The P-2000 micropipette puller represents a significant advance in the technology of fabrication of micropipettes, optical fiber probes, and nanospray tips. The P-2000 integrates a CO2 laser-based heat source with the technology derived from our extensive experience with conventional pullers. This system offers capabilities unmatched by other pullers.

While the P-2000 is suitable for working with most conventional glasses, its primary advantage is the ability to work with quartz glass (fused silica). Quartz offers superior material properties for a variety of research applications. Quartz is stronger than other glasses and can facilitate penetration through tough tissues which would normally break conventional pipettes(1) . For applications requiring a low noise glass, users will find that quartz is the lowest noise glass available(2,4). Quartz contains none of the metals used in conventional glasses(3). Optically, quartz is virtually free from fluorescence when illuminated.

A CO2 laser was selected as the heat source for the P-2000 for several reasons. First, the nominal emission wavelength of the laser approximates the resonant frequency of

the SiO2 lattice in glass. Thus, quartz and other conventional glasses can be melted when the appropriate laser power is supplied. Second, laser heat is clean and leaves no metal residue on the pipette as do conventional heating filaments. Third, laser heat can be turned off instantly, leaving no residual filament heat. Lastly, the user can program the amount and distribution of heat supplied to the glass.

The P-2000 can store up to 100 separate programs, with each program consisting of up to 8 command lines. Programmable parameters include; laser power level, scan width, trip velocity, delay/ laser on time, and hard pull strength.

One important consideration for the use of the P-2000 is the diameter of the glass used. The P-2000/G is designed to produce even heating on glass up to 1.2 mm in outside diameter. Larger diameter glasses can be used with the P-2000/G (up to 1.5 mm quartz and 1.8 mm conventional glasses), but the performance is best with glass that is 1.2 mm diameter or less.

The P-2000/F works well with small diameter glasses such as optical fibers, and with small diameter fused silica capillary commonly used for the manufacture of nanospray tips. Small diameter glass (outer diameter in the range of 0.125 mm to 0.6 mm) requires special puller bars as well as an optical alignment optimized for the smaller diameter material.

As with larger diameter glass, a wide range of tip sizes and taper geometries can be produced with the P-2000/F and small diameter glass. We have drawn optical fiber tips ranging from less than 10µm to more than 5µm. Please consult our technical staff for further information.

REFERENCES
These references describe the Flaming/Brown pullers and contain valuable information applicable to the P-2000.

(1) Munoz, J.L. and Coles, J. Quartz micropipettes for intracellular voltage micro- electrodes and ion selective microelectrodes. Journal of Neuroscience Methods: 22:57-64, 1987.
(2) Rae, J.L. and Levis, R. A. A method for exceptionally low noise single channel recordings. European Journal of Physiology - Pfl.gers Archiv: 420:618-620, 1992.
(3) Zuazaga, C. and Steinacker, A. Patch-clamp recording of ion channels: Interfering effects of patch pipette glass. News in Physiological Science: 5:155- 159, 1990.
(4) Levis, R. A. and Rae, J. L. The use of quartz patch pipettes for low noise single channel recording. Biophysical Journal: 65:1666-1677, 1993.