When oxidized in a nonaqueous cell containing 1.0M LiC104 in propylene carbonate, polyacetylene develops a voltage of 3.4-4.0V vs. Li/Li + C10(. Oxidation levels at least as high as [CH(C104)0.1o]x can be produced electrochemically and then reduced to the undoped state with nearly 100~ coulombic efficiency. The electrochemical doping (oxidation) process is only efficient when carried out with a minimum of liquid electrolyte under ultraclean conditions. Similar results are observed with a LiAsF6 electrolyte. Polyacetylene is an extraordinary material of great importance for electrochemistry. However, on the basis of this and other published research, it is not yet clear that it offers major advantages over current electrodes for high energy density nonaqueous batteries.Polyaeetylene is a fascinating new material with extraordinary electrochemical properties. It is a simple conjugated organic polymer which can easily be synthesized by the catalytic polymerization of acetylene. Polyacetylene films can be chemically oxidized and reduced by a variety of species, such as halogens (I and Br) and various organo-alkali metal reagents, such as n-butyl lithium and sodium naphthalide. These reactions are generally referred to as p-doping (oxidation) or n-doping (reduction). They produce compounds of the type (CHXy)x and (MuCH)x, in which y is typically in the range of 0-0.1. What is most unusual about polyacetylene is that p-or n-doping transforms it from a virtual electronic insulator into a lustrous polymer with an electronic conductivity typical of metals (1).The reversible oxidation and reduction of polyacetylene can also be carried out electrochemically in nonaqueous electrolytes containing appropriate dissolved anions or cations. These reactions were first described by Nigrey etal. (2). The electrochemical potentials of oxidized polyacetylene films (X ----I, AsF6, Br, C104) are typically 3-4V vs. the Li/Li + electrode. The potentials of the reduced films (M --Li, Na) are about 0.5-1.5V vs. that of Li/Li+. Nigrey etal. (2) and MacInnes etal. (3) first suggested that the oxidized and reduced polyacetylenes might be used as high voltage anode/cathode couples in nonaqueous electrochemical cells.The general goals of our research have been to examine those aspects of the chemistry and electrochemistry of polyacetylene which influence its potential application in batteries. This paper summarizes our investigations of the stability and electrochemical oxidation of polyacetylene in propylene carbonate containing LiC104~or LiAsF6. StabilityPolyacetylene exists in eis and trans isomers (Fig. 1). Trans polyacetylene is the thermodynamically stable form. The cis isomer can be produced by polymerization at low (--78~ temperatures, but it is unstable toward isomerization, which can be induced by heating or by doping wiLh various chemical species (5,6,7). Polyacetylene also self-reacts, forming cross-links and defects. These reactions occur rapidly at elevated temperatures (150~176 (5).

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Towards the development of multianalyte electrochemical immunoassays three individually addressable microelectrode array (MEA) type working electrodes and a reference electrode were integrated into a 4 mL volume, planar electrochemical cell. To model the simultaneous determination of multiple antigens in the cell with enzyme linked immunosorbent assays (ELISAs) glucose oxidase (GOx), alkaline phosphatase (ALP), and b-galactosidase (b-GAL) were immobilized site specifically onto the individual MEA surfaces and the biocatalitic activity of these surface confined enzymes were evaluated by measuring the products of the enzyme catalyzed reactions directly on the gold MEA surfaces by chronoamperometry or by imaging the enzyme patterned microelectrode array surfaces by Scanning Electrochemical Microscopy (SECM). ALP and b-GAL were selected as model enzymes because they are the most commonly used enzymes labels in ELISAs. In these measurements glucose, ascorbic acid phosphate (AAP), and p-aminophenyl-b-d-galactopyranoside (PAPG) served as enzyme substrates, respectively. The electrochemical surface area of the gold MEAs did not change during the multistep immobilization process. All enzyme modified MEAs presented selective and proportional responses to their substrates and the response characteristics of the enzyme modified sensors were identical in separate and simultaneous calibration protocols, i.e., there was no crosscontamination between the closely placed MEAs. The SECM images of the enzyme patterned MEA surfaces suggest that nonspecific adsorption is negligible on the insulating polyimide surface of the MEA separating the individual microelectrode sites.

PrefaceModern drug delivery and pharmaceutical systems are incorporating new levels of intelligence in their design and performance. New materials are designed to respond to their environment; new miniaturized systems perform multiple tasks to analyze samples and deliver drugs; and new drug formulations enable targeted therapy to specific organs. This book spans work in many diverse areas of biomedical and pharmaceutical sciences which demonstrate the development and use of intelligent materials and systems.This book is the result of a symposium entitled "Intelligent Materials and Novel Concepts for Controlled Release Technologies," held during the ACS National Meeting in San Francisco, California in April 1997. The Symposium brought together academic and industrial scientists who had developed novel drug formulations, techniques to enhance delivery, and new systems and procedures to analyze biomolecules. We hope that bringing together key researchers in these diverse fields and initiating direct new dialogues between them will lead to nextgeneration intelligent systems for drug delivery and biomedical applications.