Encapsulation of bacterial spores in nanoorganized polyelectrolyte shells.

Layer-by-layer assembly uses alternating charged layers of polyionic polymers to coat materials sequentially in a sheath of functionalized nanofilms. Bacterial spores were encapsulated in organized ultrathin shells using layer-by-layer assembly in order to assess the biomaterial as a suitable core and determine the physiological effects of the coating. The shells were constructed on Bacillus subtilis spores using biocompatible polymers polyglutamic acid, polylysine, albumin, lysozyme, gelatin A, protamine sulfate, and chondroitin sulfate. The assembly process was monitored by measuring the electrical surface potential (ζ-potential) of the particles at each stage of assembly. Fluorescent laser confocal microscopy and scanning electron microscopy confirmed the formation of uniform coatings on the spores. The coating surface charge and thickness (20−100 nm) could be selectively tuned by using appropriate polymers and the number of bilayers assembled. The effect of each coating type on germination was assesse...