Laser microsurgery can be used to perform both cell biological manipul
ations, such as targeted cell ablation, and molecular genetic manipula
tions, such as genetic transformation and chromosome dissection. In th
is report, we describe a laser microsurgical method that can be used e
ither to ablate single cells or to ablate a small area (1-3 mu m diame
ter) of the extracellular matrix. In plants and microorganisms, the ex
tracellular matrix consists of the cell wall. While conventional patch
clamping of these cells, as well as of many animal cells, requires en
zymatic digestion of the extracellular matrix, we illustrate that lase
r microsurgery of a portion of the wall enables patch clamp access to
the plasma membrane of higher plant cells remaining situated in their
tissue environment. What follows is a detailed description of the cons
truction and use of an economical laser microsurgery system, including
procedures for single cell and targeted cell wall ablation. This meth
odology will be of interest to scientists wishing to perform cellular
or subcellular ablation with a high degree of accuracy, or wishing to
study how the extracellular matrix affects ion channel function.