Robert L. Dyer

Three-legged wireless miniature robots for mass-scale operations at the sub-atomic scale

We propose to bring the instruments to the samples in the form of miniature wireless instrumented robots called the NanoWalkers. With the NanoWalker robot approach, instrumentations and throughput requirements can be adjusted extremely fast by simply adding, replacing, or removing robots at will. It is the aim of this project to develop a powerful and flexible environment that we believe may revolutionize the way drug, biological, material discovery, and characterization will be performed in the future.

Synthesis of “capped porphyrins”

Abstract The synthesis of “capped porphyrins” ( 10 ), ( 18 ), and ( 28 ), and their (chloro)iron(III), iron(II), cobalt (II), and zinc(II) complexes is reported. These complexes serve as models for the active site of the oxygen binding haemoproteins. In addition to reversible binding of dioxygen by each of the iron (II) porphyrin complexes, the 1-methyl-imidazole-(“C3-capped porphyrin”) iron (II) complex ( 23 ) reacts reversibly with carbon monoxide, in solution at 25°C.

A highly flexible manufacturing technique for microelectrode array fabrication

A new technique for manufacturing microelectrode arrays is described and assessed. This technique uses wire Electrical Discharge Machining (wire EDM) to form detailed array structures from a single sample of solid metal. Chemical etching can then be used to increase the electrode aspect ratios. Electrode lengths of 5 mm, widths of 40 /spl mu/m, and spacings of 250 /spl mu/m have been fabricated using this technique. Arrays of electrodes of varying lengths can also be fabricated. For intracortical recording applications, the signal paths are isolated from one another by securing an insulating substrate.

Development of a wireless brain implant: the Telemetric Electrode Array System (TEAS) project

The Telemetric Electrode Array System (TEAS) project aims at developing and embedding entirely into the head, a three-dimensional intracortical electrode array with all electronics required for signal acquisition, processing, and wireless communication. A general description of the system, the main design issues, and its capabilities are briefly described.

Mechanical assembly of a microelectrode array for use in a wireless intracortical recording device

Fabrication of a microelectrode array assembly for neural activity recording is described. The assembly forms the mechanical front-end of the telemetric electrode array system, a wireless intracortical recording device designed for motor cortex studies in nonhuman primates. The electrodes are manufactured by wire electrical discharge machining solid titanium. They are then secured in a polyimide substrate. A flexible printed circuit board connector cable connects the array structure to the electrical frontend. Parylene and platinum are used as the encapsulation materials. Results from the implantation of a prototype microelectrode array assembly are discussed.

General description of the wireless miniature NanoWalker robot designed for atomic-scale operations

The NanoWalker is a miniature wireless instrumented robot designed for high-speed autonomous operations down to the atomic scale. As such, it requires very advanced electro-mechanical specifications and complex embedded sub-systems. The locomotion is based on three piezo-ceramic legs that are modulated at high frequencies to achieve several thousand steps per second with computer-controlled step sizes ranging from a few tenths of nanometers to a few micrometers. Each robot has an onboard 48 MIPS computer based on a digital signal processor (DSP) and 4 Mb/s half-duplex infrared communication system. A special instrument interface has been embedded in order to allow positioning capability at the atomic scale and sub-atomic operations within a 200 nanometer surface area using a scanning tunneling microscope (STM) tip. The design allows 200,000 STM-based measurements per second. In this paper, we describe the many sub-systems and the approaches used to successfully integrate them onto such a miniature robot.

NanoRunner: a very small wireless robot with three piezoactuated legs suited for design experimentations and validations through preprogrammed behaviors

The NanoRunner is designed to be primarily used as an experimental wireless robot in order ot quickly test and validate several hardware/software issues and ideas prior to being implemented on the more expensive and complex wireless instrumented NanoWalker robot. As such, the NanoRunner, Like the NanoWalker is based on three piezo- actuated legs forming a pyramid with the apex pointing upward. Unlike the NanoWlaker, the NanoRunner has much simpler embedded electronics and is not capable of an accuracy and computational throughput comparable to the NanoWalker. Because of its lighter weight, it can move or run much faster. Furthermore, the NanoRunner does not have a fast infrared communication infrastructure for downloading executable code. Instead the NanoRunner is first pre-programmed with a specific behavior suitable for the tasks to be performed. Nonetheless, the NanoRunner has all the required electronics to be fully autonomous while performing its experimentation tasks. Although not as sophisticated as the NanoWalker, the NanoRunner offers a smaller and simpler robot implementation for less demanding tasks. Another major motivation for the NanoRunner is to validate various ideas in order to decrease the overall size of the robot. The size is critical since our goal is to allow more robots to work within the same area. In this paper, the NanoRunner is described. Aspects such as construction, assembly, and the method used for downloading executable code in order to pre-program the robots behavior are also covered.

Embedded electronics for a 64-channel wireless brain implant

The Telemetric Electrode Array System (TEAS) is a surgically implantable device for the study of neural activity in the brain. An 8x8 array of electrodes collects intra-cortical neural signals and connects them to an analog front end. The front end amplifies and digitizes these microvolt-level signals with 12 bits of resolution and at 31KHz per channel. Peak detection is used to extract the information carrying features of these signals, which are transmitted over a Bluetooth-based radio link at 725 Kbit/sec. The electrode array is made up of 1mm tall, 60-micron square electrodes spaced 500 microns tip-to-tip. A flex circuit connector provides mechanical isolation between the brain and the electronics, which are mounted to the cranium. Power consumption and management is a critical aspect of the design. The entire system must operate off a surgically implantable battery. With this power source, the system must provide the functionality of a wireless, 64-channel oscilloscope for several hours. The system also provides a low-power sleep mode during which the battery can be inductively charged. Power dissipation and biocompatibility issues also affect the design of the electronics for the probe. The electronics system must fit between the skull and the skin of the test subject. Thus, circuit miniaturization and microassembly techniques are essential to construct the probes electronics.