Microprobe

From Memory Alpha, the free Star Trek reference.

A microprobe is a type of probe carried aboard Federation starships, that are used in cases where conventional probes are too large to be effective.

While inside a nucleogenic cloud being in 2371, USS Voyager used a class-4 microprobe to draw the multi-polar charges from the creature while it "sutured" the wound with nucleonic beams. (VOY: "The Cloud")

Later that year, Voyager launched a microprobe into a micro-wormhole to trace its subspace bearing, but the probe became lodged in a gravitational eddy inside. Harry Kim subsequently modified the probe to act as a subspace relay station, allowing Voyager to make contact with the Talvath on the other side. The probe was eventually crushed by the wormhole's collapse. (VOY: "Eye of the Needle")

According to the Star Trek: Deep Space Nine Technical Manual some of the microprobes might also be called subminiature class 1-S sensor probes.