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i'm working as a diy bio. I'm finding a way to create a micro glass capillary for picking up single cells. I see this video on youtube and would like to know what is the minimum I/O diameter if I pull a capillary like this. Can it be 10-50 µm at least ?

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What kind of cells do you want to pick up? From what sample? Do you absolutely need single cells? –  nico Jun 30 '13 at 8:05
    
I mean what is the minimum I/O diameter if i pull a glass capillary like that video. I'm working on single cell, inject sperm to egg ... –  Đức UltraSoft Jun 30 '13 at 11:36
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Well, depends what type of capillary you use (there are many different ones), how close you go to the Bunsen, how fast you pull, how long you leave the capillary on the fire etc. etc. The best thing would be to invest in a pipette puller, it is very difficult to establish. Also, for microinjection you will also need a micromanipulator (unless you have an incredibly steady hand). –  nico Jun 30 '13 at 11:54
    
well, i'm an IT engineer so i would like to create a micromanipulator. I don't want to purchase for a puller because it will cost too much. I just want to finding a simply way to have one with minimum cost as possible. I wonder that if i pull by hand with fastest speed i will have a capillary with 10-50 µm diameter at least. –  Đức UltraSoft Jun 30 '13 at 13:25
    
Unless you are a skilled machinist (or know one), it's going to be very difficult to make a micromanipulator from scratch. –  jonsca Jul 1 '13 at 2:39
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1 Answer

It is very difficult to establish what kind of tip you will get from pulling a capillary on a Bunsen burner. There are many variables to consider, including the glass you are using, the temperature you reach before pulling, the pulling strenght, speed and time, whether you pull once or make multiple pulls etc.

If you do not want to invest into a micropipette puller (they are indeed VERY expensive) you could at least build some mechanism to obtain a constant pull in terms of time and force.

The following paper may be of help:

An Instrument for Controlled, Automated Production of Micrometer Scale Fused Silica Pipettes

It seems you would need a fairly high speed (0.8-1 m/s) to get a tip size of <50um.

I could not really find a specific reference for pulling over a Bunsen.

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