Selection of DNA nanoparticles with preferential binding to aggregated protein target.

High affinity and specificity are considered essential for affinity reagents and molecularly-targeted therapeutics, such as monoclonal antibodies. However, life's own molecular and cellular machinery consists of lower affinity, highly multivalent interactions that are metastable, but easily reversible or displaceable. With this inspiration, we have developed a DNA-based reagent platform that uses massive avidity to achieve stable, but reversible specific recognition of polyvalent targets. We have previously selected these DNA reagents, termed DeNAno, against various cells and now we demonstrate that DeNAno specific for protein targets can also be selected. DeNAno were selected against streptavidin-, rituximab- and bevacizumab-coated beads. Binding was stable for weeks and unaffected by the presence of soluble target proteins, yet readily competed by natural or synthetic ligands of the target proteins. Thus DeNAno particles are a novel biomolecular recognition agent whose orthogonal use of avidity over affinity results in uniquely stable yet reversible binding interactions

Quantitative atomic force microscopy provides new insight into matrix vesicle mineralization

International audienc

High-Speed CMOS Switch Designs for Free-Space Optoelectronic MINs

We present the theory, experimental results, and analytical modeling of high-speed CMOS switches, with a 2-D layout, suitable for the implementation of packet-switched free-space optoelectronic Multistage Interconnection Networks (MINs). These switches are fully connected, bi-directional, and scaleable. The first design is a proof of concept of the half-switch, which is a two-to-one multiplexer, and the 2-D layout. The second design introduces a novel self-routing concept, with contention detection and packet drop-and-resend capabilities. It uses three-valued logic, with 2.5V being the third value for a 5V power supply. Simulations show that for a 0.8 µm CMOS technology the switches can operate at speeds up to 250 Mbits/sec. Scaled-down versions of both designs have been successfully implemented in 2.0 µm CMOS. The analytical modeling of the switches show that large scale free-space optoelectronic MINs using this concept could offer close to Terabit/sec throughput capabilities and ver..

An efficient mapping of Fuzzy ART onto a neural architecture

A novel mapping of the Fuzzy ART algorithm onto a neural network architecture is described. The architecture does not utilize bi-directional synapses, weight transport, or weight duplication, and requires one fewer layer of processing elements than the architecture originally proposed by Carpenter, Grossberg, & Rosen (1991a). In the new architecture, execution of the algorithm takes constant time per input vector regardless of the relationship between the input and existing templates, and several control signals are eliminated. This mapping facilitates hardware implementation of Fuzzy ART and furthermore serves as a tool for envisioning and understanding the algorithm. Keywords: Fuzzy ART, Fuzzy ARTMAP, parallel hardware, neural architecture. Fuzzy ART is a clustering algorithm that operates on vectors with analog-valued elements (Carpenter, Grossberg, & Rosen, 1991a). Adding a further layer of processing to Fuzzy ART yields a supervised clustering algorithm, Fuzzy ARTMAP (Carpenter, G..

Electrokinetic Assembly of Microsphere and Cellular Arrays

ABSTRACT We have developed a novel electrochemical system for field assisted, fluidic assembly of objects on a microfabricated silicon substrate by means of electrical addressing. The principle of our technique is based on the movement of charged species in solution to oppositely charged electrodes, as seen commonly in electrophoresis. Here, charged species such as beads and cells are moved electrokinetically through an aqueous solution towards a charged electrode. Micro patterning of the electrodes allows localization of charged species. We present a theoretical framework to predict the electric potential for assembly and disassembly of spherical objects. We correlate theoretical predictions with the motion of negatively charged polystyrene beads of 20 µm diameter on 100 µm feature micro patterned substrates. In addition, we extended these results to arraying of 20-30 µm diameter live mammalian cells by means of electrical addressing. This technique has applications in creation of 'active' cellular arrays for cell biology research, drug discovery and tissue engineering

Esener, “Optimization and theoretical modeling of polymer microlens arrays fabricated with the hydrophobic effect

High-performance polymer microlens arrays were fabricated by means of withdrawing substrates of patterned wettability from a monomer solution. The f-number ͑f # ͒ of formed microlenses was controlled by adjustment of monomer viscosity and surface tension, substrate dipping angle and withdrawal speed, the array fill factor, and the number of dip coats used. An optimum withdrawal speed was identified at which f # was minimized and array uniformity was maximized. At this optimum, arrays of f͞3.48 microlenses were fabricated with one dip coat with uniformity of better than ⌬f͞f ϳ Ϯ3.8%. Multiple dip coats allowed for production of f͞1.38 lens arrays and uniformity of better than ⌬f͞f ϳ Ϯ5.9%. Average f # s were reproducible to within 3.5%. A model was developed to describe the fluid-transfer process by which monomer solution assembles on the hydrophilic domains. The model agrees well with experimental trends