaline environment (e.g., in the stomach or inside a cell);
• Ultrasound release - the capsule is ruptured by an external ultrasound frequency;
• Magnetic release - a magnetic particle in the capsule ruptures the shell when exposed to a magnetic field;
• DNA nanocapsule - the capsule smuggles a short strand of foreign DNA into a living cell which, once released, hijacks cell machinery to express a specific protein (used for DNA vaccines).