Stable Encapsulation of Active Enzyme by Application of Multilayer Nanofilm Coatings to Alginate Microspheres

Summary: In an effort to improve the stability for long‐term biosensor use, layer‐by‐layer self‐assembly was explored as a potential technique to provide a diffusion barrier to encapsulated glucose oxidase inside alginate microspheres (<5 µm), fabricated using an emulsification technique. The total loss of encapsulated enzyme was reduced to less than 25 and 15% with the application of single PAH/PSS and crosslinked PAH/PAA coatings, respectively, in comparison to at least a 45% loss observed with uncoated and PDDA/PSS‐coated microspheres. Furthermore, it was found that enzyme within PAH/PSS‐ and crosslinked PAH/PAA‐coated spheres retained more than 84 and 60% of initial activity, respectively, after three months, whereas uncoated and PDDA/PSS‐coated microspheres retained less than 20%.Emulsification technique for alginate microspheres.