Seeking an alternative to transistor

Sure thing! Muscle Wire Actuator - NM706-Super NanoMuscle - ROB-08782 - SparkFun Electronics

Miga NanoMuscle

sku: ROB-08782

Description: Another great linear actuator from Miga Motors. The NM70 is a very small electric actuator that utilizes Shape Memory Alloy (SMA) with a 4.0mm stroke when exposed to 3.5V and 410mA.

Sorry for leaving that out.
The 2N4401 NPN is rated at 600mA (0.6A) 40V