Enzyme-Polymer Conjugates to Enhance Enzyme Shelf Life in a Liquid Detergent Formulation.

Herein, the synthesis of enzyme-polymer conjugates is reported. Four different activated polymers (mPEG-aldehyde, mPEG-NHS, maltodextrin-aldehyde, carboxymethyl cellulose aldehyde) are conjugated to the surface of protease, α-amylase, and lipase using two different strategies (reductive amination and alkylation with NHS-activated acid). Although the chemical modification of the enzymes is accompanied by losses in enzyme activity (maximum loss 40%), the covalent attachment of polymers increases the thermal stability and the stability in a standard detergent formulation compared to the unmodified enzymes.

Wide dynamic range enrichment method of semiconducting single-walled carbon nanotubes with weak field centrifugation.

The potential of single-walled carbon nanotubes (SWCNTs) to outperform silicon in electronic application was finally enabled through selective separation of semiconducting nanotubes from the as-synthesized statistical mix with polymeric dispersants. Such separation methods provide typically high semiconducting purity samples with narrow diameter distribution, i.e.

Highly Efficient and Scalable Separation of Semiconducting Carbon Nanotubes via Weak Field Centrifugation.

The identification of scalable processes that transfer random mixtures of single-walled carbon nanotubes (SWCNTs) into fractions featuring a high content of semiconducting species is crucial for future application of SWCNTs in high-performance electronics. Herein we demonstrate a highly efficient and simple separation method that relies on selective interactions between tailor-made amphiphilic polymers and semiconducting SWCNTs in the presence of low viscosity separation media. High purity individualized semiconducting SWCNTs or even self-organized semiconducting sheets are separated from an as-produced SWCNT dispersion via a single weak field centrifugation run.

Multidimensional analysis of nanoparticles with highly disperse properties using multiwavelength analytical ultracentrifugation.

The worldwide trend in nanoparticle technology toward increasing complexity must be directly linked to more advanced characterization methods of size, shape and related properties, applicable to many different particle systems in science and technology. Available techniques for nanoparticle characterization are predominantly focused on size characterization. However, simultaneous size and shape characterization is still an unresolved major challenge.

Observation of kinks and antikinks in colloidal monolayers driven across ordered surfaces.

Friction between solids is responsible for many phenomena such as earthquakes, wear or crack propagation. Unlike macroscopic objects, which only touch locally owing to their surface roughness, spatially extended contacts form between atomically flat surfaces. They are described by the Frenkel-Kontorova model, which considers a monolayer of interacting particles on a periodic substrate potential.

Proliferation of anomalous symmetries in colloidal monolayers subjected to quasiperiodic light fields.

Quasicrystals provide a fascinating class of materials with intriguing properties. Despite a strong potential for numerous technical applications, the conditions under which quasicrystals form are still poorly understood. Currently, it is not clear why most quasicrystals hold 5- or 10-fold symmetry but no single example with 7- or 9-fold symmetry has ever been observed.

Archimedean-like tiling on decagonal quasicrystalline surfaces.

Monolayers on crystalline surfaces often form complex structures with physical and chemical properties that differ strongly from those of their bulk phases. Such hetero-epitactic overlayers are currently used in nanotechnology and understanding their growth mechanism is important for the development of new materials and devices. In comparison with crystals, quasicrystalline surfaces exhibit much larger structural and chemical complexity leading, for example, to unusual frictional, catalytical or optical properties.