Electrogelation: Controlled Fast Formation of Micrometer-Thick Films from Low-Molecular Weight Hydrogelators.

The controlled electrochemical deposition of hydrogels from low-molecular weight hydrogelators (LMWHGs) allows for the defined formation of thin films on electrodes. Here, the deposition of fibrillar networks consisting of ,',″-tris(4-carboxyphenylene)-1,3,5-benzenetricarboxamide (BTA) onto ultraflat gold electrodes has been studied. This process, also termed electrogelation, is based on a local change in the pH due to electrolysis of water at the electrode.

An Integrated, Exchangeable Three-Electrode Electrochemical Setup for AFM-Based Scanning Electrochemical Microscopy.

Scanning electrochemical microscopy (SECM) is a versatile scanning probe technique that allows monitoring of a plethora of electrochemical reactions on a highly resolved local scale. SECM in combination with atomic force microscopy (AFM) is particularly well suited to acquire electrochemical data correlated to sample topography, elasticity, and adhesion, respectively. The resolution achievable in SECM depends critically on the properties of the probe acting as an electrochemical sensor, i.

A Versatile and Simple Approach to Electrochemical Colloidal Probes for Direct Force Measurements.

The colloidal probe technique, which is based on micrometer-sized colloidal particles that are attached to the end of a cantilever, revolutionized direct force measurements by atomic force microscopy (AFM). Its major advantages are a defined interaction geometry and a high force sensitivity. Here, we present a versatile and simple approach for preparing spherical electrodes in the micrometer range on an otherwise insulated AFM cantilever.

Interface-mediated formation of basic cobalt carbonate/polyethyleneimine composite microscrolls by strain-induced self-rolling.

Polyethyleneimine aids the gas diffusion precipitation of nano-structured basic cobalt carbonate sheets at the air/solution interface. Upon drying, these mineral films undergo self-rolling into 3D coiled structures. Exploring this principle for the design of self-supported functional materials, porous CoO spirals composed of interconnected nanoparticles are obtained by thermal conversion.

Electrokinetics in Micro-channeled Cantilevers: Extending the Toolbox for Reversible Colloidal Probes and AFM-Based Nanofluidics.

The combination of atomic force microscopy (AFM) with nanofluidics, also referred to as FluidFM, has facilitated new applications in scanning ion conductance microscopy, direct force measurements, lithography, or controlled nanoparticle deposition. An essential element of this new type of AFMs is its cantilever, which bears an internal micro-channel with a defined aperture at the end. Here, we present a new approach for in-situ characterization of the internal micro-channels, which is non-destructive and based on electrochemical methods.

The Next Generation of Colloidal Probes: A Universal Approach for Soft and Ultra-Small Particles.

The colloidal probe technique, which is based on the atomic force microscope, revolutionizes direct force measurements in many fields, such as interface science or biomechanics. It allows for the first time to determine interaction forces on the single particle or cell level. However, for many applications, important "blind spots" remain, namely, the possibility to probe interaction potentials for nanoparticles or complex colloids with a soft outer shell.

Low-Density Self-Assembled Poly(N-Isopropyl Acrylamide) Sponges with Ultrahigh and Extremely Fast Water Uptake and Release.

Poly(N-isopropyl acrylamide) (PNIPAM) hydrogels are well known for their temperature-dependent water uptake and release. Hence, they are ideal candidates for water management applications. However, efficiency and rate of water uptake and release, respectively, have to be optimized.

Extending the limits of direct force measurements: colloidal probes from sub-micron particles.

Direct force measurements by atomic force microscopy (AFM) in combination with the colloidal probe technique are widely used to determine interaction forces in colloidal systems. However, a number of limitations are still preventing a more universal applicability of this technique. Currently, one of the most significant limitations is that only particles with diameters of several micrometers can be used as probe particles.

Writing with Fluid: Structuring Hydrogels with Micrometer Precision by AFM in Combination with Nanofluidics.

Hydrogels have many applications in biomedical surface modification and tissue engineering. However, the structuring of hydrogels after their formation represents still a major challenge, in particular due to their softness. Here, a novel approach is presented that is based on the combination of atomic force microscopy (AFM) and nanofluidics, also referred to as FluidFM technology.

Probing the adhesion properties of alginate hydrogels: a new approach towards the preparation of soft colloidal probes for direct force measurements.

The adhesion of alginate hydrogels to solid surfaces was probed by atomic force microscopy (AFM) in the sphere/plane geometry. For this purpose a novel approach has been developed for the immobilization of soft colloidal probes onto AFM-cantilevers, which is inspired by techniques originating from cell biology. The aspiration and consecutive manipulation of hydrogel beads by micropipettes allows the entire manipulation sequence to be carried-out in situ.

A direct biocombinatorial strategy toward next generation, mussel-glue inspired saltwater adhesives.

Biological materials exhibit remarkable, purpose-adapted properties that provide a source of inspiration for designing new materials to meet the requirements of future applications. For instance, marine mussels are able to attach to a broad spectrum of hard surfaces under hostile conditions. Controlling wet-adhesion of synthetic macromolecules by analogue processes promises to strongly impact materials sciences by offering advanced coatings, adhesives, and glues.

Surface properties of spider silk particles in solution.

Recombinant spider silk proteins, such as eADF4(C16), can be used for various applications. Colloidal particles of eADF4(C16) show potential as drug delivery systems. Tuning the colloidal properties of suspensions of eADF4(C16) particles represents a major prerequisite for their use in pharmaceutical formulations.