Needle probes are amongst the most versatile designs. They can be used for surface measurements, inserted into tissue or used for single vessel measurements. The compact design also lends itself to measurements in tissues with restricted access, e.g. teeth, conjunctiva and where micromanipulation is required.
Probes can be fixed in position over tissue with a normal laboratory manipulator by clamping onto the black acetal shank.
Deeper measurements are possible by inserting the probe tip into tissue bulk, for which finer needles are suitable (VP4 and VP4s). The finest needles can be inserted directly into some tissues with the application of gentle pressure: for larger needles it may be necessary to puncture the tissue first with a hypodermic needle.
The use of specific probe holders can extend the application range of needle probes further still. Wet stick probe tips can be used to aid adhesion to moist/ mucosal surfaces. Dental putty can be used to create an individual probe holder for tooth measurement. Angled needle probes can be used to access hind teeth.
Although laser Doppler is not usually advocated for assessment of flow in single vessels, there is a role for the technique in the assessment of flow changes in small individual vessels. Moor manufactures a range of probe holders to aid this measurement.