There has been increasing interest in fabricating micropipettes from aluminosilicate glass.
In comparison with borosilicate glass, aluminosilicate provides increased hardness, improved chemical durability, reduced electrical conductivity and a lower coefficient of thermal expansion. Like silicon, aluminum combines with oxygen to form tetrahedral networks and the Al-O bonds are very strong.
While the original ratio of a borosilicate capillary's inner to outer diameter remains unchanged over its total taper length, aluminosilicate glass demonstrates a marked tendency to thin as it is drawn to a tip. This behavior allows extremely fine tips to be formed.
While Clark micropipettes and microelectrodes are used primarily in intracellular and extracellular research, the end user can manufacture their own microelectrodes and micropipettes using standard pipette pulling and microforge techniques.