Prism Glass Capillaries

Dagan Corporation is proud to offer Prism Glass, a line of premium capillary tubing. Manufactured from the finest glasses available from around the world, the capillaries are drawn to remarkably precise tolerances. These exceptional capillaries offer unprecedented reliability and quality for the most consistent electrodes possible.

Even the design of the vial for Prism capillaries presents a marked improvement for the laboratory. Each vial has a cushioning collar to protect the glass from toppling over and other accidental bumping. The rectangular shape also prevents rolling across the lab bench.

An extensive selection of glass types and sizes is available to fulfill a wide variety of experimental needs.


There are many interrelated variables to consider in choosing the best glass for a particular experiment. After considerable research and testing of capillaries, it has become evident that some attributes are more consequential for patch clamping and others are more relevant to intracellular recording. In general, harder glass has better noise characteristics than softer glass because the molecules have a more ordered structure and do not move as much. Hard glass also has higher electrical resistance than soft glass. In addition, it is generally believed that the ratio of the outer diameter to the inner diameter at the tip of the pipette is directly related to this same ratio of the capillary.

lntracellular Electrode Technology:

The inner and outer diameters of the capillaries, in particular the relative ratio of these measurements, play a vital role in obtaining the very fine tips used for intracellular recording. When a pipette is pulled, the glass is heated and pulled until the wall of the glass becomes so thin that the forces between the glass molecules can no longer hold it together At this point the capillary splits into two pieces yielding the pipette tips. For a given temperature and composition of glass, this separation will occur when the glass wall is roughly the same thickness. This phenomena will require that thicker walled glass be pulled further to get to the breaking point thickness. Assuming that the capillaries taper at similar angles.this will result in a smaller tip. However, since the outer to inner diameter relationship is conserved, the inner diameter of the pipette pulled from the thicker walled capillary will be smaller than if that same outer diameter were achieved with thinner walled glass. Because both small outer diameters for less injury during penetration and large inner diameters for lower resistance are desirable for intracellular electrodes, it should prove advantageous to try different sizing configurations with different heating and pulling parameters until the best combination is found. Once the desired size is found, it is imperative that each piece of glass be within acceptable tolerances if consistent electrodes are to be pulled. In choosing the composition of glass for intracellular electrodes, it is generally better to use hard glass. This allows one to take advantage of the increased cohesive forces that allow formation of a smaller tip, in addition to superior noise characteristics. Most scientists also prefer intracellular capillaries that have a microfilament fused to the inner wall to facilitate filling the tip. This eliminates the need for tedious procedures such as boiling or vacuum filling.

Patch Electrode Technology:

For patch clamping experiments it is critical to find the glass that forms the most stable seal with a particular cell type. An integral variable in seal formation is believed to be the composition of the glass. Certain cell types seem to seal better to particular types of glass. Because it is not necessary to obtain very small tips for patch clamping, the decrease of cohesive forces between the glass molecules is not a disadvantage. Also, softer glass may be better for whole cell clamping because it pulls into a characteristic shape that tends to lower the series resistance. The increased noise seen with softer glass may not add much experimental noise if the pipettes are coated. An additional consideration with patch electrodes is that the composition of the glass may alter channel behavior (Cota and Armstrong, Bicphys. J., 53 (107-9) 1988), so it may be useful to record data with different glasses to ascertain that there is no glass effect. Due to the large size of the tips, patch pipettes usually fill easily ,without microfilaments. The seal is believed to form with the inside wall of the pipette, so the filament may actually be undesirable as it may necessitate fire polishing. Though the sizing is not as important as with intracellular electrodes, the ratio of the outer diameter to the inner diameter can be significant. A thicker walled glass will often provide a more stable seal once the seal is obtained, but may make seal formation more difficult to achieve.

What we have to offer:

Prism glass is available in a wide variety of sizes and compositions to address these somewhat conflicting requirements. . These intracellular capillaries all have a 1.00 micron microfilament fused to the inner wall for easy filling.

Borosilicate capillary glasses with 100 micron microfilament

Catalog Number Outer Diameter Inner Diameter Softening Temp C Pieces/ Vial Glass Type Price/ Vial
FSG10 1.00 mm 0.50 mm 821 200 Borosilicate Inquire Special Order
FSG12 1.20 mm 0.60 mm 821 175 Borosilicate $28.00
FMG12 1.20 mm 0.70 mm 821 175 Borosilicate $29.00
FLG12 1.20 mm 0.90 mm 821 175 Borosilicate $28.00
FSG15 1.50 mm 0.75 mm 821 125 Borosilicate $46.00 Special Order
FLG15 1.50 mm 1.20 mm 821 125 Borosilicate $41.00 Special Order
FSG20 2.00 mm 1.00 mm 821 75 Borosilicate $35.00
FMG20 2.00 mm 1.15 mm 821 75 Borosilicate $35.00
FLG20 2.00 mm 1.50 mm 821 75 Borosilicate $35.00
FPG15 NEW 1.50 mm 1.05 mm 821 125 Borosilicate $38.00

Capillary glasses without microfilament

Catalog Number Outer Diameter Inner Diameter Softening Temp C Pieces/ Vial Glass Type Price/ Vial
SA16 1.65 mm 0.75 mm 630 100 Potash soda lead $35.00
SB16 1.65mm 0.75mm 700 100 Soda lime $48.00 Special Order
LA16 1.65 mm 1.10 mm 630 100 Potash soda lead $43.00
LE16 1.65 mm 1.10 mm 785 100 Borosilicate $39.00 Back in stock
LB16 1.65mm 1.10mm 700 100 Soda lime N/A Out of Stock
LC16 1.65 mm 1.10 mm 712 100 Kovar sealing $39.00
LG12  1.20mm 0.80mm 821 100 Borosilicate $33.00 New
LG16 1.65mm 1.10mm 821 100 Borosilicate $45.00 New lower price



Other related products:

DMZ Universal Electrode Puller


Warning: This equipment is not intended for use in human applications or human experimentation.

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