Microelectrodes pulling

The first carbon fiber microelectrode reported in literature was that fabricated by Ponchon and co-workers in 1979[18], This procedure involved pulling a glass tube to obtain a diameter of few micrometers. Then the carbon fiber (outside diameter 8 pm, length 20 to 40 mm) was threaded into the capillary, thus enabling the fiber to be pushed a few mm through the capillary. The authors reported that this method minimized the interstitial space between the capillary and the carbon fiber. Then, the capillary was inverted into a mixture of graphite powder and polyester resin to fill 4-5 mm of the body with the paste. A contact wire was then pushed as far as possible into the barrel filled with the paste. Immediately before use, the electrodes were cut to a length of 0.5 mm[18]. 

FIG. 11 Top Schematic diagram of the capillary carbonization setup. Bottom Schematic picture of the pyrolytic carbon microelectrode made from pulled quartz capillaries using this setup. 

The systems studied by these authors are chemical fluxes at the bilayer lipid membrane, which are of importance in many cellular processes (33). The experimental system for the study of the reduction of acetaldehyde by alcohol dehydrogenase is shown in Figure 25. The pH microelectrodes employed were based on antimony-filled glass capillaries, which were pulled to a tip diameter of 5 gm. The pH gradient on the turns side due to the enzymatic reaction... 

Open-tip liquid ion-exchange microelectrodes can be fabricated by pulling borosilicate glass capillary tubing to an appropriate tip diameter (0.5 to 1 /im),... 

A Initial appearance of Carbon fibre microelectrode after pulling... 

One sensor which we have developed, the carbon-fiber microelectrode, has been shown to be especially useful to obtain Information on chemical heterogeneities (4). Carbon fibers are highly conductive and are commercially available in a variety of diameters ranging from 5 to 30 pm. The sensor is prepared by sealing a single fiber with epoxy Into a glass pipette which Is pulled to a tip diameter comparable to that of the fiber. The sensing area of the... 

This section discusses the fabrication of microelectrodes with diameters of a few micrometers to tens of nanometers using a laser-pulled technique. The methods discussed focus on the fabrication of platinum (Pt) ultramicroelectrodes (UMEs) sealed in... 

Optimization of a pulling program requires patience, practice, and a bit of luck. The efficiency of UME fabrication using this technique is rarely more than 60% and when every step is taken into consideration, is typically mnch less. Under ideal conditions, one capiUary should produce two identical microelectrodes. However, small imbalances in the pulling solenoids or imprecise calibration of the laser scanning results in less than ideal behavior. 

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