Nanocomposites are the dominating class of nanomaterials to come into consumer contact, and were in general assumed to pose low risk. The first data is now emerging on the exposure from nanocomposites, but little is yet known about their hypothetical nanospecific physiological effects, giving ample room for speculation. For the first time, this comprehensive study addresses these aspects in a systematic series of thermoplastic and cementitious nanocomposite materials. Earlier reports that 'chalking', the release of pigments from weathered paints, also occurs for nanocomposites, are confirmed. In contrast, mechanical forces by normal consumer use or do-it-yourself sanding do not disrupt nanofillers (nanoparticles or nanofibers) from the matrix. Detailed evidence is provided for the nature of the degradation products: no free nanofillers are detected up to the detection threshold of 100 ppm. Sanding powders measuring 1 to 80 μm in diameter are identified with the original material, still containing the nanofillers. The potential hazard from aerosols generated by sanding nanocomposites up to the nuisance dust limit is also investigated. In-vivo instillation in rats is used to quantify physiological effects on degradation products from abraded nanocomposites, in comparison to the abraded matrix without nanofiller and to the pure nanofiller. In this pioneering and preliminary evaluation, the hazards cannot be distinguished with or without nanofiller.

Hydrophobins are available from natural resources only in milligram amounts. BASF succeeded in a recombinant production process, up-scaled to pilot plant production in kilogram scale. Strain and protein optimization by modulation of gene expression and generation of fusion proteins finally leads to two class I hydrophobins called H*Protein A and H*Protein B. By analytical ultracentrifugation, we confirm that the self-association of H*Proteins in solution is governed by their sequence, because oligomerization is induced by the same mechanisms (pH > 6, temperature >> 5 degrees C, concentration > 0.2 mg/ml) as for the well-known native hydrophobins SC3 and HFB II. Additionally, we established the triggering of structure formation by bridging with divalent ions and the stabilization of dimers and tetramers by monovalent ions or surfactants. This interplay with surfactants can be exploited synergistically: The capacity for emulsification of a 300 ppm standard surfactant solution is boosted from 0 to 100% by the addition of a mere 1 ppm of our new hydrophobins, with H*Protein A and H*Protein B having specific application profiles. This astonishing performance is rationalized by the finding that the same minute admixtures enhance significantly the interfacial elastic modulus, thus stabilizing interfaces against coalescence and phase separation.

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Lung lining fluid is the first biological barrier nanoparticles (NPs) encounter during inhalation. As previous inhalation studies revealed considerable differences between surface functionalized NPs with respect to deposition and toxicity, our aim was to investigate the influence of lipid and/or protein binding on these processes. Thus, we analyzed a set of surface functionalized NPs including different SiO2 and ZrO2 in pure phospholipids, CuroSurf(TM) and purified native porcine pulmonary surfactant (nS). Lipid binding was surprisingly low for pure phospholipids and only few NPs attracted a minimal lipid corona. Additional presence of hydrophobic surfactant protein (SP) B in CuroSurf(TM) promoted lipid binding to NPs functionalized with Amino or PEG residues. The presence of the hydrophilic SP A in nS facilitated lipid binding to all NPs. In line with this the degree of lipid and protein affinities for different surface functionalized SiO2 NPs in nS followed the same order (SiO2 Phosphate ∼ unmodified SiO2 < SiO2 PEG < SiO2 Amino NPs). Agglomeration and biomolecule interaction of NPs in nS was mainly influenced by surface charge and hydrophobicity. Toxicological differences as observed in short-term inhalation studies (STIS) were mainly influenced by the core composition and/or surface reactivity of NPs. However, agglomeration in lipid media and lipid/protein affinity appeared to play a modulatory role on short-term inhalation toxicity. For instance, lipophilic NPs like ZrO2, which are interacting with nS to a higher extent, exhibited a far higher lung burden than their hydrophilic counterparts, which deserves further attention to predict or model effects of respirable NPs.

Broadband multiplex coherent anti-Stokes Raman scattering (MCARS) microscopy allows the rapid chemical mapping and molecular imaging of untreated material samples with three-dimensional sectioning capabilities. It can be realized with a single laser in a simple and robust setup using supercontinuum generation in a microstructured fiber. The successful implementation of a MCARS microscope is discussed in detail, its parameters are characterized, and applications are shown for the identification and mapping of polymer blends. An evolutionary fitting routine is presented, which allows a fully quantitative analysis of the MCARS information resulting in high-contrast chemical maps. The established setup enables reliable day-to-day operation as a valuable tool for rapid material characterization.