Neurodegenerative disease is primarily characterized by protein misfolding and the resultant protein aggregation. Presence of soluble oligomeric aggregates of proteins including various Aβ and α-syn aggregate species can be correlated to the onset and progression of many neurodegenerative diseases. The ability to detect protein misfolding requires the design of a diagnostics assay the will enable molecular level probing. The use of nanoporous ceramic templates enables size based immobilization of the target proteins and by leveraging the principle of “macromolecular crowding” protein association can be mapped with a high degree of resolution. By tailoring the surface functionalization within nanoporous ceramic templates, macromolecular immobilization can be selectively controlled, which in turn significantly enhances the perturbation to the electrical double layer/. The changes to the electrical double layer are measured with a high degree of sensitivity through impedance spectroscopy.

Pre symptomatic diagnosis and distinction between Alzheimer’s and Parkinson’s diseases can be achieved by the specific detection and quantification of levels of each of these different toxic protein species in cerebrospinal fluid (CSF). Detection using highly selective morphology specific reagents in conjunction with the ultrasensitive nanoporous electronic biosensor showed the presence of different protein morphologies in human CSF samples. Detection is primarily achieved by identifying the specific association of the protein with its receptor using electrochemical impedance spectroscopy. Furthermore, we show that these morphology specific reagents can readily classify between post-mortem CSF samples from AD, PD and cognitively normal sources. These studies suggest that detection of specific oligomeric aggregate species holds great promise as sensitive biomarkers for neurodegenerative disease.

Delamination between thin-film metal and substrate is a major cause of failure in polyimide based neural microelectrode arrays. Chemical adhesion is the only way to establish a long-term bond that will allow two materials to stick to each other even in a wet environment, given that the materials do not deteriorate in the presence of water. This study assesses, by means of peel and shear tests, a long-term quantitative and comparative study of the adhesion of polyimide to various metallic and other inorganic layers of interest. Polyimide (BPDA-PPD) was cured on the layers, which involve platinum, gold and tungsten-titanium as commonly used implant metals and diamond-like carbon (DLC), silicon carbide (SiC), silicon dioxide (SiO2) and silicone nitride (SiN) as potential adhesion promoters to be used later as intermediate layers between metal and polyimide. The adhesion was observed over one year under accelerated-aging conditions by storing the specimens in 60°C saline (corresponding to 40000 hrs at 37°C). Only silicon carbide and amorphous carbon showed almost unaffected adhesion to polyimide over the testing period. No water intrusion at the interface was observed and the strong bond is almost fully maintained.

Biodegradable poly(3-hydroxybutyrate) -PHB- and the copolymers with poly (3-hydroxyvalerate) -PHB/HV, containing 5 and 12 mol% valerate (denoted PHB/5HV and PHB/12HV, respectively) were electrospun from chloroform solution at room temperature. The results showed that relatively low voltage and concentrations favored uniform filament formation in PHB, with filament diameters ranging from 3 to 7 micrometers. On the other hand, low molecular weight and low solution concentration favored uniform filament formation in the PHB/5HV copolymer. Strikingly, morphology of filaments and beads favored the membranes hydrophobic behavior; the membrane from PHB/12HV exhibited a water contact angle of 112°. In contrast, solution cast films from the PHAs exhibited water contact angles in the range of 65°. Analyses on the membranes morphology via scanning electron microscopy (SEM) revealed that filament diameter drives the degree of porosity and the hydrophobic behavior of the electrospun membranes.

Bi-layer material systems are found in various engineering applications ranging from nanoscale components, such as thin films in circuit boards, to macroscale structures, such as adhesive bonding in aerospace and civil infrastructure. They are also found in many natural and biological materials such as nacre or bone. The structural integrity of a bi-layer system depends on properties of both the interface and the constitutive materials. In particular, interfacial delamination has been observed as a major integrity issue. Here we present a multiscale model, which can predict the macroscale structural behavior at the interface between organic and inorganic materials, based on a molecular dynamics (MD) simulation approach combined with the metadynamics method used to reconstruct the free energy surface (FES) between attached and detached states of the bonded system. We apply this technique to model an epoxy-silica system that primarily features non-bonded and non-directional van der Waals and Coulombic interactions. The reconstructed FES of the epoxy-silica system derived from the molecular level is used to quantify the traction-separation relation at epoxy-silica interface. In this paper, two different approaches in deriving the traction-separation relation based on the reconstructed FES are described. With the derived traction-separation relation, a finite element approach using cohesive zone model (CZM) can be implemented such that the structural behavior of epoxy-silica interface at the macroscopic length scale can be predicted. The prediction from our multiscale model shows a good agreement with experimental data of the interfacial fracture toughness. The method used here provides a powerful new approach to link nano to macro for complex heterogeneous material systems.

