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Patch Clamp Glass Capillaries

Glass Capillary Properties

PG52151-4 and PG52165-4 are prepared from Schott #8250 glass (equivalent to Corn­ing #7052), one of the most widely used patch clamp­ing glasses. This is a specially formulated boro­sil­i­cate glass with a softening temperature that is 110°C lower than regular borosilicate glass (Corn­ing 7740, or Pyrex). It has excellent sealing prop­er­ties for most cells. Electrical properties are also very good.

PG10150-4 and PG10165-4 are composed of Corning #0010 glass, a high lead content (22% PbO) glass. Its thermal and elec­tri­cal per­for­mance is between the Schott #8250 and Corning #8161 glass­es described above. It is much more eco­nom­i­cal than Corning #8161 glass. It has been found that this glass causes much less alteration in chan­nel behavior than Corning #8161 and Schott #8250 glass (Furman and Tanaka, Biophys. J. 53, p287, 1988).

Patch clamp capillaries do not have mi­crofilaments.

Softening Temperature

The softening temperature determines how easily each glass type can be pulled to the desired shape and the extent to which it can be heat polished. Glass with a high softening temperature is difficult to pull and causes unnecessary wear on the heating element of the puller. This makes it very hard to make electrodes that are reproducible and of consistent quality. Patch clamp glass with a low softening temperature is preferred; however, higher softening temperature glass is stronger.

Electrical Properties

Electrical properties determine how much noise the glass capillary is likely to produce in recording situations. The lower the product of dielectric constant times the loss factor, the smaller the equivalent noise current the glass will produce (Rae and Levis, Methods in Enzymology, 207, p67, 1992). Patch clamp glass with good electrical properties is critical especially in single-channel recording.

Sealability

It is not clear what factors determine the sealing ability of the patch to the glass. Almost any glass can form a gigohm seal under the right conditions. Different glass types vary, however, in how easily they form a seal. It is important to select a patch clamp glass that seals easily. Good fire polish is critical for seal (see DMF1000).

Leachable Components

Leachable components: Substances leached from glass can alter channel behavior. Since different channels are sensitive to different glass components, it is best to record one type of channel with several different kinds of pipette glass to eliminate any artifact due to the glass.

Options

Order code	Type	OD/ID	Dielectric Constant	Softening Point ºC	Qty
PG52151-4	#8250	1.5/1.0mm	4.9	720º	100
PG52165-4	#8250	1.65/1.1mm	4.9	720º	100
PG10150-4	#0010	1.5/1.0mm	6.7	625º	100
PG10165-4	#0010	1.65/1.1mm	6.7	625º	100

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