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The investigation of Swiss chemical and pharmaceutical companies regarding their working capital management has revealed the huge potential which is lying in the management of short term assets and liabilities. Furthermore, the considerable differences between the single firms show that an optimized working capital management may play an important role for a firm’s competitiveness. A successful working apital strategy relies on the commitment and awareness of the management and on efficient working capital practices on the operative level. In addition, internal and external collaboration leads to more competitiveness, both for the firm as well as for the whole supply chain. A consistent and ongoing monitoring ensures sustainable improvements, and can be supported and enhanced by a benchmarking analysis and the adaption of best practices.

Superhydrophobic and superoleophilic polyester materials are successfully prepared by one-step growth of silicone nanofilaments onto the textile via chemical vapor deposition of trichloromethylsilane. The successful growth of silicone nanofilaments is confirmed with scanning electron microscopy, energy-dispersive X-ray analysis, and investigation of the wetting behavior of water on the textile. Even microfibers deeply imbedded inside a woven material could be coated very well with the nanofilaments. The coated textile is water repellant and could only be wetted by liquids of low surface tension. The applications of the coated textile as a membrane for oil/water separation and as a bag for selective oil absorption from water are studied in detail. Owing to the superwetting properties and flexibility of the coated textile, excellent reusability, oil/water separation efficiency, and selective oil absorption capacity are observed, which make it very promising material, e.g., for practical oil absorption.

An inexpensive and easy-to-use immunoassay platform for the sensitive detection of analytes is presented. It comprises single-use polymer test tubes and a compact fluorescence reader. The optics for the capture of supercritical angle fluorescence (SAF) has been built into the tubes allowing for the extremely sensitive readout of solid phase immunoassays in real time and without washing steps. One-step sandwich immunoassays with interleukin 2 (IL-2) were carried out with capture antibodies immobilized in the tubes. At a turn around time of 12 min, the limit of detection for IL-2 was 0.27 pM (4.5 pg/mL) and the linear range covered 3 orders of magnitude. The developed technology is also adaptable to well plates and has great potential of replacing the work-intensive and time-consuming enzyme-linked immunosorbant assay (ELISA).

Cooperative effects play a vital role in protein adsorption events on biological interfaces. Despite a number of studies in this field molecular adsorption mechanisms that include cooperativity are still under debate. In this work we use a Monte Carlo-type simulation to explore the microscopic details behind cooperative protein adsorption. The simulation was designed to implement our previously proposed mechanism through which proteins are not necessarily rejected if they approach the surface to an occupied region. Instead, we suggest that proteins can be tracked laterally for a certain distance due to the influence of preadsorbed proteins in order to reach the nearest available binding site. The simulation results were compared with experimental data obtained by using the supercritical angle fluorescence (SAF) microscopy technique. It was found that the tracking distance may be up to 2.5 times the protein's diameter depending on the investigated system. The general validity of this tracking mechanism is supported by a number of linear or upward concave adsorption kinetics reported in the literature which are consistent with our simulation results. Furthermore, the self-organization of proteins adsorbing under cooperative conditions on the surface is shown to necessarily cause density inhomogeneities in the surface distribution of proteins which is also in agreement with experimental observations.

Label-free detection of molecules and particles based on native fluorescence excited at the ultraviolet (UV) region of the electromagnetic spectrum shows great potential for molecular analysis in life sciences. It offers simple, low-cost, and fast methods for sensitive detection of important biological analytes in nature forms. This article reviews the most significant research on label-free native fluorescence detection in analytical chemistry and biochemistry, with particular focus on the instrumental requirements and applications that cover papers published to the beginning of 2009. Future development directions for label-free optical biosensors based on native fluorescence are discussed.

Despite many experimental studies on cooperative effects during protein adsorption events, this phenomenon is still poorly characterized and subject of much controversy. In this study, we address the topic of cooperativity using two distinct experimental approaches, namely, kinetic analysis and surface imaging, both based on supercritical angle fluorescence (SAF) microscopy. Several model systems comprising the two proteins BSA and fibrinogen, two different ionic strength conditions and varying pH environments were investigated. The combination of the experimental information obtained from kinetic analysis and from real-time in situ scan images unravel a clear correlation between cooperative adsorption and a heterogeneous protein layer build-up. We propose a mechanistic model of protein adsorption based on an overlap of classical Langmuir-type adsorption on unoccupied surface areas and an additional cooperative adsorption pathway near preadsorbed proteins which is consistent with the experimental observations. Moreover, the growth of two-dimensional surface clusters as an often assumed element of cooperativity could be excluded for the studied systems. The model includes the often observed phenomenon that the adsorption rate decelerates abruptly above a certain coverage limit. Furthermore, the observed evolution of the heterogeneous protein distribution on the surface is in good agreement with the proposed model.

We demonstrate that a recently developed coating composed of superhydrophobic silicone nanofilaments can be selectively functionalized to yield well defined micron-scale patterns of contrasting wettabilities (superhydrophobic/hydrophilic and amphiphobic/amphiphilic). Nanofilament ablation was performed using a near-ultraviolet (UV) laser with a wavelength of 355 nm and a repetition rate of 10 kHz. This is a highly promising approach for open channel microfluidics and microarray analysis due to its simplicity, the chemical and environmental stability of the coating, and the low cost.

The interaction of meso-tetrakis(p-sulfonatophenyl)porphyrin (TPPS) with bovine serum albumin (BSA) in neutral solution (pH 7.4) has been studied by means of absorption, steady-state fluorescence and time-resolved fluorescence spectroscopy. The formation of TPPS–BSA complex was monitored by spectroscopic characteristic changes in Soret band absorption and fluorescence emission of TPPS. Applying the time-correlated single-photon counting (TCSPC) method, BSA–TPPS interaction was also investigated by the fluorescence lifetime of tryptophan residues in BSA. The results demonstrate that deep UV laser-based fluorescence lifetime microscopy is useful for sensitive identification of protein interaction using intrinsic fluorescence.

We present a simple and versatile technique of tailoring functionalized surface structures for protein enrichment and purification applications based on a superhydrophobic silicone nanofilament coating. Using amino and carboxyl group containing silanes, silicone nanofilament templates were chemically modified to mimic anionic and cationic exchange resins. Investigations on the selectivity of the functionalized surfaces toward adsorption of charged model proteins were carried out by means of fluorescence techniques. Due to a high contact area resulting from the nanoroughness of the coating, excellent protein retention characteristics under various conditions were found. The surfaces were shown to be highly stable and reusable over several retention-elution cycles. Especially the full optical transparency and the possibility to use glass substrates as support material open new opportunities for the development of optical biosensors, open geometry microfluidics, or lab-on-a-chip devices.

We demonstrate that a recently developed coating comprised of silicone nanofilaments can be selectively functionalized to yield well defined superhydrophobic, superhydrophilic, superoleophobic or superoleophilic domains on a single substrate, constituting a simple and versatile toolbox for surface scientists to create and study surfaces with extreme wetting properties.

We present recent work on a method for depositing silicone nanofilament coatings on surfaces under mild conditions in the gas or solvent phase. The coating shows exceptional properties in an application as a superhydrophobic coating. It can be applied to a variety of substrates, is optically transparent and intrinsically superhydrophobic with typical water contact angles of more than 160° and sliding angles below 20°. It shows exceptional long term stability towards solvents and aqueous solutions of varying pH as well as natural and artificial weathering. We review the coating techniques as well as the results of our studies on the structure and properties of a silicone nanofilament coating.