• Conducting Polymer Electrodes - Analytical and Biochemical Applications

• Detection of Carbohydrates and Amines at Poly-(3-methylthiophene) Electrodes

• Polymeric Stationary Phases for Chromatography and Solid Phase Microextraction

• Use of Conducting Polymers in Cardiac Pacing and Sensing Applications

CONDUCTING POLYMER ELECTRODES -
ANALYTICAL AND BIOCHEMICAL APPLICATIONS

The use of conducting polymers electrodes has expanded over the last few years to include a number of different areas. The long-term objectives of this line of research are the development of various types of electrodes modified with conducting polymers for use as electrochemical detectors or sensors and  tailoring of these polymer electrodes for use in monitoring neurotransmitter release and in probing electron transfer kinetics in metalloenzymes.

Chemical polymerization of 3-methylthiophene in the presence of a copper-containing catalyst results in a conducting polymer from which it is impossible to remove all of the copper. Electrodes based on this polymer hold promise for use in the DC amperometric detection of carbohydrates and amines.  They should be much more easily applied than the current electrochemical detection method which is based on pulsed amperometric detection.

POLYMERIC STATIONARY PHASES FOR CHROMATOGRAPHY
 AND SOLID PHASE  MICROEXTRACTION

Dibenzotetraazaannulene (DBTAA) macrocycles (shown below) are under investigation for the development of  stationary phases for liquid chromatography and solid phase extraction.  We are especially interested in derivatives which are substituted at the positions indicated by arrows. Because of their possibilites for pi-pi interactions and their saddle shape, they are expected to be useful in several different areas ranging from metal ion preconcentration to analysis of pharmaceutical compounds and polycyclic aromatics.

                        USE OF CONDUCTING POLYMERS IN CARDIAC                  PACING AND SENSING APPLICATIONS

Although great strides have been made in the fabrication of electrodes for cardiac pacing and sensing in terms of reliability, biocompatibility (in pacing applications) and signal capture (in sensing applications) remain a problem.  Implantation of the leads into cardiac muscle for the pacemaker results in tearing of tissue and inflammation around the insertion point.  This, in turn, leads to a higher threshold potential for excitation or, in the worst case, the need for explantation of the pacemaker.  Strategies to combat these drawbacks at present focus on making the electrode smaller or incorporation of steroids into a modifying layer on the surface of the electrodes.  For sensing purposes it is important that the electronic properties of the electrode not lead to a suppression or the obscuring of signals. A number of polymers and counterions are under investigation at present.