P-2000 Laser-Based Micropipette Puller

The P-2000 laser-based micropipette puller  from Sutter Instrument Co. 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 pipettes1 . For applications requiring a low noise glass, users will find that quartz is the lowest noise glass available2,4. Quartz contains none of the metals used in conventional glasses3. 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: 1) 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; 2) laser heat is clean and leaves no metal residue on the pipette as do conventional heating filaments; 3) laser heat can be turned off instantly, leaving no residual filament heat; 4) the user can program the amount and distribution of heat supplied to the glass; 5) laser heat source means there are no filaments to burn out or replace.

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 glass can be used with the P-2000/G (up to 1.5 mm quartz and 1.8 mm conventional glass), but the performance is best with glass that is 1.2 mm diameter or less.

The P-2000/F works well with small diameter glass 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 10 nm to more than 5 µm. Please consult our technical staff for further information.

FEATURES

• Capable of pulling quartz, borosilicate and aluminosilicate glass.
• Fully programmable – including heating filament characteristics.
• The laser has no melting point limit as with conventional metal filaments; and therefore, cannot be burned out.
• Pulls electrodes with tip diameters smaller than 0.03µm.
• Optimized velocity sensing circuit for maximized sensitivity and reproducibility.*
• Operating life of the CO2 laser is expected to be in excess of ten years with normal use, after which the laser can be refurbished by the Sutter Instrument Company for a nominal charge.
• Individual programs can be write-protected in order to secure them from inadvertent changes.
• The total time that the heat is on during the pull is displayed for improved program development and troubleshooting.
• A date and time stamp is displayed to show the last time that a program has been changed.
• The P-2000/F is ideal for applications such as nanospray and NSOM.
• Preprogrammed sample programs for intra-cellular and patch pipettes. The P-2000/F also comes with an NSOM tip program.

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 – Pflügers 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.