Spherulites: A new vesicular system with promising applications. An example: Enzyme microencapsulation

A new technology is tested for enzyme encapsulation. The capsules are small multilamellar vesicles of surfactant called spherulites which are produced by shearing a lamellar phase under well-controlled conditions. Encapsulation of alkaline phosphatase into spherulites is studied here as an example. Once encapsulated, the enzyme is shown to be unable to develop any enzymatic activity on its substrate, the p-nitrophenylphosphate. This is due to the absence of contact between the enzyme and the substrate. Interestingly, the whole enzymatic activity is recovered after destruction of the vesicles. Encapsulation efficiency ranges between 70% and 95% depending upon the enzyme over phospholipids ratio. Beyond the example of alkaline phosphatase, many applications of spherulites in the medical or in the biotechnology fields seem now at hand.