Two strains of E-Coli K-12, viz, RP437, MG1655 and B/r (E. coli B derivative, not a K-12 strain) were grown on various surfaces to study bacterial adhesion and subsequent biofilm formation. We observed biofilm and large colonies on cover slides, beads made of soda lime or borosilicate glasses, on plasma treated PDMS (Polydimethylsiloxane), on Tissue Culture (TC) polystyrene, and observed some clusters on plasma treated ZnTi cover slide; but no evidence of biofilm on untreated-PDMS and ZnTi glass cover slides. From contact angle measurements, we conclude that the hydrophobic nature of untreated PDMS prevent bacterial adhesion for these three strains.

As scientists are able to understand and manipulate ever smaller scales of matter, research in the fields of biotechnology and nanotechnology has converged to enable such radical innovations as lab-on-a-chip devices, targeted drug delivery, and other forms of minimally invasive therapy and diagnostics. This paper provides a descriptive overview of the emerging bio-nano sector, identifying what types of firms are entering, from what knowledge base, where they are located, and their strategic choices in terms of technological diversity and R&D strategy. The firms engaged in bio-nano research and development span the range from start-up firm to multinational pharmaceutical, biotech, chemical, and electronics firms: two thirds of bio-nano firms are relatively young and relatively small. The United States dominates this sector, with more than half of all bio-nano firms located in the USA. Even within this sector which epitomizes the convergence of technology, there is a broad range of technological diversity, with the most diverse firms overall coming from a base in electronics, the most diverse start-up firms coming from a base in nanomaterials, and the most narrowly focused firms coming from a biotechnology/pharmaceutical base. We find that hybridization has been the dominant knowledge diversity strategy, with 93% of the bio-nano firms with nano-patents holding multiclass patents.

Characteristics of surface-adsorbed bioluminescent bacteria were examined. The bacteria were expected to function as an oxygen probe inside the biofilm. Luminescent behavior of the bacteria inside a typical biofilm was observed. Adsorption characteristics as well as the luminescence intensity change through the desorption process were investigated.

In an attempt to develop conductive, biodegradable, mechanically strong, and biocompatible nerve conduits, pure magnesium (Mg) was used as the biodegradable substrate material to provide strength while the conductive polymer, poly(3,4ethylenedioxythiophene) (PEDOT) was used as a conductive coating material to control Mg degradation and improve cytocompatibility of Mg substrates. This study explored a series of electrochemical deposition conditions to produce a uniform, consistent PEDOT coating on Mg substrates. The microstructure and morphology of the coating and Mg were visualized using scanning electron microscopy (SEM). The elemental composition of the surface was quantified using energy dispersive X-ray spectroscopy (EDS). Adhesion strength of the coating was measured using the tape test following the ASTM-D 3359 standard. The SEM results showed uniform and consistent PEDOT coating, and EDS analysis confirmed the elemental composition of PEDOT. The adhesion strength of PEDOT coating was within the classifications of 3B to 4B.

Coronary artery disease is a major problem worldwide causing 7.2 million deaths worldwide annually, resulting from vascular occlusion, myocardial infarction and its complications. Stent implantation is a percutaneous interventional procedure that mitigates vessel stenosis, providing mechanical support within the artery. However, stenting causes physical damage to the arterial wall. It is well accepted that a valuable route to reduce in-stent re-stenosis can be based on promoting cell response to nano-structured stainless steel (SS) surfaces such as, for example, by patterning nano-pits in SS. In this regard patterning by Focussed Ion-Beam (FIB) milling offers several advantages for flexible prototyping (i) practically any substrate material that is able to withstand high vacuum conditions of the microscope chamber can be used, (ii) there is high flexibility in the obtainable shapes and geometries by modulating the ion beam current and the patterning conditions, (iii) reduced complexity of the pattering process e.g. it is a single-step process with a possibility of real-time monitoring of the milling progression. On the other hand FIB patterning of polycrystalline metals is greatly influenced by channelling effects and re-deposition. Correlative microscopy methods present an opportunity to study such effects comprehensively and derive structure-property understanding that is important for developing improved pattering. In this report we present a FIB patterning protocol for nano-structuring features (concaves) ordered in rectangular arrays on pre-polished 316L Stainless Steel (SS) surfaces. An investigation based on correlative microscopy approach of the size, shape and depth of the developed arrays in relation to the crystal orientation of the underlying SS domains, is presented. The correlative microscopy protocol is based on cross-correlation of top-view Scanning Electron Microscopy (SEM), Electron Backscattered Diffraction (EBSD), and Atomic Force Microscopy (AFM).Various dose tests were performed, aiming at improved productivity by preserving nano-size accuracy of the patterned process. The optimal FIB patterning conditions for achieving reasonably high throughput (patterned rate of about 0.03 mm2 per hour) and nano-size accuracy in dimensions and shapes of the features, are discussed as well.