Polymer surface properties control the function of heavy meromyosin in dynamic nanodevices.

The actin-myosin system, responsible for muscle contraction, is also the force-generating element in dynamic nanodevices operating with surface-immobilized motor proteins. These devices require materials that are amenable to micro- and nano-fabrication, but also preserve the bioactivity of molecular motors. The complexity of the protein-surface systems is greatly amplified by those of the polymer-fluid interface; and of the structure and function of molecular motors, making the study of these interactions critical to the success of molecular motor-based nanodevices.

Mapping hydrophobicity on the protein molecular surface at atom-level resolution.

A precise representation of the spatial distribution of hydrophobicity, hydrophilicity and charges on the molecular surface of proteins is critical for the understanding of the interaction with small molecules and larger systems. The representation of hydrophobicity is rarely done at atom-level, as this property is generally assigned to residues. A new methodology for the derivation of atomic hydrophobicity from any amino acid-based hydrophobicity scale was used to derive 8 sets of atomic hydrophobicities, one of which was used to generate the molecular surfaces for 35 proteins with convex structures, 5 of which, i.

Protein molecular surface mapped at different geometrical resolutions.

Many areas of biochemistry and molecular biology, both fundamental and applications-orientated, require an accurate construction, representation and understanding of the protein molecular surface and its interaction with other, usually small, molecules. There are however many situations when the protein molecular surface gets in physical contact with larger objects, either biological, such as membranes, or artificial, such as nanoparticles. The contribution presents a methodology for describing and quantifying the molecular properties of proteins, by geometrical and physico-chemical mapping of the molecular surfaces, with several analytical relationships being proposed for molecular surface properties.

Protein immobilisation on micro/nanostructures fabricated by laser microablation.

The performance of biomedical microdevices requires the accurate control of the biomolecule concentration on the surface, as well as the preservation of their bioactivity. This desideratum is even more critical for proteins, which present a significant propensity for surface-induced denaturation, and for microarrays, which require high multiplexing. We have previously proposed a method for protein immobilisation on micro/nanostructures fabricated via laser ablation of a thin metal layer deposited on a transparent polymer.

Models of protein linear molecular motors for dynamic nanodevices.

Protein molecular motors are natural nano-machines that convert the chemical energy from the hydrolysis of adenosine triphosphate into mechanical work. These efficient machines are central to many biological processes, including cellular motion, muscle contraction and cell division. The remarkable energetic efficiency of the protein molecular motors coupled with their nano-scale has prompted an increasing number of studies focusing on their integration in hybrid micro- and nanodevices, in particular using linear molecular motors.

Microbeads on microposts: an inverted architecture for bead microarrays.

The rapid development of genomics and proteomics requires accelerated improvement of the microarrays density, multiplexing, readout capabilities and cost-effectiveness. The bead arrays are increasingly attractive because of their self-assembly-based fabrication, which alleviates many problems of top-down microfabrication. Here we present a simple, reliable, robust and modular technique for the fabrication of bead microarrays, which combines the directed assembling of beads in microstructures and PDMS-based replica molding.

Surface hydrophobicity modulates the operation of actomyosin-based dynamic nanodevices.

We studied the impact of surface hydrophobicity on the motility of actin filaments moving on heavy-meromyosin (HMM)-coated surfaces. Apart from nitrocellulose (NC), which is the current standard for motility assays, all materials tested are good candidates for microfabrication: hydrophilic and hydrophobic glass, poly(methyl methacrylate) (PMMA), poly(tert-butyl methacrylate) (PtBuMA), and a copolymer of O-acryloyl acetophenone oxime with a 4-acryloyloxybenzophenone (AAPO). The most hydrophilic (hydrophilic glass, contact angle 35 degrees) and the most hydrophobic (PtBuMA, contact angle 78 degrees) surfaces do not maintain the motility of actin filaments, presumably because of the low density of adsorbed HMM protein or its high levels of denaturation, respectively.