https://www.zora.uzh.ch/id/eprint/44154/1/Rabe1.pdf

Understanding protein adsorption phenomena at solid surfaces

The application of nanotechnology concepts to medicine joins two large cross-disciplinary fields with an unprecedented societal and economical potential arising from the natural combination of specific achievements in the respective fields. The common basis evolves from the molecular-scale properties relevant to the two fields. Local probes and molecular imaging techniques allow surface and interface properties to be characterized on a nanometer scale at predefined locations, while chemical approaches offer the opportunity to elaborate and address surfaces, for example, for targeted drug delivery, enhanced biocompatibility, and neuroprosthetic purposes. However, concerns arise in this cross-disciplinary area about toxicological aspects and ethical implications. This Review gives an overview of selected recent developments and applications of nanomedicine.

Nanomedicine--challenge and perspectives.

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.

Polyester Materials with Superwetting Silicone Nanofilaments for Oil/Water Separation and Selective Oil Absorption

Fluorescence is widely used in optical devices, microscopy imaging, biology, medical research and diagnosis. Improving fluorescence sensitivity, all the way to the limit of single-molecular detection needed in many applications, remains a great challenge. The technique of surface enhanced fluorescence (SEF) is based upon the design of surfaces in the vicinity of the emitter. SEF yields an overall improvement in the fluorescence detection efficiency through modification and control of the local electromagnetic environment of the emitter. Near-field coupling between the emitter and surface modes plays a crucial role in SEF. In particular, plasmonic surfaces with localized and propagating surface plasmons are efficient SEF substrates. Recent progress in tailoring surfaces at the nanometre scale extends greatly the realm of SEF applications. This review focuses on the recent advances in the different mechanisms involved in SEF, in each case highlighting the most relevant applications.

http://turroserver.chem.columbia.edu/surfaceplasmons/pdf/53_jpd_41_1_2008_sefsrev.pdf

Surface enhanced fluorescence

Self-assembled peptide and protein amyloid nanostructures have traditionally been considered only as pathological aggregates implicated in human neurodegenerative diseases. In more recent times, these nanostructures have found interesting applications as advanced materials in biomedicine, tissue engineering, renewable energy, environmental science, nanotechnology and material science, to name only a few fields. In all these applications, the final function depends on: (i) the specific mechanisms of protein aggregation, (ii) the hierarchical structure of the protein and peptide amyloids from the atomistic to mesoscopic length scales and (iii) the physical properties of the amyloids in the context of their surrounding environment (biological or artificial). In this review, we will discuss recent progress made in the field of functional and artificial amyloids and highlight connections between protein/peptide folding, unfolding and aggregation mechanisms, with the resulting amyloid structure and functionality. We also highlight current advances in the design and synthesis of amyloid-based biological and functional materials and identify new potential fields in which amyloid-based structures promise new breakthroughs.

/pdf/self-assembling-peptide-and-protein-amyloids-from-structure-3a2o3zyuoj.pdf

Self-assembling peptide and protein amyloids: from structure to tailored function in nanotechnology

Parkinson's disease is a common progressive neurodegenerative condition, characterized by the deposition of amyloid fibrils as Lewy bodies in the substantia nigra of affected individuals. These insoluble aggregates predominantly consist of the protein α-synuclein. There is increasing evidence suggesting that the aggregation of α-synuclein is influenced by lipid membranes and, vice versa, the membrane integrity is severely affected by the presence of bound aggregates. Here, using the surface-sensitive imaging technique supercritical angle fluorescence microscopy and Forster resonance energy transfer, we report the direct observation of α-synuclein aggregation on supported lipid bilayers. Both the wild-type and the two mutant forms of α-synuclein studied, namely, the familiar variant A53T and the designed highly toxic variant E57K, were found to follow the same mechanism of polymerization and membrane damage. This mechanism involved the extraction of lipids from the bilayer and their clustering around growi...

/pdf/mechanism-of-membrane-interaction-and-disruption-by-a-2lsvxrjheb.pdf

Mechanism of membrane interaction and disruption by α-synuclein.

We explore a new confocal microscope for the detection of surface-generated fluorescence. The instrument is designed for high resolution imaging as well as for the readout of large biochips. Special feature is the separated collection of two different fluorescence emission modes. One optical path covers the emission into the glass at low surface angles, the other captures high angles, exceeding the critical angle of the water/glass interface. Due to the collection of the supercritical angle fluorescence (SAF) the confocal detection volume is strictly confined to the interface, whereas the low angles collect much deeper from the aqueous analyte solution. Hence the system can deliver information about surfacebound and unbound fraction of fluorescent analyte simultaneously.

Supercritical angle fluorescence (SAF) microscopy

The aggregation of α-synuclein (α-Syn) is believed to be one of the key steps driving the pathology of Parkinson’s disease and related neurodegenerative disorders. One of the present hypotheses is that the onset of such pathologies is related to the rise of α-Syn levels above a critical concentration at which toxic oligomers or mature fibrils are formed. In the present study, we find that α-Syn aggregation in vitro is a spontaneous process arising at bulk concentrations as low as 1 nM and below in the presence of both hydrophilic glass surfaces and cell membrane mimicking supported lipid bilayers (SLBs). Using three-dimensional supercritical angle fluorescence (3D-SAF) microscopy, we observed the process of α-Syn aggregation in situ. As soon as α-Syn monomers were exposed to the surface, they started to adsorb and aggregate along the surface plane without a prior lag phase. However, at a later stage of the aggregation process, a second type of aggregate was observed. In contrast to the first type, these a...

/pdf/on-surface-aggregation-of-a-synuclein-at-nanomolar-3wwt7ho3dq.pdf

On-Surface Aggregation of α-Synuclein at Nanomolar Concentrations Results in Two Distinct Growth Mechanisms

We report a noninvasive fluorescence microscopy method and demonstrate nanometer resolution along the optical axis. The technique is based on the influence of the microscope slide on the angular intensity distribution of fluorescence. Axial positions are determined by measuring the proportion of light emitted below the critical angle of total internal reflection, which behaves in a classical way, and light emitted above the critical angle, which is exponentially dependent on the distance of the fluorophore from the microscope slide.

/pdf/nanometer-axial-resolution-by-three-dimensional-2ayg69znxc.pdf

Dorinel Verdes

Papers

Understanding protein adsorption phenomena at solid surfaces

Mechanism of membrane interaction and disruption by α-synuclein.

Supercritical angle fluorescence (SAF) microscopy

On-Surface Aggregation of α-Synuclein at Nanomolar Concentrations Results in Two Distinct Growth Mechanisms

Nanometer axial resolution by three-dimensional supercritical angle fluorescence microscopy.