We investigated the adsorption of bovine serum albumin (BSA) on colloidal Al2O3 particles in an aqueous environment. Changes in the zeta potential of the Al2O3 particles upon the adsorption of BSA were measured using an electro-acoustic technique. The mass of protein adsorbed was determined by using UV-vis spectroscopy. The change of the isoelectric point of the Al2O3 powder-protein suspension was found to be a function of adsorbed protein mass. It was shown that approximately one monolayer of BSA was needed to fully mask the surface and to compromise the charge of Al2O3. From titration experiments it follows that about 30-36% of the negatively charged groups of the protein form bonds with the protonated and charged Al2O3 surface. On the basis of our observations we introduced a new adsorption model for BSA on Al2O3 particles.

Colloidosomes are microcapsules consisting of nanoparticle shells. These microcarriers can be self‐assembled from a wide range of colloidal particles with selective chemical, physical, and morphological properties and show promise for application in the field of theranostic nanomedicine. Previous studies have mainly focused on fairly large colloidosomes (>1 μm) based on a single kind of particle; however, the intrinsic building‐block nature of this microcarrier has not been exploited so far for the introduction of tailored functionality at the nanoscale. We report a synthetic route based on interfacial shear rheology studies that allows the simultaneous incorporation of different nanoparticles with distinct physical properties, that is, superparamagnetic iron oxide and fluorescent silica nanoparticles, in a single submicron colloidosome. These tailor‐made microcapsules can potentially be used in various biomedical applications, including magnetic hyperthermia, magnetic particle imaging, drug targeting, and bioimaging.

During wound healing, a complex cascade of cellular and molecular events occurs, which is governed by topographical and biochemical cues. Therefore, optimal tissue repair requires scaffold materials with versatile structural and biochemical features. Nanoporous anodic aluminum oxide (AAO) membranes exhibit good biocompatibility along with customizable nanotopography and antimicrobial properties, which has brought them into the focus of wound treatment. However, despite their good permeability, such bioinert ceramic nanopores cannot actively promote cell growth as they lack biochemical cues to support specific ligand−receptor interactions. Therefore, we modified AAO nanopores with the biochemical features of collagen nanofibers or amino groups provided by silanization with (3-aminopropyl)triethoxysilane (APTES) to design a permeable scaffold material that can additionally promote cell adhesion. Viability assays revealed that the metabolic activity of both 3T3 fibroblasts and HaCaT keratinocytes on bare and silanized AAO pores was comparable to glass controls until 72 h. Interestingly, both cell types showed a reduced proliferation on AAO with collagen nanofibers. Nevertheless, scanning electron and fluorescence microscopy revealed that 3T3 fibroblasts exhibited a well-spread morphology with filopodia attached to the nanoporous surface of the underlying AAO membranes or nanofibrous collagen networks, thus indicating a close interaction with the composites. Keratinocytes, although growing in clusters on bare and APTES-modified AAO, also adhered well on collagenmodified AAO membranes. When in contact with Escherichia coli suspensions for 20 h, the AAO membranes successfully prevented bacteria penetration irrespective of the biochemical functionalization. In summary, both functionalization strategies have high potential to specifically control molecular signaling and cell migration to further develop alumina nanopores for wound healing.

Micro‐ and macroporous monoliths with in situ formed nickel nanoparticles were prepared for the first time by the combination of solution‐based freeze casting and preceramic polymers (methyl polysiloxane). This one‐step process results in macroporous monoliths composed of microporous and catalytic active nickel‐containing polymer‐derived ceramic. Four different complexing and cross‐linking siloxanes with amino functionality were screened for their ability to create small nickel particles. TEM analysis confirmed 3‐aminopropyltriethoxysilane being most efficient. High BET‐specific surface areas of 344‐461 m2 g−1 were achieved. Increased ratio of complexing groups to nickel improves the dispersion of nickel to (3.61 ± 1.49) nm. The nickel size dependence of conversion (maximum 0.49) and CH4 selectivity (maximum 0.74) in CO2 methanation emphasizes the importance of controlling the nickel size. The hydrophobic surface characteristic is hypothesized to be the main reason polymer‐derived catalysts having better catalytic activity compared with nickel‐impregnated silica. The promising catalytic activity combined with the versatile freeze casting process can prospectively address heat‐ and mass‐transfer considerations in heterogeneous monolith catalysis.

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