Surface engineering of porous silicon to optimise therapeutic antibody loading and release.

The proinflammatory cytokine, tumor necrosis factor-α (TNF-α), is elevated in several diseases such as uveitis, rheumatoid arthritis and non-healing chronic wounds. Adding Infliximab, a chimeric IgG1 monoclonal antibody raised against TNF-α, to chronic wound fluid can neutralise human TNF-α, thereby providing a potential therapeutic option for chronic wound healing. However, to avoid the need for repeated application in a clinical setting, and to protect the therapeutic antibody from the hostile environment of the wound, suitable delivery vehicles are required. Porous silicon (pSi) is a biodegradable high surface area material commonly employed for drug delivery applications. In this study, the use of pSi microparticles (pSi MPs) for the controlled release of Infliximab to disease environments, such as chronic wounds, is demonstrated. Surface chemistry and pore parameters for Infliximab loading are first optimised in pSi films and loading conditions are transferred to pSi MPs. Loading regimens exceeding 60 µg of Infliximab per mg of pSi are achieved. Infliximab is released with zero-order release kinetics over the course of 8 days. Critically, the released antibody remains functional and is able to sequester TNF-α over a weeklong timeframe; suitable for a clinical application in chronic wound therapy.

Anisotropically structured magnetic aerogel monoliths.

Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.