Hybrids of polymeric capsules, lipids, and nanoparticles: thermodynamics and temperature rise at the nanoscale and emerging applications

The importance of thermodynamics does not need to be emphasized. Indeed, elevated temperature processes govern not only industrial scale production, but also self-assembly, chemical reaction, interaction between molecules, etc. Not surprisingly, biological processes take typically place at defined temperature. Here, we look at possibilities to raise the localized temperature by a laser around noble metal nanoparticles incorporated into shells of layer-bylayer (LbL) polyelectrolyte microcapsules – freely suspended delivery vehicles in aqueous solution, developed in the Department of Interfaces, Max-Planck Institute of Colloids and Interfaces headed by Helmuth Möhwald. Understanding the mechanisms around localized temperature rise is essential, that is why we analyze thermodynamics at the nanoscale, the influence of incident intensity, nanoparticle size, their distribution and aggregation state. This leads us to scrutinize "global" (used for thermal encapsulation) versus "local" (used for release of encapsulated materials) temperature around nanoparticles. Similar analysis is extended to the lipid membrane system of vesicles and cells, on which nanoparticles are adsorbed. Insights are provided into the mechanisms of physico-chemical and biological effects, the nature of which has always been profoundly, interactively, and engagingly discussed in the Department. This analysis is combined with recent developments providing outlook and highlighting a broad range of emerging applications

Release from polyelectrolyte multilayer capsules in solution and on polymeric surfaces

Release from polyelectrolyte multilayer microcapsules represents one of the most important steps enabling practical use of the microcapsules. A number of biological and non-biological applications are envisaged by proper encapsulation of molecules of interest and their release performance. Since the invention of the microcapsules at the Max-Planck Institute of Colloids and Interfaces in 1998 the work towards microcapsule assistant release has undergone tremendous progress. Almost simultaneously with development of release approaches an extensive base of applications has been advanced. In this progress report the release from the capsules in a solution and those immobilized on the surface of polymeric films is addressed

Temperature window for encapsulation of an enzyme into thermally shrunk, CaCO 3 templated polyelectrolyte multilayer capsules

Encapsulation of enzymes allows to preserve their biological activities in various environmental conditions, such as exposure to elevated temperature or to proteases. This is particularly relevant for in vivo applications, where proteases represent a severe obstacle to maintaining the activity of enzymes. Polyelectrolyte multilayer capsules are suitable for enzyme encapsulation, where CaCO3 particles and temperature‐dependent capsule formation are the best templates and the most adequate method, respectively. In this work, these two areas are combined and, ALP (alkaline phosphatase), which is a robust and therapeutically relevant enzyme, is encapsulated into thermally shrunk polyelectrolyte multilayer (PDADMAC/PSS)4 capsules templated on calcium carbonate particles (original average diameter: ≈3.5 µm). The activity of the encapsulated enzyme and the optimal temperature range for encapsulation are investigated. The enzymatic activity is almost four times higher upon encapsulation when the temperature range for encapsulation is situated just above the glass transition temperature (40 °C), while its optimal conditions are dictated, on the one hand, by the enzyme activity (better at lower temperatures) and, on the other hand, by the size and mechanical properties of capsules (better at higher temperatures)

Hybrid inorganic-organic capsules for efficient intracellular delivery of novel siRNAs against influenza A (H1N1) virus infection

This work was supported by ARUK project grant 21210 ‘Sustained and Controllable Local Delivery of Anti-inflammatory Therapeutics with Nanoengineered Microcapsules’. The work was also supported in part by Russian Foundation of Basic Research grants No. 16-33-50153 mol_nr, No. 16-33-00966 mol_a, Russian Science Foundation grant No. 15-15-00170 and Russian Governmental Program ‘‘Nauka’’, No. 1.1658.2016, 4002