Lactoferrin (Lf) has considerable potential as a functional ingredient in food, cosmetic and pharmaceutical applications. However, the bioavailability of Lf is limited as it is susceptible to digestive enzymes in gastrointestinal tract. The shells comprising alternate layers of bovine serum albumin (BSA) and tannic acid (TA) were tested as Lf encapsulation system for oral administration. Lf absorption by freshly prepared porous 3 μm CaCO₃ particles followed by Layer-by-Layer assembly of the BSA-TA shells and dissolution of the CaCO₃ cores was suggested as the most efficient and harmless Lf loading method. The microcapsules showed high stability in gastric conditions and effectively protected encapsulated proteins from digestion. Protective efficiency was found to be 76 ± 6% and 85 ± 2%, for (BSA-TA)₄ and (BSA-TA)₈ shells, respectively. The transit of Lf along the gastrointestinal tract (GIT) of mice was followed in vivo and ex vivo using NIR luminescence. We have demonstrated that microcapsules released Lf in small intestine allowing 6.5 times higher concentration than in control group dosed with the same amount of free Lf. Significant amounts of Lf released from microcapsules were then absorbed into bloodstream and accumulated in liver. Suggested encapsulation system has a great potential for functional foods providing lactoferrin.

A highly ordered array of hollow chambers ranging from 2 to 25 μm in size are fabricated using the layer-by-layer assembly of poly(allylamine hydrochloride) and poly(sodium 4-styrenesulfonate) on sacrificial templates with imprinted patterns of wells. Polyelectrolyte multilayer (PEM) chambers collapse if made of shells that are thinner than a critical value. This critical thickness of the shells is measured experimentally and is found to depend on the chambers geometry. Euler's model of critical stress is used to describe the collapse of the chambers. Adhesive contact of the chamber’s roof with the support is suggested as a major mechanism responsible for the collapse. Deformation of individual PEM chambers made of thicker shells is studied using a sharp indenter and varying the loading speed. At loading speeds of less than 0.33 mN s⁻¹, the elastic theory describes the experimental data well for small deformations, yielding a Young's modulus of 4 ± 1 GPa for the PEM shell, while further deformation causes severe plastic buckling of the chamber. If the loading speed exceeds 0.33 mN s⁻¹, the sharp indenter starts to pierce the chamber's roof and the size of the resulted hole can be precisely controlled by changing the penetration depth of the indenter. Filling the PEM chambers with oil micro-droplets by solvent-exchange method is also demonstrated.